Forced Induction Superchargers | Turbochargers | Intercoolers

One or Two BOV's? How to decide?

Thread Tools
 
Search this Thread
 
Old Oct 3, 2018 | 08:39 AM
  #1  
Rob07002's Avatar
Thread Starter
Staging Lane
 
Joined: Apr 2014
Posts: 85
Likes: 0
Default One or Two BOV's? How to decide?

LQ4 with twin BW S366 running up to 25#. Will one TurboSmart Race Port BOV work, or do I need two smaller ones?
Reply
Old Oct 3, 2018 | 09:15 AM
  #2  
Dimeomboost's Avatar
TECH Regular
 
Joined: Dec 2014
Posts: 484
Likes: 18
From: Emory Texas currently
Default

I'm have same motor same turbos same Bov and I'm literally mocking up to add a second one as we speak it was fine till I got over 12lbs but not its causing surging back towards the turbo
Reply
Old Oct 3, 2018 | 04:53 PM
  #3  
stevieturbo's Avatar
9 Second Club
 
Joined: Nov 2003
Posts: 13,616
Likes: 185
From: Norn Iron
Default

Depends on the application etc....none is always an option too.
Reply
Old Oct 4, 2018 | 02:16 PM
  #4  
svslow's Avatar
TECH Fanatic
10 Year Member
Photogenic
Photoriffic
Shutterbug
 
Joined: Oct 2015
Posts: 1,280
Likes: 28
From: Pittsboro, IN
Default

Two gives you twice the possibility for a boost leak.
Reply
Old Oct 7, 2018 | 01:27 PM
  #5  
3pedals's Avatar
8 Second Club
15 Year Member
iTrader: (3)
 
Joined: Mar 2007
Posts: 1,931
Likes: 6
From: WPG MB
Default

I run 2 billet S476's up to 30+psi, no bov at all
Reply
Old Oct 8, 2018 | 08:35 AM
  #6  
LSswap's Avatar
TECH Fanatic
10 Year Member
Liked
Loved
Community Favorite
 
Joined: Nov 2014
Posts: 1,308
Likes: 660
Default

Originally Posted by Rob07002
LQ4 with twin BW S366 running up to 25#. Will one TurboSmart Race Port BOV work, or do I need two smaller ones?
Stick or automatic?
Reply
Old Oct 8, 2018 | 10:13 AM
  #7  
JoeNova's Avatar
Restricted User
 
Joined: Mar 2014
Posts: 7,192
Likes: 109
From: Ohio
Default

I run quad 50mm on a 4.8 with no BOV.

Anti-surge compressor housings help.
Flat shifting your manual helps too.
Reply
Old Oct 8, 2018 | 03:04 PM
  #8  
Kfxguy's Avatar
TECH Veteran
5 Year Member
Liked
Loved
Community Favorite
iTrader: (1)
 
Joined: Apr 2017
Posts: 4,582
Likes: 758
From: Louisiana
Default

I'm no pro and i'm really new to this, but in my opinion, one would be fine, its job is just to release pressure, right? I dont think that you really need to over think it, as long as you can release the pressure, your good. Plus look at all the guys running No BOV. Some stock vehicles didnt use one either, Namely a Buick grand National. So.........
Reply
LS1 Tech Stories

The Best V8 Stories One Small Block at Time

story-0

7 Most Reliable High-Performance Engines GM Has Ever Built

 Verdad Gallardo
story-1

Amazing '71 Camaro Restomod Is Modern Muscle Car Under the Skin

 Verdad Gallardo
story-2

6 Common C5 Corvette Failures and What's Involved In Repairing Them

 Pouria Savadkouei
story-3

Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph

 Verdad Gallardo
story-4

Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked

 Pouria Savadkouei
story-5

Top 10 Most Powerful Chevy Trucks Ever Made!

 
story-6

Hennessey's New Supercharged Silverado ZR2 Has 700 HP

 Verdad Gallardo
story-7

Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes

 Verdad Gallardo
story-8

Awesome K5 Blazer Restomod Comes With C7 Corvette Power

 Verdad Gallardo
story-9

10 Camaros You Should Never Buy

 
Old Oct 10, 2018 | 09:33 AM
  #9  
WSLN 6's Avatar
Staging Lane
iTrader: (3)
 
Joined: Jul 2005
Posts: 99
Likes: 4
Default

Also called a self cleaning air filter lol. A little hard on the old bearings, but never wrecked a turbo because of it....
Reply
Old Oct 22, 2018 | 06:47 PM
  #10  
imma_stocker's Avatar
TECH Fanatic
15 Year Member
Liked
iTrader: (19)
 
Joined: Apr 2007
Posts: 1,155
Likes: 37
From: Country
Default

If journal bearing, I suggest using a BOV. DBB don't care as much.
Autos need them less than stick cars. Or flat foot shift as Joe mentioned.

