turbo manifolds

[ford100ev8]

I am making some stainless turbo manifolds, whats the best grade of stainless to use ,what size tube and thickness, also whats the best design to use. Any info please. Thanks

[kiwicar]

Hi
Stainless is not ideal for a turbo manifold as to be able to get it to bend it needs to be thinne than you really want. You can use it, if you can get bends in 2.032mm+ (14G ) but 12G (2.642mm) is better and very difficult to get. Corkey Bell recomends using cast steel high pressure manifold flanges which are about 1/8" (3.175) to 3/16" (4.7mm) thick with more meat on the outside of the bends than mandrel bent tube.
Mike (boos performance) on here has some cast iron manifolds for fitting twin turbos on a rover, might save you alot of work.
Best regards
Mike

[ford100ev8]

I have got myself 2 td04 turbos, only 140 for the two,i can get the tubes bent at work ,i am thinking of using 40 mm tube 2.5 mm thick, 304 stainless and making the flanges out of 8mm 304 stainless, tig welded, any idears of designs

[kiwicar]

Hi
Can I recommend investing in a copy of this

there is a whole chapter on exhaust manifold design, and one on inlet manifold design, and one on intercoolers! it really is very good .
I think your proposed material selection should work OK, and ease of access to the material and access to the means of fabrication is always a big factor in how easy the project becomes, so I would go with what you can get. as far as design, keep the primaries short, keep the bends as open as you can and keep all the primary lengths the same, the collector should be of the "coke bottle" constant cross sectional area type and if the turbo has a split scroll then keep the primaries in pairs right up to the flange that joins to the turbo and pair them so that the exhaust pulses are as far appart as possable for each pair.
I would buy the book and have a read, it will answer far more questions for you that you haven't realised need asking!
Best regards
Mike

[stevieturbo]

I am making some stainless turbo manifolds, whats the best grade of stainless to use ,what size tube and thickness, also whats the best design to use. Any info please. Thanks

You certainly dont need big for a turbo.

38-40mm would be fine. ( 38 probably easier sourced from any stainless supplier )

1.6mm wall again will be fine, but dont be hanging too much weight on the manifolds without additional bracing, regardless of what they are made from ( unless it's a cast manifold )

Best design is simple. Whatever fits best !. A simple log design will be the easiest. Dont be fooled into thinking you need a fancy tubular setup, especially at relatively low power levels. It will probably hurt spool and offer little benefit at the top end. So keep it simple.

Where do you intend to mount the turbos ?

A simple log for a front mount could start at say 38mm, stepping up to 50mm as it passes each cylinder.
You could do a simple log all the same size with a turbo flange welded onto the middle, or again step the middle up to 50mm or so. Both will be relatively easy to construct, and compact.

[ford100ev8]

I have just orderd that book, i like the idear of the the log manifold and mount the turbos at the front of engine, sounds nice and simple, so would i be right in thinking its at tube with smaller tubes coming off it in to head?