Which cats / exhaust / chip to go for?

[ranger]

No CATS - A straight through systm will make a tremendous difference. Please keep us informed

Now we are talking langauge I understand
The 2 first cats are the ones who make the turbos "die" just drill them out...

You can also do like I have done, make a system custom, start with one 3" steelness muffler at the back if its to loud, put one more on where the midpipe was I can send pics, if you wanna se the result...

[Golich]

Ranger - please do.

What ECU mods did you do. i.e. Did you have to fool the ECU with respect to the Lambda readings. I'm not entirely sure how these things work. But I've read a long time back when the downpipes were first appearing that with the 4 lambda probes on the RS4 and 2 on the S4 they developers were having probs.

[S2tuner]

@Golich: the ECU can be reprogrammed so it doesn't worry about the cats not being there anymore. Dunno how legal the mod is but it can be done and I can do it very easily.

HTH,

Mihnea

[DaveP]

Mihnea,

Out of curiosity, what sort of gains would you expect by not having the cats ??

[S2tuner]

Mihnea,

Out of curiosity, what sort of gains would you expect by not having the cats ??

Dave, it's hard to say because I have never done any dyno runs back to back on an RS4, cats and no cats, but I'd say around 10 to 15 HP more with no cats compared to 200 cell metal cats....

we've done some testing on an RS2 with hollowed-out cats and we didn't get much more power with no ECU mods, however, power and torque came in around 500 RPM sooner with no cats... by modifiying the ECU we went up from 490Nm at 3800 to 601Nm at 3500, and from 351HP at 5800 to 364HP at 5550 RPM...

HTH,


Mihnea