boost coontroller question

[joenardo]

the top hose that runs in the boost controller does that have pressure? solenoid opens and closes but still only 9 lbs boost .if i disconnect the solenoid then it will run up to 18 lbs of boost!!! yikes!!! thanks guys

[GAboySVO]

Boost controller

On the '86 SVO, there is a hose that runs from a "T" on the compressor housing to the Boost Control Solenoid (BCS). The other hose on the "T" goes to the wastegate actuator. The other hose coming from the BCS goes to the compressor inlet after the VAF.

When not in premium mode, the solenoid valve is closed and as boost pressure rises, all of the pressure is sent to the wastegate accuator. The wastegate return spring is rated at about ~10lbs, thus the 9psi of boost you are seeing.

When in premium mode, the solenoid fires rapidly (opening and closing) which allows some of the pressure build up to "bleed off." This effectively allows the boost level to rise to ~15psi in the intake before the wastegate actuator is acted upon by the 10psi.

So, it appears that you may have a bad solenoid or a bad switch. To test the switch you can swap it with the fog lamp switch or a 3 dollar switch from a parts store.

If your BCS is bad, then you might want to purchase a manual Gillis boost valve. You can leave the BCS plugged in, but disconnect the hoses.

[richsvo]

Okay, I am also having a boost controller problem, although mine is a manually adjusted boost controller.

The problem is the MAXIMUM boost I can get is about the normal 15psi. I switched the hoses around and got only about 8-9psi.

I tried tightening the screw all the way down (should be 0 psi), and I still got about 5-6 psi. I don't get it. It seems as though the boost does rise when I turn the screw anti-clockwise. Only thing is, it max's about 15 psi, and no matter how far I turn it, I cannot get anymore....

I am using the two hoses that were originally on the stock BCS, this is correct, yes?

Any ideas?

Thanks, in advance,

Rich

[SVOeric]

rich -- it depends on what boost controler you are using--

take the (I believe top hose) all the way off, and go for a run, take it easy, (don't stand on it) but punch it a bit, and be ready to let off it and see if the boost goes above 15 -- if it does, that means your turbo and actuator are working fine, you just need to get the boost controler worked out, or swaped out, or something. I have heard some boost controlers work better with a line off the vacume tree, and others that work better like the stock setup. -- you may have to see which works better.

[GAboySVO]

How is your boost controller installed

RichSVO,

From what you discribed, I'm asuming you have a bleed type boost controller. If so, the bleed valve should be connected similar to the following diagram:

http://www.racetep.com/turbo.html#dab (the one on the lower right is the set up you want)

In place of the stock BCS, you should have a tee installed. The leg part of the tee is connected to bleed valve. Some port the bleed to atmosphere, but on the SVO you can plumb it back to the turbo inlet sense it was metered air by the VAF.

If your controller is correct, then your boost maybe limited by how much your bleed valve will flow.

If you disconnected the hose coming from the turbo compressor housing and let it vent to atmosphere, you will easily reach an overboost condition, 17.5 PSI. The bleed valve forces the pressure to back up through the compressor housing tee and acts on the wastegate to relieve/limit boost pressure.

Hope this helps.

[richsvo]

FWIW, I am using the Turbo XS Manual boost controller.

I will try taking the hose off and see what happens...

Thanks for your inputs!

RIch

[richsvo]

Okay, so I removed the hose from the BOTTOM of the boost controller, and I got about 18psi.

So, what does this mean?

By the way, joenardo, did you get yours fixed?

Rich

[GAboySVO]

How do you have it connected?

Richsvo,

It appears that you have the gillis type valve. According to the write-ups you should be able to get up to 30psi out of it.

So the question is: how do you have it hooked up?

The gillis valve installation instructions say to remove the tee from the compressor housing and plug it. the supply boost pressure via a hose from the vacuum tree. Put a cap on the fitting at the compressor inlet that used to provide return air from the old BCS. Then connect the Boost valve to the waste gate hose, keeping the hose as short as possible to minimize pressure loss.

