Just wanted ye all to know.....no opinions here....just factual, informative information to the Evo crowd.
I know this will be useful to some, and I know some may not like it.
But I just wanted to point out that headers do crack (whatever the make, I believe).
And mine did, after about 8k miles (crack was at the base where it connects to the turbo).
Will either be looking at extrude honing the cast-iron stock manifold, or getting another aftermarket manifold (price is almost the same, although I don't know if I can deal with the hassle of another cracked header).
If I could swing it, I'd just go ahead and get one of Buschur's turbo kits (I agree with his philosophy about cast-iron manifolds)

 

Buschur is the right way to go!

 

Or you can go with borla header which has a million mile warrentee

 

www.full-race.com if you want a equal length manifold to last.

 

Someone should make one from inconel. I spoke with a couple of fabrication shops who do inconel and there wouldn't even have to be a run of more than about 20 for them to do 'em for ...well...they'd cost a couple of thousand $ each, but they'd combine equal-length headers with the holy grail of not cracking.

 

Totally true, this is why sus304 is going to be a thing of the past for turbo manifolds. NA will be fine. I heard manufacturers might be switching to 309 in the future for longer lasting tubular turbo exhausts.

You might want to check out memoryfab.com manifolds they have 1 year warranty against cracking and good cost.

 

Critical point is weldments. The 304 stainless should handle the high temperatures well. The welded part has to be heat treated with a full solution anneal. This can be done at any commercial HT shop for a modest amount of money.
The manifold may distort during HT and have to be staightened and refinished to fit properly - and polished for looks. This ads cost so the JIC probably skips this step and produced an inferior product.
You can crack an inconel manifold too if not welded and HT properly.
Cast manifolds have no welds and are routinely HT - problem is the rougher ID surface from the sand casting.
Ceramic coating will hold temp down somewhat. Best is a plasma spray coating with a bond coat to make sure coating doesn't peel off, but expensive.

 

the stock manifold is frankly where its at unless you plan on bolting an aftermarket turbo on.

 

how about cams? with porting and maybe even a modified intake manifold....wouldn't you think headers would help?

although talking from experience, i have to agree that I would think about headers only when thinking about a bigger turbo.

*stock manifold is now in place....I miss that JIC manifold (before it cracked) - is all I can say

 

I wonder how many people have had cracked exhaust manifolds like this? I've used stainless manifolds on other cars for years and not had issues, but I also ran superchargers on those cars so you don't have the weight of the turbo, the heat, or the weight of the exhaust system to support..

 

What performance difference did you notice between the JIC manifold and stock?

 

pm'd ya