Stock rear silencer and stock air filter MAX hp?

[ADP]

How much i can squieez from the engine with stock air filter and stock rear silencer?Car is S6 C4 with full RS2 ( AAN engine) setup, and i concern to change them both or no need?
Many thanks for any profesional comments and opinions!

[quattrostyle]

Only stock rear silencer? What size is the rest of the system?

[UrS4boy]

How much i can squieez from the engine with stock air filter and stock rear silencer? Car is S6 C4 with full RS2 ( AAN engine) setup, and i concern to change them both or no need? Many thanks for any profesional comments and opinions!

At least 400 crank AAN hp. Been running full RS2 hardware and MRC Stg 3 software since 2004. 360 reliable crank hp with stock exhaust and intake system. Others have done more.

BTW after market "cold air" intake systems might sound okay but they let in warmer to hot air compared to the stock intake which, from the factory, is a cold air system (air comes from the bottom of the rad support).

[macspring]

Not wishing to hijack this thread, but hopefully to add to it. I was about post similar thread, but is was concerning the suitablity / danger of leaving the plastic ended UrS6 intercooler in place with an RS2 Hybrid set up.

Should I fit the UrS4 metal ended one. Don't want to cut up my front bumper for a FMIC, even though it would perform better.

To be honest if you're concerned over the inlet tract of an UrS6 you could decide to have the inlet pipe redirected to take it's incoming air from the top of the oil cooler 'funnel', but then you run the risk of wrecking the engine if you hit any deep puddles.

I think the standard inlet manifold is good enough, but as our cars are eighteen odd years old, an upgrade to Rouse??? satin black rubber look silicone boost hoses would be a very good / worthwhile idea. My Michelin man hose blew on a 50k miles car after just a chipping.

Cooling hoses should be checked and replaced especially the two underneath the inlet manifold.

Check vacuum pipes, put in the correct and correctly gapped NGK spark plugs, and new plastic or metal inserts for your upgraded injectors.

I would think with the exhaust section of the UrS6, it is definitely a good idea to change the restrictive standard exhaust manifold to a Wagner style RS2 Evo exhaust manifold, worth searching out if you can find one.

Even for a oem UrS6 car, without even a chip, ( although a chip should be put in all AAN, ABY and ADU cars as it is a fabulous improvement of the money and minimal effort ), a Wagner RS2 exhaust manifold and two cat bypass pipes, ( Ultimot.de ), is a worthwhile upgrade for the money.

A three inch down pipe may be a good idea, but it generally forces you to replace the rest of the exhaust system with 3" inch system, and if there are not enough / decent sized boxes in the system apart from the deletion of the cats, it means that the car is louder on idle and attracts attention on acceleration / wot. You loose the refinement and stealth of the oem UrS6. You also have to ensure that the pipe is fabricated to sit very tight to the underneath of a UrS6, especially a slightly lowered one, to ensure that you then do not have clearance issues with the exhaust scrapping on speed ramps, or in multi story car parks.

This is much more than you asked about, sorry for that, and please remember that these are just my own opinions from reading stuff on here and the net, others will agree or disagree with my comments which will help you make up your own mind on what you want to do for your own car / needs / budget.

Kind regards.

[ADP]

Many thanks URS4 Boy!
Quattrostyle the Down pipe is 3" after that split into 2X60mm until the rear axle ,where the original pipes of the backbox are opened and fit to this 2x60mm pipes!Yes on system no any cats and midle resonator,only the back box!

[andy10v]

JP had a 3" exhaust with a stock back box at with no issues.

PRJ mentioned a car with over 800bhp on the stock back box.

[ADP]

Sorry i forgot to mention that the exhaust manifold is Wagner ex.man. and rs2 turbocharger with 360 degree bearing and stock size billet compresor wheel.

[andy10v]

The back box is not going to be the limiting factors, it will be the injectors then the turbo.

[ADP]

Yes Andy,i know that this is limiting factors,engine is fully upgrade AAN to RS2 exsept the back box and intake box.So im curious that some one take a presure measurments into exhaust sysytem (STOCK ,WITHOUT CATS), and presure drop into the snake pipe(BETWEEN TURBOCHARGER AND AIRFILTER).
many thanks in advance!

[UrS4boy]

Yes Andy,i know that this is limiting factors,engine is fully upgrade AAN to RS2 exsept the back box and intake box.So im curious that some one take a presure measurments into exhaust sysytem (STOCK ,WITHOUT CATS), and presure drop into the snake pipe(BETWEEN TURBOCHARGER AND AIRFILTER).
many thanks in advance!

I've owned my 93 S4 since 1998 and been around UrS-related forums since 1999. I have never seen the data that you seek. There are lots of fully RS2's AANs running stock intake filters and exhausts (after the RS2 exhaust manifold) with zero problems. Those that did have a concern spent their $$$$ on a Stromung exhaust manifold back, single cat system. There was a claim of 10 to 15 hp at RS2 levels but that was never shown to be true in reality. They sound great though. Maybe (maybe) a slightly quicker spool.

Once you go beyond RS2 levels, e.g. Garrett GT 3071 and over 400 crank hp, then you *might* start to need a better exhaust system - but even then, not really.

You are fretting over nothing at this point.

[ADP]

OK,many thanks URS4boy maybe i will do this measurments and i will post the results!Only i think will be the problem with gauge which must measure the presure drop between turbo and air filter!

[andy10v]

It will be interesting as you say to see the pressure differences.

Are you planning on using a boost guage or do you have some fancy pressure sensor?

Did you see this thread on testing exhaust back pressure?

http://www.s2forum.com/forum/showthr...=back+pressure