Brentis

I've been having some issues getting up to 13psi (.9bar) or higher. I'm currently only getting .84bar and would like to know what base duty cycles you are using for your primary and secondary turbos.

I've moved the pri in the 70's (74-ish) and the secondary into the 84-86 range and it still seems that I can't get higher.

The transitional boost loss seems worse like the secondary isn't pre-spooling possibly because of the pre boost setting. Also the peak rpms seem to cut off possibly from the waste gate fluttering(?)

I just installed a y-pipe and am fairly convinced it is not a boost leak issue. My mods include

efini y pipe
greddy smic
pfc
hi flo cat
cb
dp
greddy elbow

Thanks for you insight/suggestions.

SleepR1

Chuck Westbrook points out that Bar and kg/cm^2 are two different pressure units with different psi conversion factors. The Power FC Commander boost readout is in kg/cm^2.

1 kg/cm^2 = 14.22 psi.

Thus 0.90 kg/cm^2 would be 12.8 psi.

If you are seeing 0.84 kg/cm^2, 11.9 psi, I would back the solenoid duty cycles down to the high 60s. My "high" boost setting is 0.90 kg/cm^2, 66% solenoid duty cycle for BOTH primary and secondary turbos (I like full boost with both J-spec turbos humming all the way 8000 rpm LOL ). My J-spec twins make 12.5-8-12.5 psi across the rev range (3000 to 8000 rpm redline) as read off of my column-mounted Autometer boost gauge (yes the Autometer agrees well enough with the Power FC Commander boost readout, which apparently reads boost from the map sensor).

FWIW, my "low" boost setting is 0.80 kg/cm^2, 11.4 psi, solenoid duty cycle @ 64% for BOTH primary and secondary turbos. My column boost gauge reads 11-8-11 psi across the rev range (3000 to 8000 rpm redline).

Brentis

I thought that moving the duty cycles up was the way to get to your objective boost number. So I've been moving my duty up to get to .90

Help!

ZeroBanger

Moving your duty cycle UP will make you more likely to hit a fuel cut from overboosting (.20 over base will cause a fuel cut).

I put mine at 1.0 and then run .50-.58 on my duty cycle. You just have to experiment. I think its better to move the boost up and the duty cycle way down. Less likely to hit a fuel cut.

Later

ZeroBanger

Moving your duty cycle UP will make you more likely to hit a fuel cut from overboosting (.20 over base will cause a fuel cut).

I put mine at 1.0 and then run .50-.58 on my duty cycle. You just have to experiment. I think its better to move the boost up and the duty cycle way down. Less likely to hit a fuel cut.

Later