Pacesetter Headers

[87Warrior]

For the past few weeks, I have been reading/studying/analyzing various exhaust options for my '92 once the motor comes back from the machinist.

 

This is the basics of what I will be working with:

99 XJ 4.0

•  + 0.030" pistons with 15cc dish
•  0.000" block deck clearance
•  Mopar Purple Cam Shaft #229

It's nothing fancy but should put a little more pep in the truck's giddy-up.

 

I had planned on running the stock exhaust manifold, but upon inspection I found two tubes cracked at the collector. Time for an improvement!

 

My search for replacement parts has led me to some wild headers like the Hooker cheap ebay options like the APN, and then just plain expensive ones like the Banks. Or switch to the stock two piece stuff found on late model 4.0's, but the cost of buying new stock style parts is equivalent to a high end header plus the cost of fabricating custom Y-pipes. 

 

Then I found the PaceSetter 70-1192 which seems to mix the best of both worlds in a design much like a traditional long tube header. The few reviews I have found on the PaceSetter 4.0 header have been positive.

 

Has anybody run, or have experience with the PaceSetter header? Or would would you recommend I research something else for my truck?

 

Thanks!

[jeepsouth]

I've got one still to be installed so i'm all ears too. :cheers:

[Alexia]

The headers themselves are fine, but the included down pipe is not bent in any way properly for a Comanche. Expect to have to cut the cross over section in half to rotate it into the correct position. I also had to bend the exhaust hanger at the transmission mount to get it lined up. Then there was me putting my feet on the transfer case and grabbing the pipe to bend it in the correct direction after that hanger.

 

I am going to keep the header, but replace the down pipe with a custom piece.

 

That header, no muffler, dumping out behind the cab. Skip to 3:58 for start up/idling and 4:33 for accelerating in the cab.

[HOrnbrod]

Here's the perfect header for the I6, the Mike Leach long tube. It fits the MJ like a glove even with the 1999and up intake manifold. Unfortunately it's no longer available since Mopar performance dropped it from their catalog years ago and ML stopped producing them. I got one of the last ones back in 03 from Kolak. He deals mainly in Banks headers now for the I6. Brett, his prices are very good, wouldn't hurt to email Nick for a quote. His email address:   Kolak@aol.com

 

 

[Zebvance]

I put one on my 88. I was far from impressed. Had a lot of problems with the step washers that hold the header on and also the down pipe not bent right as discussed already. If you look at my build tread you will see what I'm talking about with the problems I had.

 

Here is the link

 

http://comancheclub.com/topic/34531-1988-you-aint-chancin-unless-your-manchin-mj-build-pic-he/page-3

[johnj92131]

Spoke to Mike Leach last week about these headers.  He told me that he and about 100 other vendors were simply cut loose when Daimler took over Chrysler around 2001.  All his tooling just went away.  Asked him if he would be willing to make a custom set of headers for my 1991 Comanche. He said California rules have changed over the years and it would be a problem for him to build and sell the same headers today.  Even with exactly the same CARB approved design from 1997/98   I am not sure if he means because the firm/legal entity that owned the CARB exemption and the tooling no lnoger exists (exposing him to legal liability?) or what.  I suspect it is a legal thing because Mike did the CARB exception under a particular legal entity that he owned at one time.  Mike Leach said there is nothing with the long tubes currently on the market.  He did offer a set of JBA headers for $550

 

As a side remark, Mike said he used to build these headers in runs/batches of 50 at a time, but Daimler just cut a bunch of small suppliers when they took over.  Have to say the man was very cool.  He called me back when he said he would and gave me a good 15 minutes of his time to answer every single question I could think of asking.  What a neat guy!!

 

Really too bad and I don't think they can be built today for under $1000 per set even if you had all the prints, which Mike Leach no longer has, they just went away over time, like all the tooling.  So Don, do you feel like making a set of prints for these headers??   I may want to look at modifying/Bastardizing a set of JBA headers for longer tubes.

