Manual Boost Contrlloer on RB26 DETT

[R32D2]

My car runs about 7 PSI on stock turbos. The boost restrictor has been removed. I Installed a Vibrant Performance manual controller and it made no increase in boost. I know the ceramic wheels in the turbos are ony good for about 12 PSI before coming apart, so I was hoping to go for 10 to 11 PSI. I"m asking if this thing will work, and where in the system should it be properly installed? Should the boost solenoid be bypassed? Does anyone have a picture of where to install it? Now it is run off the charge pipe down by the O2 sensor plugs.
Thanks for reading. Heading out the door now for Capital Drift event.

[Skym]

Increase in boost level comes from removing the restrictions / back pressure (exhaust, cat) and total boost increase should be around +0.3bar if exhaust is done from turbo's. Podfilters help (+0.1bar). 1bar = 14.5psi. With restrictions removed, can boost up to around 1bar (depending on psi of stock internal wastgate springs, as they vary from engine to engine and due to age which usually means less psi, sometimes up to 1psi less).

Also stock ECU controls boost level via stock boost control solenoid (boost duty maps on ECU) and boost restrictor is part of how it helps the stock boost control solenoid control boost level (boost restrictor, stock boost control solenoid shouldn't be removed unless running a HKS or Blitz boost controller that has a better solenoid).

Boost level the stock turbo's are good to depends on age, balance of shaft. If shaft is out of balance turbo can fail quickly if boost level is turned up. More boost = high rpm on turbo.

To get what I mean, have a look at this balance data from balancing a turbo and note as the rpm (boost level) increases the turbo (exhaust or compressor wheel) gets more out of balance if it's already out of balance (can be out of balance due to age / wear and tear on bearings if turbo has done high km) -

http://www.turbo.co.nz/alltech/service.php?Page=Turbo

If exhaust wheel gets damaged (chipped or similar) or bearing on turbo side of turbo has failed, exhaust wheel side of turbo can get out of balance and break shaft. It ends up in middle of exhaust under full throttle or ceramic fragments end up in engine if back off throttle when the exhaust wheel hits exhaust housing on turbo and shatters.

Supposedly the glue holding ceramic exhaust wheel onto shaft can fail (due to high exhaust temps) and cause similar failure as when centre part of turbo (CHRA) is out of balance, but have yet to see this type of failure.

Other is running antilag on aftermarket ECU that could damage the exhaust wheels.

[Dragon Humper]

Just pulling the restrictor pill out of the vacuum line should have given you 10-11 psi. Undo what ever it was that you did and see where you are at. You only need an aftermarket boost controller (manual or otherwise) if you want to go higher than that.



Jon.

[R32D2]

Thanks jon. The restrictor was removed by previous owner. The turbos are both in excellent condition. They were inspected at time I rebuilt the engine, 3000Kms ago. So you say reconnect the boost control solenoid, but where would you put the boost controller? Maybe the stock boost gauge is not reading correctly, but I should have noticed some increase. I reads 3 mmHG at full boost under a hard load. A diagram or photo would help.

[Skym]

If bypass stock boost control solenoid ECU can't drop boost level when knock happens (knock boost duty map). If bypass stock boost control solenoid you can raise boost level, but ECU has no control over boost level if it spikes on a cold night, day or similar.

Have you checked that the manual boost control valve isn't plumbed around the wrong way???

[R32D2]

The instructions that came with it were for a single turbo. They show it installed between the charge pipe and the waste gate actuator. My RB20 buddy and my KA-T son suggested it be place were it is now, after I had tried it in place of the stock boost control solenoid.
It is presently connected to the charge pipe. Strange it hasn't worked in either location. Drag race day is tomorrow......

[Skym]

On a GTR it feeds 2x turbo's, so would think near stock boost controller should work (starves both turbo internal wastegate actuators of air which should raise boost level). If internal wastegate actuators are getting more air they should open at around spring pressure and boost level doesn't rise.

When test internal wastegate actuators on bench, you feed them with compressed air via vacuum hose with boost gauge T'd in until it over comes the spring inside internal wastegate actuator bulb which moves the arm and opens wastegate flap on back of turbo. That's the spring pressure (lowest boost level). You can test them this way on car as well with boost gauge T'd into vacuum hose, so don't need to drive car to see if it works, but boost pressure will be slightly different to on bench without turbo.

Also any intake airleaks near BOV's, on intake hose joiners that might cause a drop in boost level???

[R32D2]

So I installed it in the stock boost solenoid location, this time I reversed the lines, and it still did not give any more boost than I had before. So to sum it up, I have tried it without any solenoid boost (stock) and the lines fed into each other, with the boost controller plumbed in in both directions, and installed into the line coming from the charge pipe coming from the turbos before it goes into the intercooler. ALL made no difference in boost. There is a hard line that runs around the back of the head that tee's before going to the waste gates. This is very hard to get to. If I can determine where it comes from on the intake plenum side , I'll try the controller in there. Waste gate actuaters were both bench tested when engine was rebuilt and opened at 14PSI.No boost leaks.
Any more input appreciated from someone who has actually done this before, please.

[Dragon Humper]

There is boost pressure getting to the cans, there has to be or you would be spiking to 20psi. The boost solenoid bleeds off the pressure that is being fed to the cans to raise the boost. The restrictor does just that, it restricts the amount of boost signal pressure being bled off to keep the boost level down. Remove the restrictor and up goes the boost. The springs in the cans with the boost reference pressure is ultimately how much boost you will run, remove some of the reference pressure and the springs are allowed to hold the wastegate flap closed a little harder.


Try pulling the vacuum lines right off both cans and squeeze it a bit, I guarantee you will boost past 14psi.

Jon.

[R32D2]

OK. Bought some vacuum line and a tee, and tried something different. I left the stock boost solenoid in place. I plugged the metal supply line to the front turbo's waste gate. I run a short line from the rear turbo's waste gate supply line to the Vibrant Boost Controller. From there I run a 3" piece of vacuum line to the tee. From the tee, I run 2 ( important part) equal length lines to the waste gates, and Bob's your Uncle. I was able to adjust it to 11.5 PSI from the 7 PSI I had before. Still in the safety zone for a pair of ceramic turbos.
Drag race day is Sunday, Sunday, Sunday.

[Bruizer]

I ran 16 psi on stock turbos for 4 years. No problems.


If you need a good boost controller, I have a new in box hks evc 5 for grabs. Cost me $660 a few years back, will sell for $500 shipped since its not the newest and greatest anymore. Still badass tho