RB26DETT Sketchy boost mod?

[ARB26]

Carrying out some engine due diligence before my first drive in a 260RS that has been in storage for 10+ years, and found two lines that are susposed to be plumbed into the boost control solenoid. One of the lines (the wastegate boost supply line) to actuate the gates, had a bolt in one end blocking it.

The other line (main boost signal line) from the very rear of the intake manifold (RB26DETT) and runs up to the boost controller had this pill in the end of it as seen in photos.

Other than the obvious (T28 Ceramic turbos might well be cooked) 

Can anyone shed any light on if there is any validity at all with this mod, bleeding a constant fixed rate of manifold boost pressure off through this 3mm hole? 

Is it deliberate? 

Was this a 90s Jap mod done to RB26's?

Or has someone just fitted this without any idea of what happens to ceramic T28s if they are not gate controlled?

 

 

[ARB26]

[ARB26]

I might be way off the mark here.. there must be a T junction under the manifold. That takes manifold pressure through a check valve prior to the T, one side splits out to this bleed off orifice, the other straight to the wastegate actuators. 

[djr81]

Bit difficult to follow. Have a look below and see what the standard R32 layout was like. Note there was a restrictor in place immediately before "turbocharged pressure control solenoid" that, if removed, magically got you 1 bar boost.

[joshuaho96]

2 hours ago, ARB26 said:

Carrying out some engine due diligence before my first drive in a 260RS that has been in storage for 10+ years, and found two lines that are susposed to be plumbed into the boost control solenoid. One of the lines (the wastegate boost supply line) to actuate the gates, had a bolt in one end blocking it.

The other line (main boost signal line) from the very rear of the intake manifold (RB26DETT) and runs up to the boost controller had this pill in the end of it as seen in photos.

Other than the obvious (T28 Ceramic turbos might well be cooked) 

Can anyone shed any light on if there is any validity at all with this mod, bleeding a constant fixed rate of manifold boost pressure off through this 3mm hole? 

Is it deliberate? 

Was this a 90s Jap mod done to RB26's?

Or has someone just fitted this without any idea of what happens to ceramic T28s if they are not gate controlled?

 

 

This is just a dumb way of keeping the wastegate closed to make more boost. Undo it and either follow the factory setup or redo it properly. Manual boost controllers just use a spring preload to determine when to close in response to boost pressure so it no longer vents to atmosphere.

[GTSBoy]

56 minutes ago, joshuaho96 said:

This is just a dumb way of keeping the wastegate closed to make more boost. Undo it and either follow the factory setup or redo it properly. Manual boost controllers just use a spring preload to determine when to close in response to boost pressure so it no longer vents to atmosphere.

 

Yes, but it's not dumb or dodgy. You can build a perfectly good boost controller from a pressure reg, a relief valve (looks same same as a reg if all from Norgren or SMC, for example) and a check valve. I ran one for years. Only superceded with  EBC because I could get one for cheaps and wanted finer control.

 

THis mod is certainly not a sketchy boost mod, provided the boost is kept below the "spin to death" threshold of the turbos.

[ARB26]

2 hours ago, GTSBoy said:

 

Yes, but it's not dumb or dodgy. You can build a perfectly good boost controller from a pressure reg, a relief valve (looks same same as a reg if all from Norgren or SMC, for example) and a check valve. I ran one for years. Only superceded with  EBC because I could get one for cheaps and wanted finer control.

 

THis mod is certainly not a sketchy boost mod, provided the boost is kept below the "spin to death" threshold of the turbos.

So could it be assumed it has been installed intentionally with potentially a power FC boost controller kit? 

[ARB26]

 

36 minutes ago, ARB26 said:

So could it be assumed it has been installed intentionally with potentially a power FC boost controller kit? 

Or do we think it was installed to give 1 bar of boost max, all day, everyday?