Anyone use headers on their TJ?
- Thread starter weldedcambolt
- Start date
Heads on a 4.0 are about as much of a scam as stainless steel brake lines.
The issues with aftermarket headers for TJs is that they are prone to cracking (especially if you flex a lot off-road) as they don't have the factory flex joints in them. In addition to that, if you have a 2001+ TJ with the dual cats in the downpipe, the headers you can get are just the upper portion, and they don't flow any better than stock.
You'll be lucky if you gain 2-3 hp with those headers, and that might not even be from the headers themselves, as back-to-back dynos can give varying results based on things like heat soak, altitude, variances in the dyno, etc. In other words, the 2-3 hp you'd gain is very hard to actually prove.
Do yourself, a favor and DO NOT waste your money on headers for a 4.0. I've gone down that road myself and I can tell you without a sliver of doubt that they are a giant waste of money. The 4.0 isn't a Ferrari engine. It doesn't respond to headers like a big block V8 would (then again, the headers they make for those things are big, beefy, and a whole different story).
There really isn't many ways to get extra horsepower out of a 4.0 short of adding forced induction or stroking it. I know it's not what most want to hear, but it's the cold hard truth. Air intakes, headers, "chips", and exhausts, will yield such negligible gains in horsepower that the only thing you'll notice is an empty wallet.
The issues with aftermarket headers for TJs is that they are prone to cracking (especially if you flex a lot off-road) as they don't have the factory flex joints in them. In addition to that, if you have a 2001+ TJ with the dual cats in the downpipe, the headers you can get are just the upper portion, and they don't flow any better than stock.
You'll be lucky if you gain 2-3 hp with those headers, and that might not even be from the headers themselves, as back-to-back dynos can give varying results based on things like heat soak, altitude, variances in the dyno, etc. In other words, the 2-3 hp you'd gain is very hard to actually prove.
Do yourself, a favor and DO NOT waste your money on headers for a 4.0. I've gone down that road myself and I can tell you without a sliver of doubt that they are a giant waste of money. The 4.0 isn't a Ferrari engine. It doesn't respond to headers like a big block V8 would (then again, the headers they make for those things are big, beefy, and a whole different story).
There really isn't many ways to get extra horsepower out of a 4.0 short of adding forced induction or stroking it. I know it's not what most want to hear, but it's the cold hard truth. Air intakes, headers, "chips", and exhausts, will yield such negligible gains in horsepower that the only thing you'll notice is an empty wallet.
ya, I didnt think, they could be much of an improvement, now some of them buying them off of amazon, were saying they sound good? now if you have a crack in the factory ones, an have to replace them, since you have to get them off, would you put a set of headers on, if you were paying the same price for factory exhaust manifold? now, them stainless lines, are awesome, if they dont rust out. my pedal, has no spongy. dont be knocking on my stainless
The cracking factor alone make them worthless.
I had a set of Banks Torque tubes on my 4.0 years back. Less than a year after purchasing them brand new, they cracked. The design on the 4.0 aftermarket headers is crappy and the metal is thin.
Like I said, if you do any sort of off-roading, they crack in short order.
I had a set of Banks Torque tubes on my 4.0 years back. Less than a year after purchasing them brand new, they cracked. The design on the 4.0 aftermarket headers is crappy and the metal is thin.
Like I said, if you do any sort of off-roading, they crack in short order.
tquig01
TJ Enthusiast
Chris- coming from the sportbike world, stainless lines gave noticeably better brake response, albeit in a much different set of driving/riding conditions. With the less than stellar brakes on the TJ, I was thinking I would get some improvements going SS. I'm guessing you have already gone down this path with limited success. What was your experience with them? Short of full caliper upgrade, anything you found that helps?
SpikeMaul
Member
I had some Thorleys installed just because I wanted to. As Chris said, really no power gain. I did notice smother top end, not really any power gain. When in 4 low right off of idle there is a differance in hit. Stock had a longer sweet spot " throttle movement" for the power to roll on. With the headers it is almost to quick. Have no problems in the 3 years I've had them. Would I purchase again? With money a concern, No!
17" Big Brake/ Black Magic Kit. I have 37" 's and this jeep stops very well and quickly. Probably the best purchased made. Excellent Product!!!!
Let me chime, in since I had Banks Torque Tube headers on my TJR when I bought it.
First, despite what anyone else will tell you about aftermarket headers not having any performance benefits on the 4.0L motor are wrong. I put stock headers back on, and I lost a noticable amount of power and responsiveness. So in this regard, do not listen to anyone except those that have actually run with them! They are probably just repeating the opinions of old timers that think they know everything, that do not have any experience running them.
Second, don't do it! The power gains are not worth the downsides, which are:
First, despite what anyone else will tell you about aftermarket headers not having any performance benefits on the 4.0L motor are wrong. I put stock headers back on, and I lost a noticable amount of power and responsiveness. So in this regard, do not listen to anyone except those that have actually run with them! They are probably just repeating the opinions of old timers that think they know everything, that do not have any experience running them.
Second, don't do it! The power gains are not worth the downsides, which are:
- Prone to cracking like it was mentioned above
- Nearly impossible to properly mount and remove without dropping the motor - given how the lower bolts are blocked by the exhaust tubes
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I am an old timer, but unlike some of the old timers you reference, I do not believe that I am a walking TJ encyclopedia. I do, however, have personal experience with headers on Jeep inline 6 engines, including the 4.2, 4.0 and 4.7 stroker.
My opinions:
(1) marginal performance gains;
(2) crack more easily than the OEM exhaust manifolds for the 4.0;
(3) red flag for emissions inspectors;
(4) generally a waste of time and money; but
(5) sound like they increase performance in some meaningful way even though they don't.