FWIW, BOV have some mechanical tuning. http://www.turbosmart.com/news/adjus...our-bov-or-bpv
Yours should be fine if installed in correct location.
Reply
Old Dec 3, 2018 | 09:55 PM
  #11  
Rob07002's Avatar
Thread Starter
Staging Lane
 
Joined: Apr 2014
Posts: 85
Likes: 0
Default

Originally Posted by LSswap
Stick or automatic?
automatic
Reply
Old Dec 4, 2018 | 07:32 AM
  #12  
LSswap's Avatar
TECH Fanatic
10 Year Member
Liked
Loved
Community Favorite
 
Joined: Nov 2014
Posts: 1,308
Likes: 660
Default

Originally Posted by Rob07002


automatic
My opinion, one should do it.
Reply
Old Dec 4, 2018 | 03:53 PM
  #13  
krazy4's Avatar
12 Second Club
iTrader: (5)
 
Joined: Mar 2006
Posts: 1,457
Likes: 3
From: Yorba Linda, CA
Default

I never run them but that's just me.
Reply
Old Dec 6, 2018 | 03:01 PM
  #14  
Rob07002's Avatar
Thread Starter
Staging Lane
 
Joined: Apr 2014
Posts: 85
Likes: 0
Default

Originally Posted by krazy4
I never run them but that's just me.
drag only car with maybe a quick street hit or cruise to a show, so what would be the downside to not using a bov?
Reply
Old Dec 6, 2018 | 03:24 PM
  #15  
Kfxguy's Avatar
TECH Veteran
5 Year Member
Liked
Loved
Community Favorite
iTrader: (1)
 
Joined: Apr 2017
Posts: 4,582
Likes: 758
From: Louisiana
Default

I’m no professional. And I may be wrong. But I don’t feel that I am....first off I believe it Don’t take much of a valve to vent the pressure. I put a small, compact valve on mine. As soon as it opens, the pressure is released. Which is what you want, correct? Why do you need two? If one lets the pressure off the turbo, then why would two be better? I don’t think it would amount to a pile beans. Also, wasn’t there a few factory cars, including the grand national, that did not have blow off valves?
Reply
Old Dec 6, 2018 | 04:23 PM
  #16  
stevieturbo's Avatar
9 Second Club
 
Joined: Nov 2003
Posts: 13,616
Likes: 185
From: Norn Iron
Default

Originally Posted by Kfxguy
I’m no professional. And I may be wrong. But I don’t feel that I am....first off I believe it Don’t take much of a valve to vent the pressure. I put a small, compact valve on mine. As soon as it opens, the pressure is released. Which is what you want, correct? Why do you need two? If one lets the pressure off the turbo, then why would two be better? I don’t think it would amount to a pile beans. Also, wasn’t there a few factory cars, including the grand national, that did not have blow off valves?
Because a need to get rid of 400hp worth of air....is different from a need to get rid of 1400hp worth of air.

Some turbos are more resilient than others in terms of withstanding air stalling or trying to move backwards in the turbo, or indeed rapid speed changes of the wheel/shaft.

Many very old turbo cars did not have any....almost every car in the last 2-3 decades do though.

Reply
Old Dec 6, 2018 | 06:01 PM
  #17  
Kfxguy's Avatar
TECH Veteran
5 Year Member
Liked
Loved
Community Favorite
iTrader: (1)
 
Joined: Apr 2017
Posts: 4,582
Likes: 758
From: Louisiana
Default

Originally Posted by stevieturbo
Because a need to get rid of 400hp worth of air....is different from a need to get rid of 1400hp worth of air.

Some turbos are more resilient than others in terms of withstanding air stalling or trying to move backwards in the turbo, or indeed rapid speed changes of the wheel/shaft.

