Are there any restrictions in the exhaust manifold that can be smoothed out too?! On my Fiat Coupe a worthy mod was to grind out the manifold intake (from the head side, not turbo) making it slightly larger and smoothing out as there was a lip as the manifold holes are smaller than those in the head. It allowed the gases to get the turbo more freely, similar sort of affects as de-catting and wider diameter exhaust and it just improves the flow.
yes, I did this on my 10v, opened them up quite a bit from the head through where they all join together up to the turbo point.
smoothing this out gently (in theory) increases velocity to the turbo which thus aids spool up times.
Mine seems good from 1500rpm, although its not on full boost untill 17/1800rpm under WOT.
Thanks for your fast response.
Your recommendation is GSR air intake instead of BMC-CDA, if I right understand. But common opinion is that the BMC is best solution especially for turbo charged engines, because CDA is closed system which have not problem with hot air in engine bay, contrary to the open system like GSR.
About the removing the butterfly - whether is it OK according in butterfly function and influence in higher MPG obtaining.
The GSR is leagues above anything else on the market. A tubo car needs the shortest intake but also the smoothest whilst being designed for minimal turbulance whilst creating velocity towards the tubine.
As far as heat goes, the filter sits by the inner wing, you can create cold air flow from the bumper.
If you have it about you to fit the FMIC you should have no problem creating a heat sheild for the filter, but I think if you monitor the temps where the filter would be, you may find you don't need to do so.
The butterfly closes for a smooth engine shutdown, to prevent judder, thats all.On the 2.4 it goes down to '40-something mm'.
When running higher boost, thus creates turbulance in the intake manifold post resistriction, and pre restricion can cause overboost/turbo spike issues.
This is just my findings anyway, I did a loa of mods together so can't comment too much on the difference each one made, but work on the same theory, a short but well flowing route from the turbo through a large FMIC straight to the engine with no pipework restrictions untill you are into the intake manifold.
In a similar way, the intake to the turbo should be short and smooth tapering (narrowing) gently into the intake housing. You should havea large static pool of air for the filter to pick up from some dstance from the engine, but worry about the afore ather than heat,, you can sort any potential heat issues easily.
But as said, a 16V head would also be a good mod.