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Discussion Starter · #1 ·
Just a few thoughts about the hopefully soon to be "RS5".... if the M3 is infact faster then the R8-and the RS5 is being built to be a M3 competitor-the RS5 should be faster then the RS4-so that would mean that the RS5 would be faster then the R8(and any other production audi)

to me this doesnt make sense-if the R8 is suppose to be audi's "supercar" or high end sports car--their 2 door coupe shouldnt be faster then it-They need to up the ante on the R8 in my opinion......

-or I could just be rambling and not making any sense lol
 

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In the early UK A/S5 guide last year there were two engines listed for the S5. It was prefixed W something. W10 or W11 or something like that. By the July guide it was removed (the S-line model was in the early UK guide as well). I wouldnt be surprised if Audi plan to offer improved engines but are not ready to yet. Havent they had problems with the "Wxx" engine catching fire?

Both S5 and R8 are early in their life and they both have healthy waiting lists. The engines will change but Audi have a chance to sell the current range under high demand and then breath new life into the car later with new engines. Many of those that bought in 2007 will buy again when the spec/engine improves.
 

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Are you sure that the M3 is faster than the R8? I doubt it..
 

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The E92 M3 is not faster than the R8, not in a straight line or on the track, on the same track the M3 is a good few seconds slower, and a few seconds on a track is an eternity.

Also the R8 will have a Twin Turbo V10 next year as in the RS6 so will kick out 570+ bhp.

Lastly, it's not always about speed when people buy cars, the way the car drives and feels is a big factor. Hell thats why you don't see everyone running after the Nissan GT-R even though it can keep pace and even beat a 911 Turbo for half the money.
 

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Discussion Starter · #5 · (Edited)
2008 M3 Coupe

Audi R8 4.2 FSI





....as I said, the M3 is faster then the R8 lol (this test appears to be a straight line-around the track I'm sure the R8 is faster)

but even so-The M3 appears to be measuring up to the perforance of the R8




for anyone who wants it

S5
2008 Audi S5




....I understand that its not only about speed-just making a fair comparison because there's alot of talk going around about the RS5 being faster then the current M3-and it just appears that its not gunna be that way(as of right now)
 

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interesting...

i notice that there is a 1900 ft difference in elevation between the M3 and the R8 tests.... could that explain some if not all of the performance difference?
 

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Discussion Starter · #7 ·
....not sure- i dont know how much the would effect the results-nice catch though----maybe someone in here could help with the comparison
 

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Ask Graham... He's a fluid dynamiscist... he should be able to tell us the difference in air density... we should then be able to do some calcs... but the water content will make the biggest difference... I bet we have no relative humidity figures for the test?
 

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actually, the relative humidity is listed....

R8 was tested at 16%
M3 was tested at 59%

not sure how to interpret that tho...
 

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Discussion Starter · #10 ·
These test results are pretty interesting though.....wish we could contact road and track about the results or maybe even a restest lol with more similiar testing conditions
 

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actually, the relative humidity is listed....

R8 was tested at 16%
M3 was tested at 59%

not sure how to interpret that tho...
'
That's a massive difference... Graham could probably tell you the difference that would make to the compression ratio, but FWIW I would expect that difference to be worth quite a bit... especially when you consider the air density differences too... could be as much as 10%... or 40+ BHP.

Ambient temperature makes a difference too, as the temperature of the 'charge' can make a few percent difference.

I must apologise, I still haven't read the test results on this thread as I have been a little busy, but will take a look later in the week.
 

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OK... It was killing me I took a look... here's my £0.02

The test results are as near as damn it identical, given the variations in temp, elevation, air density etc and also the tests took place in different place, so the road surface etc will make a difference...

Given that the conditions ARE favourable for the M3 especially the air temperaure, which will help the road temperature and thus traction off the line and grip on the skid pan and slalom... where the R8 was damn near freezing I think that yes, the M3 is fast, but in identical conditions the R8 would edge it... Although you can see that once in gear, the M3 is very rapid... for a car that's 100kg heavier with less BHP... probably because the R8 is 4WD.

The tests do not really show the difference between the cars however. Skid pan Gs and slalom are not great indicators of how fast they are to drive, just a comparative measure... I would hazard a guess that iff you took the Astra VXR it would pull figures close to this.

Brake and turn-in, traction on exit etc. are what makes a car/driver fast, not the in-corner speed, so the only real way to make a comparison is to stick 'em on the same track on the same day.

...Either way, it shows that whatever, the M3 is bloody quick.

...It also shows that the S5 isn't that far behind either car!
 

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Well, Graham isn't the only aerodynamic type on the board. My help wasn't solicited, but I'll butt in anyway...

The standard-day pressure at 57°F and 650 ft (the M3 test) is 14.3 psi. The density of that air is 1.20 kg/m^3, or 98.0% of that at standard seal level conditions.

The standard-day pressure at 36°F and 2550 ft (the R8 test) is 13.4 psi. The density of that air is 1.17 kg/m^3, or 95.3% of that at standard seal level conditions.

So the air the R8 was using was 2.5% less dense, and the pressure was lower by 6.3%. That's certainly enough to notice.
 

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Well, Graham isn't the only aerodynamic type on the board. My help wasn't solicited, but I'll butt in anyway...

The standard-day pressure at 57°F and 650 ft (the M3 test) is 14.3 psi. The density of that air is 1.20 kg/m^3, or 98.0% of that at standard seal level conditions.

The standard-day pressure at 36°F and 2550 ft (the R8 test) is 13.4 psi. The density of that air is 1.17 kg/m^3, or 95.3% of that at standard seal level conditions.

So the air the R8 was using was 2.5% less dense, and the pressure was lower by 6.3%. That's certainly enough to notice.
Actually Graham isn't a fliud dynamiscist, he's an engineer who speicialises in optics! but fortunatly I've been rescued by aerodave! However I agree with Ian that the humidity would probably make the largest difference by reducing the charge inlet temp etc, etc. ( we all know how much better our engines perfom in foggy wheather. Shame you can't see where you're going enough to use it! ) I also think that the compression "ratio" in the cylinders probably remians the same, as the swept volumes are the same, but the 6.3% higher atmospheric pressure must obviously add to the total charge density.
Anyway, in my judgement, when you take all aspects of the appeal of a car into account, the M3 ( although a fantastic performer ) hasn't got waht the S5 has.
 

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Graham... sincere apologies. I don't know where that silly idea came into my head???

...You are right... the 'ratio' remaind the same but the charge is affected by the pressure and temperature, meaning that you get more fuel and air at high pressures and low tempratures... The humidity adds water to the charge, which does not compress, increasing the pressure in the cylinder, and then vapourises on ignition, increasing the force generated by the expanding gasses.
 
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