View Full Version : turning boost down

02-06-2012, 10:59 PM
I have a ka-t that was running a stock sr turbo. one day on the way home from school the turbo dropped and i ordered and replaced it with the isis t25 replacement turbo. the boost was hitting 15 pounds so i replaced the wastegate with my hks one and it made the same boost. is there any way to turn the boost down? i put a boost controller on it at its lowest level and i get the same reading.

02-06-2012, 11:49 PM
Your wg isn't flowing enough, you can try porting the hole out a bit

02-07-2012, 02:34 AM
Are you spiking to 15psi or is boost holding steady to 15psi?
Before you modify the the turbo permanently, disconnect the wastegate flapper and go for a spin, document boost. If your boost is anywhere under the 15psi and holding steady, your wastegate is too tight adjust it so it just slips over the flapper arm. Go for another spin document boost.

It could also be your vacuum/boost pressure routing, a pinched wastegate pressure source could make you overboost.

A boost controller will only raise boost over the wastegate setting. It cannot lower it beyond wastegate setting.

02-07-2012, 02:54 AM
change the wastegate spring on your HKS wastegate. you can go as low as 6 psi. just tell the seller what psi spring you want.

02-07-2012, 07:39 PM
I was under the impression that you were internally gated. If so there are no springs to swap out, just the arm length adjustment, which I also assumed was already tried since another actuator was put on.

02-07-2012, 07:44 PM
You could just find an oem actuator, they are set around 7psi.

02-07-2012, 07:53 PM
Disconnect your boost controller and just run the vacuum line straight to your wastegate. If you ran 2 different actuators and still getting the same reading your boost controller may be leaking for failing.

02-08-2012, 02:05 AM
The isis turbo has a adjustable wastegate. I called enjuku and asked what the psi is and they said its 12-13. But I turned mine down to 8.

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