boost gauge help

[wolfie1981]

i have just installed a boost gauge in psi.. now when the car is off the gauge sits at 0
 when i start the car the gauge reads -28 vac is this correct???
 when im driving im getting 8/9psi boost when i take my foot off the gas i get -30 vac
 im not sure if this is correct any help would be great

my car is vw golf gti 1.8t 2000 model agu engine
piper decat exhaust / k&n induction kit / blitz dump vavle if this helps

[rio_gti]

im sure it should read 0 when off and alspo not boosting...........

[wolfie1981]

your saying it should read 0 also on idle that dont seem rite mine sits at -28 vac

[tokemk4gti.t]

if its teed into the fpr there will be vac on idle and when you lift off thats how its works mines on -22 though not sure how much it should be but mine boosts to like 16-18 psi you had a remap?

[wolfie1981]

no remap as yet but soon will have. the gauge is only a cheap one so this maybe why reading so high ??

[Wayne]

Those figures are correct

[wolfie1981]

which figures?? mine of -28 or his at -22 lol

[JimBR]

-28 with your foot off the accelerator whilst driving. -20(ish) on idle. 8-10 on boost when standard. 0 with the engine off.

[wolfie1981]

so your say 20 (ish) so what could be wrong with mine sitting at -28 on idle could it be the cheap gauge

[Wayne]

so your say 20 (ish) so what could be wrong with mine sitting at -28 on idle could it be the cheap gauge

Yes cheap gauge, mine is 0 switched off but drops when started.