Why no blowoff valves?

Pony Express

Pony Express

Back on the road
Dec 30, 2010
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Southern CT
Hey folks,
I was just thinking the other day about blowoff valves and turbos. I know its kind of a ricer thing but it seems like turbo bark could spell trouble for a turbo so why don't most of the guys running the pulls and drag racing use blowoff valves? Or is it just that I am unaware of it?

I'm not 100% familiar with the inner workings of a turbo (as you can probably tell), but does a wastegate act sort of like a blowoff valve?

Thanks :thumb:
 
05_LLY

05_LLY

Out-A-Time
Aug 7, 2006
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Id start with the fact that diesels dont have throttle plates, would they help in some situations on a diesel....yeah but no where near like on a gasser!
 
paint94979

paint94979

Beer Nazi
Sep 18, 2006
11,714
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KEVINL said:
diesel also have no Vacuum to operate blow off valves

BD makes a kit but its like $600
Click to expand...

And it ties into the throttle position so it takes time to setup correctly... IMHO it is very easy to not bark a turbo
 
JoshH

JoshH

Daggum farm truck
Staff member
Vendor/Sponsor
Feb 14, 2007
13,597
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Some turbos bark much easier than others, and some people run a BOV on their truck. You can easily make a BOV that works off drive pressure.
 
Jetty LBZ

Jetty LBZ

work in progress
Jan 24, 2011
404
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middle TN
someone correct me if im wrong but im pretty sure that turbo bark puts a lot of stress on the shaft and its possible that it could brake it.
 
LBZ

LBZ

Super Moderator
Staff member
Jul 2, 2007
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paint94979 said:
And it ties into the throttle position so it takes time to setup correctly... IMHO it is very easy to not bark a turbo
Click to expand...

I guess if you never leave the pavement or do burn-outs.......:D

Most people run them off of drive pressure like Josh said. Not hard to set up at all either.
 
GeneralTJI

GeneralTJI

Turbo Todd
Jun 1, 2010
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Colorado
Run a very soft spring in the BOV, drive pressure is higher than boost, pipe drive pressure into the BOV (after running it through some coiled up copper tubing) and it will keep it shut under a load. When you let off DP will nose dive and boost pressure will overcome the light spring and vent.
 
Ryan T

Ryan T

Active member
Sep 5, 2010
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when your doin 125mph at the end of the 1/4 in 7000lb its easier to just let off then start rollin outta the throttle, i put a bd blow off valve on my dodge and it stoped it from barking, it was very easy to set up.. but it wasnt easy on the wallet..it looked and sounded cool though!:thumb:
 
JustinD

JustinD

Plow Truck
Nov 21, 2008
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GeneralTJI said:
Run a very soft spring in the BOV, drive pressure is higher than boost, pipe drive pressure into the BOV (after running it through some coiled up copper tubing) and it will keep it shut under a load. When you let off DP will nose dive and boost pressure will overcome the light spring and vent.
Click to expand...

Thank you!:thumb:
 
chevyburnout1

chevyburnout1

Fixing it till it breaks
Aug 25, 2008
2,368
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Berthoud, CO
Yes its very easy to control the throttle and not bark it. But I also drink and have my buddies drive me to taco bell in my truck at 2:30 in the morning. They do not know how to be easy on my truck haha.

I have a BOV hooked up on mine. Does its job at preventing bark a good 80% of the time and it is just another noise that makes my truck stand out a bit more haha. Mine was a Apexi BOV off of craigslist for $40. Had a buddy TIG weld it onto the intercooler cold pipe, ran some copper pipe to one side, tapped into the wastgate hose on the other side, slight BOV spring modifications and walla: Diesel BOV for about $55 and a case of beer :)
 
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