3800SC removal of SC Bypass ? (Page 2/2)
Lou6t4gto NOV 26, 02:16 PM
OK, Not removing it.
IanT720 NOV 29, 06:12 PM
I did it because the Actuator is ugly, vacuum lines are ugly, and I don't have to worry about it failing. Totally worth it in my opinion.
Dennis LaGrua NOV 29, 06:30 PM
The only detriment that I can see with removing the BBV is slightly less gas mileage, a bit more noise and possibly a little less life on the supercharger. I join the Mavericks that run the clean look without one.

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" THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, HP Tuners VCM Suite.
"THE COLUSSUS"
87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H
" ON THE LOOSE WITHOUT THE JUICE "

solotwo DEC 01, 10:50 PM

quote
Originally posted by Darth Fiero:

I wouldn't call it a major downside, but removing the BBV actuator and just blocking the BBV closed full time will make the supercharger work harder at all times which CAN increase wear, reduce fuel economy, and build heat in the blower housing when it isn't necessary (ie: at idle and part throttle).

There is absolutely zero performance to be gained from removing the BBV actuator and blocking the BBV closed at all times.




Great information. I went out and checked the for the BBV on the car I bought. Oh boy PO removed it. I noticed this engine is very hot and fuel mileage is low. It increased when I changed the thermostat back to 195. So it sounds like I should find a BBV Actuator and install it. It is a daily driver and I have put 26k on it since I bought it. Shooot I wonder what else is missing that needs to be put back on?

[This message has been edited by solotwo (edited 12-01-2015).]

solotwo DEC 01, 11:01 PM

quote
Originally posted by Darth Fiero:


The boost solenoid has nothing to do with normal supercharger and BBV actuator operation. The boost solenoid is PCM controlled and is only activated when the PCM wants to prevent any boost pressure from building - such as when you are in reverse gear, nearing the top speed limiter (and perhaps during an abuse condition), or perhaps during deceleration. Aside from that, the boost solenoid is energized all the time to permit normal BBV "boost enabled" operation. In all the swaps I do, the boost solenoid is removed from the engine since it does not perform any essential operation. I leave the BBV actuator installed and working unless the customer directs me to remove it.

The BBV actuator is 100% vacuum controlled unless the boost solenoid is de-energized which permits boost pressure to act upon it, which forces the BBV open. The actuator closes the BBV once the throttle is opened enough to prevent a certain level of manifold vacuum to build in the blower housing between the "roots" of the blower and the throttle body.

The BBV actuator is very fast acting. Suffice it to say it will permit boost pressure to build as fast as you are physically able to open the throttle to full. So it induces NO perceivable lag whatsoever, if we are talking about throttle response time in terms of how quickly boost can build. In other words, you are never going to notice a "usable" performance increase by removing the BBV actuator and blocking the BBV closed to force the blower to produce boost at all times.

Removing the BBV actuator and blocking the BBV closed to permit boost pressure to build at all times could possibly help the engine produce more power at moderate throttle positions. Installing a throttle with a progressive linkage would have the same effect. However, this small benefit does NOT outweigh the extra wear and tear and temperature increase you'll likely see put on the blower by removing the BBV actuator. And since nobody races down the dragstrip at half throttle, I see no benefit whatsoever to removing the BBV actuator.




Ok dumb question; where is the boost solenoid? I need to check to see if PO removed that. Oh by the way Ryan the dual fan hyper cool trans cooler that I installed back on the cradle is working fine. When the fans are on they move a good amount of air through the cooler. Thanks for the info on trans coolers. PO had a small 4 tube cooler mounted on the cradle. Not adequate. Wife wasnt happy(bitching) about spending $400 on the cooler and supplies I needed to do the installation. I asked her which is better, spending $400 on the cooler or $4000 to have the transmission replaced? She didnt have a response. Again this is a daily driver so I need the car to run so I can get to work.

[This message has been edited by solotwo (edited 12-01-2015).]

Monstertone APR 19, 07:51 PM

quote
Originally posted by djlamp14:

the little electronic sensor is for traction control. That is fine to remove. We are talking about the vacuum actuated valve that controls when the engine creates boost. The PCM has absolutely nothing to do with the bypass valve. That is 100% taken care of by throttle response. Past vacuum is boost. That is when the BV closes. Anytime in vacuum the BV has suction therefor the BV is open.




I once thought I had this all figured out. However, looking at a stock SC Riviera, I'm beginning to see things a little differently. Especially if I'm reading the qouted post correctly.

First off all, lets clarify a few things. Atmospheric pressure is +14.7 psi(a) A normal pressure gage, seeing atmospheric presuure on both sides, registers zero. Vacuum, negative pressure is anything less than atmospheric pressure. Complete vacuum is -30" Hg (mercury).

Now as I understand it, & please correct me if I'm wrong (that's why I'm on this thread) that "big ugly" thingy that controls the by pass butterfly inside the supercharger is a spring loaded diaphram type pressure actuator. Under light loads & deceleration there is sufficient negative pressure (vacuum) on the top side of the diaphram to overcome the spring. To put it in layman's terms, sucking on that diaphram hard enough to overcome the force excerted by the spring & open the bypass butterfly. Lacking negative pressure on the top side of the diaphram during acceleration, the spring to holds the by pass butterfly closed. The underside of the diaphram is vented to atomsphere.

The electronic sensor (solenoid) located close to the diaphram actuator, is a pressure actuated switch receiving both positive & negative pressure from multiple sources. Basically, it's looking for minute pressure changes, either way. It relays a signal electronically to the ECM for traction control & perhaps a few other functions unrelated to Fieros. Therefore, we are able to eliminate said switch & all associated vacuum lines in & out of it, while retaining the diaphram actuator sans any ill effects.

[This message has been edited by Monstertone (edited 04-19-2021).]