So I finally went to dyno yesterday, hopefully to lay down some nice numbers.

We started with low boost around 8psi, and worked our way gradually.

As we increased the boost to 14psi, but the car cut out early 5800. It was a clean ignition cut and the car would not rev higher to make power.

Then we tried 15psi, and the cut off came even sooner at 4800.

Basically, the higher boost we go, the lower the cut off becomes. When you're driving it feels like hitting a brick wall where both fuel & boost totally cuts out. Only at or below 12psi the car revs normal and would not cut-out early.

I have had this problem before, gapping down the plugs to 0.028" have solved the problem.

Knowing the plug gaps played a role in this scenario, we tried gapping down the plugs further to 0.023" and did another run. This time, I was able to rev up to 6600 at 14psi (vs 5800 previously), slightly higher than before but still not perfect.

My final run at 17psi and the cut out was at 4800.

No tuning was done because of the cut-out problem, my A/F ratio is around 10 in all boost range so I'm running rich and safe.

We have checked and confirmed that there is absolutely no boost leak in my setup. It seems like my ignition is not strong enough to produce the spark needed in high boost/load. So my next step is ignition upgrade, this is what I found and bought from ebay:



Hopefully this coil pack is stronger than oem and solve the cut-out problem.

I have CA18DET motor here's my mod list & dynos:

Power FC + Commander
Z32 MAF
444cc injectors
GT28R
Copper plugs
Walboro 255
Blitz ID-color boost controller
Blitz gauges (pres, EGT, boost)
FMIC
XS manifold
3" turbo back
HKS filter

13.5psi cut out at 6600:


16.8psi cut out at 4800: