exhaust header recommendations

Performance mods and Advanced Stroker discussion.
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MunkMaster
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Re: exhaust header recommendations

Post by MunkMaster »

06BLKRUBILJ wrote:I am hoping to shield the intake from a little exhaust heat with this stuff...


I used that stuff and I could tell a big difference, both with a laser thermometer on the intake manifold itself and the dare to touch while at full temp method. I put it on the bottom of the intake.

I have been running a pace setter and I am pretty happy with it.
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Re: exhaust header recommendations

Post by jwilkinson01 »

Hey guys. I was hoping to get a little more in depth into the header/exhaust discussion here. I didn't see any reason to open a new thread since there's already threads out there and this one seems to be active. This is my first post here so hopefully I am in the right place, I don't want to hijack the thread but hopefully keep it going in a direction that will be beneficial, especially to noobs like me. I have been doing a lot of reading, here and other places, over the past year but the options and opinions on this subject vary greatly. In the next couple of months I am going to order a 4.6 from Golen for my 2000 TJ. I would love to build my own but I simply don't have the time or the space. My wife was injured a while back so after taking care of her and having to run our house mostly by myself and take care of our son, I will be lucky to have time to swap in the new motor, let alone build one. I would have ordered the engine when I got my tax return but the company I work for filed for chapter 11 at the same time and I have been waiting to make sure everything is okay there before I spend the cash.

For a header, Chad from Golen seems to like JBA. After talking with him for a while he suggested the JBA shorties or he mentioned a long tube version (which I can't seem to find on their website) if I was willing to take the extra steps to get it to fit. My concern is with cracking, it seems like two piece is less likely to crack, since Chrysler put a two piece on my engine from the factory I can only assume there is something to this. I can only find a couple of options and it seems like Borla (17202) is the best choice. Early in this thread someone mentioned having a custom header made. I contacted someone local that had done a lot of work with jeeps about a custom two-piece, long tube header and you don't even want to know how much he said it would cost. Also, it seems like for a Jeep, where torque is more important than HP, that maybe a shorty would be better than the long tubes that Golden suggested, I know LS engines are their real bread and butter and for those applications a longer tube would be better. I am willing to pay more for the Borla if it is truly worth it, I guess that is my first real question after rambling on for two paragraphs. Is the Borla and the two piece design worth it for 850ish compared to 550 for Doug Thorley or other options? Is short tube preferred over long for our Jeeps? Is there something better out there that I am missing entirely?

My next questions are about the exhaust size after the headers. I have seen recommendations to run 2.5 all the way to the end, 3.0 all the way to the end. 2.5 reduced to 2.25 (which is the same as stock if I am understanding correctly) and 3.0 reduced to 2.5. I have heard over and over not to go too big and that on a stock TJ even 2.5 may be too much and reduce "backpressure" which I really think is supposed to be exhaust velocity, since my understanding is that backpressure is not a good thing. But with a 4.6, how small is too small and how big is too big? I know there will be a lot of different opinions, but hey, that's why we have forums, to hear everyone's opinions and the reasons behind them to try to make the best decisions for ourselves. The Borla (if I go that way) has 2.25 outlets, would it be best to run that to a y pipe that is 2.25 to 2.5 (once again I think that would be the stock y pipe) or have a larger y pipe made? I asked the same guy who gave me the outrageous quote for the custom header about a 2.5 header back exhaust with mandrel bent T304 with a high flow cat and muffler that dumped behind the belly skid and once again his prices seemed really high, what would you expect something like that to cost?

What this all boils down to is I want to hear everyone's ideas for the best exhaust for a 4.6 starting with the header and going all the way back, I am willing to spend a little extra if its justified, but within reason. I am willing to pay for the Borla headers if that is the direction I ultimately decide to go, and a reasonable price for a cat, muffler, tubing and labor, but I am not going to lay out anywhere near the 10k plus the guy at the local shop quoted.

Thanks for taking the time to read my long winded rambling, sorry to torture everyone.
(edited for typos)
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gonridnu
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Re: exhaust header recommendations

Post by gonridnu »

I have been running a Borla long tube header since 1996ish on the stock engine first and now on the stroker. it has not broken.

so I used to work the tech line for both summit Racing and super Shops and I have attended enough header seminars to make a man's head swim.

Here are a few things to consider.....

A long tube header makes more torque due to superior scavenging. Primary tube size is very important as it times the pulse wave. Tuning of the primary diameter and length can maximize torque and HP gains. Stainless is better than steel. Never wrap a header it voids the warantee on all brands.

That information aside it is important to understand we are buying off the shelf headers that aren't a perfect match tuning wise for our vehicles. Smaller diameter collectors and tubing generally works out to a torque advantage over larger diameter exhaust tubing. Keeping that in mind a 2.25 collector and exhaust system is perfectly adequate for most of what we are going to do in a Jeep.

The diff in headers power wise is minute and will change ranges on different engines. The difference between a quality header and a cheaply made one is HUGE when it comes to install and longevity. Remembe I have had my borla for 20 sumthin' years

Engines do not start producing large amounts of waste gas until you get in the upper RPM range. By running large diameter tubing and collectors you will likely make some more Horsepower in the upper RPM range but you will sacrifice torque in the lower RPM range to get there. My suggestion for 99% of us is go 2.25" or max 2.5" if you must but it will cost you torque in a 4500 lb vehicle. Choose wisely.

also you should never collapse or "dimple" a header tube as the one member did. The reduction in cross sectional area and thus flow is singnificant and will likely result in a hot spot and will definitely kill the flow and scavenging effect on that cylinder. Sorry.
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Re: exhaust header recommendations

Post by 06BLKRUBILJ »

Gonridnu, thanks for the info on headers and exhaust. I was having unrealistic envy of the guys who run larger exhaust on their rigs. Now I feel much better about running my Borla headers into the stock exhaust given the horsepower of my Stroker. I also agree with you on not "dimpling" the primary tubes, but, I'm that guy, & I needed to in order to meet a commitment. I knew it was going to be a VERY short term solution. Fortunately Borla sent me a correctly fabricated set of headers (that fit right without any modification) right after that commitment was over. Unfortunately for me, my crank (with unpolished thrust faces) trashed my thrust bearing and I am in the process of rebuilding the bottom end a second time. I got a whole 1050 miles out of it before having to tear it down. But that's another story.
Thanks again gonridnu, its guys like you on this forum, sharing your knowledge that made it possible for me build my Stroker. I really appreciate it.
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Re: exhaust header recommendations

Post by 02masshole »

Does anyone run an open header and if you do I've heard to put 18in past collector to get Optimum back pressure my Jeep just mud drags no Street I run a 750 Holley I'm looking to run a bigger exhaust have to make a custom the one I have now is Magnaflow I think 1.75 all to a 2.5 collector and I run a 18in piece past that I've only seen one guy make a custom long tube single exit header sounds pretty cool looks really cool but I know he put a ton of time into it didn't know if it was worth it
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Re: exhaust header recommendations

Post by SkylinesSuck »

Wow. Punctuation. That hurt to read.

There is no such thing as optimal back pressure. Just not overly large pipes to keep exhaust gas velocity up.
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Re: exhaust header recommendations

Post by jwilkinson01 »

gonridnu wrote:A long tube header makes more torque due to superior scavenging.
Sorry I didn't see your reply earlier, I must not have my notifications set up correctly for this forum. This little piece of information was a big part of what I was looking for, thank you. What I have read on the benefits of short tubes vs long for torque are contradictory or at best very not clear. In a lot of cases the information I found was from the header manufacturers so no one is going to come out and say that their product is inferior.

The problem is that for the 2000 and up TJ there aren't many options for a long tube header. Since Jeep changed the design and went with the two piece shorties with the long Y-pipe, only a shorty would be a true bolt in so thats what everyone is making for easier installation. It looks like aFe recently came out with a long tube for the 2000+ but I assume they are using a cheaper stainless steel, since it isn't specified, plus they only offer a 2 year warranty. The price is pretty high as well but it does include a cat and connecting pipe:
http://afepower.com/afe-power-48-48020- ... eet-series

I think if I am going to be able to run a header like I want, I need to go with the Edelbrock head that uses the 2000+ intake manifold but the pre-2000 exhaust manifold. That way I can run the long tube Borla header. After I swap in the motor and the new header, hopefully I can get to a muffler shop that can tie it into my existing exhaust until I get the tummy tuck installed and can see how I want the rest of the exhaust to go.

I am not certain if I am not going to do too much more to the jeep as far as power goes other than the Golen stroker and the Edelbrock head . Probably a larger throttle body once I am ready to put together a cowl intake. Unless there is anything else I am not thinking of that is recommended. After reading gonridnu's detailed write up on roller rockers I see no reason to go through the trouble, and his conclusions reinforced what I had heard from Golen. I have seen a couple of people who have suggested that a Unichip would be beneficial, but I haven't been able to find enough information on the subject to make a decision one way or the other.

With that in mind I think I would still fall into the 2.25 exhaust range according to the chart provided, but I am not positive.

Thanks again,
Jason
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Re: exhaust header recommendations

Post by BcurpKodiak »

"also you should never collapse or "dimple" a header tube as the one member did. The reduction in cross sectional area and thus flow is singnificant and will likely result in a hot spot and will definitely kill the flow and scavenging effect on that cylinder. Sorry."

Feel free to massage your headers as necessary

https://www.youtube.com/watch?v=azPKIjxmmdU
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Re: exhaust header recommendations

Post by DaemonForce »

What should I do for my exhaust manifold in the Eagle? I have a Dana30IFS and engine bracket to work around and I'm looking for any high flow manifold that has a straight down collector after the #4 cylinder to clear my engine subframe. I believe I may have found a solution with some stock TJ manifolds as I hear they may be the factory solution to this but how many manifolds are there for the 4.0L? It can't be that many. Borla looks exciting but the woes in this thread are a bit worrying. The real issue I have outside of this is getting an exhaust shop to actually do their job and make an exhaust system for this car. Nobody wants to make the exhaust for it.
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krom
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Re: exhaust header recommendations

Post by krom »

BcurpKodiak wrote:"also you should never collapse or "dimple" a header tube as the one member did. The reduction in cross sectional area and thus flow is singnificant and will likely result in a hot spot and will definitely kill the flow and scavenging effect on that cylinder. Sorry."

Feel free to massage your headers as necessary

https://www.youtube.com/watch?v=azPKIjxmmdU

was going to post that exact video
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Re: exhaust header recommendations

Post by xjason »

krom wrote:
BcurpKodiak wrote:"also you should never collapse or "dimple" a header tube as the one member did. The reduction in cross sectional area and thus flow is singnificant and will likely result in a hot spot and will definitely kill the flow and scavenging effect on that cylinder. Sorry."

Feel free to massage your headers as necessary

https://www.youtube.com/watch?v=azPKIjxmmdU

was going to post that exact video
created an account just to say "me too"
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Re: exhaust header recommendations

Post by aguiar_racer »

27C2CC06-E567-4228-BEB0-6487CEE4F137.jpeg
268131D1-1E89-4276-8814-72A8247E6480.jpeg
Any thought on these custom headers
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Re: exhaust header recommendations

Post by aguiar_racer »

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