What boost in psi?
21 April 2004, 06:54 PM
#1
Scooby Regular
Thread Starter
Join Date: Mar 2004
Location: Swindon
Posts: 400
Likes: 0
Received 0 Likes
on
0 Posts
What boost in psi?
Hi all
Have just fitted a boost gauge that reads in psi.
When i took it for its maiden voyage, acc in third it read 14psi into 4th it read about 12psi and fith, well i had to come off boost coz i was going to fast!
I have a 1993wrx but have just fitted a 1995 wrx Ra ecu. What boost should i be reading and when i install my Dawes device, what should i set it at at a safe max?
Oh just quickly. What does the vac bit mean on the gauge. Mine sits at vac 20psi on idle
Many thanks
Johnny
Have just fitted a boost gauge that reads in psi.
When i took it for its maiden voyage, acc in third it read 14psi into 4th it read about 12psi and fith, well i had to come off boost coz i was going to fast!
I have a 1993wrx but have just fitted a 1995 wrx Ra ecu. What boost should i be reading and when i install my Dawes device, what should i set it at at a safe max?
Oh just quickly. What does the vac bit mean on the gauge. Mine sits at vac 20psi on idle
Many thanks
Johnny
21 April 2004, 07:24 PM
#2
Scooby Regular
iTrader: (2)
Join Date: Dec 2002
Location: All over the place, trying to stop putting the miles on!
Posts: 1,197
Likes: 0
Received 1 Like
on
1 Post
Hi Johnny
Glad to see you've got the guage in, i installed mine yesterday as well.
Don't know what the stock boost is supposed to be on a 1993 WRX.
However the vac is bit is not in PSI, if you look carefully at the bottom left of the guage it says the callibration is in Hg.
Can't remember at the moment what that stands for but it's nowhere near as much as 20psi. There is a vac reading on most boost guages because before the turbo spools up it is actually acting as a blockage in the air inlet of the engine, and as the engine sucks air in it forms a slight vacume until the exhaust gasses can spin the turbo up. Things like the type of air filter and the length of your induction tract can also effect the ammount of vac you get before boost.
In an ideal world of course there would be no vaucume because there would be a trumpet on the turbo sticking out of the bonnet into perfectly comtaminent free air!
Dan.
Glad to see you've got the guage in, i installed mine yesterday as well.
Don't know what the stock boost is supposed to be on a 1993 WRX.
However the vac is bit is not in PSI, if you look carefully at the bottom left of the guage it says the callibration is in Hg.
Can't remember at the moment what that stands for but it's nowhere near as much as 20psi. There is a vac reading on most boost guages because before the turbo spools up it is actually acting as a blockage in the air inlet of the engine, and as the engine sucks air in it forms a slight vacume until the exhaust gasses can spin the turbo up. Things like the type of air filter and the length of your induction tract can also effect the ammount of vac you get before boost.
In an ideal world of course there would be no vaucume because there would be a trumpet on the turbo sticking out of the bonnet into perfectly comtaminent free air!
Dan.
27 April 2004, 03:28 PM
#3
You'll get a vacuum from the pistons sucking air in against an almost closed throttle.
it reads in mmHg, which is millimeters of mercury, 20 is ok for idle, it should come down to about 25 on the over-run.
Dave
it reads in mmHg, which is millimeters of mercury, 20 is ok for idle, it should come down to about 25 on the over-run.
Dave
Thread
Thread Starter
Forum
Replies
Last Post