BOV Operation
May 3, 2013 | 05:04 PM
#1
BOV Operation
Finally got my turbo kit on and to the point of testing it out. One thing that's concerning me is how the BOV is functioning. It's an RPS 50mm unit that KB sells with his kits. It has the heavy spring in there because with the light one it was always open at idle.
With the heavy spring it will only open a smidgen at full vacuum (~23 inHg), but not even enough to let out any air. But when I close the throttle at more than about 2-3 psi of boost the BOV will open. The turbo will also start fluttering before the BOV opens, and it's a noticeable gap between these two events, probably up to 1/2 second. Once the BOV opens the fluttering stops. If I close the throttle at less than 2-3 psi the BOV stays shut and the turbo just flutters.
Is this okay, or should I trim the BOV spring down so it opens sooner? I pulled it apart and inspected it, seems fine mechanically.
BTW this boost thing is addicting
With the heavy spring it will only open a smidgen at full vacuum (~23 inHg), but not even enough to let out any air. But when I close the throttle at more than about 2-3 psi of boost the BOV will open. The turbo will also start fluttering before the BOV opens, and it's a noticeable gap between these two events, probably up to 1/2 second. Once the BOV opens the fluttering stops. If I close the throttle at less than 2-3 psi the BOV stays shut and the turbo just flutters.
Is this okay, or should I trim the BOV spring down so it opens sooner? I pulled it apart and inspected it, seems fine mechanically.
BTW this boost thing is addicting
May 5, 2013 | 08:34 PM
#4
Joined: Jan 2006
Posts: 16,282
Likes: 438
From: Huntsville, AL
Open at idle isnt bad. The valve will close under boost as long as you have the referenced hooked up. The weaker the spring the more responsive. If you put in too stiff of a spring so its closed at idle it will be slower to open when you need it.
May 5, 2013 | 08:53 PM
#5
Open at idle would be bad if it's sucking air in through the BOV instead of through the air filter. Is the turbo supposed to be moving enough air at idle to prevent this from happening?
May 5, 2013 | 08:56 PM
#6
Joined: Jan 2006
Posts: 16,282
Likes: 438
From: Huntsville, AL
As long as you dont let your truck idle in a dust storm it will be fine. No the turbo doesnt necessarily have to be spinning at idle. Its mostly a case of the exhaust not having enough energy to spin it at idle.
If you are really worried about it, shim your current spring or get a stronger spring.
If you are really worried about it, shim your current spring or get a stronger spring.
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May 5, 2013 | 09:43 PM
#8
A BOV should not be open at idle. It only bleeds pressure when pressure overcomes the spring. At 2-3 psi your just hearing compressor surge. I run a 11psi spring and normally it doesn't open unless I'm over 7-8 psi. Sounds normal to me.
May 5, 2013 | 09:55 PM
#9
BOV is different
May 6, 2013 | 05:53 AM
#10
