Boost gauge readings ( aftermarket / exact figures )

[#mechanic]

CAN ANY BODY TELL ME WHAT THE NEGATIVE VACUUM IS.... opps soz about caps...


so what im after is the negative vacuum reading?

now i have search and cant find much that relates to neg vacuum every one wants to know what the boost is though

 

[PobodY]

I'm not sure I understand the question. - Negative vacuum is boost, surely? (Double negative makes it positive.)

 

[bfc10]

Mine sits about -500 mmhg negative vacuum on the standard gauge at idle if that is what you are asking?

 

[fubar andy]

Would that mean if the negative pressure was say -250 on tick over/off boost there maybe a boost leak?

 

[bfc10]

Yes Andy, mine was at -400 and put it on smoke leak tester machine and found about 3 pipes leaking, replaced them and it went down to -500 I don't know if that is the lowest it will go though???

 

[fubar andy]

Well that's another thing I'll be doing while the engine is out, hopefully that'll bring the idle down too... :hide:

Cheers

(sorry for hijacking original post!)

 

[PobodY]

Ah ha! - I think I'm at about -0.3bar at idle, but if I lift when driving that drops to -0.8bar.

I'll double check that today.

 

[pulsar kid]

mine with forge fmic, sits at idle when hot -600mmhg, that sound about right?

 

[#mechanic]

Opps should have been a / in there maybe .....

Yes so I am after the vacuum reading, so much frustration at mo, not getting good servo assist and I'm only seeing maybe 100mmhg at cold ilde get tops 280 shit brakes and fast ilde... Looks like I'll be sticking the smoke pro on it at the weekend
thanks for the figures though people

 

[PobodY]

Not been driven in a while? - Mine was doing this before the MOT, but with a bit of use the brakes came good again.

 

[#mechanic]

It was off the road for over a year they replaced the servo and master because brakes where bad...
Sat with no brake fluid in it with an open system grr! Still I've overhauled the master and vac tested the servo they are all good the front caliper slides where seized solid as you drive it it get better but never more that -300 first start up idle it's -100 if I'm lucky, revs sit around 1200 but now the rev gauge has failed fml