Why does four wheel drive hurt 0-60 times?
Discussion
chard said:
jon- said:
jimbobsimmonds said:
My understanding is down to greater transmission losses because the engine has to get all of those drive shafts and differentials up to speed as well...
I would agree, but only in a lesser powered car. Cars like the RS4 could spin all 4 wheels with ease, so any transmission losses are nullified. That said, I've not driven an RS4 so if you're saying a full RPM, side step the clutch launch wouldn't spin up all 4 tyres I'd believe you (but be a little surprised)
jon- said:
chard said:
jon- said:
jimbobsimmonds said:
My understanding is down to greater transmission losses because the engine has to get all of those drive shafts and differentials up to speed as well...
I would agree, but only in a lesser powered car. Cars like the RS4 could spin all 4 wheels with ease, so any transmission losses are nullified. That said, I've not driven an RS4 so if you're saying a full RPM, side step the clutch launch wouldn't spin up all 4 tyres I'd believe you (but be a little surprised)
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Have you ever driven an RS4? If you tried to spin all 4 wheels you would just wreck the clutch.I didn't say it could be mechanically friendly, but when is Top Gear ever nice to the press cars!
That said, I've not driven an RS4 so if you're saying a full RPM, side step the clutch launch wouldn't spin up all 4 tyres I'd believe you (but be a little surprised)I'm not going to bet the ranch on it but I reckon broken clutch. The clutchs on these cars are not that strong. They will even slip horribly if you screw up a fast gear change!!I seem to recall EVO saying that the clutch didn't engage that well when performance testing hence the relatively poor 0-30 time
chard said:
jon- said:
chard said:
jon- said:
jimbobsimmonds said:
My understanding is down to greater transmission losses because the engine has to get all of those drive shafts and differentials up to speed as well...
I would agree, but only in a lesser powered car. Cars like the RS4 could spin all 4 wheels with ease, so any transmission losses are nullified. That said, I've not driven an RS4 so if you're saying a full RPM, side step the clutch launch wouldn't spin up all 4 tyres I'd believe you (but be a little surprised)
chard said:
jon- said:
jimbobsimmonds said:
My understanding is down to greater transmission losses because the engine has to get all of those drive shafts and differentials up to speed as well...
I would agree, but only in a lesser powered car. Cars like the RS4 could spin all 4 wheels with ease, so any transmission losses are nullified. 
Someone had better tell Porsche then - 997 Turbo S - 0-60 2.9 secs.
If you had ,say a 2wd and a 4wd Sapphire Cosworth then I would say extra weight and transmission losses would account for the difference - the 4wd had 20bhp extra ,but was 0.5 of a second slower to 60mph.
I am sure I read that a degree of wheelspin is desirable to get the best time, and it is obviously harder to achieve that in a 4wd car.
If you had ,say a 2wd and a 4wd Sapphire Cosworth then I would say extra weight and transmission losses would account for the difference - the 4wd had 20bhp extra ,but was 0.5 of a second slower to 60mph.
I am sure I read that a degree of wheelspin is desirable to get the best time, and it is obviously harder to achieve that in a 4wd car.
jon- said:
pwd95 said:
It's all down to the laws of Physics chaps.
Are there any 4x4 dragsters?.........
Ask the dragster guys why............
Explain Are there any 4x4 dragsters?.........
Ask the dragster guys why............
busta said:
jon- said:
pwd95 said:
It's all down to the laws of Physics chaps.
Are there any 4x4 dragsters?.........
Ask the dragster guys why............
Explain Are there any 4x4 dragsters?.........
Ask the dragster guys why............
jon- said:
busta said:
jon- said:
pwd95 said:
It's all down to the laws of Physics chaps.
Are there any 4x4 dragsters?.........
Ask the dragster guys why............
Explain Are there any 4x4 dragsters?.........
Ask the dragster guys why............
I'd say in performance road cars, 4wd does not hurt 0-60 times but mechanical sympathy does. Type 'RS4 launch' into youtube and you get a few videos of gentle rolling starts. Type in 'M3 launch' and you get screeching tyres and long black lines
4wd just needs a better clutch.
My old evo 9 gt with just over 400hp had launch control and a twin plate clutch (cant remember the brand now, carbonetics iirc) and that was nothing short of brutal when launched. A chirp of wheelspin. no bogging (if you got it right) and within a split second you are long gone.
Launching any car doesnt do it any favours though and imo will need a better clutch. I had a stripped out 335hp e36 m3 and that could be launched as well as the evo, it was just a very fine balance between a chirp at the wheels or a full burnout.
My old evo 9 gt with just over 400hp had launch control and a twin plate clutch (cant remember the brand now, carbonetics iirc) and that was nothing short of brutal when launched. A chirp of wheelspin. no bogging (if you got it right) and within a split second you are long gone.
Launching any car doesnt do it any favours though and imo will need a better clutch. I had a stripped out 335hp e36 m3 and that could be launched as well as the evo, it was just a very fine balance between a chirp at the wheels or a full burnout.
m3jappa said:
4wd just needs a better clutch.
My old evo 9 gt with just over 400hp had launch control and a twin plate clutch (cant remember the brand now, carbonetics iirc) and that was nothing short of brutal when launched. A chirp of wheelspin. no bogging (if you got it right) and within a split second you are long gone.
Launching any car doesnt do it any favours though and imo will need a better clutch. I had a stripped out 335hp e36 m3 and that could be launched as well as the evo, it was just a very fine balance between a chirp at the wheels or a full burnout.
My EVO 9 has 400/400 but I have resisted a full on launch in the dry! Clutch being the weak point on the EVO with that sort of start!My old evo 9 gt with just over 400hp had launch control and a twin plate clutch (cant remember the brand now, carbonetics iirc) and that was nothing short of brutal when launched. A chirp of wheelspin. no bogging (if you got it right) and within a split second you are long gone.
Launching any car doesnt do it any favours though and imo will need a better clutch. I had a stripped out 335hp e36 m3 and that could be launched as well as the evo, it was just a very fine balance between a chirp at the wheels or a full burnout.
I don't really need to try this though because as soon as it's rolling and you nail it, it's pretty much gone like a stabbed rat!
24k miles and on the original clutch. My car is meant to be capable of a 4.3 0-60 time, but I have never felt the need to prove this.
I could get a bomb proof clutch fitted and give it some abuse but then it would just transfer the shock to some other part of the drive train.
It goes like stink as it is so I am quite happy with it.
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