Driving your muscle car can be an awful lot of fun! What’s not fun is buzzing the engine at 3000+ RPM driving down the highway or backroads for long periods of time and watching the gas gauge needle make a more rapid descent down to zero. Or seeing the wear and tear on your engine from extended high RPM outings.
A transmission swap may be just the thing for you.
Moving into a five or six-speed transmission affords one or two overdrive gears, which will help reduce your cruising RPM and make your drive much more enjoyable.
The transmissions of choice right now are the Tremec TKX five-speed and T56 six-speed models. There are many reputable companies out there selling these transmissions and complete transmission packages. RAM works with several of them to provide the clutch system.
When it is time to make your clutch selection for this package, don’t just settle for whatever clutch package the distributor offers. They may have their ‘own’ brand clutch systems.
RAM has been working on and building clutch systems for transmissions back into the early 2000s. We have several packages tailored for these applications based on your anticipated use of your vehicle.
Don’t Forget the Flywheel
The flywheel should never be overlooked when setting up a new drivetrain system. Don’t just reuse that factory cast iron flywheel that may be thirty or more years old! Instead, make sure to use a quality billet steel (street use) or aluminum flywheel (track use). New flywheels such as RAM billet models are typically a bit thinner overall than factory flywheels. As a result, they can allow more space to fit the clutch system with an internal hydraulic release bearing.
Pick the Right Kit
Most of the transmission distributors use some version of the factory internal slave cylinder or hydraulic release bearing. RAM has hydraulic bearing kits specifically designed for Tremec five and six-speed transmissions.
Five-speed kits include a billet replacement front bearing retainer that allows for more space in setting up the release mechanism with whatever clutch you decide on, whether it is a single or double disc.
Bottom line? Do your homework on a transmission package that is best suited to your needs and the use of your vehicle, and don’t be afraid to select a different clutch, flywheel, and hydraulics package than just what they ‘happen’ to offer.
Does this sound familiar? You just received your brand new drag race clutch system, and you can hardly wait to get it put in and fire up the engine! You have a baseline starting point for the clutch static pressure and counterweight settings. Everything should be fine to just head to the starting line of the next big event and let ‘er rip, right?
While we typically recommend starting points higher than we think you will ultimately need, that does not mean that your unique combination of gearing, engine, tire size and driving will be right on the money every time.
But, like most anything else with your race car, taking your time and having patience will pay off in more consistent performances and success with your new system.
What do we recommend?
Testing runs will be most beneficial to make sure you have the clutch adjustments correct before heading to your next event. Keep in mind that the base or static pressure will control what the car does on the launch, and the counterweight adjustments will regulate the lockup of the clutch through the gears.
Start by working with the launch and dialing in the base pressure setting. Just leave the starting line a few times and note how the clutch is feeling and what your crew members are seeing (if you have a data recorder, this is where it will be helpful!) Getting a lower RPM will give you a better indication of whether you have the static pressure right or not. ‘Soft’ or ‘lazy,’ or no wheel speed at all on launch will usually indicate the need to increase the static pressure. Continue to adjust and make hits off the line only until you are satisfied with the performance.
Once you have the launch down, it’s time to see what is happening with the gear changes. Go ahead and leave and pull a gear or two only. What is the car doing on the shift? Is it soft, or is the clutch not locking up? What does the data recorder show is happening? You may need to increase the counterweight on the fingers. Add a gram or two and retry. If it hits too hard or spins wildly on the shift, you will need to take some counterweight off the fingers. A gram or two on each finger can make a huge difference during shifting, depending on your RPM.
What are the ‘ultimate’ settings?
When you can get the car to launch with controlled wheel speed and have just enough counterweight for the clutch to hold in high gear on the big end of the track, you are there!
Keep in mind if your clutch setup is brand new or freshly serviced, it will be a little soft on the first hit or two, so tuck that info away as you make your fine-tuning adjustments. Then, with a bit of patience and an afternoon of testing, you will be on the way to optimizing your clutch combination and turning on those win lights!
Circle track racers face different challenges when selecting a clutch for their race car. The biggest is the drivetrain rules package for the sanction or specific track.
You can set your car up to legally race at one track and go down the road 50 miles and the next track will have a completely different set of rules.
It takes careful investigation to determine what will be legal for your car and select a proper clutch system to meet those particular rules. Some tracks will specify a certain flywheel weight and that’s it. Others state you need ‘stock style 10 or 10.5-inch clutch’ but nothing more.
Learning how to apply these rules to your car is the trick!
To accommodate a wide variety of rules packages for ‘street stock’ style classes, RAM offers billet steel flywheels in several different weights: 10, 12, 14, and 16 pounds. We make the ultimate lightweight pressure plates with billet machined pressure rings under 12 pounds, modified factory pressure rings around 14 pounds, and stock weight at about 17 pounds.
For disc selection, you can choose between solid center hub organic or metallic clutch discs. You can evaluate these products and watch some informative videos here.
The key is to evaluate the rules for your particular sanctioning body carefully, or if you run independently, the requirements for each track at which you plan to compete. Select the components that fit within these rules packages. You’ll now run the lightest possible combination and still work within the guidelines.
If the rules allow for the use of a multi-disc clutch, you can select from RAM Assault Weapon 6 ¼ inch dual or triple disc models or the RAM 7.25 series units. Each of these are ‘button style’ clutches and will work with a factory-style automatic transmission flexplate that matches the balance of your engine and ring gear tooth count requirement.
Multi-disc clutches are smaller in diameter, allowing the motor to accelerate and decelerate quicker, which lets you drive further into the turn before letting off and get back into the throttle quicker coming out. Your engine will maintain its peak operating RPM range for more extended periods.
We are always here to help you make the best selection of clutches for your circle track application! Use the convenient E-Tech form to send us your vehicle details, and include any rules relevant to your track.
We’ll reply or call you with a package that will meet your needs, give you long service life, and most importantly, help you optimize your engine and driveline package!
A common tech question I receive focuses on adjusting the mechanical linkage on a clutch system. Many folks have a problem getting ‘enough’ adjustment or are having hard pedal and release issues. Fortunately, there are a few things you can try to get things working properly again.
If you are having trouble getting enough travel to disengage the clutch and your clutch rod is maxed out, disconnect the rod and manually pull the fork up until the release bearing is just touching the clutch fingers. At that point, your fork should have a forward angle in the bellhousing window (driver’s side pivoting forks) or a rearward angle (passenger side pivoting forks).
If your fork is sitting in the middle or opposite of the optimum angle listed above, you could easily have a leverage or travel issue.
So what exactly causes an adjustment problem?
It could be that your pivot ball or bellhousing has been changed at some point. Maybe your car had a different style diaphragm or previously used a lever style clutch and the finger height is different on the new one. Some GM applications in the mid to late ’60s, such as the Corvette, used a long release bearing from the factory in conjunction with a ‘flat’ fingered diaphragm. Now, the clutch you are replacing it with has a high cone and comes with a short-release bearing.
Your solution is to either change the pivot ball out for a longer one or use a longer release bearing which will correct the fork angle and kick it back into a higher leverage position. Usually, this also addresses the insufficient rod adjustment length. If you are using a scattershield, the best method is to use an adjustable pivot ball.
RAM offers release bearings in short, medium, and long lengths to help you correct these fork angles.
