No. The freer flowing the better. The ideal turbo exhaust is a velocity nozzle on the end of the downpipe.

 

No. The freer flowing the better. The ideal turbo exhaust is a velocity nozzle on the turbo exhaust housing Fixed

 

Gah! What have I been smoking? Thanks for the correction. I've been thinking NA too much today.

 

pass it over

 

a freer flowing exhaust is best for most turbo kits except for this one. The internal wastegate of the greddy kit can't flow as much as it should with a freed up exhaust so this setup ends up causing boost spike. it's the reason why you don't see any of the greddy guys using 3" testpipes and exhausts on the greddy kit. it's a street kit that runs most reliably with some sort of back pressure.

 

Do you know the technical reason why this is?

Is it because the exhaust gases will still pass through the turbine due to the small size of the wastegate port?

 

when your exhaust is too free-flowing that means more air will pass of the turbine wheel, unfortunately with this small internal wastegate, it physically can't keep up to vent all of that air, so if the exhuast was restrictive, less air goes over the turbine wheel, less air the W/G has to bleed off

 

Agreed, but Joey was worried about a pinhole in his exhaust.

 

A port of the wastegate would fix the lack of "flow" problem.

 

a port would probably help, but depending on how much boost you want to run it can only do so much since you can only port so much. the CWest time attack car that used the greddy kit opted to fit an external wastegate on to the kit