Mike M.

[QUOTE]Originally posted by HeNeSSeY
[B]

When is yours coming out?

cmnsnse

I seriously DOUBT anyone has tested the S2000 OEM Cat for flow, therefore nobody even knows if its worth replacing - Its a straight through design very high flow in the first place- I would rater bet that an aftermarket cat of any caliber would be WORSE - go ahead and flame

As for the O2 sensor in a straight pipe, might work but might cause a fritz, just because the OEM location is between two elements in the cat - so the comp may be calibrated to those readings. but in that case you can fix that problem with some testing and carefull selection of an in-line resistor - DO NOT attempt on your own, cus you couls really screw things up.

I feel strongly that it is not worth it to mess with this cat unless your changing the entire engine including the ECM

Mike M.

I Dont think anyone has tested the S2000 Converter, But Comptech did Test the NSX Cat which needs to flow much more than an S2000 and the NSX has the highest flowing Honda cat. They also tested 4 or 5 aftermarket companies cats, and Car Sound came out on Top with Catco in a close second, Both Flowing twice as much if not more. IMO Yes it is worth it.

DMENACE021

TypeRmsm, do you think the check engine light will turn on with the catco or the other brand?
Since you work at a performance place, is headers a bad idea if i am not thinking of getting an exhaust?

cmnsnse

Well the NSX was brought into production when?! Don't even try to compare the two.

Comptech can test the S2000 cat also then.

I'm telling you guys that without a Ton of R&D, and were not just talking flow - but tuning characteristics. Tuning doesn't just stop after the headers. Show me an aftermarket cat that has high capacity/high flow honeycomb elements in it - of course that is specifically tuned to the F20c, and Ill show you one hell of a surprised person.

This isn't your typical econo car where performance doesn't matter, Honda developed a new type of cat just for this application. I'm sure it will be used in others, but the technology just wasn't there to put these in the NSX that many years ago, so you cant use the NSX as a baseline for the S2000.

Mike M.

[QUOTE]Originally posted by cmnsnse
[B]
Comptech can test the S2000 cat also then.

DMENACE021

TypeRmsm, put me on your list and PM me when you do the tests on an S2000 cat

marcucci

This will not work- at least not beyond the first driving cycle.

The secondary O2 is for air quality/emissions; it detects a change in the vehicles emissions over time. Hence, the first driving cycle will not report "degraded" output as an MIL unless it happens over 2 consecutive driving cycle. A modification to remove the ECUs memory/learning (reset the ECU each time you drive) will fix this, though it is a PITA and has other ramifications. With a straight pipe/O2 combo you will get an MIL/CEL on the second cycle.

Flow:
While tuning doesn't stop beyond the headers, a restriction in the exhaust is generally bad. The idea of needing "backpressure" is not usually a result of "backpressure" or restriction but of gas velocity. A 4" exhaust doesn't work well with a 2L/7000RPM motor because exhaust gas velocity drops and impedes scavenging.

In general, cats and mufflers impede flow. The real question is, how much will they flow at a what pressure drop? I suspect that Honda, in their quest for highest specific output and pushing the F20 to the max, has probably used the highest flow cat in their parts bin, if not even higher. They needed to pass emissions as well, but I think for this motor the cat selection was probably more critical. Along the vein of what cmnsense was getting at, the NSX is old enough that it probably uses early/mid 1990's catalyst technology, while the S2k probably uses the latest catalyst tech available. As the technology improves, I'm betting flow does, too.

Back to flow numbers, until someone can tell us how much ANY OEM cat is capable of flowing with minimal pressure drop, the point is moot; the difference between 340 and 380CFM (for example) doesn't matter when the motor is only pushing 320. We have no idea what the stocker flows...

Has anyone dynoed the delta change with the cat being the only difference? TypeRmsm, post your results when you have them; the proof will be in the pudding.

SilverSurfer

[QUOTE]Originally posted by cmnsnse
[B]I seriously DOUBT anyone has tested the S2000 OEM Cat for flow, therefore nobody even knows if its worth replacing - Its a straight through design very high flow in the first place- I would rater bet that an aftermarket cat of any caliber would be WORSE - go ahead and flame

As for the O2 sensor in a straight pipe, might work but might cause a fritz, just because the OEM location is between two elements in the cat - so the comp may be calibrated to those readings. but in that case you can fix that problem with some testing and carefull selection of an in-line resistor - DO NOT attempt on your own, cus you couls really screw things up.

cmnsnse

Id like to see what kind of element the comptech cat's use. The S2000's is a spiral honeycomb straight through design, which turns out to be more efficient and higher flow than the block type. Makes you wonder why Honda spent a tone of money developing the new type of cat for the F20c, hmmm.

BTW: It is a metallic catalyst rather than a ceramic one, Question for TypeRmsm , What exactly is the difference and why is it better? Ill give you 20 points and a little more faith in your claims if you can get it right . . .