Performance exhaust manifold thoughts/ideas

[Cro]

Anyone had anything made up? I know Matt from tdf had been/is working on something but havn't heard anything about it.

Bar those stainless ebay jobs theres not much else going on, but there's bound to be decent gains out some something well designed and stainless for the itb,sc,turbo clios we have about!

 

[franx]

wo'nt get much better than the 182 mani me thinks, being already cramped in there as is

 

[Cro]

Theres bound to be franx, even just with a polished stainless variation of the 1*2 manifolds, let alone any size and port differences

 

[Icarus]

172 4 - 1 or our 4 - 1 but the later isn't cheap and is designed for our SP engines not the standard F4R 730/736/738.

182 makes a bit more torque but being 4 - 2 - 1 doesn't create as "nice" a torque curve as the 4 - 1.

Also depends massively on the engine spec, lumpy cams etc. will result in different needs in exhaust manifold design.

 

[Cro]

Is there a formula or something to use going by the cam degrees as to what tubing size is best Matt or just trail and error? I presume your SP ones are stainless?

 

[unfortunately_french]

The "formula" as you put it would be found within an understanding of fluid thermodynamics and more modernly CFD (computational fluid dynamics). I've briefly covered both of these topics within my degree at university and they both play a big part in any type of exhaust design. Flow rates need to be known before a design can be produced so it would be more about knowing how much exhaust gas comes out of each cylinder per engine revolution, velocity of the gas etc to determine the size/curvature of the "higher performance" manifold. IMO, as the main difference between the 172 and 182 is the manifold, I would imagine that Renault's engineers that designed the manifold did the most they could to obtain as much performance from the manifold as possible using the above techniques, probably using years of experience and on a budget that allows thorough testing and manufacture of prototypes. In other words I think i'll leave the manifold as it is and stick with a stainless after the manifold. That is unless the sole reason you would want a different manifold is so that is stainless aswell. Personally if I was ever going to consider a new manifold for my 182, i'd make sure it was capable of having a turbo bolted to it