s346k

this is not entirely true, just with these 4 liter motors haha. I think XJs are so unresponsive because regardless of how well the intake or exhaust works, the head is the limiting factor. adding long tube headers to say...an ls1 engine will make a 10%+ increase in power with no other additions. not bad when you're starting with an engine that makes 350 hp already.

and also regarding a jeep header...the designs are almost identical by default. there's no way to make one better than the other because of space limitations and factors like the driveshaft, etc getting in the way. not to mention, with a stock head the engines won't gain enough power when comparing headers to make a hill of beans difference.

and why is the comparison of a race car and a jeep even being made here? EL OH ELLLLLLLLL

OP: I say buy the cheapest header you feel comfortable with. some friends of mine have used OBX headers on dodge neons, vettes, fbodies, and various trucks. they provide a good balance of value and durability.

mr white

Ihe won't add a noticeable amount of power. If you look at dyno results you'll see. What I was getting at is you could spend like 3k on an exhaust and does it even matter on a jeep to gain 2hp?

94JeepCherokeeMan

I don't think you're understanding what I was getting at in the first place. YES, we know that adding headers to a completely stock 4.0 Liter I-6 will not net you much gain. I agree, it's probably effing pointless if that's ALL you do.

HOWEVER... If you open up the intake, spend a little time tuning your engine, and work with what you have just a little bit, you can easily gain about 20 hp, maybe even more. That includes working with the exhaust. If you work with the head, you WILL see more power, and that's just a DIY porting job to clean it up. If you opened up the intake didn't open up the exhaust, then you wouldn't see much of a gain, would you? The two work in tandem. Note, I said that you'd be doing it wrong if you added a header and opened up the intake to only gain a horse or two.

BTW, if you're spending $3,000 on an exhaust, the Jeep better drive itself.

mr white

We are both missing each other. I am saying if I put you in a jeep with an apn header then take that off and put on a banks header you wouldn't tell the difference. You'd also be hard pressed to tell the difference if I put the stock header back on. Does it make a difference? Yeah. Is it worth dumping 600+ on a header for this application? Hell no.

94JeepCherokeeMan

Actually, I think you would see a bigger difference, and you certainly get what you pay for. The APN header design sucks, to be perfectly honest, and is probably hardly any better than stock. Using a correct header design will bring more torque across a wider range of engine speeds, giving you much more available power for what most of us do. The cost of admission is not a $600 set of Banks headers, in fact you can get a set of headers in a much better design for the same price as the APN if you shop smart.

s346k

with exception to the pacesetter design, I think they all suck. frankly the whole intake/exhaust setup sucks. whoever thought it would be a good idea to put the intake manifold on top of the exhaust manifold needs woah shamboah'd for the right to eat. I go first.

94JeepCherokeeMan

Well, time for some aluminum heat shielding, at any rate.