4 wheel drive & the real world

[blearyeyedboy]

s m said:

blearyeyedboy said:

Sorry to bring this down to something much more mundane, but it's the best comparison possible: The 2wd and 4wd versions of the Skoda Yeti. It's not exactly the PH-stuff-of-dreams but the comparison weeds out a lot of variables.

Performance Car magazine did a similar 2wd vs 4wd test back in the 90s - they compared the 2wd and 4wd versions of the E34 525i.
Motor mag also did similar with the E30 325i/325ix

Cool, do you remember what they said?

[aka_kerrly]

blearyeyedboy said:

s m said:

blearyeyedboy said:

Sorry to bring this down to something much more mundane, but it's the best comparison possible: The 2wd and 4wd versions of the Skoda Yeti. It's not exactly the PH-stuff-of-dreams but the comparison weeds out a lot of variables.

Performance Car magazine did a similar 2wd vs 4wd test back in the 90s - they compared the 2wd and 4wd versions of the E34 525i.
Motor mag also did similar with the E30 325i/325ix

Cool, do you remember what they said?

It's not the BMW test that you were looking for but here is a link to a similar exercise with a Audi A6 1.8T in FWD and 4wd formats.

In summary after performing a variety of performance tests involving slalom, handling circuits, 0-30 sprints, 0-100-0 they came to the conclusion that whilst the quattro car had a slight advantage ranging from fractions of seconds to clear seconds on the different tests in everyday driving you will only notice a slight improvement in the ability to power out of corners and enjoy the confidence factor.

http://www.audiworld.com/tech/audi2.shtml

[blearyeyedboy]

^ Interesting. Has anyone got a similar RWD/4WD comparison?

[s m]

blearyeyedboy said:

s m said:

blearyeyedboy said:

Sorry to bring this down to something much more mundane, but it's the best comparison possible: The 2wd and 4wd versions of the Skoda Yeti. It's not exactly the PH-stuff-of-dreams but the comparison weeds out a lot of variables.

Performance Car magazine did a similar 2wd vs 4wd test back in the 90s - they compared the 2wd and 4wd versions of the E34 525i.
Motor mag also did similar with the E30 325i/325ix

Cool, do you remember what they said?

That's the summary page of the E30 test



The PC one I'll have to dig out

[blearyeyedboy]

^Ta muchly!

(Though you've got to feel sorry for the guy who listened to the scribe and saved £6k buying a 325i Sport instead of an M3... )

[Kawasicki]

s m said:

That's the summary page of the E30 test



The PC one I'll have to dig out

Results match my experiences 100%.

If the handling track was covered in mud, then maybe the 4wd would be quicker.

[aka_kerrly]

blearyeyedboy said:

^Ta muchly!

(Though you've got to feel sorry for the guy who listened to the scribe and saved £6k buying a 325i Sport instead of an M3... )

Absolutely! Had they invested in a M3 it could now be worth well over 10X as much as a decent 325I Sport

[blade7]

J4CKO said:

The ability to hoof out of a junction without having to worry about traction is useful but not essential, of course you can drive a 2wd car so it isn't an issue but a 4wd system gives you options to take gaps that you may leave in a 2wd car in case you end up in a flurry of wheelspin and/or traction control, despite driving god status nobody can pull out onto a wet junction in a 2wd as fast as a 4wd with the same power, its physics, being pushed and pulled, will work better in low grip situations the pushed or pulled.

On my weekly commute there's a big roundabout on a dual carriageway, when it's pissing down it makes my day when some billy big bks in a 3 series or hot hatch tries to bully my A4 avant out of the way approaching the roundabout. When they eventually catch up further down the road I wonder if they notice the quattro badge on the back .

[Kawasicki]

blade7 said:

On my weekly commute there's a big roundabout on a dual carriageway, when it's pissing down it makes my day when some billy big bks in a 3 series or hot hatch tries to bully my A4 avant out of the way approaching the roundabout. When they eventually catch up further down the road I wonder if they notice the quattro badge on the back .

Driver makes much more difference than car.

[blade7]

Kawasicki said:

blade7 said:

On my weekly commute there's a big roundabout on a dual carriageway, when it's pissing down it makes my day when some billy big bks in a 3 series or hot hatch tries to bully my A4 avant out of the way approaching the roundabout. When they eventually catch up further down the road I wonder if they notice the quattro badge on the back .

Driver makes much more difference than car.

Undoubtedly, plus they probably aren't expecting me to absolutely hoof it round the roundabout

[nickfrog]

s m said:

That's the summary page of the E30 test

The rwd version pulls 0.84g vs 0.80g of lateral for the 4wd.

So at 0.80g, ie using all the lat grip, the 4wd has nothing left for traction, ie it has ZERO traction whereas the 2wd still has a bit of adhesion left for a small throttle input / tractive force.

So to go back to the roundabout example above, the traction benefit may only be there because Berty Big bks actually has fairly small nuts and may have stayed well within lat acceleration limits instead of using all of it, which would have allowed him a higher apex speed.

Or better still go back to the P1 vs Point and Squirt debate. Presumably, the P1 has a humongusly larger amount of lat grip, it being in the dry or in the wet, due to the low COG, chassis balance, engine position, sophisticated kinematics/dampers/etc etc. So surely, traction management / modulation is going to be a very small issue for its (skilled) driver with so much in reserve.

