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Discussion Starter · #1 ·
Hello, i tried looking thru post and couldn't find an answer.
What would be the best spring for QRJ BOV?
On green spring (3psi) it stays open on idle, on red spring (11psi) it barely opens when I let of the gas.
I just ordered the 8psi to see if its a happy medium. Any guidance? .
I dont care about sound, just care about possible issues w surge.
Thanks peeps
 

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Sounds like a similar puzzle I had to solve earlier this year with my Tial Qs. You'll need to measure the vacuum of both hoses going to the BOV to see how strong the spring needs to be before the piston starts to crack open then install a slightly stronger spring if you want to keep it closed at idle but not too strong where it'll still be responsive enough in part throttle situations. My vacuum measured -36 cmhg which is -6.97 psi and went with an 8 psi spring. Your vacuum will vary depend what you've done to the car.
 

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Discussion Starter · #3 ·
Sounds like a similar puzzle I had to solve earlier this year with my Tial Qs. You'll need to measure the vacuum of both hoses going to the BOV to see how strong the spring needs to be before the piston starts to crack open then install a slightly stronger spring if you want to keep it closed at idle but not too strong where it'll still be responsive enough in part throttle situations. My vacuum measured -36 cmhg which is -6.97 psi and went with an 8 psi spring. Your vacuum will vary depend what you've done to the car.
Thanks for the reply brother. Once I install the 8psi spring ill verify again and update w current mods. Seems like there's not a lot of info out the for the QRJs :(
 

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I just switched to the 8psi spring and I did notice any difference in sound when letting off the throttle. Maybe my exhaust is too loud.
 

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Discussion Starter · #5 ·
Does the BOV stay close at idle? The 11psi are too stiff, it barely opens and im just worried about back pressure/ surge. I just got my 8psi spring. Hopefully they are good to go
 
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