isr actuator

[sk8ercbs]

Does anyone know what the actuator on a isr/isis t25/t28 turbo is good for, boost wise. How high can you adjust the boost to and it still hold.

[boost86]

I absolutely wouldn't run it. I had GREAT experiences whenever I ran HKS actuators. They held boost and had very little creep for an internal gate. My buddy had a factory ISR t25/t28 turbo and the wastegate was bad to begin with. It leaked boost early and made the powerband very un-fun.

[jedi03]

lol I have had a bnib one on my shelf for a few years as a backup...its goin in the trash now!

[derass]

You need a boost controller. Either manual or electric. Adjusting the wastegate rod isn't a good way of increasing boost.

[brandon519]

The ISR turbos are known for boost creep aka overboosting. Even with a ported wastegate my brothers s14 keeps overboosting to like 14-15psi.

[derass]

Does he have an RS3871? Because even an authentic Garrett GT2871R will do that. The wastegate port in the T28 turbine housing is just too small for those big compressors. 15-20 psi seems to be the sweet spot for those turbos if you don't want any creep.

[brandon519]

Does he have an RS3871? Because even an authentic Garrett GT2871R will do that.
Yes the turbo is the RS3871, and yes I agree the port is way too small.