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I'm going to have to agree to disagree with you here, especially having run the Banks Torque Tube headers on my Rubicon for about a year before switching back to the stock manifold. Unless you can show back-to-back dyno charts of before and after the header install, the "noticeable power" doesn't mean much at all. In the case of something like a supercharger, it's impossible not to notice, and I would't doubt you one bit. However, based off all the dyno charts I've seen in regards to 4.0 headers in the past, the 1-3 hp people have gained is not enough to be "noticeable" other than a placebo effect.
My Banks headers made more noise, so that added to the effect of "performance gains", but it wasn't real. In addition to that, when I put the stock manifold back on, I didn't feel like I lost anything other than noise.
Often times with headers, what's happening is that power bands are being slightly shifted around. So sometimes people assume they've gained power, when they've really just changed their power band (such was the case with the large headers I put on my old E39 M5, though with those I actually did gain about 30 hp, but it was mostly in the mid to top range due to the size of those things).
Dynos have so much variance in them as well, that measuring something like a 1-3hp gain is negligible at best, and can be chalked up to a lot more than just a bolt-on modification.
So while I do indeed respect your opinion (and this is in no way meant to start an argument), I'm going to have to say that I disagree with you on the power gains 100%. I feel like I'm entitled to as well, since I have run the same headers before too.
I believe that if the 4.0 could use full length headers that went all the way from the head down past the catalytic converters, then there would be some power to be gained. But the fact that the exhaust manifold stops right as it hits the pre-cats is restrictive in my mind, and therefore aftermarket headers leave a lot to be desired.
Anyways, just sharing my opinion on this matter, don't take it personally or anything.
I come from sport bikes as well, having ridden them most of my life. You won't gain any braking power at all with stainless steel lines on a TJ. Ask someone like @mrbaline, who designs braking components and systems for our TJs. He'll school you on brakes better than anyone on this forum possibly can.
There was a bunch of good information this the "Upgrading brake lines" thread last week that @Jerry Bransford posted.
To copy and paste some of what Jerry said:
Jerry Bransford said:Despite the bogus claims by some who sell steel braid covered brake hoses, hoses have zero effect on braking performance. Factory brake hoses are reinforced with multiple layers so they absolutely do NOT expand when you apply on the brakes, even when you slam on the brakes.
To add a little more... while brake lines may look similar to vacuum hoses, windshield washer hose, etc., they're a far cry from simple single layer rubber hoses like those are. The DOT demands they meet very rigid guidelines for strength, ability to withstand expansion under pressure, etc. They do so by being made up of multiple layers that reinforce each other to absolutely prevent expansion under braking system pressures.
Not to mention many aftermarket brake line hoses only slide on their outer stainless steel braiding as decoration, it's not really reinforcing the hose it covers.
Here's one example of a stock brake line hose..
Keep in mind a couple things... first, it is the front brakes that provide roughly 75% of the braking. The brake line pressure has to be limited to the rear brakes since they lock up so much more easily during hard braking due to weight transfer away from the rear tires and onto the front tires. Improving the rear brakes is not the way to help braking.
Second, 33" tires have more leverage against the brakes than the smaller factory size tires do so the brakes become less effective as tires get larger. Which is why with larger size tires we consistently recommend upgrading the front brakes with better pads or the a dual-piston braking system upgrade from Black Magic Brakes.
Here's something @mrblaine said in the same thread:
mrblaine said:
To sum things up, I can't comment on stainless steel brake lines in extremely high performance applications such as racing motorcycles or F1 vehicles. I'll let someone like Blaine address that, since he knows more than me on the matter.
I can however tell you without a shadow of a doubt that stainless steel brake lines on a TJ will yield zero braking performance gains whatsoever. Anything you think you may feel is all in your head. I understand them from an aesthetic point of view, for sure. I just would hate to see someone put them on a TJ thinking it's going to improve braking performance.
In regards to performance, the TJ has more in common with a tractor than it does a Ferrari.
We definielty experienced different things. Dynos as you know aren't the truth of reality, and pretty much everything that I have read on the few tests done by those outside if Banks were subjective anyhow (there seems to be PR and anti-PR campaigns published). I have an intimate connection with my Jeep's performance, so I could without a shred of doubt tell the difference on low-mid end torque between the before and after as have others. I wouldn't notice 1-3 ft lbs of torque unless I had a 10HP motor. The new headers are also pretty restrictive, visually - and they do not align well with the exhaust ports coming offnof the block (in fact they block probably 15% or so, which is stupid).
If the OP is looking to scrape every ounce of additional power possible for whatever sadistic reasons, then I would say you can expect to get some gains with aftermarket headers for sure. Other than that, boost it!!!
There's nothing quite as accurate or reliable as a well calibrated butt dyno.
:drive:
tquig01
TJ Enthusiast
Thanks for the info Chris. As you know, there is a noticeable difference on a sport bike when you switch to SS lines, but bikes have a pretty basic brake system by comparison to the TJ (or any normal car). The more I think about it, I suspect the mechanics of a power brake system overcome any benefits of the SS lines. Guess I will re-direct that money to something more beneficial like better pads until a big brake kit is in the budget. Thanks again.
I replaced my factory pads and rotors recently.. I can't imagine needing a BBK, given the way I drive!
The common reason given is S/S do not swell as much as the OEM rubber flex hoses do. Sounds legit, right? The problem is they are not quite rubber like a balloon, they are rubber like the power steering pressure hose from the pump and in stock form are tested to exceed 3000 psi. Being the inquisitive sort and having access to a brake system that put out nearly 3000 psi, I hooked up each, checked the expansion with a digital caliper and found that both swell exactly the same amount at 3000 psi. About .0005 or so.
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