OEM vs. High Flow Cats

[George-CZ]

Maybe a trivial question
But what will be the difference between OEM and HF Cats in terms of emissions?

I was looking for something, but mostly the answer "I'm from Florida, we don't have emissions" or "how many horses will add HF Cats".

Here in Europe, the emission frenzy is in full swing, and if I need to return the stock tune, I would like to know what result awaits me.

I don't like the idea that I will have to change every 2 years OEM exhaust manifold with cats for emission check .

[CamaroCracka]

"I'm from Florida, we don't have emissions"

On a more serious note, I recall some threads where this was discussed over fear of failing inspection and IIRC, the consensus was that they allow more pollutants than stock cats, but perhaps not enough to make you fail.

Other options might be some kind of cutout set up or run it on E85 if you have that over there. Alcohol burns much cleaner.

[pyroguy]

The last two places I've lived have had emissions and passed with long tube headers and high flow cats. Unless you have ridiculous laws like California that require you to not have long tube headers, get some long tube headers with high flow cats tube your car, and you'll be fine. Best of luck on your situation!

[George-CZ]

Originally Posted by CamaroCracka

"I'm from Florida, we don't have emissions"

On a more serious note, I recall some threads where this was discussed over fear of failing inspection and IIRC, the consensus was that they allow more pollutants than stock cats, but perhaps not enough to make you fail.

Other options might be some kind of cutout set up or run it on E85 if you have that over there. Alcohol burns much cleaner.

So far, I am meeting the emissions for my country.
But emissions for the LS3 Camro are slightly higher than normal.

So it was always somehow solved.

Sure ... Ecology must be taken into account.
A car that smokes like a dug stove is probably not okay.
But panicking the grams of exhaust fumes at a car that drives a few hundred miles a year seems a little off.


I don't have much good experience with E85.
I tried the conversion on the other car and I couldn't reconcile it well.
Correctly, the injection cycle should be extended by 30%. But the engine was still missing. He stopped omitting up to 1%. But what is one percent of 30.

I saw a couple of destroyed engines from incorrect E85 settings.
So I'm leaving this idea in the background for now.

[George-CZ]

Originally Posted by pyroguy

The last two places I've lived have had emissions and passed with long tube headers and high flow cats. Unless you have ridiculous laws like California that require you to not have long tube headers, get some long tube headers with high flow cats tube your car, and you'll be fine. Best of luck on your situation!

California is a complete dictatorship when it comes to car traffic. Thanks God for a more accommodating approach to tuning in my country.

I have Stainless Power long tubes and Stainless Power HF cats.
The condition of the emission control is that I must not have any CEL and no warning light must be on.

That's why I have an "emission" tune created in the backup.
It's basically an OEM tune, but the rear O2 sensors are disconnected so that I don't see CEL.

So I would like to know what will happen if this situation occurs and I would record an OEM tune for HF cats.

If you say it's going to be okay, it calmed me down a bit.

[CamaroCracka]

Originally Posted by George-CZ

I don't have much good experience with E85.
I tried the conversion on the other car and I couldn't reconcile it well.
Correctly, the injection cycle should be extended by 30%. But the engine was still missing. He stopped omitting up to 1%. But what is one percent of 30.

Running E85 absolutely requires the tune be modified to turn on the flex fuel tables. You also have to add a fuel composition sensor and run a wire to the ECM. Anything less will will end up with a bad day.

They also have devices that produce a dummy signal for the rear O2s as well as extension that HFCs not throw codes. Like yours, mine are turned off, so I can't speak to how well they might work.

[pyroguy]

Originally Posted by George-CZ

California is a complete dictatorship when it comes to car traffic. Thanks God for a more accommodating approach to tuning in my country.

I have Stainless Power long tubes and Stainless Power HF cats.
The condition of the emission control is that I must not have any CEL and no warning light must be on.

That's why I have an "emission" tune created in the backup.
It's basically an OEM tune, but the rear O2 sensors are disconnected so that I don't see CEL.

So I would like to know what will happen if this situation occurs and I would record an OEM tune for HF cats.

If you say it's going to be okay, it calmed me down a bit.

