Dumping boost in third - GM Forum - Buick, Cadillac, Chev, Olds, GMC & Pontiac chat


Forced Induction All questions and problems regarding Superchargers, Turbos, NOS, ZEX, intercoolers, water injection, etc.

Reply
 
 
 
Thread Tools Search this Thread
Old 10-31-2005, 10:26 AM   #1
Senior Member
Certified Car Nut
Thread Starter
 
Join Date: Mar 2003
Posts: 12,432
Thanks: 0
Thanked 0 Times in 0 Posts
J Wikoff is on a distinguished road
Default Dumping boost in third

Ever since it got cooler a couple weeks ago, I'm dumping boost in third. First and second gear act fine, then shift to third and the boost will stay pegged for a moment, then drop to ~7 pounds and flutter just a bit. If I let off then hit it again, I can get full boost for another second before it dumps again. A short scan revealed no more KR than normal for my engine.

What'* going on? Overboost protection because of denser air?
J Wikoff is offline   Reply With Quote
Old 10-31-2005, 10:27 AM   #2
Junior Member
Posts like a Ricer Type-R
 
Join Date: Aug 2002
Posts: 10
Thanks: 0
Thanked 0 Times in 0 Posts
willwren is on a distinguished road
Default

It might be. Would be interesting to compare your MAF readings from warmer weather to now.
willwren is offline   Reply With Quote
Old 11-02-2005, 03:53 PM   #3
Senior Member
Posts like a Corvette
 
Join Date: Jul 2004
Location: Bolingbrook, IL Location: Clarkston, MI
Posts: 1,256
Thanks: 0
Thanked 0 Times in 0 Posts
llBlazin_llLo is on a distinguished road
Default

I have the same problem when I run a 2" pulley... This is one of the reasons I haven't been back to the track...

When I jump on it or even feather in the throttle (to WOT or not), boost will instantly hit 12-13 lbs. and then drop almost to ~7 lbs. and flutter. I can't even get up to full RPM (full boost) with out it doing this. The first few times it did this I thought that I had bad belt slip but I was wrong...
llBlazin_llLo is offline   Reply With Quote
Old 11-05-2005, 02:45 PM   #4
Senior Member
Posts like a Corvette
 
Join Date: Jul 2004
Location: Bolingbrook, IL Location: Clarkston, MI
Posts: 1,256
Thanks: 0
Thanked 0 Times in 0 Posts
llBlazin_llLo is on a distinguished road
Default

Is this problem only seen on stock PCM'*? By doing the 'boost bypass' trick solve this problem? I know the 'boost bypass' isn't the safest thing but I'm out of Ideas.
llBlazin_llLo is offline   Reply With Quote
Old 11-05-2005, 02:59 PM   #5
Senior Member
Certified Car Nut
Thread Starter
 
Join Date: Mar 2003
Posts: 12,432
Thanks: 0
Thanked 0 Times in 0 Posts
J Wikoff is on a distinguished road
Default

I've got a Hypertech chip. Still happens. The bypass does prevent it.
J Wikoff is offline   Reply With Quote
Old 11-05-2005, 07:03 PM   #6
Senior Member
Posts like a Corvette
 
Join Date: Jul 2004
Location: Bolingbrook, IL Location: Clarkston, MI
Posts: 1,256
Thanks: 0
Thanked 0 Times in 0 Posts
llBlazin_llLo is on a distinguished road
Default

Ok so this is happening on stock and Hypertech chips, are any Jet chips having problems with this?

Also what exactly has to be done to do the 'boost bypass' trick. With this done all I have to look out for is hitting the gov. and rev. limiter? Right? If not what else?
llBlazin_llLo is offline   Reply With Quote
Old 11-07-2005, 04:42 PM   #7
Senior Member
Posts like a Corvette
 
Join Date: Jul 2004
Location: Bolingbrook, IL Location: Clarkston, MI
Posts: 1,256
Thanks: 0
Thanked 0 Times in 0 Posts
llBlazin_llLo is on a distinguished road
Default

TTT
llBlazin_llLo is offline   Reply With Quote
Old 11-07-2005, 07:16 PM   #8
Senior Member
Certified Car Nut
Thread Starter
 
Join Date: Mar 2003
Posts: 12,432
Thanks: 0
Thanked 0 Times in 0 Posts
J Wikoff is on a distinguished road
Default

Take the vac line off the bottom of the BCA, pluge the hose if you feel so inclined, but not the open port on the BCA.

Let off a little when it'* gonna shift.
J Wikoff is offline   Reply With Quote
Old 11-27-2005, 03:27 AM   #9
Senior Member
Certified Car Nut
Thread Starter
 
Join Date: Mar 2003
Posts: 12,432
Thanks: 0
Thanked 0 Times in 0 Posts
J Wikoff is on a distinguished road
Default

Little update: after seeing rich readings on my A/F gauge, I backed the AFC off a couple percent, which seemed to reduce the boost loss. I think the boost dump was triggered by high MAF readings. Why only in third, I don't know. I'm gonna research a Jet chip or a custom one. It seems Hypertech did not foresee this complication.
J Wikoff is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
Boost Control Solenoid Maintenance and Boost Control Actuator Test for low Boost* Toddster Trouble shooting + Test Procedures 0 03-21-2009 07:24 PM
More boost via boost controller... DanCulkin Performance, Brainstorming & Tuning 14 07-02-2007 12:02 PM
2001 SSEi dumping water into the passenger floorboard es347fan 2000-2005 7 08-15-2006 09:52 PM
low stock Boost vs high stock boost hvactech Performance, Brainstorming & Tuning 12 05-10-2005 11:14 PM
Car dumping fuel. jlathem 1992-1999 6 10-18-2004 12:49 PM


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -4. The time now is 06:26 PM.


We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.