RS4 B7 Stated Power claim of 420ps

[ArthurPE]

That's not my experience, but my experience is from a couple of decades ago. In those days, BMW M3 engines were rated at 220ps (considered a limit for 2.3litre engine), but most made just over 200ps. I was fortune enough meet the BMW motorsport engineers who explained that some engines were given special treatment to produce the stated ps. NO production engine output 244ps as per your suggestion. You misunderstood what I had said about the 10% variance permitted - it was within 10%, not an average.

To increase power, they were forced to increase cubic capacity to 2.5, and this output 238ps.

Things may have changed, but why are we geting all this debate about RS4 engines?

I am not an engineer, or technically minded.

then you are incorrect...it's a tolerance +/-, not only on the low side...
as were the BMW engineers if this is a true representation...
anything else would make no sense and have no value...meaningless

it's the law, not conjecture...the link to the EU/EEC mandated testing procedure was linked here multiple times...it must be carried out by a 3rd party, not the manufacturer

a RR tests by ramping up and holding peak for <1 sec, then shutting down...the engines are tested for rating by holding peak power stabilized for 1 minute...with no rpm variation...big difference...

the control systems have no time to stabilize in <1 sec...I guarantee if you held the engine at 7500 rpm the HP would climb with time, to a peak of 400+...problem is the local dynos can't dissipate the power >308 KW, the machine would explode...

things haven't changed...a rating has always been based on an average of samples...some above, some below, the average ~ the rating...
basic manufacturing engineering...
with current tolerance that's +/- 3% on these engines...

the debate? the ill informed....or those with an agenda
btw, it's obvious you're not an engineer

[ArthurPE]

I call BS...and troll

I shall ignore that comment this time.

use the OBC, it will be more accuarte, better view of the tach

I had pretty accurate timings, a good view of the rev-counter

don't

were they in the back seat?
otherwise they were seeing it at an angle, could be off a couple 100 rpm...

[ArthurPE]

The RS4 engine is SAE cetifed/rated for 420

excerpt:
A new twist to the horsepower standard is a practice called "SAE certified." Under this optional program, an automaker allows an SAE-designated third-party witness to verify that an engine produces the advertised figure. Engines that have undergone this procedure carry the badge "SAE certified."

Since minute differences in the dimensions of engine components that naturally occur during series production—the compression ratio could be a smidge higher in one engine versus another—can result in two identical-looking engines making slightly different horsepower, the SAE allows a one-percent tolerance between the number that the witness observes and the horsepower rating that a manufacturer chooses to publish.


How the RS4 is rated in Europe:
Interestingly, the new SAE standard is closer to the European procedure, which is EEC 80/1269. There are minor differences. For example, the exhaust configuration and the specified fuel-quality requirements vary, and these can have an effect on horsepower. But we're talking about small differences, possibly accounting for a less-than-one-percent variation.

But it wasn't that simple with Porsche's latest 911. When we first previewed the car (Upfront, July 2004), Porsche said the 3.6-liter flat-six made 325 PS. We dutifully did the conversion and printed 321 hp. Then, a couple months later, Porsche released the SAE figure and said the new 911 made 325 hp, 4 hp up on our number.

When asked about this discrepancy, Porsche responded cryptically that its engine delivered 325 hp, suggesting perhaps that the company slightly underrated its engine in a manner similar to what Dodge had done in the V-10 example previously mentioned. Regardless of what Porsche said, we continued printing 321.

Porsche is not unique in this matter. Audi also claims the same figures in PS and hp. However, Audi says it retunes its engines for the U.S. market and that's why its engines have identical PS and hp ratings.

[mark758]

Sims, so I have this clear... you post on a forum, decide to leave your pc, lock the house up, drive to a suitable road, find clear traffic 5 times, do 5 timed runs to 8000 revs in your car, complete a return drive home, get back in and post the results all within 23 minutes?

In the words of Peter Jones..... Can I just stop you there, I've heard enough....I'm out!

I'll leave you to enjoy an RS4 hitting 100 in under 11 seconds but fully appreciate they have probably tried several cars and only picked the 'best' one
http://www.youtube.com/watch?v=iEsSwxw1DWU

[psg001]

this is getting a bit ridiculous! I know the title of the thread is about the power output, but really, who cares exactly what its putting out.

