cueball

I read in one of the threads that the 5.9 0-60 time was achieved with an 8000 RPM clutch drop. I know dropping the clutch often in any car is not good for the transmission. The thing I was wondering about is it any worse for the transmission if you do clutch drop at 8000 RPM on a high revving car like the RX8 with the power peak almost reached versus doing at about 5000 RPM on a car that produces the same amount of power just at a lower RPM, like a Corvette. I was wondering because an equal amount of force is running through the transmission, the only difference is the RPM. I ask this because an 8000 RPM drop may seem extreme, but when compared to a car that reached max power at a lower RPM, it may be the same. I was just wondering if engine speed affected the wear on the transmission.

I don’t know if anyone understands what I am trying to say, because it was very difficult to word. Any help would be very much appreciated.

Hercules

Where's Buger?

rotarynews.com

Wheel hop is pronounced when dropping the clutch... short of having a set of slicks on, there isn't much that can be done.

The entire powerplant from enging to diff takes the abuse, but with Mazda's, the energy is spread out over the entire sub-structure, with the power plant frame. It should be noted the the PPF is stronger than the FD's and should be able to take more abuse. (Cracking PPF's in the FD is a common problem for drag racers) Additionally, there are many points where the powerplant and body are joined, with bushings. These bushings should absorb the energy and lessen the shock to the entire system.

DTECH-RX

I would think in a car like the RX-8 you would get better 0-60 (and 60ft.)results by revving high and feathering the clutch out of the hole, keeping the car in the power band. Then again, that's not what the RX-8 is about is it? But it doesn't hurt to be able to this well either...

Speed Racer

Heh DTECH-RX those are exactly my sentiments.

I think that any one who has owned a car with a high reving / low torque engine will agree when I say that the fastest way off the line is to rev the motor until it is in its sweet spot and then slip the clutch without letting the rpms drop. If you do it right the car takes off like a rocket. If you do it wrong you smoke the clutch. Just remember that the burning smell is not only offensive but it can be expensive.

Currently I'm driving a Celica GT-S and much like the RX-8 it is ill suited for drag racing. It comes into its own when the road gets twisty. This may sound odd but the narrow power band makes it challenging to maintain a pace that falls in between leisurely and all out ballistic. The engine like most variable timing/lift engines has a distinct ON or OFF personality and in many situation you will wish that the power band was another 1-2k wider. That is where I think the RX-8 will really shine because it should have a slightly wider / more gradual sweet spot. I can't wait to take one for a test drive! :D

SPDFRK

The initial shock will be greater due to the eccessive revs but the real thing that kills transmissions and clutches over time is handling high torque loads and we all know that isn't something that will come up on the list of positive aspects of the rotary when people are testing this car.

Yes slipping the clutch to keep the motor in the powerband will get the best times but will fry the clutch done "right" or not, there is a limited amount of material on the friction plate and any slippage will decrease its effective life. So in that respect getting some wheelspin to replace the feathering of the clutch would be more economical if it is necessary for you to do drag strip like starts. For example: If you do full on acceleration drag starts with any new streetbikes the clutch will have had it after about three runs. They are not originally engineered to have the longevity of a passenger cars clutch but can easily last 20k miles still being riden aggresively.

MrWigggles

I am sure Mazda will utilize a clutch that is designed for higher RPM's but less torque.

In general this would typically mean a smaller clutch designed to spin faster.

Doe the S2000 folks go through clutches often?

-Mr. Wigggles

Randy

The S2000 clutch will smoke if you try to slip the clutch at 5000 rpm. I'm sure that the stock clutch in the RX-8 will smoke with an 8000 rpm clutch slip. The best launch on this type of car is with a clutch drop and tire slippage until the car is near the power band of 6000+ rpm. Yes, many S2000 owners go through clutches frequently, but with proper technique, it can be avoided. I have 30,000 miles on my S2000 OEM clutch with many tire spinning starts.

Skyline Maniac

The Renesis only has 160 lb.ft torque at the flywheel, so I don't think dropping the clutch will wear anything other than the clutch plate. Imagine feathering clutch at 8krpm without letting rev drop is just painful though. I am sure the RX-8 has a decent clutch, but at that kind of rpm, even a lightweight flywheel can generate enough force to shatter and fly all over the place. Dunno, if I had a RX-8, I'll just stay away from launching the car.

MikeW

Just dump the clutch off the limiter in first, you will spin both rear tires (torque sensitive diff.) but the hard part will be keeping the car straight (not extremely hard)

If the clutch is designed to handle the stock peak torque 159 ft-lbs + an extra 20-25%, lets say 200 ft-lbs is the max static friction torque of the clutch, there is only 140 ft-lbs available at 9000, the clutch will decelerate the engine, but in the process (keep foot on floor) the rear tires will break loose when the revs drop through max power (most likely around 8750), now the tires will spin back up, but since you are accelerating in a rear drive car, you will have more traction. The revs might come down (or just hang at 8500), but as the tires (hopefully) approach 0% slip, the engine will again approach redline/revlimiter.