Graph: RS4 Power, torque curves and other interesting data

[Erik]

Test performed by Rototest (very reliable) for AMS Sweden.

Click on the link, loads of interesting data.

http://www.rri.se/popup/performancegraphs.php?ChartsID=261

http://www.rri.se/spec/view/jpg/overviewimage/STR-06021701-im.jpg

Speedometer
Reading, km/h (mph)

at 50 (31) +3 (+2)
at 70 (43) +3 (+2)
at 90 (56) +4 (+2)
at 110 (68) +5 (+3)
at 130 (81) +10 (+6)

http://www.rri.se/spec/view/png/graph/STR-06021701-kW-Nm-C.png

[Julz RS4]

This is a very useful Dyno charts of the new Audi RS4. Thanks mate. :0: :rs4addict

[Benman]

Nice. I gotta admit, I never thought that engine would make 317lb/ft.:thumb:

Ben:addict:

[Goldorak]

Anyone else disappointed with the results? 18% power loss and 13% torque loss from the claimed figures seems like a lot.

Having never heard of a Rototest dyno before at first I thought it was just normal power loss for AWD but looking at other AWD car tests on their website it seems this is a much larger loss than most.

One possible explanation is the test car only had 1080 km(667 miles).

Upon further digging the Lexus RX300 Auto did worse(-21%/-19%) but that's about it. Thoughts?

[Goldorak]

Originally posted by Benman
Nice. I gotta admit, I never thought that engine would make 317lb/ft.:thumb:

Ben:addict:

It only produced 277.:vhmmm:

[Benman]

Originally posted by Goldorak
It only produced 277.:vhmmm:

To wheels yes, but not at crank, no?

Their graph shows 317?

Ben:addict:

[Goldorak]

That's simply Audi's claims superinposed on their wheel hub measurements to show the difference. If Audi had said 500 that's what it would say, note Stated engine performance.

To further establish just how poorly the RS4 tested take a look at this pdf document (http://www.rri.se/function/functiondownload.php?FileName=EDU-PTP-N05061201-WP&FileType=pdf&WhitePaper=WhitePaper). At the bottom there is a result based distribution chart of all the cars they've tested. Looks like less than 5% did as poorly as the RS4 on power and around 15% did worse on torque.

"In the end of the graph we find the discrepancies of more than 10-15%(depending on powertrain design) and there we have the bad transmissions and/or the engine performance cheaters." Ouch.:eek:

[Goldorak]

After looking at all the RS4 graphs, one discrepancy bothers me. If you go to the "available downloads" tab you can download the full graphs in whatever measurements you prefer.

I'll use the PS power output measure since this seems to be what is used in NA. Max horsepower of 349.3 is achieved at 7546 RPM. However in the overview tab the power figure given is only 342 since it is quoted at 7237 RPM. Why would they use a suboptimal RPM level?:confused:

Anyways this would only drop the power loss down to a rounded 17% figure, still not very good.:cry:

[Benman]

Originally posted by Goldorak

I'll use the PS power output measure since this seems to be what is used in NA. Max horsepower of 349.3 is achieved at 7546 RPM. However in the overview tab the power figure given is only 342 since it is quoted at 7237 RPM. Why would they use a suboptimal RPM level?:confused:

Anyways this would only drop the power loss down to a rounded 17% figure, still not very good.:cry:

So 17% drive train loss isn't good? I thought people were saying the :addict: looses 20%+?

Ben:addict:

[Goldorak]

Originally posted by Benman
So 17% drive train loss isn't good? I thought people were saying the :addict: looses 20%+?

Ben:addict:

Ben, you have to compare oranges with oranges or else you end up with fruit salad.;)

This particular dyno measures at the wheel hubs and shows an average power loss of 9% compared to the manufacturer's claims(as documented in the pdf file I linked). Rolling rock dynos will show a greater loss but even then the figures will vary based on the brand of dyno used and the conditions. Lastly automatics usually have more drivetrain loss.

The key here is all the cars seem to have been tested very competently with accurate instrumentation in a controlled environment and comparatively speaking the RS4 has done very poorly in regards to Audi's power claims.

[Benman]

Originally posted by Goldorak
This particular dyno measures at the wheel hubs and shows an average power loss of 9% compared to the manufacturer's claims...

The key here is all the cars seem to have been tested very competently with accurate instrumentation in a controlled environment and comparatively speaking the RS4 has done very poorly in regards to Audi's power claims.

