Is there a good catted header?

[SpeBud07]

Originally Posted by Tokay444

That will be a thing of the past, as it is with pretty much anything that isn't a full stand alone on just about all other platforms.

This. What Cobb did on many platforms was force an upgrade to their units when you connect them to the network new software disables the means of turning off the CEL for no catalysts. Pissed a whole lot of people off, but they were under a ton of pressure from the government. APR did the same thing.

The fines are really ridiculous if you get caught now, so many of the tuners are just washing their hands of it on some platforms. I can't say this is a blanket statement for all tuners or run around screaming like chicken little, but I'll give up 10-15% if it means being able to keep what I have.

Of course, the parts are so cheap for this car compared to many, maybe it doesn't matter that much.

[Lantanafrs2]

P&L

[blsfrs]

Originally Posted by KillerBMotorsport

The cat itself is very much a get what you pay for component. Don't shop specifically by cell count because a larger high end 400 cell cat can perform better than a cheap 200 cell cat. As far as emissions goes, same deal. A higher end cat will have better materials and coatings for improved chemical conversion (cat efficiency). So don't assume any cat will solve the P0420 dilemma. Look for EPA, CARB, or Euro emissions certification numbers. 'Race' cats are next to useless when it comes to emissions. A high dollar performance cat will perform best and leave the least amount of power on the table. Will it leave some on the table vs non-catted? Yes, but not anything like it used to 15-20 years ago. The performance gap has shrunk with improvements in manufacturing processes and materials.

I think the bigger question is what is it worth to you? Some will balk at a $1,500 header that does each OK, but many more would likely be a no-go for a $3,000 header that does both well.

Why not build a header with a removable cat? That would give everybody a choice. The cat in my Swaintech coated, AFE header went bad, so I had to knock it out. It would have been too expensive to get a new catted header and then have it coated. I would have liked to have been able to replace just the cat to stay emissions legal and not worry about the dreaded P0420.

[RToyo86]

Originally Posted by blsfrs

Why not build a header with a removable cat? That would give everybody a choice. The cat in my Swaintech coated, AFE header went bad, so I had to knock it out. It would have been too expensive to get a new catted header and then have it coated. I would have liked to have been able to replace just the cat to stay emissions legal and not worry about the dreaded P0420.

Doable but would add cost to already expensive catted headers. On-top of adding more potential issues.
The secondary O2 sensor needs to go on the pipe after the cat. A leak at the flange between the two is a no-no. Maybe a slip joint style setup would mitigate potential issues. Good luck getting that apart after its heat cycled thousands of times

[PulsarBeeerz]

Originally Posted by blsfrs

Why not build a header with a removable cat? That would give everybody a choice. The cat in my Swaintech coated, AFE header went bad, so I had to knock it out. It would have been too expensive to get a new catted header and then have it coated. I would have liked to have been able to replace just the cat to stay emissions legal and not worry about the dreaded P0420.

Packaging, performance and price.

[SpeBud07]

I was trading emails with a respected national tuner yesterday (I'll keep the names out to protect the innocent) who said if a cat is necessary, keep the factory header. Here's his take:

"We just have not seen a reliable aftermarket one with a cat, the ones we have had done we had to pull out the timing to the point of the car losing power from this modification.
Them already making about 160-170 to the wheels and losing more on top of that, makes it pretty bad."

Take that for whatever it's worth, but it's making me rethink my approach.

[spcmafia]

Originally Posted by SpeBud07

I was trading emails with a respected national tuner yesterday (I'll keep the names out to protect the innocent) who said if a cat is necessary, keep the factory header. Here's his take:

"We just have not seen a reliable aftermarket one with a cat, the ones we have had done we had to pull out the timing to the point of the car losing power from this modification.
Them already making about 160-170 to the wheels and losing more on top of that, makes it pretty bad."

Take that for whatever it's worth, but it's making me rethink my approach.

If you're thinking about making the most power, potentially a marginal gain over UEL. EL would be the way to go. A cat itself won't guarantee the absence of a CEL. But it helps in those states where a visual inspection is necessary.

I believe that if you're staying NA , but with E85, an EL uncatted will get you the most of power necessary. I may be wrong but the potential gain could be somewhere on the 5HP over UEL, uncatted.