Another common question is, ‘how much freeplay should I adjust for’? The most important thing to know is that freeplay at the pedal is NOT the same as freeplay at the fork. When checking for bearing clearance you need to be checking it at the fork. We usually recommend a minimum of ¼” bearing clearance between the bearing and the fingers. Remember that as your clutch wears, the fingers get taller, or closer to the bearing. It is better to adjust for maximum free play (or, minimum release), so you are only traveling the fingers of the clutch as much as needed for full disengagement.
Getting your fork angled correctly and the bearing adjusted properly will allow you to experience much easier pedal effort and require less travel to achieve full disengagement of the clutch system, making your drive much more enjoyable!
Have more equations about proper adjustments? Send us a message through our e-tech form!
We receive a lot of feedback on our electronic tech support or E-Tech. It’s a way many customers get answers to questions or problems they’re having. If you’re someone who prefers to make a call, there are some specific reasons why using our E-Tech form helps you receive answers to your questions without waiting on the phone.
Provide Your Information All at Once
By using the E-Tech form, we can get you answers to your questions quicker. It allows us to gather all of the information we need and recommend a solution or help you troubleshoot your problem. Often when a customer calls in, they need to go back and find important information. Utilizing our online form will eliminate multiple phone calls to determine what we need to help you the first time.
E-Tech Gives Us Time to Consider Your Questions
When you are having an issue, sometimes it requires us to think about what is going on. We may need to physically check some part or dimension or research a combination that is out of the ordinary. On the phone, this might mean giving you a quick and possibly incomplete answer. We may have to call you back (perhaps multiple times), or worse, think of something else we need to check after you’ve hung up.
Our Online Form is Available at All Hours
We often look at these E-Tech forms during off-hours or over the weekend. If it is a question that we can answer without physically looking something up or measuring at the shop, you’ll usually receive an answer faster than waiting on a call during work hours. And most likely, you’re working on your project over the weekend anyway!
You May Answer Your Own Question
Providing information to us about a problem forces you to think more about the issue you are experiencing. Customers tell me that filling out the E-Tech form turned on a light bulb and helped them solve an issue before even sending it to us!
E-Tech Helps Us Manage Technical Support
We all wear many hats around RAM. We thoroughly enjoy helping our customers with application questions and support, but doing so takes up a lot of our time. Using E-Tech helps us better manage our day. It ensures orders are shipping quickly and efficiently, and rebuilds get handled in a reasonable timeframe. And we’ll have time to address other customer service issues throughout the day.
There are Many Ways to Get in Touch With Us
Maybe you or someone in your circle is not an ‘Internet person’ and still prefers the phone. You can always request a call back once you have provided us with the basic info we need to help you with your situation! Many requests and issues can only be handled by phone, and rest assured this service is still available. And you can always shoot a quick email to firstname.lastname@example.org.
Now that you know all the different ways to get in touch with us, send us your questions so we can help you with your build!
Adding hydraulics to early model cars has become very popular, with many people doing swaps of late-model engines and/or five and six-speed transmissions. There are several positives to making this switch and a few falsehoods to remember.
TRUE– Switching to a hydraulic bearing will free up space in my engine compartment.
Making a change to hydraulics eliminates all of the factory mechanical linkages. It frees up space for later model engine swaps, big block or tall deck motors, and the use of simpler header systems without worrying about clearing the factory linkage. Additionally, most late model blocks do not have the mechanical Z-bar pivot facility to attach to the engine block.
FALSE– Hydraulic bearings are not reliable for street use.
At one time, this may have been the case, but with refinements in RAM hydraulic bearings’ design to incorporate larger o-ring seals, the overall life of these systems has increased significantly. Proper routing of the feed line and insulation from heat are also key factors.
TRUE– Installing hydraulics is easier than you think.
Many companies now offer exact fit master cylinder systems that will mount to your firewall correctly and attach properly to the pedal. They’ll provide the correct push angle and ratio to keep pedal effort down. Watch for RAM to introduce these master systems in the coming months!
FALSE– Setting up a hydraulic bearing is a pain in the butt.
RAM has made it simple to properly set up a hydraulic release bearing by providing in-depth videos and instructions that walk you through the process of installing these units. Do you have to take measurements? Yes! Do you need to take your time and do it right? Yes, especially if you are like me and prefer to only do things one time.
TRUE– Hydraulic bearings can be used with earlier lever-style clutches.
By simply changing out the snap-on bearing face on RAM hydraulic bearings, you can install a wide face bearing that will accommodate Long Style and Borg and Beck clutches. It is required to use 45-degree fittings coming out of the bearing to route the lines back in the bell housing away from the clutch cover and avoid contact.
FALSE– Pedal effort will be lower with a hydraulic bearing.
Pedal effort encompasses several factors. The size of the master cylinder has the greatest effect on pedal feel. Larger masters will have heavier effort. Getting the sizing correct will minimize effort and get the proper bearing travel to disengage the clutch correctly without over travel. The other major factor is the pickup point of the master cylinder rod on the clutch pedal. Maintaining the proper pedal ratio will minimize the pedal effort.
I talk all the time about the load factors that affect the clutch system on your street or race vehicle. One of those is ‘use of the vehicle’. Let’s dive a little deeper into why this is important when you make your clutch choice.
Use of vehicle may be something as simple as driving your car to car shows on the weekend or heading out to the local dairy pop for a quick snack. It also might mean that the same vehicle gets slicks bolted on it and heads to the race track five times a year. In the first case, the driveability of the car is most important. Funny thing is, it is still important in the second case, but we have to be mindful of the much higher load the clutch system will see at the race track.
A vehicle that will see higher loads at the track will have to be clutched adequately to hold against that load, so you are going to have to use a setup that may be a level or two higher than you would normally use for your weekend pleasure car. In some cases, this may mean a bit of compromise in the driveability you get for everyday street driving. Of course, the best solution to this situation is to use a dual-disc clutch system, where you can essentially have the best of both worlds, the smooth street engagement, and the higher torque load handling capabilities.
So what about that regular weekend car show cruiser? Assuming this car will only see some ‘spirited driving’ or an occasional stoplight blast, and otherwise is used for pleasure driving and shows, selecting a system that is right on your power level will be the best choice. Additionally, if this happened to be a restoration or vehicle that has skinny ‘factory style’ tires, the load on the clutch will be minimal since the tires will tend to spin before you overload the clutch. In this case, you may want something as simple as a Musclecar clutch set which provides the best street driving experience short of a stock replacement clutch set.
As always, we are here to help you make these critical decisions. Hit me up at email@example.com, or use our convenient tech form for a detailed recommendation based on your vehicle’s specifications.
The internet can be a great thing. If I need tips on how to cook my steak properly or paint my bathroom, a quick Google search will deliver the information I need. On the flip side, you can find bad information in your search as well. This especially applies to your vehicle. Be cautious on what you read about selecting or using your clutch system based on “tips” found on a forum or social media page. In many cases, the people offering advice have no experience and are really trying to look important!
Here are some of our favorite bad tips found online:
‘Take off in second gear at the drag strip. It will cut down on your tire spin’. Well, yes, it probably will. It will also bog the engine (if the clutch is up to the task), and if not, the clutch will slip horribly. Expect to see a plume of smoke from under the car of your buddy who tries this trick.
