aFe Long Tube Headers

Chris

Chris

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After disabling my catalytic convertors and post cat O2 sensors, the next plan is to remove the cats entirely since I won't have to worry about check engine lights anymore (we don't have inspections or emissions where I live).

I had thought about just cutting the pre-cats out and welding in some tubing in place of them. However, I'd always thought it might be cool to have some long tube headers built for the 4.0 and then have them ceramic coated. The headers they sell for the 4.0 are a joke (at least for the 01-06 4.0s with the pre-cats). You don't gain any power from them, and they are a waste of money. However, I believe with some real long tube headers they might be some power to be gained.

As for ceramic coating, I did that on a number Ducati motorcycles I owned in the past, and WOW, all I can say is that it tremendously cut down on the amount of heat that exhaust was putting off.

So I started digging around in regards to long tube headers to pair with my Magnum Powers supercharger system, and I stumbled upon something I never knew existed for the 4.0:
https://www.amazon.com/dp/B01AHNVSIW/?tag=wranglerorg-20

Yep... long tube headers!

The plan is to order a set of these and have them ceramic coated. I'm not sure if I'll gain much power from the headers or not, but at least I'll get those pesky pre-cats out of there in the process!

Just wanted to share, since I've never seen these before until now.
 
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Thermal barrier coatings are not appropriate for an intake manifold. Inlet Air Temperature (IAT) post aftercooler will be higher than ambient. If you must coat the IM, a thermal dispersant would be a better product. The good thing about forced induction is that it forgives many sins in both inlet and exhaust paths.

If you're going to spend money on an aftermarket header, be sure it has a bellows section somewhere in the exhaust pathway.
 
Another option is to have someone build me a set of long tube headers. Of course I haven’t the slightest clue how much I would pay for that.

Or I could just cut the cats out and weld in tubing in place of them. I’ve always liked the idea of headers though... but actual long tube headers. Not the crappy little ones they sell for the stock 01-06 exhaust manifold.
 
Chris said:
Another option is to have someone build me a set of long tube headers. Of course I haven’t the slightest clue how much I would pay for that.

Or I could just cut the cats out and weld in tubing in place of them. I’ve always liked the idea of headers though... but actual long tube headers. Not the crappy little ones they sell for the stock 01-06 exhaust manifold.
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I feel like the cost of custom long tubes would be astronomical. But just a guess.
 
How about posting some pics when you have it done? I would love to see it. We have state inspections where I live but no emissions checking. Worst case is you gut your cat where I live and weld a straight pip down the center of it and put it back in place so it looks like you have cats.
 
Fouledplugs said:
I feel like the cost of custom long tubes would be astronomical. But just a guess.
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I suspect it would be, as it's a lot of work!

ZEN357 said:
How about posting some pics when you have it done? I would love to see it. We have state inspections where I live but no emissions checking. Worst case is you gut your cat where I live and weld a straight pip down the center of it and put it back in place so it looks like you have cats.
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I'll post some photos when it's done. Remember, you'd have to disable the catalytic convertors and post cat O2 sensors via the PCM, otherwise you'll have check engine lights that will never go away.
 
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I gutted my cats, diabled my post 02's, and welded in a 3" 90 coming straight from the down pipe to a straight run of 3" exhaust to a performance muffler. Reducing backpressure will make tuning easier.

A cheaper option is to run the earlier 97-00 wrangler long tube headers, and delete the mini cat down pipe completely - then weld a 90 to a straight pipe. That's my next move as far as headers go. I've seen dyno's reporting 15WHP from headers on boosted 4.0's!
 
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Alex0413 said:
I gutted my cats, diabled my post 02's, and welded in a 3" 90 coming straight from the down pipe to a straight run of 3" exhaust to a performance muffler. Reducing backpressure will make tuning easier.

A cheaper option is to run the earlier 97-00 wrangler long tube headers, and delete the mini cat down pipe completely - then weld a 90 to a straight pipe. That's my next move as far as headers go. I've seen dyno's reporting 15WHP from headers on boosted 4.0's!
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I wasn't entirely sure if the 97-00 headers would fit. I thought someone had mentioned something about the heads being slightly different on the earlier models, to the point where they wouldn't be a direct bolt on. Maybe I read wrong?

I know I can get more horsepower with some actual headers from my 4.0 with the forced induction, this is one of the reasons I want to do it.

