Pelican Parts
Parts Catalog Accessories Catalog How To Articles Tech Forums
Call Pelican Parts at 888-280-7799
Shopping Cart Cart | Project List | Order Status | Help



Go Back   Pelican Parts Forums > 1- Porsche Technical Forums > 911 / 930 Turbo & Super Charging Forum


Reply
 
LinkBack Thread Tools Rate Thread
Author
Thread Post New Thread    Reply
Registered User
 
Ken911's Avatar
 
Join Date: May 2005
Location: Loxahatchee, florida
Posts: 2,665
Variable boost / bov settings

A lot of the EFI controlled cars here have variable boost settings. Usually either street versus track maps or e-85 vs premium gas maps. My question is what about the BOV if my waste gate opens at 1.3 bar on premium and 2 bar on e-85 shouldn't the BOV be opening at around the same pressure? or should the springs be set to the highest possible boost levels?
__________________
88 turbo Guards red Targa slant nose, and yes I am a horsepower junkie, 3.4liter,7.5 to 1 JE pistons, Adjustable WUR, Imagine fuel head, 1 bar waste gate headers,allthe cis toys. Now apart to become the next EFI monster. fabbing my own intake, headers Individual throttle bodies, MS-3, pauter rods, Xtreme twin plugged heads, gt-2 evo cams cop's.
05 Cayenne S lapis blue
Old 02-19-2014, 05:17 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #1 (permalink)
Registered User
 
sjf911's Avatar
 
Join Date: Dec 2006
Location: Idaho
Posts: 5,617
Garage
You want the lowest spring and then let the boost controller manage pressures above that.
__________________
Steve
Sapere aude
1983 3.4L 911SC turbo. Sold
Old 02-19-2014, 05:26 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #2 (permalink)
Registered User
 
Ken911's Avatar
 
Join Date: May 2005
Location: Loxahatchee, florida
Posts: 2,665
Quote:
Originally Posted by sjf911 View Post
You want the lowest spring and then let the boost controller manage pressures above that.
I understand that with the waste gate. But my question is the BOV. Those are never connected to the boost controller so should the spring setting be the same as the highest boost?
__________________
88 turbo Guards red Targa slant nose, and yes I am a horsepower junkie, 3.4liter,7.5 to 1 JE pistons, Adjustable WUR, Imagine fuel head, 1 bar waste gate headers,allthe cis toys. Now apart to become the next EFI monster. fabbing my own intake, headers Individual throttle bodies, MS-3, pauter rods, Xtreme twin plugged heads, gt-2 evo cams cop's.
05 Cayenne S lapis blue
Old 02-19-2014, 05:29 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #3 (permalink)
Registered User
 
Join Date: Jul 2009
Location: Ontario
Posts: 1,756
I was under the impression the BOV opened when the throttle plate closed, to relieve pressure from the turbo. Mine is not adjustable, (965 type) but always wondered what benefit there was to having it adjustable? Philip
__________________
87 930 GHL/Rarlyl8/Garretson/GT3582R/1 Bar/Wevo shift, mounts/Meth inj/LM-2/Custom Fuchs/Carrera intake manifold/Xtreme Carrera heads P&P/3.4/DR 993SS cams/ Mahl/Pauter/JE/Niresist/ARP/twin COP/8.25:1/KEP stage 2/twin tials/close 2,3,4th. MS3Pro Evo 500+ HP, BTSOMP Dyno

Last edited by philip j; 02-19-2014 at 05:40 AM.. Reason: add
Old 02-19-2014, 05:40 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #4 (permalink)
Registered User
 
