aftermarket manifolds and Header brand questions

[dustyinthedirt]

I am in the process of replacing my manifold. I am not gonna weld it where its cracked am gonna buy a new one.

I am working on a 89 4.0 L not worried at all about the old exhaust system, itll be replaced next thing front to back as i believe the cat is stopped up. And the muffler has a monster hole it. Sounded like a race car when i would get on it 

First question: Been searching around for a couple days looking through page after page of Aftermarket header and manifolds. Would love the Pacesetter Header!! :bowdown:

http://www.quadratec.com/products/77604_701.htm?gclid=Cj0KEQjw_9-9BRCqpZeZhLeOg68BEiQAOviWAnToJbPH-5vxW46kg5PLt_olHbmCY-xh-nh__t5iPwcaAu998P8HAQ

 

but for $233! I am gonna keep looking around. Found some good ones and then i ran across this

 

http://teamcherokee.com/exhaust-manifold-assembly-cherokee-comanche-4-0-liter-1991-1999/

 

the First and sixth tube have flex joints made into them. Very cool cause this is were alot of them crack. I was Planning on doing the flex joint around the bottom near the oil pan anyways. I personally think that this thing looks cheap and is also cheaper then you can find a stock one on most sites and in parts stores... I did how ever run across this one

http://www.1aauto.com/1987-90-jeep-exhaust-manifold/i/1aeem00024?f=333781&y=1989&utm_campaign=gb_csv_br&utm_content=EEM&scid=scplp1AEEM00024-333781-1989&sc_intid=1AEEM00024-333781-1989&gclid=Cj0KEQjw_9-9BRCqpZeZhLeOg68BEiQAOviWAnZjAW36YgBeYDxnpH4TpcM-DeNf6DDZ6O6kdTv65e0aArAF8P8HAQ

 

Second question: Is a header really gonna make a difference compared to a stock manifold? If so what kind? 

 

If you guys have had any good experiences with buying a replacement manifold or a header let me know! I am open to ideas 

[DirtyComanche]

The stock manifold is a header...  Header = tubular manifold.

 

There isn't a lot of power to be gained because the stock piece is not THAT bad.  At least compared with say a 70s-80s Ford/Dodge/Chevy where a set of cheap headers will make 20+HP because the factory manifolds were complete junk.

 

That Pacesetter one will actually make some power.  Some of the other ones will be a very mild improvement over stock, if anything, and some of the direct replacement ones actually might be worse.

 

You'll see a greater performance improvement from going to a better midpipe/tailpipe/muffler/cat.

 

 

Also, with the Renix there is a lot less options for aftermarket exhaust.  If you delete your EGR you can generally go to HO parts.  However, I wasn't so lucky with the Amazon header I bought and had to swap to a HO intake and do some grinding.

[dustyinthedirt]

 Also, with the Renix there is a lot less options for aftermarket exhaust.  If you delete your EGR you can generally go to HO parts.  However, I wasn't so lucky with the Amazon header I bought and had to swap to a HO intake and do some grinding.

 

I seen the post you did on it and looked that one up. Did the flange give you as much trouble as you thought it would? I can't find the link to that thread but if i do i will post it up

[johnj92131]

Just go to Amazon and look for the least expensive header/manifold you can find.  I just purchased one from Amazon as a warehouse second (meaning it had been returned), under $100.  This one has the "bellows" that are supposed to avoid the cracking problems.  I will know in a couple of years if it works or not.

 

Most of us will never notice any extra power the expensive headers claim to provide at higher (4500+) rpms, because we just don't drive at 4500 rpms.

[DirtyComanche]

 

 Also, with the Renix there is a lot less options for aftermarket exhaust.  If you delete your EGR you can generally go to HO parts.  However, I wasn't so lucky with the Amazon header I bought and had to swap to a HO intake and do some grinding.

 

I seen the post you did on it and looked that one up. Did the flange give you as much trouble as you thought it would? I can't find the link to that thread but if i do i will post it up

 

It's a long story.