Another reason is that Josh Pearl (the guy who is going to tune mine) had mentioned that if I don't get rid of the pre-cats, it's just going to hinder the tuning, prevent the ability to get more power out of it, and eventually I'd blow the cats anyways with the supercharger on there.

So the earlier 97-00 headers may actually be an option if they will fit.
 
Alex0413 said:
I gutted my cats, diabled my post 02's, and welded in a 3" 90 coming straight from the down pipe to a straight run of 3" exhaust to a performance muffler. Reducing backpressure will make tuning easier.

A cheaper option is to run the earlier 97-00 wrangler long tube headers, and delete the mini cat down pipe completely - then weld a 90 to a straight pipe. That's my next move as far as headers go. I've seen dyno's reporting 15WHP from headers on boosted 4.0's!
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That is what I would do..but I am a cheap bastard. A grand for a set of 6 cylinder headers is ridiculous.
 
Chris said:
...I know I can get more horsepower with some actual headers from my 4.0 with the forced induction...I'd blow the cats anyways with the supercharger on there...
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You don't know for certain you will achieve HP gains with an aftermarket header.

Forced induction is guaranteed to provide gains.

FI won't blow the cats out on its own. Most often catalytic converter failure in an FI application is caused by unburned fuel. A poorly designed header can hasten a cat's demise too.
 
Just want to note that header design is a non-trivial exercise in fluid dynamics engineering. Went through this with a 400 cid small block with mixed results. Wasn't worth the time and expense, and all I was paying for was materials when I attempted it.
 
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ImpactOrange said:
Take a look at these too @Chris

https://americanracingheaders.com/c...-2006-tj-4-0l-long-system?variant=29943906692
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Those are costly, but look very nice!

k-huevo said:
You don't know for certain you will achieve HP gains with an aftermarket header.

Forced induction is guaranteed to provide gains.

FI won't blow the cats out on its own. Most often catalytic converter failure in an FI application is caused by unburned fuel. A poorly designed header can hasten a cat's demise too.
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This is true, I don't know for certain. However, I do need those pre-cats out of there, and I would like to have whatever I put in place of them ceramic coated (due to my good experiences with it in the past).

Being as though there aren't too many options for the 4.0 in terms of headers, my options are obviously limited. The tuner seems very confident that with some headers I should be able to get a bit more power out of it. But I understand there is no guarantee.
 
StG58 said:
Just want to note that header design is a non-trivial exercise in fluid dynamics engineering. Went through this with a 400 cid small block with mixed results. Wasn't worth the time and expense, and all I was paying for was materials when I attempted it.
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It may be more worth it to just take the pre-cats out then and call it a day, huh?
 
Chris said:
It may be more worth it to just take the pre-cats out then and call it a day, huh?
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That's entirely up to you, of course, but there's a bunch of things to consider in header design. Even the Pro's don't get it right a lot of the time. Throw in a supercharger like you're doing and all bets are off. Even something as seemingly trivial as bend radius or collector length makes a difference.
 
StG58 said:
That's entirely up to you, of course, but there's a bunch of things to consider in header design. Even the Pro's don't get it right a lot of the time. Throw in a supercharger like you're doing and all bets are off. Even something as seemingly trivial as bend radius or collector length makes a difference.
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Interesting. I'll have to give it some more thought I suppose. I need to get the cats out of there, but there's obviously more than one way to accomplish that.
 
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Hey, @Chris, have you thought about plugging in a custom profile cam shaft to match your desired performance to that supercharger? There's bang for the buck to be had there. Get a hold of Iskenderian and have a chat with them about your requirements. I bet they have a cam, or at least a profile, on the shelf that would buy you something. Just thinking out loud here. Cam profiles differ between naturally aspirated and supercharged engines.
 
StG58 said:
Hey, @Chris, have you thought about plugging in a custom profile cam shaft to match your desired performance to that supercharger? There's bang for the buck to be had there. Get a hold of Iskenderian and have a chat with them about your requirements. I bet they have a cam, or at least a profile, on the shelf that would buy you something. Just thinking out loud here. Cam profiles differ between naturally aspirated and supercharged engines.
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Good point. That’s something I hadn’t even thought about until now. I’ll have to talk to them about it. Oh the possibilities!
 
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