Contour Enthusiasts Group Archives Forums General Common Interests Would RWD cars launch faster that AWD?

Originally posted by Kremithefrog:

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Originally posted by Russell-3L:

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Originally posted by Kremithefrog:

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You are NOT experimenting with the right amount of wheel spin. Wheel spin is not what you want.

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wrong

i ran 16.3s on a bald set of kumho 711s, with wheelspin

i ran 16.5s (in cooler weather) on a new set of azenis, with little or no wheelspin, also my 60' times were about .1 sec slower

i have timeslips to prove this

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You don't understand it though, the wheel spin itself is NOT what is making you move. Possibly having them not hook great but allowing the engine to keep it's revs up does get you moving... the bald tires may also have helped out on the rest of the run... and even if the weather is colder, there is still other factors that come into play.
LISTEN TO THIS::: WHEEL SPIN DOES NOT MAKE YOU MOVE, THOUGH IT MOST LIKELY WILL BE INVOLVED IN YOUR MOVEMENT. Understand what I'm saying?

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Your right, wheel spin does not make you move. If wheel spin was the only single factor in how fast you accelerate, then you are right.

Your clutch slipping is the same as a tire slipping. If your clutch is slipping, you are not launching as fast as you can.

If your engine put all the power out linearly, then no slip would be the fastest acceleration. Look at a dyno plot. Since torque and HP are at the higher RPMS, something has to slip (Clutch, Tires, or both) to let the engine RPM rise to a place with significant power to get the fastest acceleration. If you really want no slip, put the car in gear, engine off. Start in gear and see how fast the car accelerates.

The above is NOT true for Steam or electric motors. Electric and steam develop max torque at 0 RPM. So wheel or clutch slip is detrimental to fast acceleration for these engines.

So, with a typical internal combustion engine, something has to slip to get you going. The trick is to balance the slip (tires or clutch) so that you develop both the best engine RPM for Torqu and HP and minimizing slip.

Having said all that, AWD requires more clutch slippage for launch because it takes too much torque to spin the wheels in most cases. RWD can utilize wheel spin to some degree and save wear and tear on the clutch. Tires are easier to change than clutches anyway.

And as I stated earlier, very powerful cars accelereate hard enough that most of the weight is reansfered to the rear tires and AWD could not be used to a great advantage since the front wheels are not loaded enough to make much addition to acceleration. I notice many RWD cars (pro stock, for instance) that actually lift 1 or 2 front wheels of the ground on a hard run. AWD would not help their 1/4 mile times at all. This is why FWD is limited in 1/4 mile times. The harder you accelerate, the more unloaded the fronts become. You will never see 8 second FWD cars because the physics are wrong for that configuration.

Again, AWD will lauch faster in 12 inches of snow though.