Need some advice/experience here.

I installed a BBK Full and Ive hit a wall power wise, I can barely make 20kw more than the 9RS turbo I used to use even with 3 more psi. 9RS @ 22psi making the same power and almost as much torque as a BBK Full on 25psi? Something is definitely wrong.

Currently running a stock engine jdm 8 (stock cams).

Mods:

Full ralliart IC piping kit
Ralliart suction pipe
Ralliart foam panel filter
8MR metal BOV
ID1000 injectors
DW300 pump
Tomei dump and front pipe (ID = 66.7mm or 2.6")
200cell cat
2.5" Ralliart Ti catback (ID = 63mm)

Adding the BBK Full did increase power on average around 10kw and 20nm at the wheels in VD (Mustang mode). However it just doesn't make any more from 22psi to 25+ psi. Makes a little more torque but thats it. Was making ~220wkw/340nm tq with same setup but 9RS turbo @22psi, now making ~230wkw/360nm tq on BBK Full with 22psi and make no power gains and minimal tq gains increasing that to 25psi.

Taking the lid off the stock airbox makes no gains at all.
At 25psi BOV does not leak.
I tune it myself and there is zero knock.

What do you guys see as the issue here? The stock cams while not ideal shouldn't just wall at a certain power/flow either, right?

Do you think leaving the tomei dump/front pipe in place and changing to a 3" straight through cat back will make a big difference?

When do you guys feel that the Tomei dump and front pipe becomes restrictive?


Sorry for all the questions, just not sure what to look at first.

 

Change to 3" Turbo Back ! So Turbo Elbow , Downpipe , High Flow Cat and Cat back ...all the way 3"

 

I know the exhaust is a bit odd, 3 different diameters and all. But would it really be holding it back that severely at this 'low' power level?