I've just fitted a boost gauge onto a UK MY95 and I'm a bit confused by the readings I'm getting.

With the engine off the gauge read zero. At idle I seem to get a vacuum and the gauge reeds negative (about -5 psi I think). On full throttle I get about 5psi.

Have I connected it up correctly and should I be getting a -ve reading at idle? Should I adjust the gauge so it reads zero on idle but +ve when engine is off?

Please help me!

Cheers,

Andy

 

dont adjust it!!
the gauge will always read -ve at idle as you're not boosting!!
from what you've said eveything appears normal
alyn - as performance

 

Surely a reading of 5psi on WOT is rather low ? I would've expect it to be showing around the 1 bar/14 psi region.

It should be showing negative pressure at idle, though.

 

IIRC the boost on an old UK Scoob should be approx 12 PSI on WOT. 5 or 6 indicates the boost solenoid or the MAF sensor could do with cleaning. (You can use spray brake cleaner - search for more detailed instructions using the BBS search function.

 

Ummm just a thought....

You don't mean "full throttle" stood still, not in gear, not going anywher do you. i.e just revving it up ???


Andy

 

On my MY93wrx, my boost gauge shows 0 when the gauge is switched off...this is because the engine returns to atmospheric pressure when the engine is switched off.

At idle, there is a vacuum, and mine shows -0.5bar approx, and then up to 0.8bar at full boost.

Conversion 1bar = 14.5psi

for reference ...im totally std

 

Thanks for info guys - just what I needed to know.

Yes, I'm only getting about 5-6psi on WOT 3rd gear above 4,500rpm. In fact Í've only just got it back after a clutch change and intermediate service. Felt a bit 'flat' since getting it back and I've had a boost gauge sitting in the garage so I thought I'd fit it.

Before the service it seemed to be pulling well, so I think it would have been making full boost. Do you think it's anything they could have knackered during the service? i.e. MAF, etc?

Might an ECU reset help things?

Cheers,

Andy

 

Thanks for info guys - just what I needed to know.

Yes, I'm only getting about 5-6psi on WOT 3rd gear above 4,500rpm. In fact Í've only just got it back after a clutch change and intermediate service. Felt a bit 'flat' since getting it back and I've had a boost gauge sitting in the garage so I thought I'd fit it.

Before the service it seemed to be pulling well, so I think it would have been making full boost. Do you think it's anything they could have knackered during the service? i.e. MAF, etc?

Might an ECU reset help things?

Cheers,

Andy

 

Check they havnt overdone the oil level,if so drain some out then clean the boost solenoid

 

Checked the oil when warm (not hot) and it looks marginal. Is it really sensitive to overfilling?

Stupid question - but how do I lower the oil level? Just drain through sump plug?

Cheers,

Andy