JZA70 R Boost/Fuel cut

[JZA70-R]

Hello i am wondering if the fuel cut happens at 14 or 15 psi on the factory manual computer for JZA70 1JZGTE? I have searched the net and have been told both 14 and 15 so i am unsure, reason being is i am upgrading to a single conversion and i have the choice of 14 pound actuator or 7 pound actuator and i don't know what one to go. I am not upgrading my computer just yet so any ideas?

[wilbo666]

Run a 'boost cut defender' or similar and the boost will not be an issue.

It might be smarter to get the 7psi actuator and use a boost controller to set it higher if you wish however.

If you get the 14psi actuator you won't be able to set the boost to less than 14psi...

I'd chuck it on a dyno and check that the AFR is OK regardless...

Cheers
Wilbo

[JZA70 R]

IIRC its closer to 13.5 - 13.7 PSI. Someone has tested the ecu's voltage cut and im positive is was within the 13 psi range.

[JZA70-R]

Thaks for your help, i have let him know that i would like the 7 pound actuator

[chris davey]

you crazy? running 7psi on a 1j is just absolute crazy talk! Especially with a single turbo setup. Get boost cut defender (or make yourself) from 2jzr31, run 14-15psi on stock injectors,ecu etc and you will be fine. That is assuming that the turbo is around gt30 size. If it is gt35 size it will probably still run rich at that boost level. If that is the case, you just up the boost until the afr's get closer to 12.0:1 Crude method but it works.

7psi is less boost than stock. Any decent single turbo setup is not even going to be close to efficiency at that boost level.

[big wad]

my jz is out of a jza70 manual with a gt30, running a std 7lb actuator with a bleed valve its fine at a smidge over 13psi but at 14psi you will smack your head on the windscreen every time. cheers bigwad

[Officer Doofy]

13.8psi or 4.32v iirc