Low power output, B7 RS4

4.2 V8 32v Naturally Aspirated - 414 bhp
2manytoys
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Re: Low power output, B7 RS4

Post by 2manytoys » Sun Apr 17, 2011 10:54 pm

The report that come back from the engine engineering place said seals, so if it was guides also that wasn't talked about. I think in this case while it would have been an option to replace the seals, Audi choose to replace the heads all together. The Dealer had to reassemble the heads and send it to Germany (along with the short motor). I assume they wanted to try to find out what caused the problems.

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kiwi_mtm
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Re: Low power output, B7 RS4

Post by kiwi_mtm » Tue Apr 19, 2011 10:20 am

Got the RS4 re-dynoed today. Managed a 233.5WKW, up from the prior 213WKW.
So its a definite step in the right direction!

Since the old dyno it has:
> Had the Airbox powerflap fixed. Was suppose to open at 5000rpm, but was stuck permanently closed
> Had the inlet manifold removed and carbon cleaned.

I still feel that it should have 'more'. Given that my old B5 (stock 280kw flywheel) produced 229WKW, this B7 (309kw Flywheel) should be into the 24xWKW area considering its just been carbon cleaned.

Running out of ideas. Unless the Carbon clean was a quick one, and not thorougher?

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2014 RS6 (2023 on order)
2017 Q7
1993 E36 M3 Tarmac Rally car
2001 Porsche Boxster circuit car
2017 Porsche 991.2 GT3 Clubsport

2manytoys
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Re: Low power output, B7 RS4

Post by 2manytoys » Tue Apr 19, 2011 11:00 am

Did you log timing and intake temp during the Dyno run?

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kiwi_mtm
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Re: Low power output, B7 RS4

Post by kiwi_mtm » Tue Apr 19, 2011 7:39 pm

2manytoys wrote:Did you log timing and intake temp during the Dyno run?
No VAGCOM :(
2014 RS6 (2023 on order)
2017 Q7
1993 E36 M3 Tarmac Rally car
2001 Porsche Boxster circuit car
2017 Porsche 991.2 GT3 Clubsport

2manytoys
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Re: Low power output, B7 RS4

Post by 2manytoys » Tue Apr 19, 2011 10:42 pm

I don't think you really have anything to worry about. The power curve looks ok and the torque curve is mostly ok.

Without knowing your actual intake temp and timing it's hard to say for sure. It looks ok though.

Remember the RS4 has pretty aggressive hot air correction and depending on the Dyno setup you could have intake temps in the 50's C. I don't think the RS4 is a car that will produce great numbers on a Dyno because of this.

You really need Vagcom if you are still worried.

Cheers.

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Re: Low power output, B7 RS4

Post by P_G » Wed Apr 20, 2011 9:34 am

kiwi_mtm, the dyno runs that you have had done; was it just one power run each time or are the results you have posted the mean or the best of the runs done on each occassion?

RS4's don't tend to give peak figures until after a few runs. The difference you have seen could well be attributed to a combination of atmospheric changes (I notice temp and humidity are down and pressure is up on your improved figures as much as a correction factor is added), properly functioning airflap and the technician give your air filter a bash to clean out the crud.

It could also add to the discussion that carbon does not affect power....... :FIREdevil:

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kiwi_mtm
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Re: Low power output, B7 RS4

Post by kiwi_mtm » Mon Apr 25, 2011 12:25 am

P_G wrote:kiwi_mtm, the dyno runs that you have had done; was it just one power run each time or are the results you have posted the mean or the best of the runs done on each occassion?

RS4's don't tend to give peak figures until after a few runs. The difference you have seen could well be attributed to a combination of atmospheric changes (I notice temp and humidity are down and pressure is up on your improved figures as much as a correction factor is added), properly functioning airflap and the technician give your air filter a bash to clean out the crud.

It could also add to the discussion that carbon does not affect power....... :FIREdevil:
It was run twice only on both occasions.

I'll also note that the car had only been driven probably 1,000kms since the de-carbon.

From a bum dyno perspective, after the airbox flap and de-carbon (hard to know whats contributing) it feels noticably quciker up top and you get a real 5500 kick, Honda vtec style (but without the torque steer!).
2014 RS6 (2023 on order)
2017 Q7
1993 E36 M3 Tarmac Rally car
2001 Porsche Boxster circuit car
2017 Porsche 991.2 GT3 Clubsport

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Re: Low power output, B7 RS4

Post by P_G » Mon Apr 25, 2011 8:51 am

I got a more pronounced 5500rpm 'kick' when I replaced my air filter and cleaned the airbox / flap the other week prior to service so it may be that attribute to what you have felt.

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kiwi_mtm
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Re: Low power output, B7 RS4

Post by kiwi_mtm » Wed Apr 27, 2011 9:07 am

Pretty boring, but here is a Dyno Video of the power run.

http://www.vimeo.com/22907324
2014 RS6 (2023 on order)
2017 Q7
1993 E36 M3 Tarmac Rally car
2001 Porsche Boxster circuit car
2017 Porsche 991.2 GT3 Clubsport

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