Many very old turbo cars did not have any....almost every car in the last 2-3 decades do though.

you right. I just noticed he’s doing twin Turbo also. So I guess the right answer would be two smaller ones or one very large one.
Reply
Old Dec 6, 2018 | 08:03 PM
  #18  
LSswap's Avatar
TECH Fanatic
10 Year Member
Liked
Loved
Community Favorite
 
Joined: Nov 2014
Posts: 1,308
Likes: 660
Default

Here's what scares me without a BOV. 92 mm throttle plate is about 10 square inches. Lets say at 20 psi, you close the throttle. Now you got 20 PSI on one side of the plate and a vacuum on the other side. So let's call it 30 pounds per square inch pushing against a 10 square inch plate or 300 lbs against the plate and shaft.
Reply
Old Dec 6, 2018 | 11:58 PM
  #19  
krazy4's Avatar
12 Second Club
iTrader: (5)
 
Joined: Mar 2006
Posts: 1,457
Likes: 3
From: Yorba Linda, CA
Default

Last car I had was a 94 civic with a Borg Warner S366. Made 400whp on low boost. Drove it for a year, lots of street driving. No BOV.

After a year, there is absolutely no shaft play. Turbo seems brand new. BorgWarners are great though!
Can't say what it would be with some other turbos.

I'm no expert, just sharing my experience.
One less thing to buy, worry about, replace.
Reply
Old Dec 7, 2018 | 01:34 AM
  #20  
gametech's Avatar
TECH Veteran
20 Year Member
Active Streak: 30 Days
Active Streak: 60 Days
Top Answer: 1
iTrader: (1)
 
Joined: Sep 2004
Posts: 4,905
Likes: 906
From: Stockbridge GA
Default

I cannot imagine a reason for two BOVs. It is really not like the intricacies of proper wastegating. The job of a BOV is quite simple, and you are presumably only running one tube to your throttle body, so I don't even know where you would put an extra BOV.
Reply



All times are GMT -5. The time now is 07:01 PM.

story-0
7 Most Reliable High-Performance Engines GM Has Ever Built

Slideshow:These GM engines didn't just make huge power, they survived abuse, boost, track days, and six-digit mileage with a reputation for refusing to quit.

By Verdad Gallardo | 2026-05-21 16:45:27


VIEW MORE
story-1
Amazing '71 Camaro Restomod Is Modern Muscle Car Under the Skin

Slideshow: This heavily modified 1971 Camaro mixes classic muscle car styling with a fifth-generation Camaro interior and modern LS3 power.

By Verdad Gallardo | 2026-05-12 18:06:42


VIEW MORE
story-2
6 Common C5 Corvette Failures and What's Involved In Repairing Them

Slideshow: From wobbling harmonic balancers to failed EBCMs, these are the issues that define long-term C5 ownership and what repairs typically involve.

By Pouria Savadkouei | 2026-05-07 18:44:57


VIEW MORE
story-3
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph

Slideshow: A modern Camaro transformed into a retro icon, this limited-run "Bandit" build blends nostalgia with brute force in a way few revivals manage.

By Verdad Gallardo | 2026-04-21 13:57:02


VIEW MORE
story-4
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked

Slideshow: Cadillac didn't just crash the high-performance luxury vehicle party, it showed up loud, supercharged, and occasionally a little unhinged...

By Pouria Savadkouei | 2026-04-16 10:05:15


VIEW MORE
story-5
Top 10 Most Powerful Chevy Trucks Ever Made!

Slideshow: Top ten most powerful Chevy trucks ever made

By | 2026-03-25 09:22:26


VIEW MORE
story-6
Hennessey's New Supercharged Silverado ZR2 Has 700 HP

Slideshow: Hennessey has turned the Silverado ZR2 into a 700-hp off-road monster with supercharged V8 power and a limited production run.

By Verdad Gallardo | 2026-03-24 18:57:52


VIEW MORE
story-7
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes

Slideshow: A one-off sports car that looks like a vintage Italian exotic-but hides a C6 Corvette underneath-just sold for the price of a new mid-engine Corvette.

By Verdad Gallardo | 2026-03-23 18:53:41


VIEW MORE
story-8
Awesome K5 Blazer Restomod Comes With C7 Corvette Power

Slideshow: A heavily reworked 1972 K5 Blazer swaps its off-road roots for a low-slung street-focused build with modern V8 power.

By Verdad Gallardo | 2026-03-09 18:08:45


VIEW MORE
story-9
10 Camaros You Should Never Buy

Slideshow: There are thousands of used Camaros on the market but we think you should avoid these 10

By | 2026-02-17 17:09:30


VIEW MORE