I have recently bought a saph cossie and fitted a boost gauge the thing is should the gauge read -9psi on tickover?

 

yes

 

Unless it has Anti Lag, then yes it should

More importantly though, what psi does it show on full throttle ?

10psi if standard, 15psi if stg1, more if stg2, 3 or above.

Depending on it's service history it may be worth having it checked by someone in the know to make sure everything is in order (not that anything suggests it isn't, just a suggestion )

Hope you enjoy her, had mine over ten years, and still love the drive to work every day

 

this is the problem the car did boost to 30psi when i got it 2 months ago now i only get 20psi or so but sure the gauge read 0psi on tickover when it produced 30psi could the previuos owner tricked the boost gauge somehow? but the car did feel faster then but as everyone knows you get used to the power quite quickly thanks for the help so far

 

Best thing to do, is to get it checked with someone who has accurate gauges and knows what he's doing

Aftermarket gauges are great, they're better than the ones ford put in the car, but not necessarily very accurate.

For a specialist, check my sig and the middle link (MADevelopments), not too far from you in berkshire

 

WAHAY!!!!!!!!!!!!!! 30psi again

washed the air filter
changed dump valve (slightly leaking)
fixed air leak on the intake plenum
me beast is back, 427bhp of pure rush
better than drugs safer than sex long live the cossie!!!