Do I need a blow off valve with an automatic
well the problem is that i am running a BOV and its the cause of all my misery right now. its not holding boost and is causing me all kinds of leaking issues around the flange and the valve wasnt holding boost. i switched BOV and tighten the adjustent on the other BOV damn neat all the way down so that it almost doesnt come up at idle. im gonna see if this build me boost. if it doenst, i will be yet another believer that an auto can run just fine with out a BOV.
I think you have other issues. I run the procharger big red on my car and it does fine. Car has built 13psi and when you let off a loud whoosh. Sure people don't run them, but why risk the chance of hurting the turbo due to barking the compressor. A cheap turbo, I guess so, but not a more expensive one.
Most people talking about needing one have read it on the net and you know they can't tell a lie on the Internet! The wastegate dumps boost so why is a blowoff valve necessary? My Duramax that makes 30psi doesn't have a BOV and the turbo has 220k miles it still works great!
I agree with most. It is very good insurance. I also think that most of the people that say they don't run one and it has never had a problem yet should really place alot of emphasis on that word "yet". Also you have to think for the grand nationals, stock they had a really small turbo that could compressor surge alot better because the wheel was alot lighter and it wasn't pushing so much air. It gets a little different when you have a big 88mm turbo that is pushing 145lbs/min of air.
Originally Posted by T/ALT1:
Most people talking about needing one have read it on the net and you know they can't tell a lie on the Internet! The wastegate dumps boost so why is a blowoff valve necessary? My Duramax that makes 30psi doesn't have a BOV and the turbo has 220k miles it still works great!
Diesels don't have throttle blades.
Every engine has throttle blades, the diesel is controlled by DBW instead of a cable but yeah it still has throttle blades to let air in.
Most people talking about needing one have read it on the net and you know they can't tell a lie on the Internet! The wastegate dumps boost so why is a blowoff valve necessary? My Duramax that makes 30psi doesn't have a BOV and the turbo has 220k miles it still works great!
Diesels don't have throttle blades.
Every engine has throttle blades, the diesel is controlled by DBW instead of a cable but yeah it still has throttle blades to let air in.
Originally Posted by T/ALT1:
Most people talking about needing one have read it on the net and you know they can't tell a lie on the Internet! The wastegate dumps boost so why is a blowoff valve necessary? My Duramax that makes 30psi doesn't have a BOV and the turbo has 220k miles it still works great!
Diesels don't have throttle blades.
Every engine has throttle blades, the diesel is controlled by DBW instead of a cable but yeah it still has throttle blades to let air in.
Most people talking about needing one have read it on the net and you know they can't tell a lie on the Internet! The wastegate dumps boost so why is a blowoff valve necessary? My Duramax that makes 30psi doesn't have a BOV and the turbo has 220k miles it still works great!
Diesels don't have throttle blades.
Every engine has throttle blades, the diesel is controlled by DBW instead of a cable but yeah it still has throttle blades to let air in.
Single reasons (beside lazyness) I'm not putting BOV on either my manual or auto is because I'm afraid of hard-to-diagnose BOV leaking issue. How can you be sure that at full boost BOV doesn't leak air?
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TECH Enthusiast
Joined: Mar 2010
Posts: 519
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Buy a damn tial and you wont have a single issue. That goes for anyone with leaking bovs......if its 50 bucks off ebay more than likely that's the issue. Tial for wg/bovs always. I'll use a china turbo but when it comes to stuff like the wg and bov they need to work everytime always.
TECH Enthusiast
Joined: Mar 2010
Posts: 519
Likes: 2
well the problem is that i am running a BOV and its the cause of all my misery right now. its not holding boost and is causing me all kinds of leaking issues around the flange and the valve wasnt holding boost. i switched BOV and tighten the adjustent on the other BOV damn neat all the way down so that it almost doesnt come up at idle. im gonna see if this build me boost. if it doenst, i will be yet another believer that an auto can run just fine with out a BOV.
/thread
If that's what you already have then you have another issue or it's faulty.
Maybe pull it apart and make sure everything is intact.
Buy a damn tial and you wont have a single issue. That goes for anyone with leaking bovs......if its 50 bucks off ebay more than likely that's the issue. Tial for wg/bovs always. I'll use a china turbo but when it comes to stuff like the wg and bov they need to work everytime always.
That's cool 
Originally Posted by T/ALT1:
Most people talking about needing one have read it on the net and you know they can't tell a lie on the Internet! The wastegate dumps boost so why is a blowoff valve necessary? My Duramax that makes 30psi doesn't have a BOV and the turbo has 220k miles it still works great!
Diesels don't have throttle blades.
Every engine has throttle blades, the diesel is controlled by DBW instead of a cable but yeah it still has throttle blades to let air in.
Most people talking about needing one have read it on the net and you know they can't tell a lie on the Internet! The wastegate dumps boost so why is a blowoff valve necessary? My Duramax that makes 30psi doesn't have a BOV and the turbo has 220k miles it still works great!
Diesels don't have throttle blades.
Every engine has throttle blades, the diesel is controlled by DBW instead of a cable but yeah it still has throttle blades to let air in.
Only on the newer diesels do they have throttle blades, and these are not used to control the rpm of the engine. The only reason they have them is for emissions. The throttle blade is closed to increase egt's to help in regen of the dpf.
Manufactures spend millions in research and development programing and sizing turbo's properly, thus why you don't get turbo surge.
Will a turbo last with out BOV? yes, for a while but you don't see many aftermarket turbo setups with out BOV's going 250,000 miles....
Huh???? 
Matt, I love everything you do, but have to respectfully disagree with you here. You never have a turbo long enough to show the damage this can do. The longest you have kept a turbo on a car that I know of was FM5, and that was simply because the car wouldn't co-operate. Honestly, you have had more turbos this year, than I have total in my life I think. How many miles did the Colorado have on it before the exhaust wheel ate parts? I know it didn't have any play in the bearings, but my guess is that it still had less than 1000 actual miles on it. As cheap as BOV;s are, I can't see why NOT to run one. JMHO, and Carry on!
Last edited by rpturbo; Mar 27, 2016 at 08:56 PM.
I've been without a BOV for 8 years now. I had some issues with mine so I junked it, never got around to replace it. Car only gets about 5,000 miles a year though.
Oh ya 4 years on my sled without one. Running one would be safer but I don't see the need.
Oh ya 4 years on my sled without one. Running one would be safer but I don't see the need.
Are you an auto car? I almost wish I could ditch my turbosmart bov.... ONLY because as a supercharged car, it is wide open at idle, making my car super loud just sitting there. (Not even sure if that's the norm for SC cars). However, I do like the sound when shifting, doesn't sound ricer to me. I just can't win.
Doesn't seem to be very much long term info available unfortunately. I'd love to not run one and be 100% sure that it would never affect my turbo. It seems most run BOVs because you're "supposed" to. However it does seem alot more people have had issues using vs the few that don't, not really a fair comparison though.
ok its not 'oh hey mines been workin fine without a bov'... its you should use one! when your making boost auto or manual, when u let off the throttle between shifts or after a pull in ur auto, that air has to go somewhere...... so if you dont have a bov its going back out your turbo causing unneeded wear n tear on the turbo.... so if u have a turbo thats worth something... bov's are needed.
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Joined: Nov 2003
Posts: 13,616
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From: Norn Iron
Are you an auto car? I almost wish I could ditch my turbosmart bov.... ONLY because as a supercharged car, it is wide open at idle, making my car super loud just sitting there. (Not even sure if that's the norm for SC cars). However, I do like the sound when shifting, doesn't sound ricer to me. I just can't win.
Turbo....you could debate all day long.