fabricated inlet manifold

[Talonmotorsport]

I've been looking at producing roadster/7 friendly manifolds so that the OE ECU/megasquirt could be used for the EFI Pinto , 2000 DOHC and 1800+2000 Zetec all using the standard hardware such as the OE throttle body , injectors , TPS, MAP ect. It has been suggested that ali casting could be used and produced at a reasonable cost rather than faff around fabricating them. I'm currently looking in to this although with out drawings or a pattern to work from I seem to be getting the brush off.
I know a few on here have made their own inlet manifolds for the zetec using parts of the orignial plastic casting but can any body tell me why they have gone for using ali rather than mild steel or even stainless? I know there will be heat transfer between the head and the inlet but the cast ali and plastic manifolds must suffer from this also? So can any body say if a mild or stainless manifold would make any difference to the performance of the manifold?

[Tatey]

From working as a student design engineer at triumph motorcycles for the past 12 months on powertrain the reason for going for ali and plastic are to save weight, and for plastic to save cost.

There will be heat transference between the head and the inlet but it will be within the working limits of the material used, cold air is drawn through the inlet manifold which will help cool it, the inlet manifold would normally get to about 80-150°C depending on if the engine has a steady stream of air moving over it or if it is in a heat soak phase e.g. if sitting at traffic lights after an aggressive run.

Aluminium has a higher specific heat capacity when compared to steel and will therefore conduct more heat, hence why aluminium is used for heat sinks.

There will be no real issues when using steel/stainless steel other than the potential for galvanic corrosion to occur between a steel and aluminium interface if the head is made from aluminium. However a gasket between the two should prevent this from occurring, or at least minimise its affect.

[Talonmotorsport]

That is probably going to be the most comprehensive answer that I will get to that question, thank you. So if weight and cost are the only concerns I'll go about looking for some suitable very common tubing and see how I can hold it in the vice to machine it.

[mikemph]

Don't forget if you use steel and the car is sat for a while you will get rust inside the manifold..... Guess where it will end up when you start it up next time!!! Just food for thought :-D

[baz-r]

silvertops had a sandwich plate with the injctors and fuel rail on a plenum could easly made to fit this as it would all be tube work
its a tricky afair realy as there is such a variation on whats fitted for orignal injection systems and all of thease would need looking into
i have a silver and a black top inlets and all the stuff is diffrent so it could be a real headache to sort
on the other hand if your thinking megasquirt then you can use anything you like realy couple that with a base map to suit what you made it could almost be plug and play
i hear a rover manifold from the old turbo twincam engine can be made to fit with a simple sandwich plate
would be an easy option i have no idea how easy thay are to find