Boost/vacuum leak

mcmental · Post by **mcmental** » Mon Apr 08, 2013 5:39 pm

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???

DEVONMAN · Post by **DEVONMAN** » Mon Apr 08, 2013 7:39 pm

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

mgbv8 · Post by **mgbv8** » Mon Apr 08, 2013 9:09 pm

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.

mcmental · Post by **mcmental** » Tue Apr 09, 2013 5:18 am

Aha,thanks for that.