Blow off valve spring PSI

[Gazski66]

OK, I have been looking at uprated springs for BOV, now my question is the springs are set for different PSI.....
How can I find out what I need?
I have now got my uprated BOV (06F 145 710 G) but cant work out what spring would be best or stick with the OEM spring.
Any views and thoughts please

[Chris_Blue]

Is Jamie not sorting u out Gaz? If you look at Jamie's build post, he says %25 stronger, which would tally with %25 increase in boost

[Gazski66]

Is Jamie not sorting u out Gaz? If you look at Jamie's build post, he says %25 stronger, which would tally with %25 increase in boost

he is getting some springs made but trying to figure out the PSI thing

[Chris_Blue]

All to do with boost pressure increase
On the catch can bit, myself, still. Lol

Stronger spring - you will notice the lag if you need one

[cyclone]

Is Jamie not sorting u out Gaz? If you look at Jamie's build post, he says %25 stronger, which would tally with %25 increase in boost

Changing the spring in the bypass valve will not give any more boost. The amount of boost is regulated by the waste gate which when open lets the exhaust bypass the turbo so it can only produce so many PSI. If your stock recirculation valve was leaking because it was unable to hold closed under the increased psi of a mapped engine then it would give you back the pressure that you are loosing. The stronger spring would also close the valve quicker keeping more boost pressure and allowing you to start building pressure sooner after the valve closes.
Did not say that well but then I am not good at explaining things.

[lfcrule1972]

Clear for me, thanks cyclone

[Chris_Blue]

Sounds good Cyclone. What I meant was if your turbo is boosted by %25, then the spring needs to be %25 stronger- to slam the door so to speak.

[Superfly Guy]

Sounds good Cyclone. What I meant was if your turbo is boosted by %25, then the spring needs to be %25 stronger- to slam the door so to speak.

If you installed bath taps with a 25% higher flow rate and a plug hole 25% bigger, would the bath fill and empty proportionately quicker.

[Jamie@SPTuning]

U guys don't understand how these recirc's work.
If you've ever handled one of these springs you'll already know that they're not very strong, certainly not strong enough to hold back 1000 mbar of boost(1350mbar in my case). Even the uprated spring is not much stronger than of that in a Biro.
So....how does it hold back the pressure???? Can anyone work it out???
Look to the picture below at the plungers design and you might be able to work it out

I'm beginning to sound like Czar lol



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[Chris_Blue]

Count me out as I'm learning all the time.
Wild guess- A piston inside pushing out?

[colganraz]

high pressure on top of the plunger, creates a low pressure area on the underside of the plunger resulting in lift, like an aeroplane wing. guessing here but im defenaitely thinking pressure/vacuum is somewhat involved!

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[Gazski66]

U guys don't understand how these recirc's work.
If you've ever handled one of these springs you'll already know that they're not very strong, certainly not strong enough to hold back 1000 mbar of boost(1350mbar in my case). Even the uprated spring is not much stronger than of that in a Biro.
So....how does it hold back the pressure???? Can anyone work it out???
Look to the picture below at the plungers design and you might be able to work it out

I'm beginning to sound like Czar lol



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This is why u are the tuner and I am not lol, any news on the springs Jamie?

[Jamie@SPTuning]

Think, if you had let's say 1000mbar boost of pressure trying to lift the valve of its seat, how much pressure would you need to keep it sealed???
The spring is only rated to 1" of compression with 1lb of load. So nowhere near enough force to keep it closed.



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[cyclone]

read this explains it well unlike me. http://blog.perrinperformance.com/al...-recirc-valve/

When the equalizing force of the pressure signal cancels out the boost then it is the wee little spring that provides the overcoming force to close the valve. With the electro valve to open it or in a normal blow off valve the pressure now turned vacuum signal line with closed throttle.

[Jamie@SPTuning]

Yes that's right...a nice description you found there cyclone, saved me typing it up
The Alta valve looks worthwhile testing as well.



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