‘Don’t worry about breaking the clutch in, just let ‘er eat!’ A clutch needs to seat properly to give you maximum performance and life. If you back out of the garage, put it on 5000, and dump the clutch, expect slippage, failure, or at the least, greatly reduced clutch life. If you want to learn more about properly breaking a clutch in, check out our blog post.
‘I hooked my truck up to a tree, then just slipped the clutch to break it in’. Or, ‘Just pull up against a wall and slip the clutch to get her seated’. It is hard to even comment on these two, but suffice it to say that proper break-in is critical to the clutch’s life, and trying to shortcut or cheat this procedure will cost you down the line.
‘Use your traction control at the drag strip to cut down on tire spin.’ Will this work? Maybe, but most traction control systems cycle the brakes and/or engine RPM to do their job, putting an extreme load on the clutch system. Turn off all the engine controls when racing.
‘I just slipped my clutch a whole bunch to put heat in it and break it in.’ The process of breaking in a clutch is about systematically seating the friction materials on both sides of the disc to the flywheel and pressure plate, similar to bedding in brakes. Introducing extreme or quick heat to these unseasoned components will cause the components’ to warp, and from there, watch for premature slippage and even non-release from your new clutch system.
‘Race cars don’t break in their clutch, and I don’t need to either.’ It’s correct that race cars don’t break in their clutch, but a race clutch is typically seated with higher initial pressure on the first few runs, and then the pressure is backed off to optimize the combination. Also, race clutches get constant maintenance to keep surfaces flat and consistent and maintain repeatable performance. This doesn’t happen with a typical street vehicle.
Here we go kicking off a new year with much uncertainty still surrounding our daily lives. For many of us our respite is our passion for all things automobile and racing, and that is what kept us going through the last year. ‘Staying at home’ found tons of folks dusting off project cars that have been sitting in the corner for weeks, months, or years. This was obvious due to the volume of interest in products that were being discussed and sold in 2020. From a manufacturer’s perspective, it kept our nose to the grindstone making our products and company continue to grow and be better at what we do.
We are cautiously optimistic about how we work towards our ongoing lives, but at the same time we are full-bore ahead on creating and bringing to market new products for 2021 that will continue to help everyone make their race cars a little faster, their street cars a little more driveable, and their dual purpose vehicle perform better both at the track and on the street.
2020 saw the introduction of our billet 10 inch single sintered iron systems, designed to fit in more applications and give racers a stronger, longer living clutch system than the older long style based systems. We introduced new bolt in dual disc systems for Challenger and Mustang that makes those installations easier to complete and the cars more fun to drive. For 2021, we are continuing down this path and plan to introduce several new products for both racing and street. Additionally I see our hydraulics line growing with some dramatic additions coming as early as spring.
I hope you had a chance to watch our Industry Week 2020 video series. This provided a good look at our street and race systems for vehicles such as Mustang, Challenger, Camaro, and Corvette, as well as a couple of deep dives up close with race cars that many folks see on the track, but never get a close up look at. If you haven’t checked these out, I encourage you to watch them!
So my simple message is this – keep up your faith that life is moving towards more normalcy, and dig in hard on those projects to get ready for spring! It will be here before we know it!
2020 certainly won’t be a year that sticks in our memories for all the good things that have happened, but it should, because there are quite a few!
Who would have thought 12 months ago that we would all be walking around wearing masks and worried about how many people we were inviting over for holiday dinners? Yet here we are, learning to adapt and how to keep moving forward in what has become my least favorite words… such uncertain times.
For RAM, this has been a year of change and most of it has been for the good. We have been able to stay the course and continue to move our company forward in the market, refining systems and working on new products through it all. Our employees have been models of consistency and dedication, working in smaller crews though the early months and maintaining necessary safety protocols, all the time keeping good attitudes and helping us exceed our goals every single month since the start of the pandemic.
I have sorely missed traveling and visiting our customers as well as working with our sales team in the field. For the first time ever we have seen our annual industry trade shows cancelled along with several consumer and customer shows already being cancelled for 2021. Zoom meetings are now the new way to communicate with our large customers as many continue to work from home.
This month we are continuing to make lemonade as we transition towards 2021. One way is the introduction of a 4 week video series titled ‘RAM Industry Week 2020’. In this series we are highlighting some of the products and people that have made 2020 a success on the business front. I encourage you to follow us through this series and, we hope, be entertained as well as informed. These will be running concurrently on social media and we encourage you to share these videos through your own social media!
On behalf of our entire staff and my partner Pat, we sincerely wish each and every one of you a blessed Christmas season and a Happy New Year. I look forward to getting back on the road and seeing many of you in 2021!
If you ask 100 people about how to break in your new single disc or dual disc clutch, you will get about 99 different answers. We have heard some crazy ones over the years!
“Pull up against a solid object and slip the clutch until you smell it.”
“Take off in third gear a couple of times to get it good and hot.”
“Drive 20,000 miles.”
“Break in is not necessary, just let ‘er rip!” Ugh!
What is really important to know about breaking in your clutch?
The act of breaking in a clutch is really about seating the friction material of the disc, or discs, to the metal surfaces that they contact when the clutch is in the engaged position, and making full contact across these surfaces. We surface grind our friction surfaces on higher performance pressure plates and RAM flywheels to ensure that you have a perfectly flat mating surface for this to work properly. This surfacing is critical to proper break in – flywheels that have a machined or lathe turned finish are much harder to get an initial seat of the clutch disc against. Yes, there are performance clutch companies out there that skip this critical step.
Once you have those perfect surfaces, you can achieve the proper break in and seating. Think of breaking in your clutch much like you bed in a set of brakes – you want to achieve a couple of complete heating and cooling cycles to help set the fresh metal surfaces without overheating them, which can cause uneven seating, distortion, chatter, or warping of the pressure ring or floater plate on dual disc units.
How to Break In Your Clutch
To begin, take the car out on a ride around the neighborhood or local area. You want to have lots of engagements and disengagements as you drive to bring the engine and drivetrain completely up to temperature. Next take the car back home or to the shop and let it cool down completely. Repeat this cycle 1 to 2 more times.
At this point you should have decent contact with all the metal and facing components. Time to put some miles on the unit, driving in a fairly conservative manner for a couple of hundred miles with lots of shifting before you really pour the steam to your combination. Driving 100 miles down the highway to Aunt Nancy’s house and back is NOT what we mean here!
And finally a note about chassis dynos – this is the hardest load you can possibly submit your clutch system to. Do NOT take the car directly off the installation lift and onto the chassis dyno unless you plan to be replacing the clutch again soon. Complete the break in process first, or even consider making your tuning pulls with your old clutch system just in case there is a problem that subjects the clutch to an extreme torque load.
Taking care to properly break in your clutch system will ensure a longer life, smoother engagement, and better long term performance.
Often overlooked when comparing clutch systems in single and dual disc is the clutch size, diameter, and mass. The simple fact is that a larger diameter clutch is going to give you better holding power. As added benefits, the increased surface area of a larger clutch will dissipate heat better to keep the clutch surfaces flatter, and the increased mass of the clutch is going to require less slippage to take off from a stop. All these points are essential to consider in selecting a street clutch system.
