Rb20 Manual Boost Controller

[Luke HCR32]

Got the car running tonight. Took it for a run with the bleed valve fully closed and boost was definitely peaking at about 7psi (assuming the halfway point on the boost gauge is 350mmHg as the max is 700mmHg). How do I tell if I have an R33 actuator? What kind of problem could be causing such a low peak if I do have an R32 actuator? Is it likely to be a leaking line to my boost gauge?

[Luke HCR32]

Any ideas guys? I recall the guy I bought if off saying it was restored to the 'factory' boost of 7 pounds by a tuning shop, could they have changed something? I have ordered a turbotech and pretty keen to nut out this issue so I can use it.

[GTSBoy]

Put an accurate boost gauge on it for another test run before making any further work for yourself. The dash boost gauge is not always trustworthy.

[Luke HCR32]

Moved my aftermarket boost gauge so I could see it properly and did see a peak of 0.65 kg/cm2 (nearly 10 psi).

Both my dash gauge and aftermarket gauge are hooked up to the intake manifold not the turbo itself, how much higher would the boost be at the compressor?

Did a test where I disconnected the t-piece which connects both gauges to the manifold and the aftermarket read 0 while the dash gauge was reading about 100mmHg vacuum, I guess that shows which one is to be trusted.

[Rolls]

Put it at the manifold, at the turbo will be slightly higher due to the restriction of the pipes and intercooler.

[Luke HCR32]

How can I be sure the boost at the compressor isn't unsafely high at a certain manifold boost?

[GTSBoy]

Don't worry about it. At the power levels you're making (ie essentially standard) the extra boost at the compressor is well within safe limits* when you're at 10 psi at the plenum.

*safe limits is a rubbery number of course because some standard turbos will let go at standard boost, and some will last forever at 14psi at the plenum - when 14 psi at the plenum could mean that it's more like 16 at the compressor. It's impossible to completely re-assure you, but it's unreasonable to try to scare you or let you scare yourself at the boost that you're at.

[Luke HCR32]

Should I be safe to run 12 pound at the manifold? I'll be using a turbotech gated controller and buggering off my gfb bleed valve.

[31GUN]

My 3 R31 RB20s all ran 7psi stock.

Nics red top

ECCS redtop stock turbo.

ECCS redtop RB25 roller turbo

Ran the ceramic RB25 turbo for 11 years at 14 psi, never a problem.

The Turbotech is a lot better than Turbospike sorry smart or bleeder type controllers.

With your setup 12psi will run forever.

Even my RB20DET-R ECCS redtop with a stock bunch of bananas manifold and TO4E turbs ran 7psi stock.

[Luke HCR32]

Ok thanks mate, I'll get onto it.