Mr2 Mk1.5 vs Audi RS4

[Charged]

I was heading around a round about heading onto the motorway, driving sensibly and going past an Audi RS4 (estate) in the inside lane who was in the lane to go the opposite way down the motorway to me, I thought nothing of it until he put his foot down, cut in front of me and was in front of me heading down the slip road I was now on.
The slip road was a slight corner and my passenger and I could see the Audi twitching, he was right on the limit. I put my foot down as soon as I could, didn't want to lose the back end on the corner , 2nd gear, 3rd gear, starting to gain at the top of 3rd, by 4th gear we had caught up with him and had to slow down as we were almost on the motorway. Me and my passenger laughing our heads off, the mighty little Mk1 had claimed a big scalp there!
The Audi owner seemed less than impressed that he hadn't blown us away and instead of slowing when entering the motorway, kept his foot flat, went into lane one, then two, then got blocked and back into lane one, then onto the hard shoulder kicking up a lot of gravel and then pulled violently back into lane one, and then out to lane three.
I had proved my point down the slip road so let him get on with it but what an absolutely nutter! Really, really dangerous driving. The only time I've seen anything like it is on police camera action!

I am very pleased with the way my 1.5 performed, as mentioned I had a passenger and also the car was filled with equipment, bags etc..

Mr2 Mk1.5 1 Audi RS4 0

[matt_mr2t]

Definately an RS4 and not just an S4? There's a few different variants of both but i believe the hottest RS4 is 420 bhp V8 and would think in gear and rolling it'd be pretty damn quick. I saw an RS6 on the M1 last weekend. It was earily quiet for something packing a 572 bhp 5 litre V10! Think it was just coasting along in fairness.

[GBTurbo]

Hard shoulder

Bit extreme! Somebody tried to undertake me the other day just before we went into a national speed limit

Stupid TDCI mondeo got made to look like a fool with his girlfriend in the car aswell!

[Charged]

Definately an RS4 and not just an S4? There's a few different variants of both but i believe the hottest RS4 is 420 bhp V8 and would think in gear and rolling it'd be pretty damn quick. I saw an RS6 on the M1 last weekend. It was earily quiet for something packing a 572 bhp 5 litre V10! Think it was just coasting along in fairness.

One of these Matt:

http://www.pistonheads.co.uk/sales/1718540.htm

I've had a run in with an S4 before and it couldn't keep up at all.

Bare in mind the power to weight ratio of the Mk1 with a 3sgte fitted, and of course my amazing driving skills

[Charged]

Hard shoulder

We couldn't believe it.. I felt sorry for the people in lane one who must have been showered in stones that it was kicking up. Very violent lane changes as well, we were convinced he was going to lose it, my passenger was screaming, "he's going to die"!!

[matt_mr2t]

Definately an RS4 and not just an S4? There's a few different variants of both but i believe the hottest RS4 is 420 bhp V8 and would think in gear and rolling it'd be pretty damn quick. I saw an RS6 on the M1 last weekend. It was earily quiet for something packing a 572 bhp 5 litre V10! Think it was just coasting along in fairness.

One of these Matt:

http://www.pistonheads.co.uk/sales/1718540.htm

I've had a run in with an S4 before and it couldn't keep up at all.

Bare in mind the power to weight ratio of the Mk1 with a 3sgte fitted, and of course my amazing driving skills

Those are 375bhp and about 1.6t so power to weight is 234bhp per tonne. What's yours?

The good thing about those older model RS4's is that being turbo they're much easier to get up to and way past the 420bhp the V8 model has. Although never in a month of Sundays will it sound is good.

[Charged]

Those are 375bhp and about 1.6t so power to weight is 234bhp per tonne. What's yours?

260BHP and maybe just over 1100kgs, both guesstimates though..

[matt_mr2t]

Those are 375bhp and about 1.6t so power to weight is 234bhp per tonne. What's yours?

260BHP and maybe just over 1100kgs, both guesstimates though..

236bhp per tonne then Couldn't be closer matched if you tried.

[toxo]

Those are 375bhp and about 1.6t so power to weight is 234bhp per tonne. What's yours?

260BHP and maybe just over 1100kgs, both guesstimates though..

236bhp per tonne then Couldn't be closer matched if you tried.

Don't forget transmission loss... RS4 is 4wd isn't it (maybe even Haldex), so will have much higher losses to the wheels than Ollie's 16%.

[matt_mr2t]

260BHP and maybe just over 1100kgs, both guesstimates though..

