[PresaMat]

Hey All,
Ive been looking at different exhaust setups. I plan to go with Riss catless downpipes. Ill probably go with some sort of semi custom exhaust... (custom piping... maybe eissenman MS mufflers). I was wondering if anyone has put High flow cats in their exhaust similar to the supersprint setup? I would like to be able to pass emissions but have better performance. Anyone have any recommendations on the cats?

Mat

[e.n335]

AFAIK RISS will provide a "Supersprint configuration" as well. I will get catted DP's.

- Eugen

[Evo8MRto335I]

I thought of a similar set up as well, the only problem would be the 02 sensor harness. It would have to reach all the way behind the cats to read properly.

This would involve cutting the existing harness to make a extension. Other than that I think this configuration is the way to go. You would have much lesser gas velocity by the time the airflow reaches the cats in the back in contrast to the cats in the downpipes.

my .2c

[e.n335]

^ right unless you need a "stealth" install.

[PresaMat]

Originally Posted by Evo8MRto335I

I thought of a similar set up as well, the only problem would be the 02 sensor harness. It would have to reach all the way behind the cats to read properly.

This would involve cutting the existing harness to make a extension. Other than that I think this configuration is the way to go. You would have much lesser gas velocity by the time the airflow reaches the cats in the back in contrast to the cats in the downpipes.

my .2c

Yeah i was thinking the same thing... what about something to trick the o2?

[orientblue3]

the rasp of catless DP's turned me off big time. not worth the addition few hp IMHO.

[335i_Danny]

I'm sure someone will hit the market with resonated downpipes at some point. That said, I will also be keeping the cats in mine.

[midlife]

Originally Posted by PresaMat

Hey All,
Ive been looking at different exhaust setups. I plan to go with Riss catless downpipes. Ill probably go with some sort of semi custom exhaust... (custom piping... maybe eissenman MS mufflers). I was wondering if anyone has put High flow cats in their exhaust similar to the supersprint setup? I would like to be able to pass emissions but have better performance. Anyone have any recommendations on the cats?

Mat

registered

[tintivilus]

Couldn't you just re-locate the 2ndary O2 sensors from the downpipe to the stock exhaust after the 2ndary cats?

I also think that the "Supersprint" setup would be ideal, but its general absence from the market suggests I'm missing something

When I was shopping for Z3's I noticed a common mod was to switch from USA to European exhaust to move the cats from under-hood to under the car, so it can't be completely unreasonable.

[hl0m4n]

passing emissions all you need is the xpipe and mufflers. as long as you don't touch any 02 sensors, etc.

or you can get the complete exhaust system, and swap out the connecting to factory and redo after. you pretty much can sell your factory muffler if you decide to do that way or the xpipe and muffler way as well.

[stressdoc]

I forget, what is the price guesstimate on the catted DPs?

[XPO186]

I was looking at pretty much the same type of setup -- something along the lines of either catless dp, high flow cat, resonator delete, and aftermarket muffler, OR catted dp and full meisterschaft (all three sections).

I would like to do the latter(and not have to cut any piping to make it happen) and pass emissions.

I'm just wondering about the efficacy of the cats on catted dps and whether I can pass smog w/just that.

[tintivilus]

What's the impact of catted DP's (OE or aftermarket) on underhood temperatures? Is it really that helpful to move the primary cats further back, or is it just a waste of money?

To phrase the question another way: should I care *where* the cats are, or just that they're decent?

[midlife]

Originally Posted by tintivilus

Couldn't you just re-locate the 2ndary O2 sensors from the downpipe to the stock exhaust after the 2ndary cats?

I also think that the "Supersprint" setup would be ideal, but its general absence from the market suggests I'm missing something

When I was shopping for Z3's I noticed a common mod was to switch from USA to European exhaust to move the cats from under-hood to under the car, so it can't be completely unreasonable.

if u do not already know, see the new Riss Racing downpipe thread. their new dps throw NO codes at all.

[midlife]

Originally Posted by stressdoc

I forget, what is the price guesstimate on the catted DPs?

stressdoc: see the new Riss Racing downpipe thread. dps just released i think for $799 group buy. note catless version throws NO codes.

[tintivilus]

Originally Posted by midlife

if u do not already know, see the new Riss Racing downpipe thread. their new dps throw NO codes at all.

I don't really care about "throwing codes"; I'd like to keep some semblance of a functioning emission-control system.

UR said they'd had reports of "no code" catless DP users occasionally seeing CEL's. I'd rather just not mess around with O2 sensor fakery whether mechanical or electrical.