Vomit

Has anyone out there tried removing one of the cats from their C32? Any performance improvement? Still pass smog (in CA)? I have a feeling that this is the mod that the mysterious Mr. Nima did to get his C32 to run a 12.6

Please don't give me the environmental prosthelyzing. If any of us gave a rats butt about the environment, we would be driving Civic Hybrids (JK . I would only remove one if (1) there is a performance gain to be had, and (2) the emissions don't go through the roof.

My thought is that maybe MBZ put two cats on to qualify as some sort of super ULEV. If one cat will do 99% of the job, then I might remove the other.

Any thoughts?

more151please

well i have a C55 and im interested in the same thing, my roomate has a mach1, and has taken 4 of his 6 out, and has improved his car, also how many are there in the C55, just a question. Sorry i couldn't answer your question though "Vomit"

BenzoAMGpower

I ran a 12.7 @ 108mph with the following mods: Greenfilter USA filters, SL55 intake splitter, RENNTech ECU and Pulley. My exhaust has gone untouched yet. It was on a 1.9 60ft time in 70degree f. weather. Either cooler weather or a 1.8 60ft time, i beleive i can drop .2 seconds off my ET.

Vadim @ evosport

C32 and C55 have four converters.

Two up front, next to exhaust manifolds, are primary. They are monitored by oxygen sensors at inlet and outlet.

Two converters in the middle are secondary. Their function is more of a backup for the primary conveters in case they fail.

We will be offering a bypass pipes to remove secondary converters (Off-road use only) in addition to resonator bypass pipe. Dyno graphs will follow, IMHO on a C32 with pulleys, software and headers, we can find around 10-15 HP from secondary converter removal.

evanswan

Why only for off road use. Would it be illegal for street.

Steve Clark

Definitely very illegal in the US.Can't say for certain about other areas.Getting caught would be rather expensive and you could see your car impounded in a worst-case scenario.

However,if you don't gice a rat's butt about the environment,be my guest.

BTW- what is "prosthelyzing"?.

Vomit

sorry, "proselytizing"

Vomit

Vadim:

Aren't all four of the C32's cats located between the resonator and the engine? I just seem to remember seeing them right up near the exhaust manifold when they were removing my resonator.

BenzoAMGpower

i dunno, i wouldnt mess with removing the cats unless i had the ECU tuned for it... ECU might detect something different with the air flow and start pulling back on timing!!! A member here put an higher flowing exhaust on his C6 vette and it ran slower then what it did stock for example.

Vadim @ evosport

Yes, they are. But as you can see only fronts have O2s. The rears are there as backup.

As far as re-tune after their removal. I do not expect a big gain in (10-15) HP, and therefore in airflow - and therefore in fuel. Stock adaption should be able to handle it.

1313

Vadim,

Does removing secondary cat or resonator provides better flow? And does the check engine light comes out if we removed the sec. cat?

Thanks