 

JJ

Here's the perfect header for the I6, the Mike Leach long tube. It fits the MJ like a glove even with the 1999and up intake manifold. Unfortunately it's no longer available since Mopar performance dropped it from their catalog years ago and ML stopped producing them. I got one of the last ones back in 03 from Kolak. He deals mainly in Banks headers now for the I6. Brett, his prices are very good, wouldn't hurt to email Nick for a quote. His email address:   Kolak@aol.com

 

 

[HOrnbrod]

John, it's good you got to speak at length with Mike. I've never had the pleasure. I can't believe he doesn't have the prints anymore. I was lucky to get a long tube; all that's available now are the stubbies and they are not much better than the stock manifolds. These headers do pop up occasionally over on the strokers forum, but everyone wants one. I heard Hesco has a few around too. And no, I won't be trying to make a print anytime soon - sorry. I wouldn't know how to anyhow.  :yes:

[87Warrior]

Thank you all for the comments and discussion.

 

That Mike Leach header looks very nice. It's a shame so many products disappear out from beneath us.

 

I was lucky to get a long tube; all that's available now are the stubbies and they are not much better than the stock manifolds.

This is what I find amazing. It seems even the high dollar headers today are simply tubular style stock manifolds. Perhaps there is a reason for that. I don't know.

 

I think I'll give the PaceSetter a shot. I will strip the paint and apply a real header coating, then bake the paint on in the kitchen oven (when my wife isn't home). Modifying the cross over pipe is no big deal as I plan to install a flex joint in there.

[Zebvance]

Thank you all for the comments and discussion.

That Mike Leach header looks very nice. It's a shame so many products disappear out from beneath us.

I was lucky to get a long tube; all that's available now are the stubbies and they are not much better than the stock manifolds.

This is what I find amazing. It seems even the high dollar headers today are simply tubular style stock manifolds. Perhaps there is a reason for that. I don't know.

I think I'll give the PaceSetter a shot. I will strip the paint and apply a real header coating, then bake the paint on in the kitchen oven (when my wife isn't home). Modifying the cross over pipe is no big deal as I plan to install a flex joint in there.

 

Did you look over my build thread and the problems I had with the step washers. Just be prepared to deal with that too. You will have to re grind down each one to fit perfectly...

[Oyaji]

"Headers" are not only supposed to flow exhaust with less back pressure than stock manifolds, but also are supposed to generate pulses of negative pressure to increase volumetric efficiency. Those negative pressure waves reduce pumping losses of the engine and actually "suck" exhaust gas out of the combustion chamber. They only generate those pressure waves around the engine RPM for which the pipes are tuned. The principle is harmonic resonance (the same principle a pipe organ uses to amplify sound): the longer the pipes, the lower the resonant frequency and the lower the RPM at which flow is enhanced. Back pressure drastically inhibits the scavenging effect, so pretty much ever since the advent of catalytic converters the benefit of headers has been limited.

Additionally, headers tubes need to be equal-length for maximum flow (~31" long for higher RPM power gains, ~36" for lower RPM band), and there is no power/efficiency benefit from using special heat-insulating coatings/paints. (I suppose headers look nice to some people when the hood is open though. I reckon that is the primary benefit for street-driven vehicles these days.)

 

Here's the perfect header for the I6, the Mike Leach long tube. It fits the MJ like a glove even with the 1999and up intake manifold. Unfortunately it's no longer available since Mopar performance dropped it from their catalog years ago and ML stopped producing them. I got one of the last ones back in 03 from Kolak. He deals mainly in Banks headers now for the I6. Brett, his prices are very good, wouldn't hurt to email Nick for a quote. His email address:   Kolak@aol.com

 

 

Note that in the above picture, the layout is 2 3-into-1 collectors that funnel into another 2-into-1 collector farther downstream. None of the primary tubes are of equal length. nor are they long enough to generate scavenging at any practical engine speed for a 4.0. (Just eyeballing them, tubes that short would be tuned for maybe 12,000 or more RPM. It is beyond ridiculous to call them "long tube headers", and only the ignorant, the imaginative, and/or the disingenuous would do so.) To produce significant power gains in 4.0 you would be looking for 2 separate  3-into-1 collectors with 33"-36" equal-length primary pipes that feed into a dual exhaust system with no catalytic converters, glass-pack mufflers with no baffles (or else no mufflers at all), and tailpipes exiting somewhere behind the doors.