Let’s look at 4 clutch sizes – 9.5 inch, 10.5 inch, 11 inch, and 12 inch. If all clamp pressure specifications were equal on these units, the largest unit (12 inch) would have the highest holding capacity, followed by the 11, 10.5, and 9.5 inch units.
A good example is RAM LS single disc clutch systems. These packages include a steel flywheel and feature a 12 inch pressure plate and disc, which gives you a nice increase in clamp load yet easy pedal effort. The mass of this unit is going to allow a driver to slip the clutch less on takeoff to get the car moving, and the surface area will wick heat away to keep the pressure ring flatter and less susceptible to hot spotting. Without this, the life of the clutch would be reduced over time and also can lead to premature chatter and ultimately, inability of the clutch system to hold.
The same goes for selecting a dual disc clutch system. While some of our competitors tout smaller diameter systems, we have learned that for street use, especially in heavier late model musclecars, there is no substitute for using a 10.5 inch clutch over a 9.5 in terms of both driveability and longevity in the clutch system. Additionally, the larger clutch systems offer increased clamploads, which can only further increase the life of the clutch system. Think about a Dodge Challenger at 4400 pounds weight – is it going to like a larger/heavier or smaller/lighter clutch better for street use?
There are certainly situations where a lighter clutch system is better. These center around applications where you want to have faster acceleration and deceleration of the engine such as autocross, road racing, circle track, or drag racing where gearing can be optimized. In a drag car, smaller can be quicker. The tradeoff here is that the ‘window of adjustment’ on these sophisticated systems becomes smaller, sometimes making it more difficult to hit on the exact setup that will optimize the performance of the car.
Not sure what you really need for your car? Use our E-Tech tool to send us specs on your car and we will be glad to help you select the best system for your application.
Think carefully about your application before selecting the clutch system that is best. Smaller is definitely not always better, and as they say, size does matter.
Back in the day, installing a clutch in a vehicle was much simpler. Mechanical linkages made it easy to readjust the release of the clutch, and if your new clutch was a slightly different height from the old one, it was simple to compensate for the difference.
Not so with today’s modern hydraulic release mechanisms. Most of the newer vehicles utilize an internal hydraulic bearing (often called the CSC, or concentric slave cylinder.) These slave bearing assemblies work on the principle of preload, or a certain amount of push back on the bearing as the transmission is slid back in place. There is a limit to this total amount of preload, and a delicate balance between getting enough preload for the clutch to disengage properly, and having enough remaining room for the bearing to retract to allow for wear in the clutch over time.
Clutch manufacturers must keep this variable in mind when designing new clutch systems such as our Pro Street dual disc. We have to carefully evaluate the stock clutch system and measure for overall height constraints as well as examine and test the factory slave cylinders to insure compatibility with the new clutch unit.
If you have ever purchased a RAM clutch system for one of these later model vehicles, you no doubt read your instructions (you did, right?) and saw the setup height measuring charts and instructions. Then you probably said, “Do I really need to do this?”
The answer should be yes. While double checking these setup measurements might take a few extra minutes, the time it will save you if there is an incompatibility or oddity with your application will be minor in relation to the time it takes to completely disassemble the car and start over.
The easiest way to understand how to do these setup measurements is to watch our detailed video on factory hydraulics setup, also see below. It will give you a good visual on how the process works and what you are actually looking for.
Are there situations where a RAM clutch may not work with factory hydraulics? Absolutely. In those cases there will be a RAM aftermarket hydraulic bearing assembly that will facilitate your install. And if that factory slave is worn out, this might be the perfect time to upgrade to our bearing unit.
Take your time, take the measurements, and ensure that you will not have any issues with your clutch install down the road.
There seems to be a common misconception that a lighter weight clutch and/or flywheel is going to make your car faster or perform better. We even have one manufacturer in our industry that tells you “put in an aluminum flywheel and make more horsepower!” The fact is it depends on how you use your car or truck that determines whether you can benefit from a lighter weight clutch or flywheel.
Remember the job of the flywheel – to transmit inertia to help you get your car moving. On the street, this means slipping the clutch less on takeoff to get rolling and make a smooth transition. At the drag strip, balancing flywheel weight with gearing will allow you to launch most efficiently without excessive tire spin or bogging the engine. This is especially true in heavier vehicles!
In general, a street car benefits most from a moderate weight flywheel and clutch package that provides the best driveability, both on takeoff and at low speeds driving along. If you have ever been in a heavily cammed car and driving along at lower engine speeds, you may have noticed a ‘bucking’ or ‘jumping’ that occurs when the RPM drops too low. Having more flywheel and clutch weight in this case helps to smooth out the lower RPM engine pulses and keep the driveability smooth.
Drag cars of all different power levels can use lighter weight units IF the proper gearing can be used in the transmission and rear end. If these gearing options for the transmission are not available, some extra flywheel weight may be needed to achieve a proper launch.
When Lighter is Better…
Applications that can really benefit from lighter weight clutch and flywheel combinations are in circle track, road race or autocross vehicles. These applications require the engine to accelerate and decelerate quickly to make the most of the combination. A lighter assembly allows you to drive further into the turns and have the engine decelerate quickly, and accelerate quicker out of the turns to get the engine back up in the peak operating RPM range. This is why circle track clutches are often multiple disc and smaller diameter.
Balance is Key
So for street, balance is the key. To that end, RAM introduced a line of lighter weight steel flywheels over the last 2 years that help provide the inertia needed for good driveability, yet allow for a crisper throttle response than you would get with a heavier steel flywheel. Pair these with the Concept 10.5 dual disc for a great combo of holding power and driving experience!
As with most decisions you make about what parts to use in your vehicle, it pays to carefully consider what you expect from it in the situations you encounter daily. Do I need this system to allow me to comfortably cruise around, or do I have a different performance objective? Carefully considering these ideas will help you make the best choice for your car or truck.
During the crazy period of Covid 19 ‘lockdown’, we have taken the time to revamp many of our internal procedures at RAM in order to faster and more efficiently support our RAM end users. One of these is revising how we handle technical support questions and issues.
Clutches and hydraulics are some of the most technical products to recommend and troubleshoot. There is a variety of information we need in order to either recommend a clutch system for a specific application, or to troubleshoot problems. Having all of this information up front helps us to not only make the best recommendation for your specific application, but also to more easily and quickly help solve any problems or answer any questions that may come up.
To achieve this goal, all future end user technical support will be initiated from the website ramclutches.com. By clicking on the ‘Get Technical Support’ button at the top of all the pages, you will be able to submit a support request that will provide us with all the necessary information to help you with your application. This saves numerous phone calls back and forth just to get the initial information we need to best assist you. Once this information is received, we will be able to quickly analyze the questions or issues, do any research that is necessary, and get back to you with good answers to your questions. Additionally, you will have a hard copy of these answers that you can refer back to in the future.
Once you enter this technical support space, you will find many other useful documents. All of our instruction sheets are available from this section, as well as many helpful videos that cover subjects such as ‘How to set up your RAM hydraulic release bearing’. We also offer a large FAQ section, which may answer your questions without ever having to submit a support request. We will continue to build on this section to help make it easier for you, our customer, to find the information you need to solve a problem, even on the weekends.
And speaking of weekends, we often check these support requests during off hours, as we are able. So even though it may be Saturday when you are working on your project, you may be able to get the help you need without waiting until Monday. More involved requests that require us to check or measure parts will be handled the first following work day.