Ken911's Avatar
 
Join Date: May 2005
Location: Loxahatchee, florida
Posts: 2,665
It does open when the throttle plate is closed and you set the presure at which it opens by changing the spring in it. I just wanted to make sure i pick the right spring so that it's not opening while on boost and when the throttle plates close the pressure isnt so high that it stalls the turbo.
__________________
88 turbo Guards red Targa slant nose, and yes I am a horsepower junkie, 3.4liter,7.5 to 1 JE pistons, Adjustable WUR, Imagine fuel head, 1 bar waste gate headers,allthe cis toys. Now apart to become the next EFI monster. fabbing my own intake, headers Individual throttle bodies, MS-3, pauter rods, Xtreme twin plugged heads, gt-2 evo cams cop's.
05 Cayenne S lapis blue
Old 02-19-2014, 05:43 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #5 (permalink)
Registered User
 
sjf911's Avatar
 
Join Date: Dec 2006
Location: Idaho
Posts: 5,617
Garage
Sorry, miss read the post. You want to make sure it doesn't open at part throttle, idle, or low vacuum loads. The boost will keep it closed no matter what the spring rate is.
__________________
Steve
Sapere aude
1983 3.4L 911SC turbo. Sold
Old 02-19-2014, 05:48 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #6 (permalink)
 
Registered User
 
Ken911's Avatar
 
Join Date: May 2005
Location: Loxahatchee, florida
Posts: 2,665
Whats yours set at? and whats your boost setting?
__________________
88 turbo Guards red Targa slant nose, and yes I am a horsepower junkie, 3.4liter,7.5 to 1 JE pistons, Adjustable WUR, Imagine fuel head, 1 bar waste gate headers,allthe cis toys. Now apart to become the next EFI monster. fabbing my own intake, headers Individual throttle bodies, MS-3, pauter rods, Xtreme twin plugged heads, gt-2 evo cams cop's.
05 Cayenne S lapis blue
Old 02-19-2014, 06:16 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #7 (permalink)
Registered User
 
sjf911's Avatar
 
Join Date: Dec 2006
Location: Idaho
Posts: 5,617
Garage
I'll have to look but as I recall it is the plain spring on a 50mm Tial so -10 spring rate. My idle vacuum runs a MAP of about 40, max boost so far is 1.2 but currently under 1 until I can get the e85 sorted.
__________________
Steve
Sapere aude
1983 3.4L 911SC turbo. Sold
Old 02-19-2014, 06:38 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #8 (permalink)
Registered User
 
Join Date: Jul 2006
Location: S. Florida
Posts: 7,234
With your high flowing individual throttle bodies you'll have less boost pressure drop through the throttle bodies on the intake side below them during boost then with a single throttle body and plenum chamber so the vacuum side of the BOV piston where the spring is will be seeing almost the same positive pressure as the business side of the BOV piston.
Therefore the BOV standard spring pressure should hold the BOV shut during boost. You can experiment with shims under the spring or try different springs to test reaction time of the BOV in relation to throttle positon and boost/off boost transitions.

On another note I think your brake booster vacuum line should be connected to only one intake runner.
When I had a BMW 2002 with dual sidedraft Weber 45 DCOE carbs thats how it was set up. At the same time it was 4 seperate carbs that had to be synchronized to idle smooth. One 45mm carburator throat and butterfly for each 500cc cylinder and not EFI so maybe that doesn't correlate.
Old 02-19-2014, 07:00 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #9 (permalink)
Registered User
 
Ken911's Avatar
 
Join Date: May 2005
Location: Loxahatchee, florida
Posts: 2,665
I'll have two manifolds that I rout the vacuum lines from each cylinder too. One just for the brakes. The other for idle bleed, vacuum signal to the boost controller and bov's etc.
__________________
88 turbo Guards red Targa slant nose, and yes I am a horsepower junkie, 3.4liter,7.5 to 1 JE pistons, Adjustable WUR, Imagine fuel head, 1 bar waste gate headers,allthe cis toys. Now apart to become the next EFI monster. fabbing my own intake, headers Individual throttle bodies, MS-3, pauter rods, Xtreme twin plugged heads, gt-2 evo cams cop's.
05 Cayenne S lapis blue
Old 02-19-2014, 07:56 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #10 (permalink)
Registered User
 
Join Date: Nov 2012
Posts: 227
I might get some sh#$%$ for saying this but you should run a real BOV, The bosch (plastic, non adjustable, rubber diaphram, weak spring=junk)stuff is barely adequate and a lot of people just don't realize how important that little device is and how adjustments can really affect things. Even an old style Greddy RS valve is night and day superior over these little factory cost savers...
Old 02-19-2014, 09:05 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #11 (permalink)
Registered User
 
