Pennock's Fiero Forum
  Technical Discussion & Questions
  3800SC removal of SC Bypass ?

Post New Topic  Post A Reply
Email This Page to Someone! | Printable Version


next newest topic | next oldest topic
3800SC removal of SC Bypass ? by Lou6t4gto
Started on: 11-22-2015 03:07 PM
Replies: 15 (669 views)
Last post by: Monstertone on 04-19-2021 07:51 PM
Lou6t4gto
Member
Posts: 8436
From: sarasota
Registered: May 2008


Feedback score:    (7)
Leave feedback

Rate this member

Report this Post11-22-2015 03:07 PM Click Here to See the Profile for Lou6t4gtoSend a Private Message to Lou6t4gtoEdit/Delete MessageReply w/QuoteDirect Link to This Post
Is there a Major "Downside" to removing the SC "Bypass valve" ???? Thanks
IP: Logged
PFF
System Bot
Darth Fiero
Member
Posts: 5919
From: Waterloo, Indiana
Registered: Oct 2002


Feedback score: (5)
Leave feedback





Total ratings: 361
Rate this member

Report this Post11-22-2015 05:40 PM Click Here to See the Profile for Darth FieroClick Here to visit Darth Fiero's HomePageSend a Private Message to Darth FieroEdit/Delete MessageReply w/QuoteDirect Link to This Post
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.

------------------
More is more. Less is not enough.

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

IP: Logged
Lou6t4gto
Member
Posts: 8436
From: sarasota
Registered: May 2008


Feedback score:    (7)
Leave feedback

Rate this member

Report this Post11-22-2015 07:09 PM Click Here to See the Profile for Lou6t4gtoSend a Private Message to Lou6t4gtoEdit/Delete MessageReply w/QuoteDirect Link to This Post
Only reason I'm asking is it makes it easier to use the Fiero thermostat housing. Has anyone got a picture of the Fiero thermostat housing on a 3800 With the bypass valve "In place" ? Thanks
IP: Logged
djlamp14
Member
Posts: 144
From: Grand Meadow, MN
Registered: Oct 2012


Feedback score: N/A
Leave feedback

Rate this member

Report this Post11-22-2015 09:22 PM Click Here to See the Profile for djlamp14Send a Private Message to djlamp14Edit/Delete MessageReply w/QuoteDirect Link to This Post
Use the 3800 t stat housing. Leave that bypass valve alone. No reason to remove it. It's not difficult to bleed the system if you have a jack.

------------------
11.8@115mph 1/4 mile 1999 Regal GSX
11.044@122mph 1/4 mile 87 Fiero GT
11.8 sec pass>>http://www.youtube.com/watch?v=SQT4X2eBlR8
11.044 pass>>https://youtu.be/FsboH9Ba7ZY

IP: Logged
Spoon
Member
Posts: 3762
From: Sadsburyville, PA. 19369 / USA
Registered: May 2004


Feedback score:    (16)
Leave feedback





Total ratings: 61
Rate this member

Report this Post11-22-2015 09:48 PM Click Here to See the Profile for SpoonSend a Private Message to SpoonEdit/Delete MessageReply w/QuoteDirect Link to This Post
Not sure who's pic this is but perhaps it will help. I'm also on the 3800 bandwagon gathering parts.




Spoon

------------------
"Kilgore Trout once wrote a short story which was a dialogue between two pieces of yeast. They were discussing the possible purposes of life as they ate sugar and suffocated in their own excrement. Because of their limited intelligence, they never came close to guessing that they were making champagne." - Kurt Vonnegut

IP: Logged
Lou6t4gto
Member
Posts: 8436
From: sarasota
Registered: May 2008


Feedback score:    (7)
Leave feedback

Rate this member

Report this Post11-22-2015 10:33 PM Click Here to See the Profile for Lou6t4gtoSend a Private Message to Lou6t4gtoEdit/Delete MessageReply w/QuoteDirect Link to This Post
That's what I needed. I have to "tilt" the housing a little more where I did the cut/weld it the first time. (but it Will Work) .
I already have a 3800SC using the 3800 housing, and using a 3rd heater hose (capped off) for a filler . I'd rather the Fiero housing.
IP: Logged
Dennis LaGrua
Member
Posts: 15139
From: Hillsborough, NJ U.S.A.
Registered: May 2000


Feedback score:    (13)
Leave feedback





Total ratings: 328
Rate this member

Report this Post11-22-2015 10:58 PM Click Here to See the Profile for Dennis LaGruaSend a Private Message to Dennis LaGruaEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Spoon:

Not sure who's pic this is but perhaps it will help. I'm also on the 3800 bandwagon gathering parts.




Spoon



This looks like a new bracket was made to move the BBV away from the thermostat housing. On a separate note I have been running w/o the BBV solenoid for 6 years with no ill effects. I've run several other cars with Weiand roots blowers and all survived a long time w/o BBV's . I do not doubt that the BBV is helpful in a small way but I read a while back on the Eaton site that it was put there primarily to cut down on noise. I was just wondering how much of a delay the BBV causes when you hit WOT. The BBV is open at idle and cruise and it is directed by the PCM to close when the throttle opens wide. So the process is that sensor signals are sent to the PCM that the throttle blade has been made wide open by the driver slamming the gas pedal. The PCM receives those signals and then sends a signal to the BBV to close. The BBV solenoid is activated and must react. Solenoids do not close instantaneously . I would guess that you would lose a .5 to 1 second in the process.

