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post #1 of (permalink) Old 09-18-2003, 05:55 PM
Distraktion
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Help! To header or not to header!

Ok I couldn't think of a better subject heading but it seems appropriate. I drive a 1998 Jeep Wrangler that currently has a crack in the exhaust manifold. Apparently this is a fairly common problem with TJ jeeps. Now as I muddle over my options I am hoping for some advice. I could

1. replace the cracked one with a new manifold from I think Mopar that supposedly doesn't crack anymore. This seems boring.
2. or i could go with a header system.

As my Jeep ages I want to build a better bionic Jeep and am inclined to go with headers. I am just wondering....

are they worth the extra cost to put in?
While I am replacing the manifold with the headers should i be replacing something else so that I get optimal performance?
Are they legal in California, particulary where there are stricter smog regulations?
Will they make my Jeep more fun?
How long will they last?
What should I look for in a good header?

I've been looking at headers from Banks, Borla and Gibson. Any thoughts on which are the best headers to get? Either from one of these companies or some other Ihaven't heard from.

All help much appreciated.

Distraktion



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post #2 of (permalink) Old 09-18-2003, 06:28 PM
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Re: Help! To header or not to header!

1. 4 or 6 cyl ?
2. what do you plan to do with your jeep?
3. how much $$$ do you want to spend?



-all of those companies make a good product that is legal in the socialist republic of Kalifornia. Clifford also makes one if you have the six (dunno if they make one for the 4).
-more flow on the backside of the engine will not do much for you without increasing the flow into the other side of the engine.
-it will raise your power band to a higher rpm (lose a bit of low end torque, or rather moves it)
-if you have a six it will make it sound a little louder (alos depends on what you put behind it (you are going to have to screw around with the rest of the exhaust if you switch to a header.
-if you get a stainless of HPC coated header then they should last a very good long time

-thats about all i can think of right now as my house is getting ready to float away [img]images/graemlins/40BEER.gif[/img]

-web
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post #3 of (permalink) Old 09-19-2003, 02:30 AM
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Re: Help! To header or not to header!

[img]images/graemlins/tongue.gif[/img] I look at it this way..... Headers will add some HP IF and only IF the engine is suffering from an exhaust restriction, and that hardly ever occurs under 5000 RPM. [img]images/graemlins/crazy.gif[/img] The stock exhaust manifold for the 4.0 has pretty good, header-like flow already. Headers CAN be trouble long term with leakage and so forth. [img]images/graemlins/tongue.gif[/img]
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post #4 of (permalink) Old 09-19-2003, 02:34 AM
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Re: Help! To header or not to header!

good headers with good flow mufflers might get ya 10-20 horses on a v-8 go figure??
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post #5 of (permalink) Old 09-19-2003, 06:11 AM
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Re: Help! To header or not to header!

</font><blockquote><font class="small">In reply to:</font><hr />
I look at it this way..... Headers will add some HP IF and only IF the engine is suffering from an exhaust restriction, and that hardly ever occurs under 5000 RPM.

[/ QUOTE ]

And the other side of that coin is .... Headers will cost some HP at lower RPMs. Exhaust systems have a scavenge effect where the exhaust from one cylinder helps pull the exhaust from the next cylinder similar to a siphon.

Yep, headers might get ya 10-20 horses on a v-8 but that's at one and only one given RPM value. It starts dropping off either side of that.

For the past 30 years, automotive engineers have been trying to squeeze every fractional horsepower available from the smaller engines. If headers worked, they would have used them and in some cased have used short versions. But, if your driving style is totally different than what the engineers expected by only making 1/4 mile trips and accelerating from a standing stop to 200+ MPH, the headers are for you.
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post #6 of (permalink) Old 09-19-2003, 06:19 AM
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Re: Help! To header or not to header!

i have the same problem. what i have found is you can buy an aftermarket header cheaper than a mopar replacement manifold. just replaceing the manifold with a header will basically be an unoticable power difference. now the truth is these cheaper headers are just that cheaper. i have seen some custom manifolds on ebay with expansion joint on the front and rear exhaust ports. they are also cheaper than mopar replacements and seem to be as good. Has anyone used one of these?
post #7 of (permalink) Old 09-19-2003, 06:21 AM
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Re: Help! To header or not to header!

I've never liked headers on a street driven vehicle, not even my fast street cars! The HPC coatings have brought them a long way in the way of lifespan, but they just don't last long term. They end up leaking and cracking (the problem you are fixing) and rusting. They just aren't worth the hassle.
On a 10 second drag car that you are revving to peak RPM in all gears... YES, but in a Jeep that sees most of it's work load in the 1500 to 2500 RPM range, just not worth the hassles. Get a new manifold is my opinion.
If you do get a header, get it HPC or Jet Hot coated (ceramic) and get one with the thickest mounting flanges and tube thickness you can find, it will last the longest.
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post #8 of (permalink) Old 09-19-2003, 06:23 AM
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Re: Help! To header or not to header!

http://cgi.ebay.com/ebaymotors/ws/eB...tem=2433170610
heres what i was talking about.
post #9 of (permalink) Old 09-19-2003, 11:04 AM
 
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Re: Help! To header or not to header!

When I rebuild my CJ7 completely, I did a header. I didn't like it because:

- lots of extra heat under the hood and near the brake lines
- Far less clearance - I had problems near the auto tranny and proportioning valve.
- Did not add any performance until above 4000rpm, where I will never run my Jeep at
- Caused the engine to run lean with too little backpressure, it was impossible to tune

I switched to a factory exhaust manifold. It runs much better, cooler, and I have many less routing problems.

I would suggest you find a good used factory manifold, and use it. Just make sure it is flat first ($20 to get it surfaced). Headers are just not worth the hassle (my opinion).
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post #10 of (permalink) Old 09-19-2003, 10:26 PM
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Re: Help! To header or not to header!

its all about air flow, from the top of the intake to the combusion chamber ,threw the head or heads to the entire exhaust system with least amount of restriction as possible,port and polish all the runners and match all the tubes so that all air , intake and exhaust flows freely,and to have no turbulance to cause more back pressure and weeken the flow and power.
my 97 mustang has factory headers, wonder why?? to increase HP on V6 3.8 ..i bet ,, not for looks.
DEX
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98 more and i'd have a dollar. LOL LOL
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