If you have a tune that eliminates any CEL's or other warning lights you should be good. The last place I lived had a piece they put in my exhaust pipe in addition to making sure I didn't have any lights on. The first time I was inspected after getting my cam swap done I was sweating bullets, but passed. Not knowing your local laws I won't 100% guarantee you'll be fine, but state side I've been fine for years.

[George-CZ]

Originally Posted by CamaroCracka

Running E85 absolutely requires the tune be modified to turn on the flex fuel tables. You also have to add a fuel composition sensor and run a wire to the ECM. Anything less will will end up with a bad day.

They also have devices that produce a dummy signal for the rear O2s as well as extension that HFCs not throw codes. Like yours, mine are turned off, so I can't speak to how well they might work.

At the time, I was testing it through a module that plugged into the injector circuit.



But as I wrote. The engine did not run well.
So I left this idea.

I won't lie that I wouldn't like the E85 conversion. They say it works wonders with the car.
But when I asked my tuner about the Camaro, it is said that it does not convert to the E85.

And I don't dare do it myself.

[George-CZ]

Originally Posted by pyroguy

If you have a tune that eliminates any CEL's or other warning lights you should be good. The last place I lived had a piece they put in my exhaust pipe in addition to making sure I didn't have any lights on. The first time I was inspected after getting my cam swap done I was sweating bullets, but passed. Not knowing your local laws I won't 100% guarantee you'll be fine, but state side I've been fine for years.

Yeah ... That's exactly how it goes here, too.
Inserts the sensor into the exhaust and maintain the engine speed at 2800 rpm.
And you have to fit on the scale.

I didn't interfere with the engine.
I did things around. Long tubes, cats, CAI and ported throttle body and tune.

So when I return the original tune, the engine should be back in factory mode. But the question is how much it will affect HF Cats.

But I also think that if there is a difference, so small.

[pyroguy]

Originally Posted by George-CZ

Yeah ... That's exactly how it goes here, too.
Inserts the sensor into the exhaust and maintain the engine speed at 2800 rpm.
And you have to fit on the scale.

I didn't interfere with the engine.
I did things around. Long tubes, cats, CAI and ported throttle body and tune.

So when I return the original tune, the engine should be back in factory mode. But the question is how much it will affect HF Cats.

But I also think that if there is a difference, so small.

2800 rpms?! That's a bit extreme. If you're cruising at 2800 rpms in a Camaro, unless you need to shift you're really moving fast down the road.

I'd be careful with going back to a stock tune though. With long tube headers they will throw a code.

[George-CZ]

Originally Posted by pyroguy

2800 rpms?! That's a bit extreme. If you're cruising at 2800 rpms in a Camaro, unless you need to shift you're really moving fast down the road.

I'd be careful with going back to a stock tune though. With long tube headers they will throw a code.

The test takes place in laboratory conditions.

The car connects to the OBD port, inserts a probe into the exhaust and the test takes place on a static car.

I assume you'll have it anyway.

The test itself takes a few seconds.
The only thing that could light up is the CEL of the rear o2 sensors. And these are off. So that should be fine.

[TheButcher]

Here in Kommiefornia we are officially screwed. We can’t really change anything cat forward except some CARB #’d shorty headers. Can’t touch the cats at all. The difference as far as emissions actual data? No clue. But I do believe most HF cats are “spun metallic” and stock are standard platinum style cats. Sorry, don’t know the technical name. On my GTO’s the HF cats were a big performance gain, for the money.

[pyroguy]

Originally Posted by George-CZ

The test takes place in laboratory conditions.

The car connects to the OBD port, inserts a probe into the exhaust and the test takes place on a static car.

I assume you'll have it anyway.

The test itself takes a few seconds.
The only thing that could light up is the CEL of the rear o2 sensors. And these are off. So that should be fine.

I was guessing it was in a controlled environment, but to hit 2,800 rpms on the road you're really moving. It just seems like an unrealistic simulation. My last emissions test was at 2,000 rpms, a much more realistic traveling rpm.

[George-CZ]

Originally Posted by pyroguy

I was guessing it was in a controlled environment, but to hit 2,800 rpms on the road you're really moving. It just seems like an unrealistic simulation. My last emissions test was at 2,000 rpms, a much more realistic traveling rpm.

I agree. 2800 ot. on 6 gears ...
I really don't ride that. I'm usually below 2,000 rpm.

But looking for reason in the European Parliament is like looking for a needle in a haystack.