Tuning inlet manifold size

[jonjg]

hello. i have a 1.1 cinq with 866 cam, recently managed to fit a john ashley branch manifold to it. ive got the standard 1.1 tb on it but do have a punto 75 38mm tb im hoping to put on. does anybody know what port size to grind the cinq inlet manifold to to get the best of the flow? also with the spacer that sits under the tb to manifold, do i need to adjust that too?

any help would be great.thankyou.

 

[purf]

I'm not sure if the punto 75 is an easy swap on an spi cinq? The spacer will need modifying/machining. I have fitted the punto 60 (32mm) throttle body in the past which is bolt on, plug and play.

Manifold doesn't have to be enlarged for the 32mm tb but people do enlarge and match the outlets of the manifold.

 

[Sir16v]

can use the p75 throttle body space (metal) but will require longer bolds to mount it.

as for spacer being plastic should be able to widen hole out to match said diameter or the new tb

 

[sparky5]

You don't need to open out the manifold inlet as 40mm TB's fit fine, you would need to bore out the plastic spacer though.

 

[jonjg]

would you need to bore out the inlet exit where it bolts to the head?

 

[rallycinq]

Use the inlet manifold gasket as a guide to where to remove some material from both the head and the inlet.

Be careful not to penetrate any waterways.

Not too smooth either, will cause drop out if too smooth.

D

 

[biggelmo]

Have I missed something here?
If you fit a P75 throttle body to a Cinq inlet manifold where is the fuel going to come from?

A P75 has a "dry" throttle body to go with its 4 separate injectors.
A Cinq has a "wet" throttle body with a single injector.

Or am I being thick.

 

[henseyseries3]

Have I missed something here?

If you fit a P75 throttle body to a Cinq inlet manifold where is the fuel going to come from?



A P75 has a "dry" throttle body to go with its 4 separate injectors.

A Cinq has a "wet" throttle body with a single injector.



Or am I being thick.

Simple you fit the spi injector plate to the p75 tb it's been done quite a few times