Still, where's scherzkeks when you need him ? ;-)

Edited by nickfrog on Tuesday 28th January 01:07

[Mave]

Doubt it. 2g at speed means stiff suspension- hardly optimised for potholed B roads...

[Kawasicki]

nickfrog said:

The rwd version pulls 0.84g vs 0.80g of lateral for the 4wd.

So at 0.80g, ie using all the lat grip, the 4wd has nothing left for traction, ie it has ZERO traction whereas the 2wd still has a bit of adhesion left for a small throttle input / tractive force.

So to go back to the roundabout example above, the traction benefit may only be there because Berty Big bks actually has fairly small nuts and may have stayed well within lat acceleration limits instead of using all of it, which would have allowed him a higher apex speed.

Or better still go back to the P1 vs Point and Squirt debate. Presumably, the P1 has a humongusly larger amount of lat grip, it being in the dry or in the wet, due to the low COG, chassis balance, engine position, sophisticated kinematics/dampers/etc etc. So surely, traction management / modulation is going to be a very small issue for its (skilled) driver with so much in reserve.

Still, where's scherzkeks when you need him ? ;-)

Edited by nickfrog on Tuesday 28th January 01:07

Yes, the 4wd has significantly less lateral grip potential....but but but marketing said....

[PhillipM]

Mave said:

Doubt it. 2g at speed means stiff suspension- hardly optimised for potholed B roads...

Apart from a lot of that is generated from aero and active arb's. On bumpy roads I wouldn't discount the advantage that will still offer even with limited suspension travel.

Anyone trying to outpace a P1 even on a wet bumpy road in a standard scooby etc, is probably taking so many risks he's a hazard to everyone else on the road.

Edited by PhillipM on Tuesday 28th January 02:44

[jonno990]

997c2 vs 997c4 with The Stig driving
http://www.youtube.com/watch?v=mpa0SwE4CW4

[Shambler]

Kawasicki said:

nickfrog said:

The rwd version pulls 0.84g vs 0.80g of lateral for the 4wd.

So at 0.80g, ie using all the lat grip, the 4wd has nothing left for traction, ie it has ZERO traction whereas the 2wd still has a bit of adhesion left for a small throttle input / tractive force.

So to go back to the roundabout example above, the traction benefit may only be there because Berty Big bks actually has fairly small nuts and may have stayed well within lat acceleration limits instead of using all of it, which would have allowed him a higher apex speed.

Or better still go back to the P1 vs Point and Squirt debate. Presumably, the P1 has a humongusly larger amount of lat grip, it being in the dry or in the wet, due to the low COG, chassis balance, engine position, sophisticated kinematics/dampers/etc etc. So surely, traction management / modulation is going to be a very small issue for its (skilled) driver with so much in reserve.

Still, where's scherzkeks when you need him ? ;-)

Edited by nickfrog on Tuesday 28th January 01:07

Yes, the 4wd has significantly less lateral grip potential....but but but marketing said....

The tyres are quite different chaps

[BorkFactor]

For performance driving, RWD is better I think. Plenty of other people have illustrated why.

However for an everyday car that is usable in all conditions I would be picking AWD. Dad's A4 3.0 TDI is perfect for these duties with a set of Vredstien Quadtrack tyres - he drives all over rural Scotland throughout the year in all weathers and it is perfectly suited to the job. Sure footed, comfortable, and reasonably brisk when you need it to be.

I have driven it a lot, and to be honest 99% of the time I don't drive hard enough to really notice the drawbacks of AWD vs RWD.

So basically, it depends what you want the car for!

[Pints]

Vladimir said:

I am always amazed at how many people think RWD = immediate death.

My MiL is one of those. She's not hidden the fact that she's terrified my next car will be a BMW (because they're RWD, you know!) and the inevitable will happen while her beloved grandchildren are in the car.

Not sure whether to or

[Scuffers]

Shambler said:

I think if you are being honest, a good spec four wheel drive car such as the sti or evo in the wet on a country road will be extremely hard to beat. Did Chris Harris not say something similar in his review of the A45. The limiting factor for the P1 is it's size, width of tyres and road clearance.

blearyeyedboy said:

I think choice of tyres makes almost as much difference as drivetrain for the majority of people.

Mave said:

Doubt it. 2g at speed means stiff suspension- hardly optimised for potholed B roads...

Good to see some here have actually thought about it and come up with the pertinent points....

as an example of what I am getting at, if anybody has been to Bedford Autodrome for a trackday when it's wet, you will know that it get's somewhat slippery.

try driving an Elise on Pzero's round there and it's just comically slow, basically zero grip and even less traction - basically, too light a car on the wrong tyres, (I actually managed to out-corner them easily in a 2+ tonne Jeep)

in the dry, completely different story.

[bennyboysvuk]

RWD allows easy access to many roundabout exit drifts or the kind of exit of a roundabout where the steering points straight ahead and you finish the corner with the rear wheels. I've not had the opportunity to try power-sliding a powerful 4WD off a roundabout so don't know how it feels. Can anyone with an Audi RS model, GTR or FQ360 comment?

A small (or big) power-slide off a roundabout is great fun, but I would expect it to be nigh on impossible in a 4WD unless you gave it a serious scandinavian flick to get it going.