FWD vs. RWD launch

MMamdouh · Post by **MMamdouh** » Sun Dec 25, 2005 9:43 pm

imagen two cars on a drag strip

both got 1000 kgms of weight
both put 100HP to the wheels
both got equally talanted drivers
both got the same tire size and specs
both got same tranny
both got identical power band from the engine

which one will pull faster? i was arguing with Zikas that the RWD will pull faster as it has better traction during the launch... he was arguing that you lose power by transfering torque from the front to the back and he is right but our test cars are rated at 100HP AT THE WHEELS so i still think the RWD will kick the FWD car's ass... what do you think guys??

MMamdouh

kinkyllama · Post by **kinkyllama** » Mon Dec 26, 2005 2:37 am

Since its at the wheels.. i think RWD. If it wernt at the wheels i couldnt say

Audacity Racing · Post by **Audacity Racing** » Mon Dec 26, 2005 2:40 am

alot depends on grip... but i would saw fwd actually...

since the same power is at the wheels, and the same tires are used... the torque translation from the front to back on a rwd car takes up a lot of the energy... i dunno though

BosnianLanos · Post by **BosnianLanos** » Mon Dec 26, 2005 4:30 am

@ Only 100 HP, I don't think that traction would make a big difference because there isn't enough power for a crazy amount of wheelspin. @ Only 1000 kg, I don't think that the FWD would have enough rear end swat to allow its front tires to spin faster.

In all probabilities, it would be a dead heat.

I might even say that the FWD would take it because there is more weight on the drive tires because of the engine, giving it better weight distribution during the launch.

I guess... it is a hard question.

Post by **Efratech** » Mon Dec 26, 2005 3:52 pm

MMamdouh · Post by **MMamdouh** » Mon Dec 26, 2005 4:59 pm

Ok lets make this intresting... they are 4 cars weight of each 2350 kgm and all got 1000 HP to the wheels... now the extra two cars are front engined AWD and the other is rear engined RWD whereas the two cars form the early example are front engined.

i recon the AWD will be first, rear engine RWD second, front engine RWD third and the FWD will be tralling behind simply be cause at launch the car weight shifts to the back giving advantage to the RWD cars, a rear engine is a plus in this case.

the AWD is pulling all wheels so it beats every thing out their but not sure if it is more effective than a RWD rear engined car... am i right??

MMamdouh

Audacity Racing · Post by **Audacity Racing** » Mon Dec 26, 2005 5:06 pm

the awd would win the launch... but prolly come in 3rd or even 4th in the over-all race

the mr, or rr car would win hands down in the long run and definitely be 2nd in the launch

the other two are up for grabs still... launch will go to the rwd because the torque is way greater than the force lost in weight transfer. it would probably win for that same reason...

LAUNCH
AWD
MR/RR
RWD
FWD

RACE
MR/RR
RWD
AWD
FWD

dhd · Post by **dhd** » Mon Dec 26, 2005 6:43 pm

i think the awd will be the first coz it will be the
fasters car to launch and to retch the max speed
coz it will be going without shifting ACC

and the Scand is the mr/rr
and thread is rwd
final fwd

karim · Post by **karim** » Mon Jan 02, 2006 12:42 am

I have seen so many races in my life, and I found most of the time is the RWD, as most of the the lunch of the FWD always spin too much, but even in RWD if you spin a lot it always leave the line fast, as for AWD it's the best just yesterday saw Toyota Rav vs Hyundai 1.6L and man the Rav just jump like crazy, and myself too when I raced against Jeep and I was in my Stralet and the guy just jumped like a frog but I did beat him at the end

MMamdouh · Post by **MMamdouh** » Mon Jan 02, 2006 8:15 am

exactly my point... maybe the FWD doesn't lose much poer to transfer torque from the engine to the wheels but its tires will struggle as hell to transfer that to the road due to weight shifting and all... RWD rules.

BTW where do you watch them races?? give me a buzz when you are going maybe i can join in some time.

MMamdouh

karim · Post by **karim** » Mon Jan 02, 2006 8:23 am

You got it right. Those races usually start anytime you really don't know just people racing in the streets.

mmamdouh wrote:exactly my point... maybe the FWD doesn't lose much poer to transfer torque from the engine to the wheels but its tires will struggle as hell to transfer that to the road due to weight shifting and all... RWD rules.

BTW where do you watch them races?? give me a buzz when you are going maybe i can join in some time.

MMamdouh

tango · Post by **tango** » Mon Jan 02, 2006 9:54 pm

Let's look at the Physics.

Rear drive cars are inherently better at acceleration because as the power is put on the car actually rotates about the centre of gravity so that the weight shifts towards the rear. This is an advantage for rear drive cars as this gives them more weight (traction) to the driven wheels. Front drive cars will tend to lose grip because the rotation shifts mass away from the driven (front) wheels. This is not as bad as you may think because manufacturers now place the engine slightly ahead of the front wheels. This causes the weight of the engine to shift a bit more rearwards to just above the wheels, thus grip can be maintained. Let's analyse the converse. If using engine braking to slow down front drivers win. The weight shifts forward under braking. The driven (engine braked) wheels need traction to slow the car and since rear-drivers lose weight on the driven wheels then engine braking is less effective. The perfect balance would be AWD of course where the driven wheel can be switched on and off (or in a seamless fashion as required). VW's Syncro system of many years ago was like this. Up to 100% to the rear under acceleration, and up to 100% to the front under braking.

In my opinion the engine's location is not necessarily an exact determining factor as to which will win.

Stefan · Post by **Stefan** » Tue Jan 03, 2006 3:03 pm

RWD would win. 60ft time would be quicker all else being equal.

karim · Post by **karim** » Wed Jan 04, 2006 10:04 am

Yep that's correct

Stefan wrote:RWD would win. 60ft time would be quicker all else being equal.

dog · Post by **dog** » Wed Jan 04, 2006 10:06 pm

You can set up a fwd to a nuetral balance under acc. still not as good rwd but those are becoming rare. My 2nd car is awd and rocks but is no drag racer.