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Boost/vacuum leak
Posted: Mon Apr 08, 2013 5:39 pm
by mcmental
Well I've just fired up the twin turbo up and it's ticking over nicely,I was just watching the boost gauge and I noticed it was at -5 on Rickover but built up as I revved it, is this normal or have I got some leak somewhere???
Posted: Mon Apr 08, 2013 7:39 pm
by DEVONMAN
There are 2 types of boost gauges.
The first type reads manifold vacuum as well as manifold pressure as the boost builds up. This type is normally connected to the inlet manifold and usually won't show any boost until the car is on the road with the engine under load. At tick over it will show vacuum.(manifold depression) like a normal vacuum gauge and when the engine is stopped it shows zero.
The second type just measures boost pressure and is usually connected to the inlet system at a point where no vacuum ever exists.
Regards Denis
Posted: Mon Apr 08, 2013 9:09 pm
by mgbv8
Mine shows vacuum at idle. And will only show a touch of boost if I rev it hard and quickly. But when under load the bosst registers quick quickly.
As Denis says. Its normal to see vac at idle if you are reading from the inlet manifold.
Posted: Tue Apr 09, 2013 5:18 am
by mcmental
Aha,thanks for that.