Any ideas whats broken (turbo system)

OK I have been having some odd boosting lately and thought I would play about with taking boost controller on and off etc. When the controller is on I seem to have to have it set quite high (70 with a gain of 18 - Blitz Dual SBC) to achieve 1.0 bar. The car is BPU. In 1st and second I dont seem to get much over 0.7 but it does increase through the gears, which I think is normal. When i removed the controller the car ran okay and was similar to with the controller, however today the second turbo is not coming online at all. I have stuck it in TTC mode and all is well both turbos online, I stopped going for it at 1.0 bar and have to admit I quite like they way it drives.

I do seem to have a broken VSV/actuator. From my long winded explanation does it point to a specific one, and anyway to trouble shoot it simply. I have read Ian C's thread on the sequential system and that would point to the IACV which I believe is made redundant with a boost controller which would explain why it works with the controller. - Please correct me if im talking rubbish.

On another note, would running the TTC mod on a standard ECU cause many issues. I did read a very long thread about it but that question was not answered fully, and which type of the TTC should I do to run permanently.

Cheers for any help in advance.

Sounds like the iacv vsv, which is the one directly above the second turbo.

That was certainly the case with mine, when it went bad.

There's a simple procedure in the bgb that explains how to test it, would be worth doing before buying another one, and will also help narrow the fault down of yours tests ok

Just noticed I put that the boost controller eliminate the IACV which is me talking rubbish, it eliminates the waste-gate VSV.

Anyhow thanks for the reply, and excuse my ignorance but what is the BGB.

cheers

No worries mate. The bgb or 'big green book' is a coined phrase for the workshop manual. Pretty sure you can download it from the technical section on here, or if not, download the tsrm from the app store or play store if you have an android or ios phone.

Got the VSV off and will test it tonight.

Does anyone know if when reinstalling the boost controller whilst in TTC I need to plum it in any differently than the normal instruction.

Cheers

The same way mate, install the solenoid hoses between turbo no.1 and its actuator

All done, cheers for the help. Now just to check the vsv's. I have removed the iacv vsv and have checked it with my multimeter, however I can only get a reading when the meter is set on 200k of which I get a reading of 83.6. The manual states 38.5 - 44 ohms, and I'm no good out working them things out. Does anyone know if this sounds right. Also what's the best thing to use to run air through it. Also as its dark outside anyone with any ideas of what I could use to test the vsv with a 12v power supply whilst I'm inside and bored.

Cheers

Just had a thought. Would my car battery booster pack work as a 12v power supply. I read that people have used them in this way.