 

Such a system would be LOUD - but that is the hallmark of pipes that actually boost power.

[87Warrior]

Did you look over my build thread and the problems I had with the step washers. Just be prepared to deal with that too. You will have to re grind down each one to fit perfectly...

Sure did. You did a great job showing what needs to be done to achieve a perfect fit. I am not sure how my results will vary as I will use the later model header and a 99 intake. Regardless, I have grown accustomed to grinding on parts to make them fit.

 

Oyaji - Thanks for the detailed explanation/information. Some was familiar to me while some was new.

[Alexia]

Sure did. You did a great job showing what needs to be done to achieve a perfect fit. I am not sure how my results will vary as I will use the later model header and a 99 intake. Regardless, I have grown accustomed to grinding on parts to make them fit.

 

Oyaji - Thanks for the detailed explanation/information. Some was familiar to me while some was new.

My step washers were perfect for the 1999+ intake manifold.

[88whitemanche]

Just saw this today....

 

http://miami.craigslist.org/brw/pts/4134758889.html

[HOrnbrod]

Note that in the above picture, the layout is 2 3-into-1 collectors that funnel into another 2-into-1 collector farther downstream. None of the primary tubes are of equal length. nor are they long enough to generate scavenging at any practical engine speed for a 4.0. (Just eyeballing them, tubes that short would be tuned for maybe 12,000 or more RPM. It is beyond ridiculous to call them "long tube headers", and only the ignorant, the imaginative, and/or the disingenuous would do so.) To produce significant power gains in 4.0 you would be looking for 2 separate  3-into-1 collectors with 33"-36" equal-length primary pipes that feed into a dual exhaust system with no catalytic converters, glass-pack mufflers with no baffles (or else no mufflers at all), and tailpipes exiting somewhere behind the doors.

 

Such a system would be LOUD - but that is the hallmark of pipes that actually boost power.

 

My my, aren't we getting childish. More disparaging comments, now highlighted in BOLD! How sad.

 

It's obvious you have never seen any dyno runouts comparing peak power and torque numbers of the various available headers on the same 4.6L stroker engine. And I'll be sure to suggest to Mopar Performance that they should rename their long-tube Mike Leach header based on an eyeball calculation from some unknown wannabe. They'll get a good laugh. Keep up the amusing prattle; it's very enjoyable.

[Oyaji]

 

Note that in the above picture, the layout is 2 3-into-1 collectors that funnel into another 2-into-1 collector farther downstream. None of the primary tubes are of equal length. nor are they long enough to generate scavenging at any practical engine speed for a 4.0. (Just eyeballing them, tubes that short would be tuned for maybe 12,000 or more RPM. It is beyond ridiculous to call them "long tube headers", and only the ignorant, the imaginative, and/or the disingenuous would do so.) To produce significant power gains in 4.0 you would be looking for 2 separate  3-into-1 collectors with 33"-36" equal-length primary pipes that feed into a dual exhaust system with no catalytic converters, glass-pack mufflers with no baffles (or else no mufflers at all), and tailpipes exiting somewhere behind the doors.

 

Such a system would be LOUD - but that is the hallmark of pipes that actually boost power.

 

My my, aren't we getting childish. More disparaging comments, now highlighted in BOLD! How sad.

 

It's obvious you have never seen any dyno runouts comparing peak power and torque numbers of the various available headers on the same 4.6L stroker engine. And I'll be sure to suggest to Mopar Performance that they should rename their long-tube Mike Leach header based on an eyeball calculation from some unknown wannabe. They'll get a good laugh. Keep up the amusing prattle; it's very enjoyable.

