Boost Controller Runaway Boost - Typical Cause?

[rtune]

my ebc can control boost under all situations when dialed at 19psi, but at 22psi

I can get runaway overboost (to 26psi+) under certain ramp, load and gear .. not

always, but sometimes.

Should I try a different EBC.. or is the most likely cause insufficient wastegate

diameter (split dumps), or inadequate actuator - unable to dump boost fast enough

when it hits target?

[riceyr33]

my ebc can control boost under all situations when dialed at 19psi, but at 22psi

I can get runaway overboost (to 26psi+) under certain ramp, load and gear .. not

always, but sometimes.

Should I try a different EBC.. or is the most likely cause insufficient wastegate

diameter (split dumps), or inadequate actuator - unable to dump boost fast enough

when it hits target?

what bov do u have?

[rtune]

what bov do u have?

stock r34 gtr bov, stock N1 actuators

but how does bov get involved with over-boost. Doesn't bov come into play when throttle slams shut?

[rtune]

Ok after some searching...

it seems that having a better flowing exhaust with

less back pressure than stock can mean the wastegate flapper no longer opens

enough, or fast enough.. problem seen first at high psi, and high revs.

So the solution is either add back back-pressure (undesirable), or widen (grind out) the

wastegate ports and increase size of poppet covers.. (or buy bigger turbos that

are designed for that much flow in the first place).

I think I'll stay below 19psi instead !

[EVL-R33]

I just installed a Greddy Profec B Spec II controller, and out of all the boost controllers that I have used before this is by far the best, holds boost at high and low RPM perfectly.. would recommend this to anyone..

PS. I got a HKS 2530kai and I got 2 settings, low boost at 16psi high boost 22psi

Edited February 21, 2009 by EVL-R33