Stainless vs mild turbo manifolds....

[RedMist]

I have a bit of a dichotomy.
My offroader is currently getting built with mild steel manifolds. The reason being the engine is pretty exposed and I'll be fording with some regularity.
From my understanding stainless doesnt react well to being repeatedly quenched and will crack.
I'm also a bit scared of simply burning through the mild steel manifold at consistantly high temperatures.
Any fact based recommendations would be appreciated. But please note there is no bling factor considered. The buggy is plain ugly and putting some stainless manifolds on it isnt going to improve that fact.

[sergei]

steam pipe? If you use normal exhaust tube, it will crack in no time.... Stainless is usually very thin and cannot withstand vibrations/heat stress in that thickness.

[flygt4]

steampipe is most definately the way. just get it hpc coated and you're away.
my manifold is made of it, and it hasnt cracked yet. i havent yet seen my steampipe manifold glowing red, which the cast manifold on other turbo cars ive had did with ease. its had it fair share of heat through it too.

[QikStarlie]

steam pipe is best option as others said. sch40 stuff. welded correctly you wont have any issues. stainless pretty average for manifolds. and your aplication will stuff it pretty quick.

[matt dunn]

we always ran steampipe manifold.

After time they do start to flake and crack.

We were welding cracks on my old steam pipe manifold every 3-4 events,
but it the manifold was over 10 years old, and had never been HPC'd or anything back then.

Not sure on stainless.

[Crucible]

My mani is steampipe, It used to get quite hot (glowing red) when I was running higher boost on the stock ecu, for obvious reasons, but its held up fine. Barry had it on his old gtz and I have run it on my one for quite a while now.

As far as Stainless goes, I think the thicker gauge stuff is fine. Action Dan used to stand by the stainless manifolds he made saying that they wouldnt crack in his Trademe listings.

not too sure about you're application though, quenching it with water through big puddles etc may change things a bit, but it will probley have the same effect with mild steel as well, would it not?

[gasman]

stainless steel has a slightly higher coefficient of expansion compared to mild steel so probabily not the best idea to be using it if its going to be quenched frequently.

[IH8TEC]

if any reason i would have said use steampipe because it's gonna be getting alot of airtime as well i imagine and a crap load of vibrations going through it even with nice shocks

[RedMist]

if any reason i would have said use steampipe because it's gonna be getting alot of airtime as well i imagine and a crap load of vibrations going through it even with nice shocks

The shocks and spring rates are still very high, there are studder jumps where I can't see. Weird sensation being shaken so hard that your vision fails.

Steam pipe it is.

[strx7]

from memory the best stainless steel to use on manifolds is 321 which is rather expensive. Stainless doesn't like to be expanded and contracted as much as a turbo manifold see's and hence they crack after a couple of years (generally)