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 [email protected]. 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 protected].
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.
More questions about using a dual disc? Drop us a line at [email protected]!
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.