------------------
" 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 "

IP: Logged
djlamp14
Member
Posts: 144
From: Grand Meadow, MN
Registered: Oct 2012


Feedback score: N/A
Leave feedback

Rate this member

Report this Post11-23-2015 09:13 PM Click Here to See the Profile for djlamp14Send a Private Message to djlamp14Edit/Delete MessageReply w/QuoteDirect Link to This Post
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.

------------------
11.8@115mph 1/4 mile 1999 Regal GSX
11.044@122mph 1/4 mile 87 Fiero GT
11.8 sec pass>>http://www.youtube.com/watch?v=SQT4X2eBlR8
11.044 pass>>https://youtu.be/FsboH9Ba7ZY

IP: Logged
phonedawgz
Member
Posts: 17091
From: Green Bay, WI USA
Registered: Dec 2009


Feedback score:    (23)
Leave feedback





Total ratings: 290
Rate this member

Report this Post11-23-2015 09:20 PM Click Here to See the Profile for phonedawgzClick Here to visit phonedawgz's HomePageSend a Private Message to phonedawgzEdit/Delete MessageReply w/QuoteDirect Link to This Post
Same type of argument was used to dismiss vacuum secondarys. If it was anything near a second, GM wound have never used it. Did you drive the 3800 before you pulled it? Did you notice any lag?
IP: Logged
Darth Fiero
Member
Posts: 5919
From: Waterloo, Indiana
Registered: Oct 2002


Feedback score: (5)
Leave feedback





Total ratings: 361
Rate this member

Report this Post11-23-2015 09:24 PM Click Here to See the Profile for Darth FieroClick Here to visit Darth Fiero's HomePageSend a Private Message to Darth FieroEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Dennis LaGrua:


I do not doubt that the BBV is helpful in a small way but I read a while back on the Eaton site that it was put there primarily to cut down on noise. I was just wondering how much of a delay the BBV causes when you hit WOT. The BBV is open at idle and cruise and it is directed by the PCM to close when the throttle opens wide. So the process is that sensor signals are sent to the PCM that the throttle blade has been made wide open by the driver slamming the gas pedal. The PCM receives those signals and then sends a signal to the BBV to close. The BBV solenoid is activated and must react. Solenoids do not close instantaneously . I would guess that you would lose a .5 to 1 second in the process.



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.
IP: Logged
Lou6t4gto
Member
Posts: 8436
From: sarasota
Registered: May 2008


Feedback score:    (7)
Leave feedback

Rate this member

Report this Post11-26-2015 02:16 PM Click Here to See the Profile for Lou6t4gtoSend a Private Message to Lou6t4gtoEdit/Delete MessageReply w/QuoteDirect Link to This Post
OK, Not removing it.
IP: Logged
PFF
System Bot
IanT720
Member
Posts: 1703
From: Whitmore Lake, MI
Registered: Sep 2010


Feedback score:    (9)
Leave feedback

Rate this member

Report this Post11-29-2015 06:12 PM Click Here to See the Profile for IanT720Send a Private Message to IanT720Edit/Delete MessageReply w/QuoteDirect Link to This Post
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.
IP: Logged
Dennis LaGrua
Member
Posts: 15139
From: Hillsborough, NJ U.S.A.
Registered: May 2000


Feedback score:    (13)
Leave feedback





Total ratings: 328
Rate this member

Report this Post11-29-2015 06:30 PM Click Here to See the Profile for Dennis LaGruaSend a Private Message to Dennis LaGruaEdit/Delete MessageReply w/QuoteDirect Link to This Post
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.

------------------
" 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 "

IP: Logged
solotwo
Member
Posts: 5374
From: Grand Rapids, MI. USA
Registered: Jun 2002


Feedback score:    (9)
Leave feedback





Total ratings: 62
Rate this member

Report this Post12-01-2015 10:50 PM Click Here to See the Profile for solotwoSend a Private Message to solotwoEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
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).]

IP: Logged
solotwo
Member
Posts: 5374
From: Grand Rapids, MI. USA
Registered: Jun 2002


Feedback score:    (9)
Leave feedback





Total ratings: 62
Rate this member

Report this Post12-01-2015 11:01 PM Click Here to See the Profile for solotwoSend a Private Message to solotwoEdit/Delete MessageReply w/QuoteDirect Link to This Post

solotwo

5374 posts
Member since Jun 2002
 
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).]

IP: Logged
Monstertone
Member
Posts: 63
From: Central Point Oregon, USA
Registered: Mar 2016


Feedback score: (1)
Leave feedback

Rate this member

Report this Post04-19-2021 07:51 PM Click Here to See the Profile for MonstertoneSend a Private Message to MonstertoneEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
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).]

IP: Logged

next newest topic | next oldest topic

All times are ET (US)

Post New Topic  Post A Reply
Hop to:

Contact Us | Back To Main Page

Advertizing on PFF | Fiero Parts Vendors
PFF Merchandise | Fiero Gallery | Ogre's Cave
Real-Time Chat | Fiero Related Auctions on eBay



Copyright (c) 1999, C. Pennock