Ken911's Avatar
 
Join Date: May 2005
Location: Loxahatchee, florida
Posts: 2,665
was planning on using turbosmart BOV's and wastegates. This time around and wondering which spring to get with the BOV's. Since it's twin scroll with my own fabbed intake plenums there will be two Waste gates and two bov's
__________________
88 turbo Guards red Targa slant nose, and yes I am a horsepower junkie, 3.4liter,7.5 to 1 JE pistons, Adjustable WUR, Imagine fuel head, 1 bar waste gate headers,allthe cis toys. Now apart to become the next EFI monster. fabbing my own intake, headers Individual throttle bodies, MS-3, pauter rods, Xtreme twin plugged heads, gt-2 evo cams cop's.
05 Cayenne S lapis blue

Last edited by Ken911; 02-19-2014 at 02:29 PM..
Old 02-19-2014, 01:24 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #12 (permalink)
Registered User
 
Join Date: Nov 2012
Posts: 227
Turbosmart makes some very nice ones. I used to run both on a twin turbo 928 I built years ago. Good choice. Also the 965 elbow is really not the best option even though people believe it is because the factory used it. The BOV is better placed on the charge pipe right before the throttle body. It does make a difference there even if you run it back to the 965 elbow to dump. I prefer it open as I like the sound Some even bung it off the outlet side of the IC although I never have. JFairman Gave good advice above if that is your set up he is referring to.
Old 02-19-2014, 02:31 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #13 (permalink)
Registered User
 
TurboKraft's Avatar
 
Join Date: Mar 2005
Location: Phoenix, AZ
Posts: 2,500
Quote:
Originally Posted by Nuen Werke View Post
I might get some sh#$%$ for saying this but you should run a real BOV, The bosch (plastic, non adjustable, rubber diaphram, weak spring=junk)stuff is barely adequate and a lot of people just don't realize how important that little device is and how adjustments can really affect things. Even an old style Greddy RS valve is night and day superior over these little factory cost savers...
And those inexpensive factory nylon diverter valves are better than most of the bolt-in replacement aftermarket billet diverter valves.

Can't go wrong with Turbosmart wastegates or blow off valves.
__________________
Chris Carroll
TurboKraft, Inc.
Tel. 480.969.0911
email: info@turbokraft.com
http://www.facebook.com/TurboKraft - http://www.instagram.com/TurboKraft
Old 02-19-2014, 04:49 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #14 (permalink)
Registered User
 
Ken911's Avatar
 
Join Date: May 2005
Location: Loxahatchee, florida
Posts: 2,665
ok so which BOV should i get the one with the 7 pound spring or the 14 pound spring?
__________________
88 turbo Guards red Targa slant nose, and yes I am a horsepower junkie, 3.4liter,7.5 to 1 JE pistons, Adjustable WUR, Imagine fuel head, 1 bar waste gate headers,allthe cis toys. Now apart to become the next EFI monster. fabbing my own intake, headers Individual throttle bodies, MS-3, pauter rods, Xtreme twin plugged heads, gt-2 evo cams cop's.
05 Cayenne S lapis blue
Old 02-20-2014, 04:36 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #15 (permalink)
Registered User
 
Join Date: Nov 2012
Posts: 227
I would agree Chis if we were talking about their intended purpose on a stock car sure. Get the BOV Ken, the adjustments are very wide in stock form. Unless you are planning to run over 25-30 psi..AND AS JF mentioned above I believe you can shim for further tension but that is stratospheric boost for 930's. just install it, run it open or closed and experiment with the settings while you are boosting the hell out of it. You will find the sweet spot
Old 02-20-2014, 06:40 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #16 (permalink)
Reply

Thread Tools
Rate This Thread
Rate This Thread:

 


All times are GMT -8. The time now is 03:00 AM.


 
Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2018, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2018 Pelican Parts, LLC - Posts may be archived for display on the Pelican Parts Website -    DMCA Registered Agent Contact Page
 

DTO Garage Plus vBulletin Plugins by Drive Thru Online, Inc.