I am putting 3800sc out of a 1999 Buick Ultra I was told to disable the boost control solenoid. If someone had a pic of what it looks like when it is disabled it would help out a lot...

I cant find a pic, but basically you flip the lever over pointing toward the throttle body and you can use a bolt with a jam nut screwed into one of the BBV mounting holes to lock it open.

You can just remove the boost control solenoid and leave the vac port it plugged into on the actuator open. Leave the top port on the boost bypass actuator connected to the top vac port on the blower housing as it was stock and it'll still work like it is supposed to (minus computer control, of course - which it doesn't need).

Since I disabled the boost control solenoid code in your custom programming, you should have no problems removing it.

-ryan

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OVERKILL IS UNDERRATED

Custom GM OBD1 & OBD2 Tuning | Engine Conversions & more | www.gmtuners.com

Ok if I understand I can remove the selonoid and vaccume lines then basically jam the butterfly open..

no dont jam anything open.... there is a small solenoid on the bbv ( (boost bypass valve) with one 10mm nut holding it on... take that solenoid off and the hose that is connected to ..nothing else no other hoses and nothing being jammed open.

[This message has been edited by black88fiero (edited 03-17-2011).]

A pic of what it should like would be very helpful!!!

If you want to totally get rid of the vacuum diaphram and solonoid you will need something holding the lever open, If you want to keep the BBV function you keep the vac diaphram and remove the electrical solonoid. Mine has been running around 8 years with the entire BBV system removed and held open, no problems and get 30mpg with an auto trans.

Thanks Mike that is the pic i was looking for!!!!!

if you hold it open you will get little or no boost, all of the air is bypassing the rotors and going straight into the intake... you might as well have bought an n/a motor

So who is right??? I think it the solenoid looks ugly, but I dont want to loose boost!!!

loose it!

Black does not know what he is talking about.
I don't have mine and yet I have boost all day long.

Hell even the GTP guys are welding that butterfly hole shut to make the SC sound louder( but I don't think that is such a good idea.)

Do like the pic Mike shows ya, that is fine and does work.

http://www.fastfieros.com/t...enoid_bypass_mod.htm

[This message has been edited by revin (edited 03-17-2011).]

I have a boost gauge, and get plenty of boost with it held open, you can feel it when you hit the throttle !

Let's start over from the beginning to alleviate some of the confusion here.

The boost control system used on these supercharged engines consists of two modes of operation. One is PCM controlled and one is vacuum controlled.

The PCM controlled portion works like this: When the PCM desires there to be NO or very little boost (which it wants to happen when the auto transmission is in reverse gear, the car is decelerating, or the car is nearing the top speed limiter), the PCM will shut off the BOOST CONTROL SOLENOID which will allow boost pressure (if any is present) to pass thru it to the bottom port on the boost bypass valve actuator. If boost pressure makes it to the bottom port of the actuator, it will OPEN the boost bypass valve which will allow boost pressure to vent from the outlet of the blower back into the inlet - thus reducing boost to a very low level (if any). During all other times of engine operation, the PCM commands the boost control solenoid ON which blocks boost from getting to the bottom port on the bypass valve actuator so boost pressure cannot force it to open (but vacuum still can, read below). This portion of the system does NOT allow the PCM to REGULATE boost pressure, it is more of an ON/OFF function.

The VACUUM-Controlled function of the actuator works regardless if there is a boost solenoid present or not. During idle and low-medium throttle openings, vacuum is present in the blower housing between the roots and the throttle body. The boost bypass valve actuator's top port is connected to a vacuum source that references this. When vacuum is present, the vacuum signal going to the actuator makes the actuator open the boost bypass valve inside the supercharger which will prevent any significant level of boost from being able to build. This ALSO reduces the working load of the supercharger which has the effect of saving fuel and reducing heat build-up within the blower. When you open the throttle far enough to drop vacuum levels before the supercharger roots to zero, a spring inside the actuator forces it to close the boost bypass valve in the supercharger which will allow the supercharger to develop boost pressure.

What MIKE and REVIN are talking about doing is removing the bypass valve actuator from the blower and rotating the valve around backwards and holding it closed with a bolt or other means. This will effectively put the supercharger into a mode to produce boost all of the time, whether it is required or not. Doing this will NOT increase engine performance but it can make the blower work harder since it will be trying to build boost pressure at all times (during all engine operating circumstances) whether it is needed or not. If you remove the boost bypass valve actuator and do not rotate and hold closed the boost bypass valve, your supercharger will never be able to make boost.

If your goal is to clean up your engine by removing the boost bypass valve actuator, you can certainly do what MIKE and REVIN suggest. I don't remove them on swaps I do (unless the customer requests it) because there are no performance gains to be had from doing so aside from the cosmetic "gains" if you want to call it that.

Here's a picture of what you should end up with if you only removed the boost solenoid (but left the actuator intact and functioning)...



-ryan

Well Ryan I trusted you with programing my PCM, so there for I will trust you know what you are talking about here and will hook it up like you suggest!!! Thank you!!

quote Originally posted by Darth Fiero: Here's a picture of what you should end up with if you only removed the boost solenoid (but left the actuator intact and functioning)... -ryan

Do you need to put a cap on the actuator nipple that looks like it is open?

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-Brian

My 87 GT Poly Suspension Upgrade (all pics) thread
Removing the roof panel

so you guys are technically pinning it closed by rotating it around all the way... so what they said is right...you guys kept saying hold the lever open so in my mind the butterfly valve is open. I got confused i didnt know it would roatate 180 degrees and close again..confusion on my part...

We are all here to learn.

quote Originally posted by MulletproofMonk: Do you need to put a cap on the actuator nipple that looks like it is open?

No, leave that bottom nipple on the actuator open.