rs4 doesnt feel as powerful as the old one.....help i need more power!
12-01-2006, 02:47 PM
#1
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rs4 doesnt feel as powerful as the old one.....help i need more power!
going from an rs4spec to the news rs4......i feel that there is a lack of that turbo torque feeling......anyone have an idea without suggesting supercharger how to change up the rs4? and do they have any chips out there? my buddy is dying to get it going....
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12-01-2006, 03:00 PM
#2
Biggest bolt-on gains will come from replacing the downpipes...
get rid of the 4 restrictive cats and put 2 HFC in place or testpipes. Otherwise you'll be waiting for a SC option. Keep in mind the new RS4 will have a much more linear powerband thus not feeling as fast as a car with small turbos that spool quickly feeling like a kick in the ***.
12-01-2006, 03:05 PM
#3
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Limited mods available.
To my knowledge, no company has a supercharger kit...and I've looked extensively, talked to tuners, etc.
Supposedly...PPI is developing a supercharger system for the Q7, but no one knows if there's enough space under the hood to accommodate any kind of blower kit in an RS4.
From looking at the motor, it appears that only an Eaton style roots blower (like the Mustang Cobras) would work, assuming it would be low-profile enough.
That still leaves someone to sort out the FSI direct injection system, ECU mods and last but not least, figure out how to deal with the extremely high compression (12.5:1) on these motors.
My prediction? If anyone ever does make one, it'd be limited to probably 4-6psi, include a watercooled intercooler, be insanely expensive and add less than 50hp.
For a car with such limited production numbers, I don't see it happening.
My advice? Air filter replacement, cat back exhaust, downpipe mod, and as much lightening of the vehicle you can stand. That's my plan.
Supposedly...PPI is developing a supercharger system for the Q7, but no one knows if there's enough space under the hood to accommodate any kind of blower kit in an RS4.
From looking at the motor, it appears that only an Eaton style roots blower (like the Mustang Cobras) would work, assuming it would be low-profile enough.
That still leaves someone to sort out the FSI direct injection system, ECU mods and last but not least, figure out how to deal with the extremely high compression (12.5:1) on these motors.
My prediction? If anyone ever does make one, it'd be limited to probably 4-6psi, include a watercooled intercooler, be insanely expensive and add less than 50hp.
For a car with such limited production numbers, I don't see it happening.
My advice? Air filter replacement, cat back exhaust, downpipe mod, and as much lightening of the vehicle you can stand. That's my plan.
12-01-2006, 03:34 PM
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What power gain can I get by replacing just the downpipe?
I am not sure about using test pipes but I think it will cause CEL. If it doesn't than I would like to remove all the CAT.
12-01-2006, 03:37 PM
#5
It will cause a CEL without a tuning program to get rid of it...
but othewise a good 200cpsi HFC setup may gain upwards of 30hp/30tq. I am making over 310whp and 295wtq and running a 13.20 1/4 mile with just the minor bolt ons like this on the 340hp S4.
12-01-2006, 04:14 PM
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Why the hell would you use a stock exhaust?
Dude, either you want power or you don't.
If you do, you'll need to address the same areas that every internal combustion engine in the world needs to:
Increase air flow
Remove spent exhaust gases as rapidly as possible
I can get into a whole discussion about the principles of internal combustion engines, about them basically being giant air pumps, increasing compression (static or dynamic), etc.
Bottom line:
Do the cat back exhaust
Do the intake
Consider the downpipe after someone shows a video or pictures of a B7 RS4 running bigger downpipes (up to a reasonable size) using 200cpsi or similar freer-flowing cats. To my knowledge, no one has done it.
Since I work for an exhaust company, I can tell you that when you are working around cats, it's very easy to trigger a CEL and put a car into limp mode. Saw a B4 RS4 last night making only 180hp....with his mods, he should be making 550hp, all because of bad tuning and the wrong downpipe.
If you do, you'll need to address the same areas that every internal combustion engine in the world needs to:
Increase air flow
Remove spent exhaust gases as rapidly as possible
I can get into a whole discussion about the principles of internal combustion engines, about them basically being giant air pumps, increasing compression (static or dynamic), etc.
Bottom line:
Do the cat back exhaust
Do the intake
Consider the downpipe after someone shows a video or pictures of a B7 RS4 running bigger downpipes (up to a reasonable size) using 200cpsi or similar freer-flowing cats. To my knowledge, no one has done it.
Since I work for an exhaust company, I can tell you that when you are working around cats, it's very easy to trigger a CEL and put a car into limp mode. Saw a B4 RS4 last night making only 180hp....with his mods, he should be making 550hp, all because of bad tuning and the wrong downpipe.
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12-01-2006, 07:51 PM
#9
In order to do this you need to test each change made...
What I can tell you from testing is that the pipes and cans do reduce backpressure, but not as much as the stock cat setup. I have a couple exhausts I use right now. The catback portion produces the least amount of gains, but for me I dont mind the noise of the catback with the downpipes so that is what I run most of the time. For track duty, I use downpipes and I now have a straight pipe setup with absolutely no resonators or mufflers. One could also go very conservative with the catback portion using OEM or a resonated Milltek which uses the same sized piping as OEM (if they are looking for the most power they can get while retaining a stock like sound for family members...not something I need but some may want this). To give a different example, I found the same thing testing the FSI turbo car. We actually saw zero gains replacing the catback portion (not the case with the NA car) and didnt see any gains until we replaced the cat with a testpipe. So, just outlining some options. The big gains come from killing the cats and some smaller additional gains can be seen from replacing the mufflers with free flowing units, preferably straight through cores.
But for the sake of what you are saying, JUST replacing the catback portion is not going to net the most gains. That portion of the exhaust is RELATIVELY (to the rest of the system) efficient. The larger restrictions are seen at the quad cats most obviously. After that, I agree some more smaller gains are seen at the catback portion.
But for the sake of what you are saying, JUST replacing the catback portion is not going to net the most gains. That portion of the exhaust is RELATIVELY (to the rest of the system) efficient. The larger restrictions are seen at the quad cats most obviously. After that, I agree some more smaller gains are seen at the catback portion.
12-01-2006, 07:54 PM
#10
That's not what I have settled on but yeah that would be an option...
for those looking for the most gains AND who have to retain the most unobrusive sound. For those that dont mind the added noise of a full system, go for it. Thats the most gains, but if considering ONLY a catback or ONLY downpipes, the downpipes represent a much larger restriction and will net a larger power gain.