DIY Manifold

[Driftben]

does anyone know where i can pick up some stainless pipework i.e. bends, etc. that i could build my own exhaust manifolds?

cheers

[kam-325i]

Local to you or just a supplier in general ?

[Driftben]

both to be honest, i don't mind ordering it all in but if theres one down the road then thats a bonus.

[kam-325i]

Ive always used these guys, Concept Stainless...

http://www.concept-stainless.co.uk/index.html

Even though they don't list small bore bends on their site, they do stock them.

When ordering, just remember that pipe is sized on the inside bore of the pipe, not the outside diameter......and wall thickness is a % of the bore, so for a fanimold, you would order pipe/fittings that are "schedule 5 S" or "Shed 5 S", or "Shed 10S" maximum..

One more thing, go for welded pipe, not seamless (Dairy pipe), as seamless is mega expensive

[Driftben]

ohh cool thanks for that kam, whats the difference between shed 5s and shed 10s? quality of stainless?
also ill be using the pipe for a manifold, i doubt any woman would let me go near their lady garden with sharp stainless pipe

[kam-325i]

Schedule 5, 10, 40 & 80 relates to how thick the wall of the tube/pipe/fitting is in relation to the bore (inside diameter) of the pipe/tube.

The "Grade" or quality of the stainless will be either 304, 306, 308, 310, 316 or 318....

I would recommend grade 316.

you can get two types of bends, Short & Long radius, for a 4 cylinder engine, you would need approx. 10-12 short radius bends just for the manifold.

[DanThe]

Exhaust stainless tube is measured on the outside diameter

[kam-325i]

Exhaust stainless tube is measured on the outside diameter

Tube is sized by the outside diameter, pipe is sized by its bore...

[Driftben]

This is going to be for my twin turbo m60 so will need probably double that, think the mrs will have to sit down while I'll tell her the price of that.
So say I want 1 3/4" pipe and bends, should I go for shed 10?

[kam-325i]

Err, yes, Shed 10S, especially if you have got two snails hanging of it, I would even say go for Shed 15S if you can afford it....

(The S after the Shed number denotes stainless)

[Driftben]

ok cool i shall give them a call on tuesday when they are open, see what the difference in between shed 10 and shed 15 in price

cheers for that Kam

[appletree]

We do 316 stainless dairy pipe at work and have plenty of off cuts, I could sort some out for the rest of the system. I made my system from it.

We do 1"-4" in 1/2" increments and bends

Might be good to find some stainless donuts for the manifold there good as you can cut then to the radius you want.

[Driftben]

That would be wicked if you could round up some off cuts dude and I'll drop you over some monies for them, I'll have to pick up some doughnuts as well for Some longer radius too.
Next hurdle is building a all in one exhaust flange

[ross_jsy]

The collector? I would be tempted to buy a prefabbed one

[Driftben]

I'm struggling to find a prefabbed set of manifold flanges. I can't even use the gaskets as a template because they are separate units

[kam-325i]

have you still got the old manifold ?

[Driftben]

I have but I don't want to cut it up because iv already built it to fit the E30, so someone else can benefit from using it instead of going through the ball ache of building their own

[appletree]

Could you just draw around the one you have at the minute to get pretty good template?

[daimlerman]

I would suggest that a two piece manifold section would be better than a one piece,the cast manifold has a known tendency to warp,pulling studs out of the head...this allied to the practical difficulty in threading a one piece unit in and out of the engine bay would suggest,to me,that a manifold made up in more than one piece would be easier to cope with.

[Driftben]

The manifold isn't a cast unit it's going to be stainless so hopefully I won't have that problem of warping too bad.
as for the one or two piece you was referring to, because each bank of cylinders will have a turbo to go though they will have to go to a turbo flange so I won't beable to do a split manifold.
Does that make sense?
May have to draw a pic, might be easier

[kam-325i]

got a few 2" elbows lying around !!!

[Driftben]

holy moly that looks like pure gold to me, how much are you after for them Kam