wait, hold on a sec...

the manifold isnt part of the exhaust? are you serious?

and your sayin cast is not good for heat?

 

manifold exposed to high pressure?

and the exhaust isnt exposed to high heat? have u never seen a DP glow?

 

No cast is good. But the manifold is under vary different conditions from the rest of the exhaust. So if you're gonna go that road, is the turbo part of the exhause or the intake, smart guy?

 

from what i recall we were comparing engine to exhaust, not exhaust to engine.

but a turbo mechanically would be exhaust

 

DP's usualy glow through contact heat transfer with the turbo not through pressure.
But ya know what.
Do whatever the hell you want.

 

heat from the exhaust turbine spinning super fast with hot EGT's

and im going to go with a cast manifold cuz i dont want it to crack

 

I've seen a DP glow from excess fuel getting dumped into it and ignited never from just how air flow though.

also your manifold will more than likely be the sole support for the weight of your turbo. thats why you don't go cheap. metal weakens as it heats and becomes more malluble. now imagine you hit a pothole and all the force of that turbo droping has to be supported by that now hot/weaker manifold. also as you torque the motor it rocks side to side it will sling the turbo the mainifold must support that force. and then you have the force of the turbo pulling itself forward under load. so now your looking at least 3 forces at all times it variant directions being supported by a manifold that is be rapidly heated and cooled. SO.... don't go cheap. your saying its not as important as your internals but a shitty header can take away near half of your hp. why do you think the good ones are so important because there is alot of engineering that goes into them. personally... i don't care what you chose to do.. but if you ask for advice and don't go with what we refer you to... don't bitch when it breaks.

 

cast maniolds are generally the ones you have to worry about cracking. go tubular...

 

how will cast crack before tubular?

and say i buy that tubular manifold off of ebay, and then have my dads friend re-enforce the welds internally and externally?

and i plan on making some sort of support for the turbo, any suggestions?

 

design, shape, way the metal was formed. tubular > cast


umm.... wel iff you know anything about welding just slapping more bead on there dosn't make it any stronger it just makes it a waste of time. as far as supporting the turbo, you better brace it to the engine(remeber it rocks) otherwise you'll just break it.