Here are a couple of sites to learn more about how it al works and some diagrams.

http://www.boostvalve.com/tech/IC_install.html

http://www.boostvalve.com/moreinfo.html

http://johnmonnin.netfirms.com/Boostcontrol.html

One of these should help you straighten it out. Let us know the final results.

[NO 5 OH]

Originally posted by richsvo
I tried tightening the screw all the way down (should be 0 psi), and I still got about 5-6 psi. I don't get it. It seems as though the boost does rise when I turn the screw anti-clockwise. Only thing is, it max's about 15 psi, and no matter how far I turn it, I cannot get anymore....

I am using the two hoses that were originally on the stock BCS, this is correct, yes?

Rich,

I use the exact same boost controller that you do, and here is how I have mine hooked up and what I've learned from experience:

As far as I know, there isn't a way to set any controller to 0 psi boost level. Even with the adjustment screw turned all the way down you'll still see boost, although at a very low level. I never turned my controller all the way "down" but from what I've read most manual controllers with the screw all the way in will register around 6 to 9 psi.

I'm thinking you hooked the new controller up in place of the old BCS, using the exsisting lines from the compressor housing and from the "T" on the inlet elbow. I did the same thing when I first hooked up my controller and got basically the same thing as you did, but I only saw around 9-10 psi. If you hook your controller up like this you should see a noticable difference:

1) Take all the factory lines off the controller, unscrew the "T"
fitting in the compressor housing.
2) Get a 90* brass nipple (available at your local auto parts
store, or hardware ) and screw that in the compressor
housing... use teflon tape or similar liquid sealant.
3) Buy new vaccum hoses and run one line from the turbo to
the the nipple on the right side of the controller, run the
other line from the bottom of the controller to the waste-
gate actuator.
4) Cap the nipple on the "T" fitting on the compressor inlet,
installation will be complete.

This should get you able to make much more boost than 15 psi

If this doesn't solve your problem, then tell me exactly how your controller is hooked up and I'll try to help you from there.

Shannon

[joenardo]

hey rich yes i did i just got the car and the previous owner had the hoses backwards!! thanks

[svobud]

Originally posted by richsvo
Okay, so I removed the hose from the BOTTOM of the boost controller, and I got about 18psi.

So, what does this mean?

Rich

Are you still using a STOCK boost gauge?

[richsvo]

No, not factory boost guage. Using an Autometer guage. I am going to undo everything, and hook it up as shown above and see what happens...

Thank you to everyone who has helped out here with replies. I will post the results!

Thanks,

Rich

[svobud]

Originally posted by richsvo
No, not factory boost guage. Using an Autometer guage. I am going to undo everything, and hook it up as shown above and see what happens...

ok - but without looking at the links shown .. I do know that the "boostvalve" is NOT hooked up as a TurboXs valve. It's also a VERY different design - using a check ball set up .. not a bleed restrictive pin/orfice like the XS valve. If you can stand to wait til this evening (after I get some sleep). I'll be happy to take some pics of how mine is installed on the 9L car. Until then .. you might do a search. I'm pretty sure I posted some pics of it once before here ... some time ago.

[richsvo]

Thanks, Bud...that, of course would be very helpful.

I appreciate all the responses thus far...I just need to make time to go out there and play with it. That will probably not be until after work, so sometime this evening.

Thanks,

Rich

[GAboySVO]

SVOBUD

According to the info from a Turbo XS site, it is a combination of boostvalve and bleeder type. See below:

"The HPBC has two (2) boost control mechanisms built into it. One is a ball and spring mechanism for large and coarse boost pressure increases and the other is a bleed valve system for precise boost pressure setting. The ball and spring mechanism keeps pressure out of the wastegate until the preset boost level is reached, significantly reducing wastegate creep and providing quicker turbo spool up. Boost is adjusted with the simple turn of the screws using the included 2mm hex key."

I am very interested to see how you have it connected.