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BOV Spring PSI??

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Old 04-30-2008, 12:51 AM
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Default BOV Spring PSI??

got most of my OFI kit today. must say...awasome work

i was going threw all the boxes and foud my BOV. on the side is said PSI 11...i have a stock lt1 and dont plan on running more then 7psi ish.

does this mean i need to find a new spring for this(and probly the waist gate as well?) or how does this work exactly...im still pretyt new to all this. i read a lot on here, turbomustangs and good ol google

thanks

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Old 04-30-2008, 01:07 AM
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wastegate controls psi not BOV the spring in the wastegate will be what psi u see at the motor maybe 1 to 2 pounds less depends on intercooler and what not.
Old 04-30-2008, 10:30 AM
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Can you tell us what type of BOV you have? Is it adjustable?
Old 04-30-2008, 12:00 PM
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I will be watching this thread , i understand his question if he is only running 7 psi what pressure should the BOV be set to release pressure ???
Old 04-30-2008, 12:01 PM
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The spring in the blow off valve is not related to boost but more to engine vacuum - the stiffer the spring (11psi) the harder it is to open to BOV and let the boost out.

We find that 11 is a little on the stiff side for an LS1 (LT1) - you can just switch over to the Tial 7 psi spring and it will be ok. What I normally recommend is to install it on the car with the 11 and see if the valve flutters at idle...if it opens and closes rapidly with small revs, leave it. If it never opens, switch to the 7psi spring.
Old 04-30-2008, 12:48 PM
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Originally Posted by 70Stang
The spring in the blow off valve is not related to boost but more to engine vacuum - the stiffer the spring (11psi) the harder it is to open to BOV and let the boost out.

We find that 11 is a little on the stiff side for an LS1 (LT1) - you can just switch over to the Tial 7 psi spring and it will be ok. What I normally recommend is to install it on the car with the 11 and see if the valve flutters at idle...if it opens and closes rapidly with small revs, leave it. If it never opens, switch to the 7psi spring.

so the BOV is opened by vaccum?? makes sense now that i think about it on decel eng goes to vaccum opens BOV and allows press to escape, jump back into boost and BOV is closed. cool thanks for the advise.
Old 04-30-2008, 01:30 PM
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You got it
Old 04-30-2008, 09:14 PM
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Why would you not drop to the 9psi instead of going directly to the 7? I am trying to decide which one to order with mine and was thinking 9.


Originally Posted by 70Stang
The spring in the blow off valve is not related to boost but more to engine vacuum - the stiffer the spring (11psi) the harder it is to open to BOV and let the boost out.

We find that 11 is a little on the stiff side for an LS1 (LT1) - you can just switch over to the Tial 7 psi spring and it will be ok. What I normally recommend is to install it on the car with the 11 and see if the valve flutters at idle...if it opens and closes rapidly with small revs, leave it. If it never opens, switch to the 7psi spring.
Old 05-01-2008, 01:18 AM
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i thought the BOV was pushed open buy a build of pressure, not pulled open????

ill get betetr pictures 2morrow as im planning on mocking it up.

what would little revs be? *into boost. to zero vac. less vac then idle*

if it opens at vac...wouldent it be open all the time at idle then?
or dose it just..."soffen" up the spring so that it is opened with less work?

i know the wastegate controlls boost psi...i still havent gotten that, so that will be another fun thing to try and find a new spring for if its not 6-8psi



another question...being as the flanges as thinner then the stock manifolds. what do guys with headers / turbo builds use..do you keep the support bracket for the alt on the passnegers side, first bolt at the front of the motor?.. was looking at it last night and it dosent look like the stock ones will work..ill try 2morrow tho
Old 05-02-2008, 05:43 AM
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I haven't read too much of your build other than the stock block on the LT1. Based on 12 years of driving, maintaining, racing LT1s of mine and a large part of the Houston Fbody group, I'll just beg you to at least use a methanol kit of some sort to help save your pistons. Both my own power adders and buds of mine have cracked the stock pistons within months of installations. The pistons are brittle and it just doesn't take much detonation to lose a ring land or two. I really like the OFI kit's look. Top drawer stuff there. I didn't read what brand of BOV you have. I have the Turbosmart Megasonic.



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