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Forge BOV

908 views 6 replies 5 participants last post by  its_tricky83 
#1 ·
So I got a Forge BOV in my hands. I dont know what spring is in there.

I was looking at Forge's website and was thinking of ordering the "spring tuning kit".

Which one should I get? Whats the stock psi on the TD04? I'm not running a MBC or anything...so boost is all stock.

The reason I ask is, it's not as loud as my stock Bosh BPV. Maybe it has TOO strong of a spring in it?
 
#2 ·
Don't be scared... open her up and have a look at the spring. All you need is a little allan key to suit.

I purchased the tuning kit, mostly useless when all you want is one spring... you get 3 springs of different stiffness and 3 little spacers for fine tuning.

I originally had a yellow spring and was boosting way too high on my T25. So I've gone down to a green spring... (still boosting a bit high, but oh well).

You might like to fiddle with the Wastegate Actuator in pair with the BOV to get the required settings you want.
 
#4 ·
Since the BOV's function has nothing to do with boost pressure, how do you "tune" a BOV?

It's function is solely to dump boost when the thottle valve is closed suddenly. The spring is there to push the valve closed against the boost pressure when the vacuum signal is removed. Not much pressure would be required to achieve this. Once it is closed I can't see how the boost pressure could affect it at all.

What am I missing here?
 
#6 · (Edited)
Both our valves and our actuators have different springs.

Valves are relatively simple mechanical devices but in practical application things are a bit more complex than internet engineers make it out to be. In an idealized situation pressure on either side of the piston (or diaphragm) will be the same and will be applied at the same time allowing for a minuscule amount of spring pressure being enough to close the valve. However in a real world application there will be both a difference in pressure applied to either side of the piston and a slight delay from when the charge pipe is pressurized and when the boost reference switches from vacuum to boost. If spring pressure isn't sufficient to resist both of these forces the piston can be forced slightly open (and stabilize there) resulting in a leak.

Here is a link to a post on another forum that explains it a bit more.
 
#7 ·
Yep, so as Patty said.. I have differen't springs for tuning both my BOV and Actuator. I've got 3 different springs and 3 little fine tuning disks for the BOV, and 2 different springs for the Actuator.

If you somehow have the wrong spring, contact Forge and they're more than happy to sort the situation out to the customers satisfaction. Probably the best customer service I have ever experienced.
 
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