Traction
 

Was pondering whether its worth looking at a 4wd car over a 2wd car, say an S3 versus a Leon Cupra R.

I have a Saab turbo and its rubbish at putting its power down, I had a T5 which was also bad, a Fiat Coupe that once it had some decent tyres on was ok for a 2wd turbo car.

So, say you had two identical cars, one with 2wd and one with 4wd, does the 4wd have twice the traction, or more ?

I can do without pulling out of a wet greasy junction and staying still, this is a problem for all cars but especially front wheel drive ones with turbos, the new gernation diesels suffer as well, my wife has problems getting her Sharan to move (in the wet) without it spinning the front wheels.

So will a 4wd car with 225 bhp experience as much wheelspin as a 2wd car with 112 bhp (say like a MK2 Golf GTI 8 valve which is afflicted by wheelspin of the front wheels) and say a MK2 Escort RS2000 which has a similar problem at the back, or due to torsen diffs and stuff is it more complex than that to the point where you get more than double the traction, allowing also for better tyres and electronic aids.

At what ammount of horsepower does it start to be a problem again as I am sure that anything with say 500 bhp will experience so kind of traction issues.

Also, for moderate power cars, 250 bhp or less, do 4wd systems give much trouble, I know most Calibra turbo's ended up 2wd due to the transfer box being crap, I remember old Audi's 4wd's having problems with the Torsen diff if the tyres were a few mm more worn one end to the other, is that still the case ?

MY experience is that 4 wheel drive is amazing for pulling out of greasy wet junctions.i have pulled across junctions with huge trucks bearing down on me with 100% confidence.minimum wheelspin then off like a rocket.this was on my old impreza.my honda civic type r was a royal pain in the arse wheelspining everwhere.

Depends on the road. In a straight line AWD is amazing. I would say the result of AWD is greater than the sum of its parts. Even 90bhp in front wheel drive is a nightmare to put down in the wet. Add 2 more driven wheels and you can put down 300bhp without too much trouble in the wet.

Handling is another matter.

I've had 3 AWD cars - a Cavalier 4x4, a Scorpio 4x4 and a Scooby L-series which was part time AWD - normally FWD. The Cavalier was incredible - it had the 130bhp SRI engine and you could boot it out of a wet junction with not a hint of wheelspin.

I've now got an Octavia vRS with 231bhp/251lbf, In the dry you can't give it full welly until you're into 2nd and doing about 40 mph. Then it takes off :norty::norty:

In the wet...................I've seen the ESP warning light coming on at 70mph in 3rd giving it stick in a straight line :eek::eek::eek:

Weight transfer is worth considering. On acceleration the weight is transferred to the back, unloading the front wheels. And FWD is worse still if there is no LSD because the front inside wheel unloads in a corner and squeals away the torque. RWD with an LSD seems to have much better traction, but the oversteer isn't always fun in adverse conditions. A nice neutral AWD setup may not be as much "fun" but for safe progress in average hands it is great.

John, yep, average hands over here !

The S2000 has an LSD and has excellent traction in the dry in a straight line. You have to monumentally dump the clutch to break it. It is also very progressive and predictable when cornering in the dry with break away and oversteer being manageable unless you do something silly. The bonus of the LSD is no one wheel is spinning like a maddie.

In the wet though you can't escape the fact that there isn't much actual weight over the rear as there would be with an MR car and as a result she'll spin pretty easily. All and all I'd say traction is no better or worse that it was in my VTS in the wet but in the dry the S2000 posted much better 60ft times and was quicker off the line when launched. In fact, the S2000s dry 60ft times were not a million miles away from my Scooby's. In the wet through the Scooby was great - i used to launch off the lights all the time when wet :D

So, is it possible that a 4wd car may actually post a better 0-60 on a damp/wet road as the wheels can spin a little keeping the engine from bogging down ?

I think so, my 0-60 in 3.97, 0-100 in 8.7 and 0-125 in 12.1 was done in damp conditions with Andy F and his AP22 in the passenger seat with "only" 434 BHP.

That will give me something to look farward to when i have my vRS remapped then wont it :D

I think it depends on the set up of the car. My scooby had a TDO4, decat and JB ecu fettling and I would say it was quicker in the dry. It was fun spinning all 4 wheels in the wet but ultimately overall acceleration was compromised through loss of traction. In the dry you could ping the clutch from around 4000rpm and the car would hammer off the line with 'churping' from the wheels and critically very little lag from the small decatted turbo.

I'm sure one of the magazines did their 0-60mph test on a standard 1997 turbo and posted 5.3 seconds in the wet :)

As a Gtir owner can I ask "what's wheel spin?"

I was at Elvington last year in the monsoon that saw AndyF go off backwards and I was only 0.2s slower in the wet than in the dry (mainly due to my standard clutch slipping) . Having been timed since, I know that was sub 4s to 60 in the pouring rain.

I can say this isnt a problem in my 1.0 Nova winter hack so 40BHP is a safe bet..

Any one want to swop there dangerous turbo FWD car for it?

Ill throw a packet of McCoys in on the deal,beef flavour, still in the glove box.

After driving many of both, awd is definatly better for day to day road driving.

Worst I ever experience was a an old Supra turbo with bodged mods to make it faster (wastegate fiddled with so it wouldnt open) on budget tyres on a damp road, truly terrifying, at 70 mph if you booted it, it would attempt to rapidly swap ends

:norty::norty::norty::norty: