Stainless LS4 Headers
For the right price (don't know what that is yet), I'd be in line for a set. keep posting progress.

edit: Is direct bolt up to the Hogan DP necessarily a good thing? The Hogan has a smaller inlet to match up to the stock rear exhaust outlet. Consider having a 3" flange installed instead, I'd pay to have the Hogan DP modified to a 3" inlet.
Last edited by TiredGXP; Feb 3, 2008 at 08:05 AM.
I really want to see this happen, so good luck.
For the right price (don't know what that is yet), I'd be in line for a set. keep posting progress.

edit: Is direct bolt up to the Hogan DP necessarily a good thing? The Hogan has a smaller inlet to match up to the stock rear exhaust outlet. Consider having a 3" flange installed instead, I'd pay to have the Hogan DP modified to a 3" inlet.
For the right price (don't know what that is yet), I'd be in line for a set. keep posting progress.

edit: Is direct bolt up to the Hogan DP necessarily a good thing? The Hogan has a smaller inlet to match up to the stock rear exhaust outlet. Consider having a 3" flange installed instead, I'd pay to have the Hogan DP modified to a 3" inlet.
Scott...didn't notice if you hopped over to NAIOA yet...but do so. There are a few "dedicated" members there that don't come here often or at all. Might want to stir something up over there, or if you'd like, I'll relay information from here if I cannot get them to sign up here.
Maybe some of the ClubGP members here could do the same...?
Maybe some of the ClubGP members here could do the same...?
Scott...didn't notice if you hopped over to NAIOA yet...but do so. There are a few "dedicated" members there that don't come here often or at all. Might want to stir something up over there, or if you'd like, I'll relay information from here if I cannot get them to sign up here.
Maybe some of the ClubGP members here could do the same...?
Maybe some of the ClubGP members here could do the same...?
Thanks for the reminder...Just popped over there and registered...
Should I reg and post on ClubGP...?
--Scott
Ok..here is what I got...
1 3/4" primaries
2 1/2" crossover
2 to 1 merge with a 3" outlet
We did touch on hogan and custom dp as well.
I also suggested to the owner to keep the price reasonable if he is looking to move these.
From a quality standpoint, these will be done right.
Unfortunately, the shop is very busy, so production/availability timeframe will be sometime this year. I was hoping for sooner....
I will continue to follow up on this. I have a personal interest in this.
With any luck, I can push things along.
As far as codes, it is good practice to tune after any engine profile change.. HPTuners does support this platform..Once I install, I will furnish a full report...
I will post post this info up on NAIOA and ClubGP
Thanks guys..all of this feedback has been very helpful
--Scott
1 3/4" primaries
2 1/2" crossover
2 to 1 merge with a 3" outlet
We did touch on hogan and custom dp as well.
I also suggested to the owner to keep the price reasonable if he is looking to move these.
From a quality standpoint, these will be done right.
Unfortunately, the shop is very busy, so production/availability timeframe will be sometime this year. I was hoping for sooner....
I will continue to follow up on this. I have a personal interest in this.
With any luck, I can push things along.
As far as codes, it is good practice to tune after any engine profile change.. HPTuners does support this platform..Once I install, I will furnish a full report...
I will post post this info up on NAIOA and ClubGP
Thanks guys..all of this feedback has been very helpful
--Scott
Huge mistake if your going to get headers done without a coating on them. Your going to want atleast a ceramic coating and also a 409 SS system. the 304 is too soft. If you look at SLP, TOG and others, they use 409 and also a ceramic coating System.
You have to remember, these cars have alot more engine heat and will require something to better then what you are talking about.
You have to remember, these cars have alot more engine heat and will require something to better then what you are talking about.
Huge mistake if your going to get headers done without a coating on them. Your going to want atleast a ceramic coating and also a 409 SS system. the 304 is too soft. If you look at SLP, TOG and others, they use 409 and also a ceramic coating System.
You have to remember, these cars have alot more engine heat and will require something to better then what you are talking about.
You have to remember, these cars have alot more engine heat and will require something to better then what you are talking about.
How do these cars have more engine heat? Same stock thermostat as virtually any LSx engine. Are you talking about EGT? EGT is primarily a function of timing and AFR, any reasonably tuned, street driven, LSx engine is going to have an EGT within a fairly narrow band.
We may have more engine bay heat, but that is nothing compared to the EGT.
That being said, yeah, coated headers would look nice, and the coating will probably help extend the life of the headers.
Unlike all the rest of the LSX engines, which have true dual exhaust headers, Left and Right bank, we only have a front exhaust that collects into a crossover pipe and then into the rear exhaust that collects into a downpipe. All the other LSX engines have 2 dual exhaust pipes pushing the hot engine exhaust away from the left and right sides. Where our cars are trying to push that kind of exhaust out by a single crossover pipe and single downpipe.
So what 2002ScottOnyxSS is trying to have built are tubular exhaust headers dumping into a 3" downpipe.
Pros:
-Less restriction to flow (I assume you've seen the abomination that passes for a rear exhaust manifold on the LS4? The entire flow from the front bank goes through a runner barely larger in cross section than an individual exhaust runner, and appears to interfere rather significantly with the flow from #8 cylinder.)
-Less mass to absorb heat compared to cast manifolds
-More surface area to radiate heat (how much really depends on the design of the headers, but will be countered to some extent by a ceramic coating).
Cons:
-Will probably end up being a "shorty" style due to space restrictions, but one can hope for better.
-Single exhaust - no room for true duals due to body construction.
BUT: Both headers will flow into a 3" downpipe without the 2.25" restriction at the rear exhaust manifold flange anymore. With a 3" catback such as the one NachoSS had built, the DP/Catback system could flow 78% more air than stock (probably 100% more using mandrel bends as opposed to the factory bends), and is equivalent in flow capacity to a true dual using 2 1/8" pipe.
Rather than worrying about heat, I'd be more concerned with ensuring that the crossover and rear header have a properly designed collector to merge their flow into the downpipe.
Pros:
-Less restriction to flow (I assume you've seen the abomination that passes for a rear exhaust manifold on the LS4? The entire flow from the front bank goes through a runner barely larger in cross section than an individual exhaust runner, and appears to interfere rather significantly with the flow from #8 cylinder.)
-Less mass to absorb heat compared to cast manifolds
-More surface area to radiate heat (how much really depends on the design of the headers, but will be countered to some extent by a ceramic coating).
Cons:
-Will probably end up being a "shorty" style due to space restrictions, but one can hope for better.
-Single exhaust - no room for true duals due to body construction.
BUT: Both headers will flow into a 3" downpipe without the 2.25" restriction at the rear exhaust manifold flange anymore. With a 3" catback such as the one NachoSS had built, the DP/Catback system could flow 78% more air than stock (probably 100% more using mandrel bends as opposed to the factory bends), and is equivalent in flow capacity to a true dual using 2 1/8" pipe.
Rather than worrying about heat, I'd be more concerned with ensuring that the crossover and rear header have a properly designed collector to merge their flow into the downpipe.
I think we would be better off going with Milzymotorsports for our headers if you want someone wanted them right now. Otherwise just wait, because there is a company working on them. I cant not say who it is at this time, but lets just say the name wont suprise anyone when they are released.

