On3 bov spring - Ford Mustang Forums : Corral.net Mustang Forum
 
LinkBack Thread Tools Display Modes
post #1 of 12 Old 02-26-2019, 04:42 PM Thread Starter
Registered User
 
Trader Feedback: (0)
Join Date: Jul 2015
Location: Rockland n.y.
Posts: 342
On3 bov spring

My engine makes a good amount of vacuum at idle around 20in or so. I have an on3 bov that came with the kit and I think the issue of why Iím not making boost untill way up in the rpms is because the bov spring is to weak. What brand springs can be put in these bov because it looks like on3 does not sell replacements


1992 black notchback... 347 boss block, afr 185 renegade, 80lb injectors, edelbrock rpm II, on3 7675, tko 500, 3.55 gears
Powerstroken is offline  
Sponsored Links
Advertisement
 
post #2 of 12 Old 02-26-2019, 05:59 PM
Corral Elite Member
 
Saleen414's Avatar
 
Trader Feedback: (2)
Join Date: Feb 2012
Location: Levant, Maine
Posts: 2,292
Google BOV springs. They are all pretty much the same. Find a spring rated for the pressure you want and try it. They are fairly cheap, so you can get a few springs plus or minus your target and go from there. That is what I did.


1989 Saleen 414 358cid SBF 2.8L Kenne Bell S/C
26 X 8.5 Hoosier
Best 1/4 mile time 8.623 @ 159.82 mph with a 1.34 60' (5.57 1/8th at 128)
Best 1/8 mile time 5.339 @ 133.46 mph with a 1.29 60'
08' Bullitt #4097 N/A 340ish RWHP <<<<<FOR SALE!
Saleen414 is offline  
post #3 of 12 Old 02-26-2019, 06:14 PM Thread Starter
Registered User
 
Trader Feedback: (0)
Join Date: Jul 2015
Location: Rockland n.y.
Posts: 342
Ok cool I didnít know if they where brand specific. Was there a certain brand spring you used? Such as ones for turbo smart or tial because I see that even different tial bov require different springs

1992 black notchback... 347 boss block, afr 185 renegade, 80lb injectors, edelbrock rpm II, on3 7675, tko 500, 3.55 gears
Powerstroken is offline  
Sponsored Links
Advertisement
 
post #4 of 12 Old 02-26-2019, 07:07 PM Thread Starter
Registered User
 
Trader Feedback: (0)
Join Date: Jul 2015
Location: Rockland n.y.
Posts: 342
Will a stiffer spring actually help spool time? Like I can drive the car up to 4000 rpm but not putting too much load on it and I am still in vacuum. Or is that normal

1992 black notchback... 347 boss block, afr 185 renegade, 80lb injectors, edelbrock rpm II, on3 7675, tko 500, 3.55 gears
Powerstroken is offline  
post #5 of 12 Old 02-26-2019, 07:16 PM
Registered User
 
JFraser27's Avatar
 
Trader Feedback: (17)
Join Date: May 2016
Location: Rochester NY
Posts: 542
Garage
Quote:
Originally Posted by Powerstroken View Post
Ok cool I didnít know if they where brand specific. Was there a certain brand spring you used? Such as ones for turbo smart or tial because I see that even different tial bov require different springs


I would use the Tial 50mm blow off valve springs. Thatís the one the On3 resembles. I ended up buying another valve off fleabay (knockoff Tial) that came with a few other springs


Sent from my iPhone using Tapatalk

Stock bottom end, gt40x, Ported GT40 tubular, On3 turbo, TKO, 5 lug, 4 wheel disc, etc
JFraser27 is offline  
post #6 of 12 Old 02-27-2019, 09:15 AM
Registered User
 
Trader Feedback: (4)
Join Date: Dec 2010
Location: Dallas/Houston
Posts: 1,756
Honestly I don't think a bov spring is supposed to affect spool time at all. The valve should be lightly closed at idle so the spring is only supposed to be slightly stronger than the vacuum pressure in the valve dome. In overrun conditions when the valve needs to open, your manifold vacuum will be greater than idle vacuum so it'll pull the valve open to release trapped pressure but the valve will be closed as you normally drive it and as soon as you give it throttle because there will be less vacuum in the manifold, allowing the spring to keep it shut, keeping air from escaping.

Spool time is generally more controllable via wastegate and obviously turbine sizing.

