I have a simple question but was unable to find the answer in previous threads.

I know this not a fair question because of the many variables involved, however I was wondering if an AWD car with the same whp where to race a RWD (lets say both cars weigh the same) at roll of about 80mph would the cars accelerate to say 150mph around the same time? Or would the AWD provide more of a burden at higher speed? Thanks.

 

If they're making the same power AT the wheels, i think it should be a fairly close match with the conditions that you listed being met. The reason why 4wd sucks at the top end is because the power is distributed to all for wheels instead of two. That means more drivetrain loss. However, if both cars are making the same power at the wheels, that means the AWD motor is making more power at the crank to compensate for the disadvantage of more drivetrain loss.

 

No if they're making the same power at the wheels, then AWD would not be at a disadvantage to RWD.

Although it would kick it's butt light to light.

 

well, depends on how technical you want to get. If even it an AWD was putting out the same whp as a RWD, if you hold everything else constant, the AWD would be heavier than the RWD simply b/c of the extra parts, and that may affect top end acceleration.

Though, its a tough call. If you were to ask me about two cars with the same flywheel hp, id have to say the RWD hands down. But havng the same whp on an AWD with drivetrain loss factored in would mean more engine power obviously...and you have a tough prediction

 

If they have the same whp, whoever has better gearing would win.

 

Let's ignore the gearing for a moment here, even though that def is a factor, and talk about whp. In our scenario the AWD is making more power at the engine to compete with the RWD whp. That being so, if the AWD were to convert to RWD it would make more whp. So the advantage of AWD is greater traction at the expense of having to produce more engine hp than a RWD car to get the same whp. I guess this is why buschur decided to convert their talon to RWD. I guess it is also safe to assume that if shepherd converted his AWD talon to RWD, he would have even lower times than he has now. Personally I think it's awesome that his AWD car can do 8.76 seconds. I love the practicality of AWD, but it seems that from a professional drag racing stand point, it is better to go with huge slicks and RWD because you are losing less hp at the wheels.

 

top end speed has as much to do with coefficient of drag (CD) then power or gearing. The .37 CD of the Evo kill's it's top end pull as much as the added weight & parasitic loss to the awd driveline.

 

No, for high powered drag racing, RWD launches harder then AWD.

 

IF you have the traction (tires & suspension to back up the power).

On street cars, awd generally launches harder, but not with race/drag cars.

 

No, for high powered drag racing, RWD launches harder then AWD.

 

The answer is: You have to take it on a case by case basis. Most of the quicker RWD cars I can think of are actually quite a bit heavier than the Evo. Weight, gearing, torque curve, redline, and area under the curve all come into factor.

 

Assuming equal weight, equal wheel horse power (over the full curve), equal gearing, equal aerodynamics, equal driver ability, the rwd could have a slight advantage. That would be if the car was dynoed in say 3rd gear, and the race was in 4th gear. This is because the drivetrain loss would be greater in the higher gears (higher build up of inertia). That's about the only way I can think of that would allow the rwd to win.