236bhp per tonne then Couldn't be closer matched if you tried.

Don't forget transmission loss... RS4 is 4wd isn't it (maybe even Haldex), so will have much higher losses to the wheels than Ollie's 16%.

16% is a bit of a made up pub stat though isnt it, lets face it. And measuring it as a % means that a standard rev 3 would lose 39bhp but a 1k hp drag monster would lose 160bhp. Where is the extra power being lost?

And there's other things to consider in 2wd transmission losses vs 4wd losses. Like on a 2wd car the driven wheels are working extra to move the undriven wheels which themselves suffer more friction on the road. A 4wd car is proven to have less of an issue there. So it can be argues the power loss is countered by the decreased friction.

IMO it really isnt ever as simple as "less power is lost on 2wd cars"

If 4wd was so bad it wouldnt be used so widely.

[toxo]

16% is the calculated difference between flywheel and wheel power on all the rolling road runs I've done in my MK2 with an E153 box, which is the same box Ollie is running... I'm happy to accept that as a reasonable figure. Friction between surfaces causes kinetic energy to be transferred into heat energy, the more friction = the more energy lost via it. A 1000bhp drag car is going to be putting the power into the gearbox faster, generating the same amount of friction over a much shorter period of time, thus generating more heat and losing more power.

A 2wd car has fewer gearsets between the flywheel and the wheels than a 4wd does... in fact if the Audi is running Haldex 4wd then it will have at least 2 if not 3 electronically controlled diffs as well as the gearbox. That's a lot more places to generate friction and heat, and thus a lot more places to lose power.

[matt_mr2t]

I dont doubt there are more power losses mechanically (and electronically) on 4wd cars. But you cant ignore the fact that 2 wheels are causing substantially less friction on the road once moving which completely changes the line of thinking.

[matt_mr2t]

Btw, the RS4 has a longditudinally mounted engine, so I could be wrong, but think that rules out Haldex?

[toxo]

Btw, the RS4 has a longditudinally mounted engine, so I could be wrong, but think that rules out Haldex?

Yeah, I did some more reading and you're right... it has a Torsen centre diff.

[matt_mr2t]

I guess the best way to do it is the Skyline way with it running 2wd most of the time only the 4wd kicking in when it loses traction. Although you still get the additional weight of the 4WD running gear.

[toxo]

See that's what Haldex does... except it's FWD most of the time and switches the power about when it detects wheel slip. I guess due to the fact that most people are used to FWD and having it that way round feels more comfortable.

[matt_mr2t]

That might also have something to do with the engine mounting, I think the ones that run FWD are transverse and the ones that run rwd are longditudinal. Although I could be wrong there. Thats not Audi specific, thought that was for all 4wd cars that run part time 2wd.

The Nissan GTR is a bit mad. Engine longditudinally mounted up front, prop shaft going to the rear for the rear mounted gearbox then another propshaft going back to the front to power the front wheels. Must be epic mechanical transmission losses there

[toxo]

The Nissan GTR is a bit mad. Engine longditudinally mounted up front, prop shaft going to the rear for the rear mounted gearbox then another propshaft going back to the front to power the front wheels. Must be epic mechanical transmission losses there

Ford RS200 did that, except the other way round, engine at the back and gbox at the front.

[BarronMR]

The Nissan GTR is a bit mad. Engine longditudinally mounted up front, prop shaft going to the rear for the rear mounted gearbox then another propshaft going back to the front to power the front wheels. Must be epic mechanical transmission losses there

I don't think there'll be any more significant drivetrain losses than usual 4wd setup. Drivetrain losses are the result of frictional losses caused by mechnical devices. By my count the standard 4wd setup has 1 gearbox, 2 diffs and 4 hub assemblies, as does the GTR setup. The extra shaft length between the engine and gearbox will be insignificant.

[matt_mr2t]

The Nissan GTR is a bit mad. Engine longditudinally mounted up front, prop shaft going to the rear for the rear mounted gearbox then another propshaft going back to the front to power the front wheels. Must be epic mechanical transmission losses there

I don't think there'll be any more significant drivetrain losses than usual 4wd setup. Drivetrain losses are the result of frictional losses caused by mechnical devices. By my count the standard 4wd setup has 1 gearbox, 2 diffs and 4 hub assemblies, as does the GTR setup. The extra shaft length between the engine and gearbox will be insignificant.

Are you sure?

How does that explain torque steer, which is caused by unequal length drive shafts resulting in more torque being delivered to one wheel than the other?