 

What is sad is that sales literature can get away with calling a product something it is in truth not: it is patently obvious from the photo that the primary tubes are nowhere near 31" or longer. They don't even look to be half that, nor are they equal-length tubes, for that matter, so it is a stretcher to even call them "headers". (It's also pretty sad that you feel the need to launch personal attacks, and that you feel free to do so with impunity under the mantle of the "moderator" title.)

 

Unless those results to which you refer came from a steady-state load-controlled chassis dyno, they are of limited value. Since such start at around half a million dollars these days, I doubt very much that more than a few people have even seen one, nor that your vaunted tests utilized one. Still, you are correct that I have not seen the data from tests you mention. It is certainly true that objective data from a statistically relevant sample that does comparison tests is of greatest value. If you have that data, you should post it here, along with the test methodology and conditions.

 

That does not change the fact that calling the headers in the illustration "long tube" is inaccurate (actually an outright lie). In combination with a properly-designed intake manifold, with the use of true long-tube headers it is possible to achieve volumetric efficiency of ~ 1.05  (105%) on some engines. This feat is only possible otherwise with some form of forced induction, which is why the phenomenon to which I referred is called "pressure wave supercharging". For reference, your stroker Jeep engine probably has only about 70% volumetric efficiency (maybe even less).

 

With pressure-wave supercharging on a carburetted or mechanically-injected engine (pre-dating digital engine management, mind you), figures of 100 horsepower or more per liter were common... and this in the day when figures half of that were considered noteworthy. Accomplishing that on a 4.0 would net 400 horsepower! (Not ever gonna happen with the 4.0 head, but just consider that figure for a minute.)

[HOrnbrod]

The comparison tests were run under the same conditions and same RPM sequences for each header. Same engine, same dyno, different headers. The so-called long-tube Leach header, marketed by Mopar Performance until 2000, outperformed the others including the other ML designed Mopar header pictured below. That's the main reason I purchased it, even though it was around $400 at the time. I am still looking for the late 90s header dyno test data. It was on the Mopar Performance site, but it's long gone now. Here is an interesting article regarding various 4.0L header designs:  http://jeep-xj.info/HowtoExhuast.htm

 

Of course a header with longer equal-length tubes is best for optimal performance, but with the limited real estate in the XJ/MJ engine compartment, it couldn't happen. And most Leach headers were designed to fit in all Jeeps of the era with the 4.0L engine. They accomplished this by using different collector end pipes. I suspect the XJ engine compartment was the limiting factor on header tube length.

 

 

 

[jeepsouth]

Wow is my pacesetter even worth installing?

[Oyaji]

Wow is my pacesetter even worth installing?

 

I guess it depends on what you expect out of them, and what the value of money is to you. Without seeing good hard numbers from objective testing (manufacturer's numbers are automatically suspect as being merely ammunition for advertising - independent test results are far more trustworthy - no results are 'gospel' without methodology and test conditions plainly reported), I wouldn't buy any from any maker. As Hornbrod mentioned, the limited space available in the engine bay severely limits the potential of any headers I have seen for this application. The link he posted is a critique and comparison write-up on the subject (sadly, lacking hard data) by a (in my opinion) fairly well-informed Australian, and is worth reading: http://jeep-xj.info/HowtoExhuast.htm

[HOrnbrod]

If your engine is normally aspirated, you probably will not notice that much difference w/o other intake modifications to complement it. But it's a good starting point. 

[jeepsouth]

Ok then since my oem manifold has a slight leak,and I already have it i'll go with it ,and hope for the best. Thanks for the information.Hornbrod what mods would you suggest?

[87Warrior]

Just saw this today....

 

http://miami.craigslist.org/brw/pts/4134758889.html

That particular header is designed for the 01 XJ and 00+ TJ/WJ. 

