Chap I've been chatting to is having issues with itbs.
He's got a reading of 14kg at 800rpm
What would cause it to be so high?
He's running Jenvy on a silver top zetec
I wouldn't worry about what the reading is as long as each cylinder is roughly the same. But high vacuum is a sign of a strong engine with no air leaks
Are all 4 tb's the same?
Could be they need balancing. If the one he's taking the reading on has the throttle closed off more than the rest, it'd give a high reading.
If they're all the same don't worry.
It depends where the vacuum is being measured. At idle the throttle plate is almost shut so downsteam of the throttle plate is naturally a high vacuum
as the engine tries to draw in air past the throttle plate. A distributor vacuum take off is positioned just by the throttle plate so sees a low
vacuum at idle and then the vacuum goes up as the throttle plate moves off idle.
High vacuum is what you would expect at idle.
My 2ltr turbo has vac levels of 20-30kpa (absolute) at idle.
[Edited on 23/4/21 by coyoteboy]