B7 RS4 Cold Air Intake Development

[Phillydriver33]

Hello to everybody

I have a 2007 audi RS4 and i am currently developing a cold air intake for my car. I did not like the stock air box look so i am making a heat shield and developing the mass air flow sensor connector and tubing. I will be posting pictures of the developmental stages by the end of this weekend if i can get some feedback on it will be great.

[sonny]

Nice one, will look forward to your development. I was running a GruppeM system on my car for some time, great induction noise, bit loud at speeds of 70mph+

..and welcome.

[pippyrips]

Are you doing it for looks or power gains? That engine bay gets mighty hot!

Do you have access to vagcom it would be interesting to see before and after results.

[silverRS4]

Yes, Vagcom data would certainly be worthwhile. I've looked at mass flow data before for a modified B7 RS4 air box. I never saw the modification, but apparently it was more of a ram air box than a cold-air box. The mass flow numbers appeared good at first glance, almost too good to be true. Funny thing was, the lambda correction changed by the same exact same percentage (it had to lean the mixture by the same percentage to maintain the proper lambda). So the end result was the same air-fuel ratio and injector pulse width time. What does that say? The modified box must have induced enough turbulence to make the mass air sensor reading incorrect. The wide-band lambda correction luckily kept everything on target. So basically, it was alot of needless correction to get the same result. As a side note, the engine "load" is derived very strongly from the sensed mass flow. So with the turbulent flow introduced by the modification, the calculated load was incorrect as well as all the engine parameters driven by load-based tables. Cooler air and/or more air will only help a mass-flow-based engine if it's accurately measured.

[ArthurPE]

you will be hard pressed to do better than the oem package...
more air will not help without software and a rev limit increase...
iirc the RS4 race Champion built used the stock airbox...

[P_G]

IIRC when I last had a look at GMG Racings website htey were developing a carbon / cold air box but no details on site as yet just 'under development' You blokes over the pond could ask them what it is all about? Certainly may be a credible alternative to GruppeM given it is near £1k GBP to buy now!

[silverRS4]

As Art pointed out, the RS4 Challenge car uses a stock air box (and filter!). Once that became fairly well known, anyone working on a replacement air box realized they would have to get out very special smoke and mirrors to make people believe the stock setup was somehow inadequate. And look, it appears to use the stock PCV system as well! The Challenge car achieved 500HP with custom headers, no cats and custom ECU tune - that's it. Awesome engine from the factory...

[ArthurPE]

As Art pointed out, the RS4 Challenge car uses a stock air box (and filter!). Once that became fairly well known, anyone working on a replacement air box realized they would have to get out very special smoke and mirrors to make people believe the stock setup was somehow inadequate. And look, it appears to use the stock PCV system as well! The Challenge car achieved 500HP with custom headers, no cats and custom ECU tune - that's it. Awesome engine from the factory...

do you know what they rev'ed it to?
any other specs?
thnx

[silverRS4]

Here's a link to the article...its near the bottom of the page. With stock internals, I can't imagine the RPM limit would have been changed alot, if at all. With race gas, I'm sure timing targets could be altered with very good results. The current Supersprint header thread on the SRS forum (Evolution of a B7 RS4) does lend credibility to the idea that custom headers (and a complete race exhaust such as on the Challenge car) could very well improve the VE of an already stellar engine.

http://www.audiworld.com/news/07/alms-v ... tent.shtml

[ArthurPE]

Here's a link to the article...its near the bottom of the page. With stock internals, I can't imagine the RPM limit would have been changed alot, if at all. With race gas, I'm sure timing targets could be altered with very good results. The current Supersprint header thread on the SRS forum (Evolution of a B7 RS4) does lend credibility to the idea that custom headers (and a complete race exhaust such as on the Challenge car) could very well improve the VE of an already stellar engine.

http://www.audiworld.com/news/07/alms-v ... tent.shtml

thanks, cool article

to get 'around' 500 HP as they state, I would almost guarantee a rev increase, maybe to 8400+ vs stock 7800 (power peak)
the RS5 almost the same engine is 8250 iirc
longevity would not be a concern, lol

the wt is amazing <3000, now THAT will make a huge difference in speed!
maybe we can ask John Stahmann

[P_G]

As Art pointed out, the RS4 Challenge car uses a stock air box (and filter!). Once that became fairly well known, anyone working on a replacement air box realized they would have to get out very special smoke and mirrors to make people believe the stock setup was somehow inadequate. And look, it appears to use the stock PCV system as well! The Challenge car achieved 500HP with custom headers, no cats and custom ECU tune - that's it. Awesome engine from the factory...

Mmmmmm.... custom headers....


That's that where true power increase is to be had. How do I get hold of some?

[sonny]

P_G you seent he guy over on SRS who is having the custom headers done ? Looks brutal. its posted in the RS4 section.

http://audisrs.com/ftopic13337-15.php

[ArthurPE]

Mmmmmm.... custom headers....


That's that where true power increase is to be had. How do I get hold of some?

niiiice

[P_G]

P_G you seent he guy over on SRS who is having the custom headers done ? Looks brutal. its posted in the RS4 section.

http://audisrs.com/ftopic13337-15.php

I had seen that but the overall size is a good bit bigger than the OEM one. There is little enough space in there presently so I don't know how Supersprint are going to get that into the space available. It is also an engine out job IIRC which is why it is so pricey to R&D.

[Phillydriver33]

These are some pictures of the developmental stage. I am going to make an adapter piece out of aluminum however right now i cut up my oem air box and i made modifications to the tubing. Already i have noticed a difference in driving the car is not starving from air at all. I never have to worry about the power flap not opening and i have blocked off a significant amount of heat with the heat shield. Also there are a number of different areas from which air can to get into the engine bay once you remove the air box which takes up a lot of space.





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