crossover pipe material choice.

[Pro]

hi folks.

another quick query - just chasing opinions really.

in my project plans, i'm running unequal length headers because i have a big single turbo in the front RHS of my engine bay. the crossover pipe from the LH bank of cylinders will go down under the crank pulley and come up under the turbo. the turbo flange wil be braced to the old power steering mounts as well.

if i chose thin-ish (like 2.4mm instead of the usual 3.0mm) steam pipe to do the job (braced to the sump bolts near the crank pulley), would that be considered too heavy? remember this will be 2.5in (about 60mm) diameter stuff.

i could build the lot out of mild steel exhaust grade pipe, but i am worried it will crack - even with the 2 bracing points.

thoughts?

 

[krayn]

I made mine entirely out of exhaust tubing and it has not yet cracked but i have not done a lot of hard long driving yet.

 

[Pro]

okay ... so is it well braced yeah?

would good bracing be enough to stop lightweight stuff cracking?

 

[JBrady]

Standard exhaust tubing either mild steel or stainless will work fine. Weld L's or steam pipe can make good turbo manifolds but is excessive for cross-over pipes or any long runs IMO.

 

[Pro]

awesome - that's all i wanted to know.

thanks guys!

 

[Toysrme]

You got it.
Regardless of what you do, you'll want flexpipe off the headers & the rest of the system mounted securely with brackets/mounts of some type. You must not under-brace the system. Otherwise you're gonna have 50lbs of pipe+turbo on 20-30lbs worth of headers yanking on the heads. Also, the #1 cause of failed custom headers isn't *horrible* welding. It's incorrect loading.

Once you get past the headers & the major heat of that area. It's not going to make a real difference between generic mild-steel pipe, or thick mild steel steam pipe.
I agree with JBrady. Steam pipe is great but, not always worth the weight & extra time spent welding it.
My vote is use the mild-steel pipe *unless* you've got a massive turbo to sling up there. Then it might be better to go with steam pipe.

Just don't forget your flexpipe & bracing.

 

[Pro]

flexpipes inhibit flow so i wont be using one at all.

and my turbo weighs about 15kg - that's why i'm bracing the flange to the PS pump position and the lower part of the manifold to the sump bolts.

 

[Toysrme]

Whatever works for ya. :veryhappy I really like using flex pipe to take the stress off of everything when the engine is rocking around.

33lbs isn't very much. No worries.

Sounds like fun!

 

[Racing-Solutions]

Try 14 gauge aluminized mild steel, I've never seen it fail even under the most demanding apps on crossovers. You might also try the dual lined flexes, they have an internal lock liner that makes them *near* smooth inside as opposed to the standard highly restrictive ribbed flexes.

 

[Pro]

thanks for the tip - i'll check them out.