Edit: Just making sure I capture the OP issue here but even if the spring is very weak, it still adds force to the equalized pressure above and below the valve keeping it shut. I think you'd basically have to have no spring in order for this to potentially become a problem.
5.0thunder is offline  
post #7 of 12 Old 02-27-2019, 11:57 AM Thread Starter
Registered User
 
Trader Feedback: (0)
Join Date: Jul 2015
Location: Rockland n.y.
Posts: 342
Right now I have my wastegate to my manifold because my turbo didnít have a bung. So if I tap the turbo housing it may help? My hot side is a .96 and I have a 347 I thought that would work good together but it builds boost like a turd

1992 black notchback... 347 boss block, afr 185 renegade, 80lb injectors, edelbrock rpm II, on3 7675, tko 500, 3.55 gears
Powerstroken is offline  
post #8 of 12 Old 02-27-2019, 01:23 PM
Registered User
 
Trader Feedback: (4)
Join Date: Dec 2010
Location: Dallas/Houston
Posts: 1,756
Quote:
Originally Posted by Powerstroken View Post
Right now I have my wastegate to my manifold because my turbo didnít have a bung. So if I tap the turbo housing it may help? My hot side is a .96 and I have a 347 I thought that would work good together but it builds boost like a turd
pressurizing the gate from the turbo housing vs manifold doesn't make *much* of a functional difference on these cars, but can in other cases, which is why the housing is usually chosen for wastegate signal. It shouldn't affect spool time.
5.0thunder is offline  
post #9 of 12 Old 02-27-2019, 01:25 PM
Registered User
 
Trader Feedback: (4)
Join Date: Dec 2010
Location: Dallas/Houston
Posts: 1,756
many other factors affect spool time aside from housing A/R. what are the rest of the turbocharger specs (impeller sizes, housing sizes, connection type), and what is the diameter of your hot side tubing?
5.0thunder is offline  
post #10 of 12 Old 02-27-2019, 07:17 PM Thread Starter
Registered User
 
Trader Feedback: (0)
Join Date: Jul 2015
Location: Rockland n.y.
Posts: 342
Iím trying to figure out what to do. The car didnít make good power and Iím trying to go through everything now and figure it out. I know number are numbers but it was disappointing


1992 black notchback... 347 boss block, afr 185 renegade, 80lb injectors, edelbrock rpm II, on3 7675, tko 500, 3.55 gears
Powerstroken is offline  
post #11 of 12 Old 02-27-2019, 07:24 PM
Registered User
 
JFraser27's Avatar
 
Trader Feedback: (17)
Join Date: May 2016
Location: Rochester NY
Posts: 542
Garage
I just drilled and tapped my housing because thatís what the precision wastegate instructions recommended to do lol. I donít know if it will be any better but it did make plumbing easier. I wonder if it has more to do with the .96 AR housing? Iím sure a .81 would make it spool a lot faster


Sent from my iPhone using Tapatalk

Stock bottom end, gt40x, Ported GT40 tubular, On3 turbo, TKO, 5 lug, 4 wheel disc, etc
JFraser27 is offline  
post #12 of 12 Old 03-22-2019, 09:19 AM
Registered User
 
Trader Feedback: (4)
Join Date: Dec 2010
Location: Dallas/Houston
Posts: 1,756
Edit: nvm, I'd expect a healthy 347 to spool a 7675 pretty easily. I'd also tap the exhaust housing and run that line straight to the lower gate port, then make sure you have no other vacuum leaks in the system.
5.0thunder is offline  
Sponsored Links
Advertisement
 
Reply

Bookmarks

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Ford Mustang Forums : Corral.net Mustang Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Similar Threads
Thread Thread Starter Forum Replies Last Post
On3 302 Valve Spring Upgrade Necessary? aaronb31 Turbochargers 7 02-15-2017 09:07 PM
For Sale ON3 performance bov and wastegate Derek Zartman Power Adders 2 06-05-2014 06:44 AM
Ok On3 Kit for the spring is a go jwright94 Turbochargers 8 09-22-2013 10:55 PM
For Sale On3 50mm bov with flange 02gt2v Power Adders 1 08-04-2013 09:20 AM
coilovers vs conventional on front? durty Drag Racing 19 08-29-2008 10:52 AM

Posting Rules  
You may post new threads
You may 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 On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome