Blowoff valve spring pressure

[Bow]

Morning folks,

now I finally have my turbo bandit up and running, having an issue with the BOV chattering all the time.  So know the spring pressure is way to low.

Do any of the wise ones have any idea of the vacuum inHg on a bandit 1216 motor on tickover ?

I don’t have a gauge accurate enough to measure it.

Looking to install a correct pressure spring,  rather than stabbing in the dark.

TiAl Q50 BOV copy,as fitted by Loopie when we built the kit.

[Gixer1460]

I would asume you have access to vacuum gauges to set up your carbs? These should have the resolution you need, then follow . . . . . 

[NipsuGoesRace]

Idle 70-75 kPa or -9 to -7 inHG

Cruise 85-90 kPa or -4.5 to 3 inHG

Engine braking below 60 kPa or -12 inHg

[Bow]

Thank you guys,  that’s precisely the information I needed.

went over the unit this afternoon and measured my inlet vacuum,  comes out at -8 inHg,  so going by the calculations, I need to purchase a 6psi spring.

@Gixer1460,  that TiAL info sheet is extremely helpful,  and I’d not even thought of using my vacuum gauges,  blinded by posh individual gauges I’d been looking at   thank you .

[Gixer1460]

Sometimes 'we can't see the wood for the trees!'