Is there an optimum header length for exhaust manifolds on turbo engines?
I was considering moving my turbo round to the side of the engine, as I have seen done on quite a few Zetec Turbos, and I was wondering if that has any serious side effects on spoolup? How much does it affect the egt?

Ta

 

The optimum runner length will be spec dependant.
Generally long runner lean more towards a low rpm tune and short runner to high.
With very long runners ideally you would want a very good design,good material coupled with a correctly sized turbine housing(or full turbo for that matter) to ensure good gas speed is kept aswell as good gas temp.
Materials such as inconnel for the manifold and twin scroll turbo's are starting to become more common in.....road going cars. Its bloody expensive though.