Partly what trinidex said, also partly because a turbocharged manifold is pressurized (30+ psi is not uncommon), bolted to the turbocharger and under more load.

Also, though I can't speak for street bikes, the EGT in naturally aspirated applications is usually quite a bit lower than turbocharged applications. But things get hairy when the N/A engine is revving to 18,000 RPM and the mixture is still burning as it exits the head.

 

yamaha R6's run really high compression and redline at 17,500 rpm.

 

Here is the A-Spec manifold that never went into production:

 

looks serious!

 

That looks crazy badass But I wouldnt buy it hehe

 

see what i want someone to tell me is how is the coloring on that thing. doe sit show weakness? i know blue is acceptable and gold is great on SS but... ti????? clueless.

 

Google (ok actually, Azom, they rock), mang: http://www.azom.com/details.asp?ArticleID=1245

The welds look good, by that standard! AFAIK, the goldish color is just a natural and thin coating of titanium nitride which forms any time titanium gets hot enough. But I'm not completely sure.

 

cool... i know the headers are very thick... it's like almost 4mm of material.

 

You would think Ti turbo manifold would work for a street car at least.. i mean i can understand it not working for race cars because they are full throttle the whole time.. but a street car how long can you hold down the throttle befor hitting a light or getting pulled over lol ....

soo the only other option is inconel which seems to not be to much better then stainless it seems.. Does any aftermarket company make inconel turbo manifold for the evo or is that a custom only.. thanks everyone.

 

it's cheaper to cast inconnel than to bend and weld it i thinks... and the tooling shouldn't be drastically different from casting anything else.

supposedly there are many cast inconnel manifolds. but i haven't personally come across any.