Ahh... I see what you're saying.:thumb:

Ben:addict:

[skratch]

how acurit are wheel hub dynos compared to rolling drum dynos

there is an m5 on there that spun 472ps on that site

130 ps to the wheels more than the rs4

either there dynos read high or the m is underated

there is also a cls 55 amg that put down 453 ps

[7:53 RS6]

This is what AMS swedish version is saying about the issu.

AMS saying RS4 only has 349hp on wheels, and that this is a lost of power on 17% which they think is way to much. Lost of tourq is 13% at wheels. To sum it up they mean it could never be 420hp in engine. They also say it cut by 8050 rpm in test which is 200 rpm before whats stated. Its a manual awd so RS4 is in AMS words in doubt aproved in this rotortest.

[Spada]

What confuses me is how this can be true when you compare it to the actual performance. There's a test between the rs4 and an m5 that someone has posted here and the rs is only marginally slower. It is in fact faster to 60. So how can this be if it's apparently developing so little power? My rs4 feels substantially more powerful than my old b6 s4. I'm confused.

[Z07]

Originally posted by Goldorak
After looking at all the RS4 graphs, one discrepancy bothers me. If you go to the "available downloads" tab you can download the full graphs in whatever measurements you prefer.

I'll use the PS power output measure since this seems to be what is used in NA. Max horsepower of 349.3 is achieved at 7546 RPM. However in the overview tab the power figure given is only 342 since it is quoted at 7237 RPM. Why would they use a suboptimal RPM level?:confused:

Anyways this would only drop the power loss down to a rounded 17% figure, still not very good.:cry:
Cars often gain 10% during run in, so don't threat about it too much.:thumb:

[Goldorak]

Originally posted by Spada
What confuses me is how this can be true when you compare it to the actual performance. There's a test between the rs4 and an m5 that someone has posted here and the rs is only marginally slower. It is in fact faster to 60. So how can this be if it's apparently developing so little power? My rs4 feels substantially more powerful than my old b6 s4. I'm confused.

First off, there is no way in hell anyone could tell the difference on a butt dyno if it's missing 10 or 20 hp, that's why we have testing done in controlled environments. 419 should feel more powerful than 344 but then again so should 409 or 399...

As to the M5 0-60 comparison, a lot of that comes down to traction(Quattro) and weight. A Lotus Elise only has 189 hp and it runs a quicker 0-60(but also weights under 2000 lbs).


Z07, I mentioned the 667 miles in my first post, the problem with that argument is many of the other cars tested also have low mileage. Hopefully more dyno results on higher mileage cars will start coming out soon. There's also the possibility this was just a "weak" car, there's always going to be some variance in what 2 supposedly identical cars produce. Time will tell...

[7:53 RS6]

Originally posted by Z07
Cars often gain 10% during run in, so don't threat about it too much.:thumb:

What ever it say in the tripo meter when new 000000000, its alredy broken in, as all other new cars of today is as well :revs:

[Z07]

Originally posted by 8:05 RS6
What ever it say in the tripo meter when new 000000000, its alredy broken in, as all other new cars of today is as well :revs:
Well maybe, but I know that Ford GTs have increased from 550 to 600bhp after 6000 miles or so. It doesn't say how long the car was ran for before the test.

A common feature is that the more powerful cars lose a higher percentage. The M5 is RWD (only one diff) and loses 9%. The RS4 has 3 diffs and loses 18%.

The Corvette C6 is 10% down!! That car is widely known to produce more than its quoted power. It's all swings and roundabouts with power testing. It only works if you run two cars back-to-back on the same day.

There's an interesting bit about ambient correction too:



Modern computer controlled engines have the possibility to self-correct for ambient conditions (increase, decrease power). This is especially true for forced induction (turbo, compressor, etc) equipped engines where the boost can be controlled to absolute levels (instead of relative). Applying a correction on engines with a self-correction feature is incorrect and is not allowed according to the standard.

So basically, they don't correct for temperature with modern engines because of ISO standards. They assume the engine will correct itself. This is rubbish. Take your modern car out on a warm summer day and take it out on a cold winter night. Huge difference, computer control or not.

Lastly. It's an 8200rpm engine, give it time, it is not ready yet.

[Z07]

Originally posted by Goldorak


Z07, I mentioned the 667 miles in my first post, the problem with that argument is many of the other cars tested also have low mileage. Hopefully more dyno results on higher mileage cars will start coming out soon. There's also the possibility this was just a "weak" car, there's always going to be some variance in what 2 supposedly identical cars produce. Time will tell...
Well if it doesn't reach its stated power, in with the cat-replacement pipes.:mech: