Inlet and exhaust manifold flange thickness

[sonus]

I am having some flanges cut to make an intake and exhaust manifolds for my Daimler V8.

I am considering both stainless, mild steel and aluminium for the intake manifold. Which thickness should I have these cut in for each material?

For the the exhaust it'll be either stainless or mild steel - what thickness should these be?

And where can I get megaphones made that are Inner Ø28mm one side and inner Ø40mm the other side with a length of 175mm?Or is this easy to make out of a flat piece? If so how?

[hario]

1/2" or 12mm minimum, otherwise too bendy

[sonus]

1/2" for stainless and mild steel aswell? For aluminium I was considering 10mm for the inlet.

[kevins]

Most production cars with welded manifolds seem to be around 8-10mm, might be worth getting them a bit thicker though so you can get them machined flat if they distort during welding.

[discostew38]

Ones I've bought in the past have been either 8mm or 10mm

[usedabused]

I work with inconel manifolds for Nascar F1 and WRC etc and there flanges are 4 to 6mm..

However in the real world I would say 10mm minimum you must always have the flange bolted to a block of metal preferable alloy as it disipates the heat...

A spare head is perfect for this.

Tac the primaries and work through the secondries etc but always split each pipe frome the flange to fully purge weld it..

Theyou can make adjustments for each pipe as they move because they will move....

[usedabused]

Also if you can go stainless for both.

Alloy is a pain to weld diy and mild is just a short term fix...

As for "megaphones" just adjust the tube you are using with a meric adjuster ..

Any more Q's just shout up and post pics...

Jesus loves pics....................







Edit...

90% of F1 stuff is now 3D printed.....