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The mkiv Supra Owners Club

Greddy Profec 2 Spec B Boost Controller


SupraJames

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Ok have the above boost controller installed, it was set up at Abbey Motorsport while on their Dyno pack, however Dan @ Abbey said that the controller only seemed to be adjusting boost levels on the first turbo.

The second turbo was unaffected, is this right..? and what can be done about it ? Also it is set to run at 1.2 Bar, but I have never hit that, peak boost is 1.11 Bar.! Is there something else stopping boost levels rising..?

Have tried running the car in sequential and twin modes and does not seem to make a difference, I make good boost (approx 1 bar) on the first tub then the boost just drops off as the second comes in (back to around 0.7/0.8 bar) i.e stock levels.

Help and advice required.

 

Cheers

 

James

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Wastegate solinoid duty may not be set right (if it can be set on the Profec 2???) You get the same problem with the AVCR's and its just a matter of increasing duty until you get the desired boost. I've never played with a Profec 2, but will have a look through the manual later.

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No offence takin paul, But when somebody says "the controller only seemed to be adjusting boost levels on the first turbo" I would walk away from them. Boost control is done via the second turbo :blink: Id at least expect them to do a little investigation into the problem especially if your paying for Dyno time.

 

If everything is connected properly i.e. unused Wastegate port and OE solenoid ports Capped off, and there are no vac leaks on any of the installed lines, i would say that a weak wastegate Spring could be the Culprit.

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Dan @ Abbey said that the controller only seemed to be adjusting boost levels on the first turbo. The second turbo was unaffected, is this right..?

 

There is only one wastegate when both turbos come on so no, that's not right. If your boost is dropping when the second turbo is supposed to be coming online then the most likely thing is that it isn't being opened up properly. What method of running in TTC did you use? If you just bypassed the IACV VSV and EGCV VSV then the second turbo may still not come on if there's a problem with the pressure tank or if one of the actuators or corresponding valves are sticking.

 

Try running TTC by mechanically wiring the IACV and EGCV open and blocking the boost feed to the pressure tank. This will effectively rule out a sequential system problem. If you don't boost ok with this you're probably looking at a boost leak. :)

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No offence takin paul, But when somebody says "the controller only seemed to be adjusting boost levels on the first turbo" I would walk away from them. Boost control is done via the second turbo :blink: Id at least expect them to do a little investigation into the problem especially if your paying for Dyno time.

 

yep fair point mate, perhaps they cant be arsed with supras, maybe if it had an R34 badge !

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Also just look the vac pipes coming from the boost controller solenoid are both connected to the first tub. Pipe coming out the bottom of the solenoid goes to the tub and pipe coming out the side of the solenoid goes to what i think is the actuator. Is this right..? Have pics will post them up later.

 

Like to point out Abbey did not fit the controller.

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Also just look the vac pipes coming from the boost controller solenoid are both connected to the first tub. Pipe coming out the bottom of the solenoid goes to the tub and pipe coming out the side of the solenoid goes to what i think is the actuator. Is this right..? Have pics will post them up later.

 

That's probably right but it depends on the orientation of the solenoid. The pipe coming from the port marked COM on the solenoid should go to the wastegate actuator and the one from the port marked NO to the boost source just after the turbo. The other port on the actuator should be blocked off.

 

As for your previous post, UK turbos should be fine with 1.2 bar when both are online, Ian was pointing out that making over 0.8bar with just the first is putting too much strain on it.

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Boost control is done via the second turbo :blink: Id at least expect them to do a little investigation into the problem especially if your paying for Dyno time.

 

 

Boost is controlled via the single wastgate, you want a max boost of approx 0.8bar upto approx 3500rpm (turbo 1) and then 1.2bar upto redline (both online)

 

1.2bar is supposed to be safe but not for one little stock tubbie on its own.

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