Chevrolet Cruze Forums banner
1 - 18 of 18 Posts

·
Registered
Joined
·
647 Posts
Discussion Starter · #1 ·
hey i see a lot of us not knowing what spring to run in the BOV. most every one is saying green but for some of us green is leaking off a lil boost at 21, 22psi. BUt i see for a lot of the other forge bov's they make shims to fine tune the spring you are using. it look like a shim with the green spring would work best for all of us tuned. Cause the yellow seems to hard and the green is just a lil soft for when we are switching over to sport mode. 1 shim would make the green spring hold to about 25psi. i am going to call them and see how to get a hold of these "shims"
 

·
Registered
Joined
·
2,000 Posts
Good find smorey! That sounds exactly what can be the fix for the spring tuning.
 

·
Registered
Joined
·
2,000 Posts
I would hope the shims are already tested along with the springs to give a specific boost level before blow off or valve opening. Yeah anyone can use a washer to test with but buying a shim that should already be done hence the price difference
 

·
Registered
Joined
·
647 Posts
Discussion Starter · #5 ·
Ok here is what they said. there is no rating for the 2 springs. the 2 springs we get is just a soft (green) and harder (yellow) no boost rating Some one already has a thread on this...but the kits they sell with the springs that are rated and shims to fine tune will not work on this BOV. but the concept is still true...by adding a small thin washer to the cup side of the bov where the spring is would make the green spring better...but we don't know what size washer ie shim will fit and we don't know if there will be any piston travel problems. in other words this would be a try it and see what happens type of thing. he did say that if the vacuum line comes from the intake to a solenoid than to the BOV that this could be the hang up. it would be better to run a straight line from the intake to the BOV...but this would take out any safety feature that gm may of built into the boost controlling side of the car. that solenoid may help with traction control and all so maybe what causing the boost to very so much on our cars. i guess at this time we need to talk with our tuning department!
 

·
Registered
Joined
·
2,000 Posts
Thats what I was thinking too. Time to ask the tuners on this. Hopefully one of the venders will chime in on this. Id like to leave the testing to the pros if I can.
 

·
Premium Member
Joined
·
2,020 Posts
Ok here is what they said. there is no rating for the 2 springs. the 2 springs we get is just a soft (green) and harder (yellow) no boost rating Some one already has a thread on this...but the kits they sell with the springs that are rated and shims to fine tune will not work on this BOV. but the concept is still true...by adding a small thin washer to the cup side of the bov where the spring is would make the green spring better...but we don't know what size washer ie shim will fit and we don't know if there will be any piston travel problems. in other words this would be a try it and see what happens type of thing. he did say that if the vacuum line comes from the intake to a solenoid than to the BOV that this could be the hang up. it would be better to run a straight line from the intake to the BOV...but this would take out any safety feature that gm may of built into the boost controlling side of the car. that solenoid may help with traction control and all so maybe what causing the boost to very so much on our cars. i guess at this time we need to talk with our tuning department!
Except for the shims, all of this info is here http://www.cruzetalk.com/forum/34-1-4l-turbo/10745-forge-bov-bpv-spring-selection.html. I was going to try the direct vacuum tap but I wasn't aware of what the consequences would be by bypassing the solenoid. I'd rather shim it if that will actually work.

I believe that Jerry had a bout with another member who was suggesting shims so I have a feeling that it might not be recommended. We could always send the spring to a spring manufacturer and have them spec out a spring that would work for us.
 

·
Premium Member
Joined
·
2,020 Posts
I just sent an email to an old friend who is an actual engineer. He knows a lot about springs. If I get a response, I'll post what he says. I asked him how we can test the springs, what affect shimming has on the life of the spring and where we can get a spring made up.
 

·
Registered
Joined
·
2,000 Posts
Thanks titan. A spring engineer is exactly what we need on this subject. Can the spring itself be altered im wondering, such as stretching it to loosen its strenth in the yellow spring?
 

·
Premium Member
Joined
·
485 Posts
Hey smorey did Forge recommend an tuning for are BPVs/BOVs from them?
On the product page it says "When installed on any GM vehicle to avoid the possibility of a P0101 trouble code the ECM must be reprogrammed with a tune optimized for atmospheric discharge. We recommend the tuning services of Trifecta Performance: www.trifectaperformance.com"
 

·
Registered
Joined
·
647 Posts
Discussion Starter · #13 ·
for the bpv no tune is needed. but for the BOV the ecp tune is needed cause of the mas air flow sensor setting a dtc.
 

·
Registered
Joined
·
647 Posts
Discussion Starter · #15 · (Edited)
sorry. now i understand. at this time they do not have a tunning kit for the cruze bov. but now that so many of us are looking for one they are looking into it but thats all...just looking. the tunning kits they do sell are for there bigger bov. infact the green spring and yeloow spring have nothing in common with there other springs. they do not follow there standred of the green good to 18psi yellow good to 25 and red good to 30. these 2 springs were mad just for the cruze bov.

he did say we could try to fit a shim in the bov but they did not know what the out come would be. they dont know if it would limit travel of the piston to the point that the bov would not work right. he more or less recommended that the vacuum line be run stright to the bov instead of to the solenoid than the bov.
 
  • Like
Reactions: Jnoobs

·
Registered
Joined
·
83 Posts
Or, unless you are past the limits of a stock bpv/stock bpv is leaking, you can just leave it alone since it works great OEM and make a "pshhshhhhhh" sound with your mouth every time you shift. Or get an intake and a tune. And avoid all of this headache...... just a thought.
 

·
Registered
Joined
·
354 Posts
I left the Green spring in my BOV, i can easily hear when it opens even at 6 grand. Im getting up around 22 psi and i assure you its not leaking untill you get a atleast a 3-5 PSI difference between PRE/POST throttle blade. I think the green spring holds pressure very well.

Remember that it only opens the BOV if there is pressure difference between the Intake manifold and the turbo. Otherwise there is an equal amount of pressure holding the BOV closed as there is trying to open it.
 
1 - 18 of 18 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top