 

This is the model I am looking at (without the fancy coating)

 

My intent for this thread was not to discuss any hard or artificial data regarding header design and construction or actual power output. My primary goal was to search out a header that is well built, has a decent fit and finish and should resist cracking. I am not trying to eek out another 1/10 second in the quarter, I am trying to assemble parts that work with each other for many years to come. While the information explaining why a certain product is 'lacking' is certainly helpful, it is rather useless to the guy who wants to make an informed purchase if no suggested product is given or if no such product exists. 

 

Wow is my pacesetter even worth installing?

The PaceSetter continues to become a more attractive option in my mind as a 4.0 exhaust manifold replacement. The cost is not much more than stock replacement parts (remember, I was going to reuse the stock manifold until I discovered several cracks), it exists at two points like the late model 4.0 manifolds (which are more resistant to cracking) and it seems to be well received by the folks who own and use it.

[HOrnbrod]

Ok then since my oem manifold has a slight leak,and I already have it i'll go with it ,and hope for the best. Thanks for the information.Hornbrod what mods would you suggest?

 

Depends on your pocketbook. For starters, an HO head because of the mismatched exhaust ports for your Renix head for the header. This will allow you to install an HO throttle body, a 99+ intake manifold w. a 97 and up power steering pump and bracketry. Then you will need to do the TPS work-around if you stay with the Renix system.

 

I'm not a Renix fan, support parts are drying up for them, and to me it's like polishing an obsolete turd. BUT I respect those who love their Renix Electronique machines, are comfortable with this French/Bendix system, and will not change. If you are dead set on keeping the Renix setup, others are much more qualified to respond than I.

[Stacks]

If you are looking for a quality replacement for a stock header, one that addresses the cracking issue,  Check out this link.  Myself and two other people have these 'headers' on our TJ's and XJ's.  Fit great, stock exhaust connects right up, and they are stainless!! 

 

http://www.1aauto.com/1A/exhaust-manifold/Jeep/Comanche/1AEEM00146/250323/1992

[Oyaji]

Look guys, I appreciate that the desire to make modifications that improve on the original design is part of the allure of owning a Jeep, but if there is no significant benefit to be had, is there any reason to do a given modification? You might as well save your money and spend it somewhere else where it will do more good.

 

You can also look at it this way: the benefits of scavenging exhaust headers have been well recognized and documented with the mathematics to design them for many decades now. With all the pressure on vehicle manufacturers to increase fuel economy and power, don't you think if there was practical benefit to be gained that they would have included them in their products by now?

 

...

 

That said, if there was sufficient interest for an off-road application that would generate at least 500 orders, I would consider looking at designing a skinny-tube true long-tube header for use with short dual exhaust with target retail price of $500, ordered direct. I don't expect sufficient interest, and fewer orders than 500 @ $500 would make such a project unprofitable and a waste of time and resources.  :(

[jeepsouth]

 

Ok then since my oem manifold has a slight leak,and I already have it i'll go with it ,and hope for the best. Thanks for the information.Hornbrod what mods would you suggest?

 

Depends on your pocketbook. For starters, an HO head because of the mismatched exhaust ports for your Renix head for the header. This will allow you to install an HO throttle body, a 99+ intake manifold w. a 97 and up power steering pump and bracketry. Then you will need to do the TPS work-around if you stay with the Renix system.

 

I'm not a Renix fan, support parts are drying up for them, and to me it's like polishing an obsolete turd. BUT I respect those who love their Renix Electronique machines, are comfortable with this French/Bendix system, and will not change. If you are dead set on keeping the Renix setup, others are much more qualified to respond than I.

I have the renix pace setter header ,and bought it from a fellow CC member as it was a good deal ,and new in box. Was only looking to fix a problem at the time ,and any gains would be a plus. I think i'll re-gear to 3.55 ,and install the header and call it good until something bad happens to my engine.Pocketbooks kinda light ,and will be that way till I get my house paid for.