 

I cut it off and put a V-band flange on it. :rotf:

 

I wound up building the entire exhaust system using the modded header, a band flange/clamp, an O2 bung from Summit, a box of bends, some straight pieces, and let's not forget the extremely expensive 'Pypes' muffler.

 

I have no idea if a HO downpipe/midpipe would have fit on it, but I really think it probably had the wrong angle/position since the header they cloned is for 01+ applications (or something like that).  The end of day reality was I needed to build the entire exhaust system from scratch anyways, everything else is a little too custom on that thing.  Actually, I don't think I have bought a single part for it and actually had it bolt on without having to screw around with something to make it work. :doh:

[schardein]

I have my 91 XJ, 91 MJ, and I ran a 1991 4.0 in my CJ7 for over 10 years.  All of the factory manifolds crack.  Every one I look at in the junkyard are cracked.  The ones repaired by welding are cracked.  Using a factory replacement would be a waste of money.  It will crack.

 

I got a Borla for my CJ7.  Works fine and no cracks in 10 years.  Got a good deal on a used one on ebay, but still expensive.

 

For my XJ and MJ, replaced both of the cracked originals with the "cheap" one you listed, with the bellows on the end tubes.  And, they are used.  I pulled them off XJs in the junkyard.  Paid between $45 and $60 for them at picapart prices.  Both are still going strong with thousands of miles on them.

 

The intake/exhaust manifold-to-head gasket and manifold-to-downpipe seal are cheap at Rockauto.  

[dustyinthedirt]

 

 

For my XJ and MJ, replaced both of the cracked originals with the "cheap" one you listed, with the bellows on the end tubes.  And, they are used.  I pulled them off XJs in the junkyard.  Paid between $45 and $60 for them at picapart prices.  Both are still going strong with thousands of miles on them.

Alright noted. Not as cheaply made as they seem. Very cool idea. I was thinking of just spending the money and buying a good one since i plan on keeping the thing for a long while. I have been searching the pic a part for the past couple weeks and the XJs around here are like a bake sale after a full day of people foundling the brownies and all the good stuff is gone and all thats left are stripped bolts, snipped wires, and greasey hand printed interior

 

 

 

 

I cut it off and put a V-band flange on it.  :rotf:

i read the reviews on that one and was i think i may get something that fits a little better hahaha

[75sv1]

The only real difference between a RENIX and HO header is the bung or boss for the EGR system. If not in Cali, or other CARB state, then ???. Also, check Clifford and possibly Borla or Banks. On the Clifford, I think you have to drill through one wall or the tubing, to 'activate' the EGR system. I think most of the after market headers are more durable than the OEM. I think most of the power comes from the 'better' down pipe. I did have a Pace Setter. It was with their Amour Coat.  Some of the edges had a bit of rust, but otherwise very good. Probably should have kept it.

[dustyinthedirt]

I live in a state where emissions isnt hard to pass. so i don't think the EGR is gonna be a big deal for me

[DirtyComanche]

The only real difference between a RENIX and HO header is the bung or boss for the EGR system.

 

The problem with that thinking is that yes, that is the only real difference with the factory header, but there is other differences between the engines that may cause a problem with aftermarket parts.  My cheap header hit the Renix intake, because the runners are much lower on it than on a HO intake.  Of course the header I bought fit so poorly that it still didn't clear the HO intake either, but it was definitely close, as opposed to not even being possible.

 

Also, the HO ones probably won't have the O2 bung in it, since it's normally in the downpipe/midpipe.  But you would need to use that part from a HO anyways.

[schardein]

1991 MJ.  Can't speak to fitment problems on a renix, but this type aftermarket manifold worked on both the early and late HO intake manifolds.  If you are going in, now is the time to replace the driver side motor mount if it hasn't been done.