Digital technical support is not going to solve all questions and situations, but by providing the initial information, we can then call you with additional questions or recommendations as needed, or if the questions or recommendations are just too detailed to be handled electronically.
We are excited about these changes and keeping RAM Clutches on the forefront of technology, not only with our products but also with our procedures to better serve you, our valued customers.
When we decide to create a new clutch system for an application, there are many factors that need to be evaluated before the chips start flying!
The first thing we do is evaluate the clutch that came in the vehicle. How is the pedal effort? Where is the engagement point on the pedal? Does it take much RPM to take off right now? Is there any chatter? Does the car accelerate well or feel like it lags? By evaluating these ‘driveability’ factors, we are better able to decide what the features and benefits of a new clutch system will be. This helps guide the R&D process.
For instance, the first time we drove a fifth gen Camaro, we immediately noticed that the clutch engaged right at the top of the pedal, and that the release length (point when the car begins to move on the pedal stroke, to the point when it is fully engaged) was very long. This actually led to the creation of another product that has become very popular, our Pedal Height Adjuster system.
The next step is to disassemble the car and evaluate the factory unit. Later model vehicles utilize internal hydraulics, so it is critical that we design our package to fit not only within the constraints of the bellhousing, but also within tolerances that will make it compatible with these factory hydraulics. We also look closely at the unit overall weight, and try to determine if making the clutch either lighter or heavier would be an advantage in driveability for our new unit.
Many of the later model clutch systems are much heavier than most people realize. The clutches in newer Mustangs, Challengers, C7 Corvettes, and Camaro’s are upwards of 55-65 lbs. These units are roughly 20-30% heavier than the assemblies found in earlier generations of these vehicles. The additional mass can greatly improve the low end driveabililty in today’s performance cars. Coupling this increased mass into a dual disc clutch system and you now have a setup with a relatively light pedal effort, great holding capacity, and nice smooth engagement and street manners.
Once the system is designed around the factory hydraulics, holding capacity, and pedal effort we then begin the process of machining the components and doing the installation. After the clutch system is assembled and tested in the shop we do the initial installation and begin testing the unit’s performance – in other words the fun part of our job!
So as you can see, we put a lot of thought into what we want a clutch system to be based on the vehicle itself. It is not enough just to take your last great design and adapt it, we must always be thinking ahead to the next great design!
Over the last year we have seen a pretty good spike in shipping charges from both FedEx and UPS. Shipping companies know EXACTLY what it is costing them to ship these packages based on weights and dimensions. We certainly deal with this increase on our end when we ship products to our customers.
But very often, customers ship us parts for repair, and we know everyone wants to pay the least amount for shipping as possible. Here are some things that we’ve learned, and you should know, to minimize these shipping charges.
How to Save Money When Shipping Packages TO RAM Clutches
Heavy Packages Get an Extra Charge – FedEx is now placing surcharges on shipments over 50lbs. This is pretty easy to achieve when shipping clutches and flywheels. UPS does this also but it is not shown on the shipping label detail and thus ‘hidden’. Breaking up your packages into multiples under 50lbs may save you money.
Package Dimensions Matter – When shipping parts, it can pay to keep dimensions to a minimum. Of course you need to package your shipment well, but using a huge box may cost you more than you need to be spending. Try to use a box that best fits your needs instead of just any old box that might cost you more in the long run.
How to Save on Shipping Charges When Ordering FROM RAM Clutches
Home Delivery – A bonus of FedEx shipping home delivery is that now your package can get delivered up to 7 days a week. The downside is that they apply a special fee for home delivery versus a business. We are checking all shipping addresses prior to shipment to make sure we are using the correct service.
Ship to Your Place of Work – Having your package sent to your place of work/business will save you shipping charges versus home delivery. Keep in mind, if you ‘work’ at home or your shop is located at your home, for shipping purposes UPS and FedEx MAY treat your location as a home delivery.
Ship Using Your Account – You may receive a special discount or perk if you regularly ship from your business. We can ship your order using your UPS or FedEx shipping account on request.
By being aware of these tips, you can help save yourself some extra cash! If you have any questions about packages being shipped from RAM Clutches, or need to make a special shipping request, email us at firstname.lastname@example.org. We’re here to help!
When putting together your race car, the clutch is often one of the final pieces that brings everything together. For a clutch to perform well it has to have enough capacity to handle your combination – the engine, chassis, gearing, and tires. Too little capacity and your clutch will have a very short life with disappointing results and elapsed times. As a general rule, it is always better to have a little more capacity in your clutch system than you need. Always consider the load factors below in selecting a clutch system:
Engine – we need to know a little about your engine. How many cubic engines is it? What is the horsepower and torque of the engine? Even if you do not have precise dyno numbers, a solid estimate will help. Lastly, we need to know the intended operating RPM of the engine – what the RPM will be when shifting and leaving the starting line.
Chassis – it is important to know how much the car weighs (with driver) even if it’s a close estimate. Is this a complete tube chassis car or a back half car?
Tires – what size tires are you planning to run along with the rollout of the tire? The tire is what is applying the grip to the racetrack, and ultimately provides the load back through to the clutch system.
Gearing – what are the rear end gear and the transmission ratios? Ultimately, the rear end gearing should be determined through the engine operating RPM, car weight, and tire size so that you cross the finish line at the upper limit of your desired RPM range. The transmission should then be geared to optimize acceleration and traction through low gear with the subsequent ratio drops in each gear keeping the engine in the optimum RPM range.
Other factors such as rear shocks, struts, four link settings, and tire pressures will also affect your clutch system, but they should be able to be worked around in the clutch adjustments if you have properly applied the information from the engine, chassis, tires, and gearing above.
Lastly it is always good to understand your expectations of the clutch system as well. With a clutch system that is frequently serviced like a Pro Stock Car, you can push the capacity harder (smaller size, less plate load) because it is constantly being maintained. In other applications where the clutch is serviced periodically, you need more capacity (larger size, additional pressure) so the clutch system will provide a more consistent and longer period of use between servicing.
If you have further questions about selecting the right clutch system for your race car, please reach out to us at email@example.com.
We receive many technical phone calls with questions on our products, and at RAM Clutches, we’re always here to help. But like you, we want the quickest answers to our questions, and the quickest way to resolve our problems. There are many things that are a big hindrance to us helping you quickly and efficiently, but these are a sure fire way to slow down that process. Here are our tech line’s greatest hits:
1. I didn’t read the instructions
Yes, we always think we know exactly how to put things together and don’t need to read instructions. Some products are simply more involved to install than others. Just like IT support will ask if you’ve turned it off and on again, we’ll ask if you’ve read the instructions first.
2. I don’t have the part number
If you really want us to be able to help you with your application or part, we really need to know what you have. Just describing it makes it very difficult to diagnose any problems or help you deal with an issue.
3. I haven’t checked the website for more information
Every RAM instruction sheet is available on our website. Additionally we have product install videos that help you step through the installation of items such as our hydraulic bearings.
4. I don’t have the setup measurements
To help troubleshoot any hydraulic bearing installation, we MUST have the setup information included on the worksheet with your instructions. You cannot diagnose bearing problems by looking through the inspection hole and guessing. This form gives us the information we need to help you troubleshoot your hydraulic bearing install.