If you go either UEL, or EL, catted, the amount of power that you'd be missing if marginal at most, unless it really does matter to you.

I have a JDL Catted UEL, also NA, and the car feels great specially after getting a custom OFT tune. Have not run into any issues and I'm about 30K miles into it. I don't have access to E85 so I can't speak on the power comparison. But I also at the same time, don't drive the car constantly on the red line, which is where you wold have to be to really enjoy every single HP your header provides, regardless of your choice.

[SpeBud07]

Originally Posted by spcmafia

If you're thinking about making the most power, potentially a marginal gain over UEL. EL would be the way to go. A cat itself won't guarantee the absence of a CEL. But it helps in those states where a visual inspection is necessary.

I believe that if you're staying NA , but with E85, an EL uncatted will get you the most of power necessary. I may be wrong but the potential gain could be somewhere on the 5HP over UEL, uncatted.

If you go either UEL, or EL, catted, the amount of power that you'd be missing if marginal at most, unless it really does matter to you.

I have a JDL Catted UEL, also NA, and the car feels great specially after getting a custom OFT tune. Have not run into any issues and I'm about 30K miles into it. I don't have access to E85 so I can't speak on the power comparison. But I also at the same time, don't drive the car constantly on the red line, which is where you wold have to be to really enjoy every single HP your header provides, regardless of your choice.

Thanks, that's good data. I have been in contact with JDL and they just got some GESI G-sport cats back in, and will be putting them back out for those interested. I'd love to see something like an HJS cat, but those are really expensive and probably more than most of us want to pay.

[Tatsu333]

It's not inexpensive, but HKS makes their "Super Manifold with Catalyzer GT-Spec", which is their 4-2-1 equal length header with a cat in the stock location. It was originally what I had planned to do with my build (though my plans have changed now).

Vs. the 2017+ OEM header, the layout is basically the same, the primaries are smaller (42.7mm vs. 45mm - FWIW, same as the pre-2016 header), secondaries are slightly larger (50.8 mm vs. 48.6 mm) and the collector and cat are larger (60 mm vs. 54 mm).

Given all that, I'm not sure there would be much, if any, improvement over a 2017+ OEM header, and the OEM would 100% be emissions-legal, if that's your main concern, so...up to you!

[ACT86]

Strange question I realise, but if you’re just after the boxer rumble, could a decent exhaust shop just lengthen two of the stock header pipes to create the same effect, or are they specifically tuned to a certain length?

[Tatsu333]

Originally Posted by ACT86

Strange question I realise, but if you’re just after the boxer rumble, could a decent exhaust shop just lengthen two of the stock header pipes to create the same effect, or are they specifically tuned to a certain length?

Could you? Sure, but why not just buy a catted UEL in that case?

Any such modification to the stock header would most likely render it not emissions-legal in many jurisdictions, so if you're going to be illegal anyway, why not go with a catted aftermarket UEL that would have better piping diameters for power?

[PulsarBeeerz]

Originally Posted by ACT86

Strange question I realise, but if you’re just after the boxer rumble, could a decent exhaust shop just lengthen two of the stock header pipes to create the same effect, or are they specifically tuned to a certain length?

Is he after the boxer rumble? I must have missed that. I doubt any exhaust shop wants to modify a factory exhaust with emissions devices on them atm.

[ACT86]

Originally Posted by PulsarBeeerz

Is he after the boxer rumble? I must have missed that. I doubt any exhaust shop wants to modify a factory exhaust with emissions devices on them atm.

Was just a question really. Retains the factory cat, so no change with emissions / CELs etc. Just slightly lengthening two pipes.

[ACT86]

Originally Posted by Tatsu333

Could you? Sure, but why not just buy a catted UEL in that case?

Any such modification to the stock header would most likely render it not emissions-legal in many jurisdictions, so if you're going to be illegal anyway, why not go with a catted aftermarket UEL that would have better piping diameters for power?

I was led to believe that the Catted aftermarket heads don’t make THAT much difference in power over the 2017 headers. Main reason being that they are $1850 landed here, plus the FT86 headers still throw a code, so a tune would be needed, which is another $1k or so. Be a couple of hundred bucks for the local exhaust shop to lengthen two pipes slightly with a similar end result.