 

[schardein]

 

 

 

For my XJ and MJ, replaced both of the cracked originals with the "cheap" one you listed, with the bellows on the end tubes.  And, they are used.  I pulled them off XJs in the junkyard.  Paid between $45 and $60 for them at picapart prices.  Both are still going strong with thousands of miles on them.

Alright noted. Not as cheaply made as they seem. Very cool idea. I was thinking of just spending the money and buying a good one since i plan on keeping the thing for a long while. I have been searching the pic a part for the past couple weeks and the XJs around here are like a bake sale after a full day of people foundling the brownies and all the good stuff is gone and all thats left are stripped bolts, snipped wires, and greasey hand printed interior

 

 

 

 

I cut it off and put a V-band flange on it.  :rotf:

i read the reviews on that one and was i think i may get something that fits a little better hahaha

 

Over the years, I'm gonna guess I've looked at 500 XJs /20 MJs in the yards.  Only found 1 aftermarket header and maybe 8 of these type manifolds.  They take about 30-45 minutes to pull depending on how the downpipe goes.  I think they are found/interchange on some Grand Cherokees also.  Anyway, on those odds, getting one off amazon may be the ticket. 

[dustyinthedirt]

1991 MJ.  Can't speak to fitment problems on a renix, but this type aftermarket manifold worked on both the early and late HO intake manifolds.  If you are going in, now is the time to replace the driver side motor mount if it hasn't been done.

 

It doesnt look so "cheaply made" in this picture. And good looking out on the moter mount. i already changed the freeze plugs while i was in there.

[dustyinthedirt]

Does it have a bung for the O2?

[schardein]

Does it have a bung for the O2?

No, I think someone already mentioned it's in the downpipe on the HOs.  The manifold in the picture was pressure washed, light hit with a wire wheel, some 80 grit paper here and there, and then sprayed down with por-15 metal prep and brushed with por-15 hi temp paint.  Or was it just hi-temp aluminum spray bomb on this one?  Can't remember now.  I think they are a low grade stainless like the originals so rust through shouldn't be a problem.

[schardein]

If you pull a manifold from the yard, save the heavy, thick metal washers.  Even if you don't need them for your manifold, they are for a 3/8" bolt and come in handy for other projects needing a heavy washer.

[cody4359]

 

1991 MJ. Can't speak to fitment problems on a renix, but this type aftermarket manifold worked on both the early and late HO intake manifolds. If you are going in, now is the time to replace the driver side motor mount if it hasn't been done.

 

It doesnt look so "cheaply made" in this picture. And good looking out on the moter mount. i already changed the freeze plugs while i was in there.

I know someone with one of these that they want to sell.

 

My manifold was cracked and I replaced it with a Banks torque tube. Spendy, but I did notice a little low end improvement, then with a bored out throttle body a bigger improvement. I'm thinking of having a ported intake/head done as well as a cam of some sort

 

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[dustyinthedirt]

So i bought this..

 

 

And this thing is sweet!!!! It does not feel or look cheap in person. It feels really well made. Picked it up off of ebaby new from a guy who bought it and never used it. $90 Shipped! Thats what I'm talking about! 

 

Thanks so much everyone for the advice! Especially schardein! You convinced me  :thumbsup:  :bowdown: 

[schardein]

^{I hope it doesn't present problems when used on a Renix.  I don't know if they are a direct bolt in.}

[DirtyComanche]

The pipes downturn pretty fast, so it hopefully will clear the intake.

[dustyinthedirt]

Hey now don't be making me regret my decision before even taking it to the shop!  :fs1: Your supposed to say "Oh!!" "DAMN!!!!!" and the classic "Nice"

[DirtyComanche]

Nah, I'm pretty sure it will fit.  The one I had that didn't fit had #1 and #6 pipes turn towards the midpoint of the engine rather than turning downwards.  It would have probably cleared fine on the 00+ intake, not even close on the Renix, and not quite on the early HO one.

 

But you're going to have to try it. :cheers: