Welcome to the Connecticut Z Car Club Forums




Username:  
Password:  
Log me on automatically each visit
Register 
It is currently Thu Mar 28, 2024 5:10 am
Welcome to the Connecticut Z Car Club Discussion Forums   
If you have trouble logging in or encounter any issues, please send an email to webmaster@ctzcc.com.

All times are UTC - 5 hours





Post new topic Reply to topic  [ 7 posts ] 
  Print view Previous topic | Next topic 
Author Message
 Post subject: Boost issues
PostPosted: Sun Aug 07, 2011 1:23 pm 
Offline
User avatar

Joined: Wed Aug 26, 2009 8:39 pm
Posts: 298
Location: Enfield, CT
So yesterday I installed a manual boost controller on my Z, had it set to 8psi. Today I took her out for a spin and had a boost spike up to 10. Now I thought the B.O.V. was supposed to prevent it from boosting over 8psi. Any ideas?? Also no matter what psi I'm running it makes that blow off valve pssssh sound. Is that normal? Its my first running turbo Z31 so just curious.


Top
 Profile  
 
 Post subject:
PostPosted: Sun Aug 07, 2011 1:33 pm 
Offline

Joined: Wed Apr 09, 2008 5:53 pm
Posts: 14778
Location: CT
Doesn't sound right, but I'm not a Turbo guy.

Anybody?

_________________
1970 240Z


Top
 Profile  
 
 Post subject:
PostPosted: Sun Aug 07, 2011 2:30 pm 
Offline
User avatar

Joined: Sat Mar 07, 2009 1:33 pm
Posts: 415
The blow off is typical.. Is the boost control electronic or manual ?


Top
 Profile  
 
 Post subject:
PostPosted: Sun Aug 07, 2011 2:35 pm 
Offline
User avatar

Joined: Wed Aug 26, 2009 8:39 pm
Posts: 298
Location: Enfield, CT
Its a manual boost controller.


Top
 Profile  
 
 Post subject:
PostPosted: Sun Aug 07, 2011 5:17 pm 
Offline
User avatar

Joined: Sat Mar 07, 2009 1:33 pm
Posts: 415
A 2 psi spike isnt all that bad. Check all your vacuum lines If any are old or deteriorating It can create a spike. Remember adding boost requires more fuel so dont go too crazy 8) I would turn it down and see If you still have it. Determine If its between shifts or on the top end.
The bov releases pressure from the intake and prevents compressor surge. When you let off when in boost the bov allows the compressed air out instead of bouncing off the closed throttle or surging the turbos.


Top
 Profile  
 
 Post subject:
PostPosted: Sun Aug 07, 2011 6:41 pm 
Offline
User avatar

Joined: Wed Aug 26, 2009 8:39 pm
Posts: 298
Location: Enfield, CT
I think for now I'm gonna turn it down and leave it at 7psi until I get a fancy electronic boost controller..looking for an old Greddy profec-b spec 1. I dont have a b.o.v. on my z...I heard it makes the car run rich unless you convert to map or use a blow-thru setup. Thats why I'm confused when my car makes the noise.


Top
 Profile  
 
 Post subject:
PostPosted: Sun Aug 07, 2011 8:16 pm 
Offline

Joined: Sun Feb 15, 2009 6:47 pm
Posts: 307
Location: Niagara falls, NY
Boost controller opens the wastegate, not the BOV. BOV releases accumulated pressure in the intake system when you let up on the throttle suddenly, so that pressure doesn't slow the spinning compressor down.
If you are having boost spikes it can be because the wastegate is not large enough or not opening completely. If so, an electronic boost control won't solve your problem. If you have a mechanical boost control, your problem may simply be that it's not properly calibrated....you set it at 8 but it really is off calibration and allowing 10. Mechanical boost controls are basically just a spring, and they open gradually as pressure rises, instead of going straight from fully closed to fully open wastegate. A BOV should not have any effect on your mixture control, not sure where you heard it would.It keeps the turbine spooled up between shifts so you don't drop below the boost threshhold each time you shift, and you definitely want one.
The simplest electronic boost controls let you set your wastegate spring for low boost but then you put the control valve in the pressure line that goes to the wastegate. The electronically controlled valve doesn't open till whatever pressure you set it at is reached, and the wastegate fully opens all at once.

_________________
71 on a rotisserie, two more in pieces in my shed...and a 69 1600 waiting for me to get to it


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 7 posts ] 

All times are UTC - 5 hours


Who is online

Users browsing this forum: No registered users and 7 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
cron









Powered by phpBB © 2000, 2002, 2005, 2007 phpBB Group
mile200 v1.0.1 designed by Team -Programming forum- .