Has any one got any suggestions on what size tube should be used for making a custom turbo manifold for a zetec turbo conversion. I am in the process of a ZT build and am trying to create a one of manifold, but not sure what size the internal diameter of the manifold should be. Would the same size or nearest size to the exhaust ports on the zetec head be ok or does the manifold need to be slightley bigger to get the gases out into the turbo quicker? i know quite a few people are going the zt root now and would be greatfull for any information

 

around 36-38mm (40mm outer) is the most popular.

 

Cheers for that matey,
thats a big help. people are still very funny about sharing there zetec turbo infomation an still tent to keep info close to there chests but thats a great help thanx!

 

For good spool up and response go with 1.5" pipe which is good for upto 500bhp

For for more than that go with 1.75 to 2" pipe