View Full Version : Is this low vac.?

04-26-2003, 10:58 PM
I just picked up a 90 anniversary car which seems to run just fine, but i kindof think there is something goofy with the vacuum with it. On the stock guage, and idle, it pulls about half way between 10 and 20. Shouldnt this pull more towards 20?? Also when im traveling down the highway around 70-75 it says im almost not pulling any vacuum, like only 1 or 2". This doesnt seem normal to me. Could this be part the car maybe having a boost leak problem? Thanks For the help

04-26-2003, 11:01 PM
not sure about when driving. at idle it should be at 18-20 in-hg. what is your max boost psi?

04-27-2003, 12:09 AM
my 35th at idle sits just a hair bove 20 in-hg...i was told it was normal for stock cams...but my max boost is 13 psi....

04-27-2003, 12:30 AM
i get 24-25hg of vaccum at idle the only time i had 20hg was at 4200ft

04-27-2003, 01:38 AM
wow, 24-25? why so much? mine has 19 in-hg and 16 psi max boost. i have a stock guage and it goes just past the last line were 16 would be.

04-27-2003, 02:01 AM
Do you get about 13psi on the boost gauge when you get on it? If it is lower then the line that runs from the lower mnifold adapter to the boost gauge probably has a crack in it.