will new gesi cats pass ecu check sums?

[949]

gesi cats have now been out in the market for a minute now. so will the newer versions be able to deliver more flow but also allow the O2 sensors to work properly with them?


https://gsportbygesi.com/high-perfor...tems-products/

[Boomerdw]

gesi cats have now been out in the market for a minute now. so will the newer versions be able to deliver more flow but also allow the O2 sensors to work properly with them?


https://gsportbygesi.com/high-perfor...tems-products/

Passing EPA doesn’t
Necessarily mean passing. CARB for us in California.

[CXSnail]

This is all about proper catalyst sizing.

In recent times, Cobb offered a GESi catted downpipe for the focus ST. They were trying to get it CARB certified in lieu of the upcoming "green speed" movement. A guy I know purchased one of those downpipes and the cat monitor passed for about a year, then it began throwing the p0420 code. They quit making those downpipes since.

My point is, in this example they used the right cat but the wrong size substrate.

[Spinnetti]

Here's the problem. Cat's have a specific operating temp, and need to come up to temp as quickly as possible and also not overheat. The emissions requirement and performance requirement are at odds with each other. If you meet the emissions requirement, it will make little if any extra power, so why bother? The extra power comes from moving the cat downstream and tuning the mixture for peak power. If you have a cat in the stock location but the fuel mixture is optimized for power it will overheat the cat. Just can't get there from here. IMO, if you want to keep it all on the up and up, just do stage I and be done. The new cars seem to make stage II power on stage I mods compared to just a few years ago.

[TurboTimmy]

No one makes an "emission passing" downpipe for the reason that in the eyes of the federal government it is illegal to replace a working catalytic converter, end of story. The rules for replacing a legitimate failing catalytic converter or in current times, it was stolen, require a lot more work than just slapping a new cat on. There are rules the manufacturer has to meet, it has to be OE equivalent, there are records that need to kept by the manufacturer, the installers, and customer, etc, etc.

Aftermarket downpipes wth catalytic converters that may work enough to get your readiness monitors to set are still illegal, and at least for some states wouldn't pass a visual anyway. So it's a gamble when you go get your inspection if person doing the inspection even looks to see you have OE cats. In my state there is a check box for OE cats on the inspection form, last time I had to go for emissions I'm pretty sure the guy just checked the box and didn't even look. So it's up to the individual if you want to roll the dice and see if you can sneak by with an aftermarket downpipe and cat or switch the downpipe out every time you go for an emissions test. Obviously there are states that don't do anything in regards to emissions and inspection so people will still be rolling with their aftermarket downpipes (still illegal on a federal level), just no one is enforcing it. Manufacturers have gotten away with "for offroad use only", but there isn't the incentive anymore with the EPA cracking down. APR saw the writing on the wall after getting their hand slapped, hence their new strategy going forward.

[TurboTimmy]

For fuck sake, it's right in the link you posted. Just do whatever the fuck you want

[Stubek]

For fuck sake, it's right in the link you posted. Just do whatever the fuck you want

This post does not answer his question about the O2 sensors functioning properly.
His question while inferring passing smog is not explicitly about that.

So, does anyone know if these new ones flow enough to keep the secondary O2 from throwing a code?

[949]

This post does not answer his question about the O2 sensors functioning correctly.
His question while inferring passing smog, is not explicitly about that.

So, does anyone know if these new ones flow enough to keep the secondary O2 from throwing a code?

Impressive. Your ability to read and understand tells me you might have a high educational degree. You did not deviate nor add in other unstated information. Do you have an English or Law degree? Just curious.


And you are correct in my post. My main concern is about the o2 sensor. Other than placement and type of cat in the stock downpipe, I wonder if using an aftermarket cat of higher quality or a properly spec'd out cat would still allow the o2 to work correctly.

[Stubek]

Impressive. Your ability to read and understand tells me you might have a high educational degree. You did not deviate nor add in other unstated information. Do you have an English or Law degree? Just curious.


And you are correct in my post. My main concern is about the o2 sensor. Other than placement and type of cat in the stock downpipe, I wonder if using an aftermarket cat of higher quality or a properly spec'd out cat would still allow the o2 to work correctly.

The primary O2 sensor (first one, pre-cat) tells the ECU important information and the ECU uses that info to adjust various engine parameters. The secondary O2 sensor (second one, post-cat) only is used by the ECU to tell the car if the cat is working as intended. The car things that if some amount of exhaust gas with various chemicals in it goes into the cat, that less than that amount should come out. If the amount coming out is more than the car expects, then the car thinks the catalyst is no longer effective, but it doesn't actually do anything to change how the car runs, just gives you the CEL.

[949]

i wonder if we know what numbers it needs to show on the o2. Could we find a cat that could simulate that? something like an SUV or larger vehicle that uses a larger flowing cat but can cut out the extra chemicals.

example. use an OEM stock BMW x6M or merc AMG c63s cat. weld those to the aftermarket downpipe on our cars. since those would normally pass smog with a higher flow compared to our smaller engine. how would we make that work? not so much how it wouldnt work. since we know right from the gate it wouldnt be pnp. what solutions could we make it work is what I would like to see here.

[CXSnail]

i wonder if we know what numbers it needs to show on the o2. Could we find a cat that could simulate that? something like an SUV or larger vehicle that uses a larger flowing cat but can cut out the extra chemicals.

example. use an OEM stock BMW x6M or merc AMG c63s cat. weld those to the aftermarket downpipe on our cars. since those would normally pass smog with a higher flow compared to our smaller engine. how would we make that work? not so much how it wouldnt work. since we know right from the gate it wouldnt be pnp. what solutions could we make it work is what I would like to see here.

Necessity is the mother of invention!

I've wondered this exact thing myself. You would think with the larger surface area, it would naturally be higher flowing. Never enough to try it out myself, though.