exhaust manifold - primary lengths??

[Shovey]

I have a 4-2-1 manifold

when people talk about primary lengths - are these logicaly the length of pipes b4 they merge to two?

This manifold was new from Torque Technique in March - but there is some concern that the design is not good enough for the targeted bhp of 165. (which we aint getting right now > fingers are pointing to manifold design)

who are the best people to talk to?

[kipford]

You are correct, the four pipes from the manifold are the primary pipes.

An oldish Book by Alexander Graham Bell called Tuning Four Stroke Engines (I think this is the title) has a lot of good SIMPLE advice on exhaust lengths and diameters. My Local library used to have a copy.

I used the data on a F750 Car very successfully.

[BLOGGY S7]

It all depends on what you are looking for? Torque, Power or a compromise between the two. The best people to talk to are a firm called Primary Designs, however I must warn you they are not cheap, but they do make exhaust for all the top rallye teams and a for a few race cars, as well as road cars. Thet can be contacted on 01844 216057. To give you an example, they are the company that makes a Stainless steel manifold for the Focus RS (Duratec Turbo) thats said to release about another 14 BHP and 50 Ibsft of Torque, all from a manifold!!

[Eccentric_Rich]

An oldish Book by Alexander Graham Bell called Tuning Four Stroke Engines (I think this is the title)

It must be an old book, didn't the same bloke invent the telephone way back in the 1870's