5. I didn’t do the setup measurements
In this case, there is NOTHING we can do to help you until you drop back and follow the instructions to set the hydraulic bearing up properly. Chances are pretty good that if you do this, you will solve your own problem.
6. I didn’t measure the factory bearing preload before installing my hydraulic clutch
Perhaps it seemed like a pain to do, but the extra 15 minutes to verify preload when installing a clutch with factory hydraulics may have saved you hours of work later if you have a disengagement issue. We provide very detailed video instructions for this procedure in the hydraulics section of our instruction pages on the website. We WILL ask you for this setup number information if you contact us and say your clutch won’t release.
7. I bought a used clutch, it’s red
There are many used clutches out there floating around. These can range from 1 to 45 years old. We cannot possibly tell you what clutch you have by describing it, let alone know what the static pressure is. We can POSSIBLY help you partially identify it if you take pictures and email them with your question to firstname.lastname@example.org.
8. I bought a used billet race clutch. How should I set it up?
This is similar to the above except more dangerous. There are many of these units floating around and some could be 30 years old or more. Before even thinking about buying a used race clutch, look for the most recent SFI certification date, as well as the first, to determine how old it is. If the unit is out of date, it will have to come back to us for inspection and recertification, at which time we can check the static pressure, what levers are in it, and possibly help you with setup. Remember, if the deal looks too good to be true, it probably is.
I get asked all of the time, why should I use a dual disc clutch? Or, why should I spend all that money on a dual disc clutch?
We work hard to make all of our clutch systems as user-friendly as possible. We have been driving, racing, and tuning performance cars ourselves for over 40 years and know first-hand that trying to drive a clutch that is too aggressive on the street is just not any fun.
Less Static Pressure Needed
When you use a dual disc clutch you are essentially doubling the holding power of the clutch system without adding any extra pedal effort. This allows you to have the extra performance and increased friction surface area without ending up with a left leg that is twice the size of your right from a stiff pedal!
Less Aggressive Friction Materials Needed
By using multiple discs, we can use organic friction material for most street-driven applications and maintain a very smooth engagement and good street manners. The same application with a single disc clutch would require a more aggressive friction material that is more likely to chatter on takeoff.
Typical customers do not do their entire build at one time. It may progress over a few years starting with a few bolt-ons, then eventually grow to include forced induction or nitrous. By starting with the dual disc when you are still at the lower power levels, your combination can continue to grow without the need to keep stepping up clutch levels every time you make an improvement.
When you price everything out, the difference between a single disc and dual disc is minimal, and taking into account the other plusses listed here to using a dual disc, it really starts to make more sense.
Better Clutch Life on the Street
Using a dual disc clutch lets you see an increased clutch life over single disc units due to the overall higher capacities that these clutches give you.
Better Clutch Life at the Track
By using a dual disc clutch with metallic friction, you will see increased clutch life at the racetrack also. Metallic friction materials stand up to the heat much better, and with the increased number of friction surfaces in the dual disc clutch, you will get better heat dissipation which equals increased life.
Over my 38 years of selling clutches, it seems I would have seen just about every possible mistake that can be made on an install, and then someone out there pops up and surprises me! Many of these may seem painfully obvious to you, but it can’t hurt to review!
Installing the Clutch Disc Backwards
Often I wonder how this is even possible, yet we receive returned discs for alleged warranty that are virtually turned inside out bent when a customer tries to put the disc in backwards. When you have the flywheel installed on the engine, lay the clutch disc up on the flywheel and rotate it some. It must sit flat the flywheel and not be contacting the flywheel bolts as you rotate it. It the disc does not sit flat, make sure you have it in correctly, or stop until you figure it out.
Using Power Tools to Tighten Down the Clutch Cover
This is a huge no-no and written in every instruction sheet RAM has ever provided. Tightening down the cover puts a load on the clutch cover flange since you are pulling it down against the pressure of the diaphragm or coil springs. Using powered tools can cause this flange to become bent, which in turn will leave the fingers uneven once the clutch is fully tightened down. This can cause extreme clutch chatter.
Tightening the Cover Bolts Down All the Way at One Time
Another way to damage the flange of the clutch cover is to tighten the bolts down completely in one shot instead of in a star-shaped pattern. This can damage the flange and cause the fingers to sit unevenly. Tighten the cover bolts ONLY with hand tools, and use a star-shaped or crisscross pattern, a few turns at a time, just like torquing your wheels in place.
Improper Release Bearing Adjustment (mechanical or cable linkage)
Setting the proper release on your clutch is very important – not only initially, but periodically going forward. A mechanical linkage should be adjusted for minimum release; that is only enough release that the clutch will disengage cleanly for shifting. This will result in a pedal lower to the floor and leave maximum freeplay. As the clutch disc wears, the fingers of the clutch will get taller, and if you have the bearing adjusted too close, it could ultimately unload the clutch fingers and not let the plate put its full load on the disc. This will cause undue slippage and wear.
Not Resurfacing the Flywheel Before Install
“The flywheel looked pretty good so we just went ahead and installed the clutch.” I can’t tell you how many times I’ve heard this. No matter how good the surface may look, if you want the new clutch to seat properly it needs a fresh friction surface to seat against. Otherwise it would be like installing new brake pads and reusing the old rotors.
Changing Out Only the Clutch Disc
Obviously the clutch disc is the part of your system that will physically wear the most. Changing only the disc is setting yourself up for problems. As the clutch, disc and flywheel wear in, the surfaces build a taper that the clutch disc will conform to. If you install only a disc, it is going to make contact on just the outer edges and will never properly seat. Ultimately this will cause premature slippage and most likely will also chatter on takeoff.
Does this scenario sound familiar? Racing season ends and the car gets pushed in the corner or left in the trailer. Sometime around the middle of February, or in a worst case scenario about a week before the first event, you decide it’s time to start getting ready for the new season. Whoops! I forgot the clutch was slipping a little on that last pass, or it has been 50 runs since I had this thing out and inspected. Sure enough, you pull it out and it needs rebuilt.
That is the time of year that we get bombarded with rebuilds and RUSH rebuilds. Not only does it put you in a bind to get everything back together in time, it is hard for us to process the unit thoroughly and get it back to you in time.
So what should you do in the offseason?
CLUTCH INSPECTIONDo this sooner rather than later. Now is the time to make sure you have all of your clutch components fresh and make any changes or upgrades to the system to improve performance.
PRESSURE PLATEInspect for warpage and signs of extreme heat. A pressure plate will build a taper to the inside edge over time that grabs the clutch disc only on the outer edge. This can either cause the clutch to get more aggressive on launch, or slip on launch. High heat signs include bluing of the metal, shiny spots on the surface, and heat cracking or smearing in extreme situations.
CLUTCH DISCHere you need to know your minimum thickness and the number of runs on the disc. On sintered iron clutches, you will usually hit the run limit before you wear it out. We recommend no more than 75-100 passes on these discs as the hubs and rivets will tend to fatigue over time, and if this disc comes apart, it will cause major damage in the bellhousing, or worse…
FLYWHEELSteel or aluminum flywheels should be inspected for the same signs of wear as the pressure plate. Many times the flywheel can be resurfaced, but with aluminum flywheels it may be necessary to replace the insert.
