okay so the manifold i built was using some scrap bends and tubing i found . came out very good though..

butttt

i want to make a really nice turbo mani for my truck ( after the jackson meet).

i have some options.

304 stainless
409 stainless
316 stainless

or has anyone ever tried using chromoly ?

all of this will be make from .80 -.120 wall tubing ,no need for the thick stuff


lookin for some ideas!

 

im no manifold fab guy but if i were building one id stay away form 409 if possible because that will still corrode unlike a 3 series stainless. of course you will pay more for a 304 or 316 but if you spending the extra for stainless why not have it look pretty all the time. id also think youd need a 3**L which is a low carbon, i think itd help you in a few ways. why you thinking chromoly? price is up near that of stainless with no real other benefit to regular steel in this purpose. youd have to look at what adverse affects the higher carbon content of the moly will have at elevated temps. it may tend to crack but then again dont quote me on that. also ive never seen off the shelf tight bend moly tubes. something 1.75 with .080-.120 wall will bend with no kinks on a jd2 bender but thatd be out at like a 5" centerline radius. anything tighter will give you trouble if you can even find a die small enough

 

Stainless is fine, just go here, or a similar place https://www.mandrel-bends.com/catalo...unt/login.html and get your tubing.
Probably wanna stay with 16g and thicker.

Here's one I just did if it helps with ideas.

These pieces feel strong and won't bend.

 

304L is what i would use, but nothing thinner then .080 and .120 is even better. I've seen WAY to many built out of 16ga. (.061) that have cracked over time. SS just has to high of an expansion rate from cold to hot.

 

very true about the expansion rate. if at 16g you could run those slip joints that help with the expansion but they get expensive. also would want to not have the weight of turbo hanging from that

 

304 will be fine. If you don't mind spending the extra money 321 would be better. Read this about 321 vs 304. http://www.viperalley.com/forum/vipe...stainless.html

I made the headers for the turbo system for my Chevelle out of 304. My headers arent completely done in this pic, but you get the idea.

 

those look pretty good^ did you back purge?. there is a cryo treatment guy around here. i want to get my manifold cryogenically frozen , he said it helps alot in the strength department!!!


as for the thickness... i plan on having a seperate turbo support coming off the front of the head. i dont want to rely on the flange and the bolts holding it up since im doing a thin wall manifold next

 

Any benefit from a cryogenic treatment will be lost the first time the manifolds get warm enough to change color.