If you are not happy with the power of your car that you have bought, take it back / sell it. the fact that most of the users on here are still here and happy with their car tells u something -

1) they are happy with their car and performance
2) it delivers in more areas than just raw power and is more than a match for its competitors in terms of power / handling / practicality / class / comfort / sound / enjoyment etc...

i've driven new 911's, the E92 M3, the E46 M3 ( a lot!) and obviously own an RS4. It feels like its putting out about the right power to me. not scientific at all i know, but one thing I seriously doubt audi are underquoting would be the cars weight. If it can perform as it does and its about 1650kg, I think its either the most efficient 300 bhp car in the world or its actually doing the business!

[Sims]

this is getting a bit ridiculous! I know the title of the thread is about the power output, but really, who cares exactly what its putting out.

If you are not happy with the power of your car that you have bought, take it back / sell it. the fact that most of the users on here are still here and happy with their car tells u something -

1) they are happy with their car and performance
2) it delivers in more areas than just raw power and is more than a match for its competitors in terms of power / handling / practicality / class / comfort / sound / enjoyment etc...

i've driven new 911's, the E92 M3, the E46 M3 ( a lot!) and obviously own an RS4. It feels like its putting out about the right power to me. not scientific at all i know, but one thing I seriously doubt audi are underquoting would be the cars weight. If it can perform as it does and its about 1650kg, I think its either the most efficient 300 bhp car in the world or its actually doing the business!

Clearly you have not read my posts in this thread. Most people are very happy with the RS4 package, but there are many who are unhappy about the DRC issue (an engineering matter) and the power output. Please do a search and you will find more than just 1 person raising questions, many questions. You have a right to be content with what you have have, but if Audi found a way for more power to unleashed from this very same engine, would you be in the queue?

[Sims]

Sims, so I have this clear... you post on a forum, decide to leave your pc, lock the house up, drive to a suitable road, find clear traffic 5 times, do 5 timed runs to 8000 revs in your car, complete a return drive home, get back in and post the results all within 23 minutes?

43 minutes, but don't let facts get in your way.

[Sims]

It is obvious there is a lot of debate on the issue about the power output. Tuners relish this, and people have tried additives etc to mitigate the issues with the carbon build up. This issue was raised with Audi America.

Has anyone ever raised this issue with Audi UK or Germany?

Does anyone know what the German forums are saying about this issue?

[P_G]

Regarding DRC 'issue' there was a common fault in the DRC vs II which was put on RS4's, this has been identified and the modified part has been instralled on those with the fault.

There appears to be few of at all any people with the modified parts who have subsequently experience failure in the system again.

So getting back to power output, have you done your timings yet?

[HYFR]

power output power output!!

where is the proof!!! Dyno's ?! there is already a world of argument that these cannot read the power accurately....perhaps on some models, but not on all

all the people unhappy with their power output are unhappy after a RR.

Is anyone really unhappy because their car feels slow, or they got outrun by an S4 with only 344ps??

no that i've seen

stay away from RR to get a power number, only use it to guage power increases after mapping

[Sims]

Regarding DRC 'issue' there was a common fault in the DRC vs II which was put on RS4's, this has been identified and the modified part has been instralled on those with the fault.

There appears to be few of at all any people with the modified parts who have subsequently experience failure in the system again.

Therefore that remains a worry.

So getting back to power output, have you done your timings yet?

Raining where I am, so perhaps not today.

[P_G]

How does it remain a worry when there is a fix 'should' it fail on a particular car? It then becomes as much of a worry as any other part wearing out or breaking on a car and given they are consumables, it will happen.

[P_G]

power output power output!!

where is the proof!!! Dyno's ?! there is already a world of argument that these cannot read the power accurately....perhaps on some models, but not on all

all the people unhappy with their power output are unhappy after a RR.

Is anyone really unhappy because their car feels slow, or they got outrun by an S4 with only 344ps??

no that i've seen

stay away from RR to get a power number, only use it to guage power increases after mapping

+1

[Sims]

How does it remain a worry when there is a fix 'should' it fail on a particular car? It then becomes as much of a worry as any other part wearing out or breaking on a car and given they are consumables, it will happen.

Ok I get it, absolutely no-one (apart from me) is worried about the DRC issue on the B7 RS4. Yet people have given up on it altogether.

I remain concerned for I do not put the DRC in the category of consumables in the accepted meaning of the term.

[HYFR]

i've had x2 RS 6 and now an RS 4.

I have not been worried in the slightest by the DRC...why, because it warrantied.

If it breaks, they fix it, then when they fix it, they warranty the new fix for 2 years. If its so bad, it will fail in 2 years, and so we go on again.

I have confidence Audi have sorted it, otherwise they would not have continued with it in their £80k flagship RS 6