Keep in mind that these components wear as a system. As the disc wears and surfaces on the pressure plate and flywheel wear, the disc will conform to those surfaces. Thus, just changing a disc or pressure plate and using other components that are not fresh and flat will not allow for proper seating of the new component. This will throw your combination way off when you hit the track, or worse yet might just fail.
While you are inspecting these components, be sure to check all of your backup parts. There is nothing worse than being at that first event of the season, having an issue, and when you go to change out the clutch all you have is last year’s worn out backup that you forgot to send in for rebuild!
The offseason is also a good time to review your run records and data and determine if other changes to the car may help improve performance. Rear gearing, transmission ratios, tire sizes and types can be modified or changed based on the data you review to help improve your performance for the upcoming season.
If your budget and time allow for it, plan to test over the early months of the year. This track time is valuable to helping improve your performance for the season, and allows you to try different combinations and parts away from the time constraints of big events. Remember that great teams are built in the offseason, so choose to be different and ready for the 2020 season!
Avoid these pitfalls when making your single disc clutch set selection
Previously, we have discussed many of the factors to consider in selecting a clutch for your application. Now let’s take a look at some of the things NOT to do when selecting a single disc clutch set.
Not taking into account your expectations from the clutch system
When we spec out a clutch for your application, the most important thing is to understand your expectations. Are looking for smooth engagement? Is holding power at the track the most important thing for you? What about balance? We always ask these questions when customers inquire about the clutch selection. Understanding your expectations and what you hope for the clutch to do helps us determine the right build for your vehicle.
Ignoring load factors
If you haven’t reviewed our previous blog about load – this is a good time to do so. Don’t fall into the trap of picking a clutch system solely based on the ‘rating’ of the unit.
Assuming that the clutch rating is etched in stone
This goes back to the load factors (as you can tell, this is important). We have seen plenty of situations in which a customer selects a clutch rated for up to 650 horsepower and it slips at 500. We also see the opposite happen. A customer is using a clutch with a rating far below the power level. Be sure to take into account the load factors, use, and driving style in your selection.
Reading the wrong information online
There is good information on the Internet and you can learn a lot about clutches and your system. But beware of “keyboard jockeys” who post and may not have any experience with a particular clutch (but they do have a lot of opinions). Do your research on who’s writing the content you’re reading and make sure they have knowledge and experience with the product you are interested in.
Picking a clutch because ‘that is what my buddy uses’
Similar to reading online, don’t be deceived by information that may not apply to you. You may think your cars are the same, but when reviewing the load factors you will see that there are differences that need to be taken into account before making your final selection (tires, shift RPMs, gearing, etc).
Buying a cheaper unit because it’s ‘all you can afford right now’
If this is the case, you need to carefully consider if it is worth waiting a little while until you can purchase what you really need!
Under buying when you know future mods are coming
Think about your long term plan for your vehicle. A future mod that will be beyond what your system can handle is something to consider. Better to step up now and make sure you are covered into the foreseeable future.
What are the mistakes that you have made in the past? We would love to hear from you. Check out our blog and our YouTube channel for more information on clutches and the work we do.
You’ve been thinking about installing a hydraulic release bearing in your vehicle. This is a great choice for gaining valuable space in your engine compartment and simplifying the clutch release system. Before you pop the hood, let’s go over some common mistakes (with real examples) to avoid for your installation.
It’s critical to have the correct measurements. We provide very detailed instructions and video to help you through the setup of the bearing. A setup sheet gives you the exact measurements you need to successfully install the bearing. You’ll need a quality set of dial calipers for your measurements. Take your time and check to make sure your numbers are accurate . If you email for tech support, we will ask you for these measurement numbers!
3. Not Using Teflon Tape on the Fittings
The inlet fittings to the hydraulic bearing must be installed using Teflon tape. You may think you have a super sealing liquid or other miracle product; don’t fall for it. Trust us, we have personally made this mistake.
4. Improperly Diagnosing Leaks
Nearly every call we receive involving a leak with the hydraulic bearing can be attributed to the fittings or hose connections. The best way to diagnose the origin of a leak is to hang the bearing under the car with the lines connected and have someone operate the pedal. Pinpoint the cause of the leak precisely using this method BEFORE you contact us. This will save you lots of time that would be lost if you sent us the part without locating the leak.
5. Improper Orientation of the Bearing/position of the Bleed Fitting
For easiest bleeding of the bearing, the fittings should be angled between the 9 and 3 o’clock positions. Do not point the fittings down. The top fitting should be connected to the bleed line. When you perform the bleed the fluid is forced up and through the bearing, reducing the chance of air bubbles.
6. Setting Too Little or Too Much Bearing Clearance
Let’s be frank. Both of these are bad. If you do not set up the minimum clearance of .150”, you are not leaving enough room for the clutch to wear and it could fail prematurely. Setting up too much gap will cause the bearing to bottom out on the snap ring. This results in non release of the clutch, or potentially blowing the bearing off the piston. Keep in mind – the RAM bearing is a constant contact bearing and once you cycle the pedal, the bearing only returns as far as the clutch fingers push it back. It is always starting right at the fingers.
Why does RAM Clutches race? We could just build our clutches for street or street/strip based on the OEM design, add more aggressive friction material, and call it a day. This is called ‘bottom-up’ design. But we do things a little differently. RAM chooses to manufacture specific units for a variety of classes from Pro Stock to Street Stock. We then use ‘top-down’ design and apply what we learn in abusive racing conditions to build a much better product for the street or street/strip applications. The result of this is excellent performance while maintaining driveability, which means you get the most enjoyment out of your vehicle.
Working with our race teams provides us with valuable knowledge and feedback that helps our design team build a better product for you. We are not just at the track putting stickers on cars for promotional purposes. We are there to learn! We constantly evaluate different types of unit weights, static pressures, friction materials, and release pressures to achieve the best performance for a given application and situation. The end result is we are able to offer products that perform well in your car.
What does this all mean for you? To provide the best possible product for your application, we need to have the most accurate info about your car in order to make a recommendation. It is why, in previous articles, we have explained in detail how to evaluate your application based on the load the vehicle will experience. We’ve set up our E-Tech help tool to make asking questions and improving your system simple and easy.
Is your muscle car a track car or a cruiser? Will it be taken to the track once a month or just to see how it will run? Is on-track performance of the utmost importance to you or is low-end driveability? Will you make further upgrades on the build or are you buying a clutch for the completed project? These are questions to keep in mind when working with us. The answers will help provide the highest performance product for your needs.
Looking to get started? The RAM E-Tech tool is the best way to communicate. Once we know more about your situation, we can take your information and evaluate exactly what the expectations are for your application.
We want to understand your car and how you intend to use it so we can help. Whether you are restoring a Muscle Car with a crate engine and Tremec Transmission or turning your late model Camaro or Mustang into a beast at the racetrack, we’re here to build the best system for you.
In previous posts, we’ve discussed the load factors of your clutch system and how to use this info to make the best clutch selection. Now it’s time to look at some of the situations that put a hard load on the clutch, and create the most opportunity for the clutch to slip, wear prematurely, or even break. I’m sure that none of you have ever done any of these things…
Chassis Dyno – The chassis dyno will inflict about the most load on the clutch system. There is no tire slippage (in most cases) and the goal is to load up the drivetrain to the max in order to tune and obtain numbers. Taking your vehicle from the install lift to the dyno rollers with no break in and you are asking for the clutch to slip.
Taking off in the wrong gear – Whether intentional or unintentional, the load from taking off in a higher gear is extremely hard on the clutch system. We see customers trying to leave in 2nd gear at the track in order to reduce tire spin. It will probably do that… and also cause the clutch to slip or wear out quickly.
Traction control at the race track– Always make sure you turn traction control off when you are at the race track (or on the dyno). Traction control methods will load the clutch system harder and increase the risk of damage to the clutch system.
Shifting 1st to 2nd, then back to 1st – Most good racers will admit when this happens, it inflicts a severe reverse load on the driveline that can cause clutch hubs, diaphragm straps, or in severe cases, clutch covers/rings to break.
Not rev matching on downshifts – Autocross and road racing is where this is most common since downshifting it is critical to match RPMs as you re-engage the clutch. Failure to do this will put a hard reverse load on the plate or floater and straps, causing bending or breakage. In other words, you will not be racing anymore that day.
Lugging the engine at low RPM – If you have ever driven along and the RPMs dropped enough for the car to start ‘bucking’ or ‘jumping’, you have lugged the engine. This puts extreme stress on the clutch hub center section and is a big cause of clutch disc breakage.
Not clutching at the end of a big drag strip pass – Don’t use your engine as a brake at the end of a drag strip run. Push in the pedal and kick the car out of gear – the reverse load against the clutch can cause damage or breakage.
These are just some of the major situations we run across on the tech line. You may have invented your own – if so, we’d love to hear about it! Be smart about how you treat and use your clutch system and it will be your friend for a long time.
In our last post we discussed selecting the proper clutch for your application based on load factors the clutch will experience. Today we tackle the dos and don’ts of selecting the correct flywheel for your application.
Have you ever heard this line before? ‘Put in a lighter flywheel and you will make more horsepower.’ Some manufacturers will tell you this, and it is simply false. Heck, I once had a customer who was told a light flywheel would ‘increase his gas mileage!’ Is it possible for a lighter flywheel to create quicker engine acceleration? It can, depending on the gearing of the car. Will it allow the car to decelerate quicker? Absolutely. This is why circle track and autocross racers want to use the lightest possible flywheel and clutch combination for their vehicle. It allows the car to drive deeper into the turns and have the RPM drop quicker as they let off the throttle. The engine can then accelerate back into the peak range quicker out of the turn.
For your street driven car, flywheel selection is critical to the driveability of your vehicle. The job of the flywheel is to transmit inertia to help get the car moving; be it pulling away from a stop sign, or leaving the starting line at the drag strip. The proper flywheel weight, in conjunction with the correct gearing, will optimize your driving experience. Other load factors discussed in “It’s all about the load, silly!” will also affect this, such as vehicle weight.
The typical tech call for a clutch recommendation starts like this: “How much power will your RAM xxx clutch hold?” Customers have been conditioned by other manufacturers to select their clutch by ‘stage’ or ‘level’ or ‘rating’. While the horsepower and torque are certainly important, they are not the end all of clutch selection. We have seen plenty of 400 horsepower applications that can slip a 650 ‘rated’ clutch.
I am much more interested in hearing about the load factors that the clutch system is going to see. These are more important in the initial recommendation. So what are the biggest load factors to consider?
Vehicle weight – this is perhaps the most important load factor as well as selection factor in determining the clutch needed. Simply put, the heavier the car, the more work the clutch has to do to hold without slipping.
Vehicle gearing – This applies to both rear gear and low gear in the transmission. Higher rear gearing (lower numerically) requires more slippage on takeoff to make a transition, and puts a much bigger load on the clutch with a harder launch or acceleration. Likewise, a higher low gear in the transmission could be like starting out in second gear in terms of the load the clutch will see.
Rear tire used – as you might imagine, a larger, stickier tire or slick that is more likely to hook up and not spin is going to put a much harder load on the clutch. So what tire will you be running?
Use of the vehicle – If you plan to spend time at the race track where traction is good compared to the street, this is going to load the clutch system harder on launch and through the gears, whereas on the street it might be more likely that the tires will spin.
Horsepower/torque – Yes, this is certainly a selection factor to consider as it will affect the load the clutch sees.
Now consider this worst case scenario – a potential customer has a 4000 pound, 450 horsepower muscle car that they are converting from an automatic to a manual. They have meticulously acquired all of the parts to do this conversion including pedals, linkage, etc. They install a Muncie transmission with a 2.49 low gear and leave the 2.90 rear gear in the car that it had with the automatic. What is going to happen when they let out the clutch on this combination? LOAD LOAD LOAD! Not to mention, they will have to slip the clutch for an eighth of a mile just to get it rolling and engaged!
Bottom line? Get all of your ducks in line when selecting and setting up your clutch system. Give yourself the best chance for success by making smart decisions not just with the clutch, but also with your gearing. And have realistic expectations for what you will do with the vehicle and how the clutch is going to perform based on the load factors you introduce into the combination. Understanding these load factors will help you make the best selection of both clutch and flywheel, which we will tackle in another blog post.
So here you are. Clutch feels like it is starting to slip. Or it feels mushy. Or it isn’t disengaging completely. Time to pick a new one, but how do you know what to choose? This title says it all, picking a clutch is like picking a suit. No one size or style is going to be right for everybody. You need make your selection based on YOUR car and YOUR desired ‘feel’ and ‘performance’.
Here is how NOT to pick a clutch. Put a post on your favorite social media platform and ask for advice. You will get 532 different answers and some of them will be from people who don’t even have a clutch in their car, or just advocate for a specific brand because their ‘buddy’ has one in their car (or did in 1980). Instead, consider these more personal questions:
What are my expectations for a new clutch system?
Do I want it to drive smoothly and have a light pedal like stock? Do I need extra holding power for engine upgrades, now or in the future? Am I okay with sacrificing some driveability (i.e. smoothness of engagement) in order to have a higher holding capacity?
What sort of load will the new clutch system see in my car?
Load is the most important factor in selecting a clutch, and we’ll talk more in depth about that in a future column. For now, keep in mind that this means any factors that will contribute to more load on the clutch system. These include, but are not limited to, Tire size and type, rear gearing, low gear in the transmission, and perhaps most importantly, the weight or mass of the vehicle. Any time you are adding load to the clutch system, you must compensate in kind with your selection.
What kind of driver am I, and where is the car going to be used?
This is where you have to level with yourself! If your intended use is to drive your car every other weekend to car shows and back home to the garage, you probably don’t need an aggressive clutch that is capable of massive holding power. Conversely, if you are a ‘spirited’ driver, or if you ‘beat the crap out of’ your car, or go the track every other weekend, you need to compensate properly in your clutch selection with something capable of holding more power or withstanding higher loads.
Don’t get hung up on horsepower ratings.
The most important factors in your clutch selection are those listed above. Sure, the horsepower is a consideration, but it’s far from the only one.
When I get a call asking for a clutch recommendation, these are some of the most important questions I ask. And the manufacturer you choose should be asking the same questions. If they are not, find one that does and truly cares about getting you in the right clutch for you, not just selling you the ‘one size fits all’ cookie cutter suit.