snk-huntr

iTrader: (2)

I have a 94 firebird with the lt1 and was wondering if any one knew how much vacuum it should have? Wedone a vacuum test on the intake and it was around 16 inches of vacuum, is this right? When we snapped the throttle it went to zero up to 25 and back to 16. Any help greatly appreciated. Thanks

Ralls

iTrader: (32)

16 is low. You want 19-21 inches of mercury. Your snap acceleration is correct. It should bounce off zero then go around 25. Decelerating gives you the most vacuum than anything (good gas mileage).

16 is something minor like a leak somewhere. If you have large spark plug gaps or bad wires, you will also get low vacuum, but usually lower than 16.

the_merv

iTrader: (88)

Yea, I got a Cam, and it's steady at 17". Check your Vacumn lines.

maybe2fast

iTrader: (4)

how does the car run?

C_Rules

iTrader: (7)

how do you check vacuum. ever since i got the new cam i think im a lil low on vacuum.

Ralls

iTrader: (32)

Hook vacuum gauge to any vacuum feed off the intake manifold. I would do the one going to EGR Solenoid. Get car fully warm and check it.

C_Rules

iTrader: (7)

how much vacuum should you have if you have a cam in between a cc305 and cc306 with ll emissions equipment deleted?

96capricemgr

iTrader: (1)

That is nowhere near enough info for anyone to guess.

C_Rules

iTrader: (7)

is there a range that i should be aiming for? or a number that would be considered low?

SincalT/A

iTrader: (16)

At about 12 in.hg. you lose power brakes.So it would be wise to stay above that.

brickonwheels

iTrader: (6)

yeah, i'm at 10 inches of mercury, and my brakes suck compared to stock.

Magna5.7

Most cars are happy in the range of 20 or so cams definetly bleed off alot of vac. As do minor leaks. If you go much lower than 15 or so you will have a definate laopy idle. wich you can fix by ignoring/enjoying it or turning up the idle speed . The power brakes stuff is good info but wouldn't a vac canister help in that situation?

kinglt-1

iTrader: (26)

stock lt-1 should see 18-20in of vacum. My car sees about 16 on cold start and 18 when it's up to temp. I would say your on the low side, check all vacum lines and inspect for cracking or dry rotting.

SincalT/A

iTrader: (16)

Most guys here Do not run canisters because.1 its just more money.2 There's not alot of room in our engine bay to be adding more parts.3 If you car has that low of vacum there's probably somthing wrong with it i.e tunning,vacum leak,etc. 4A cam with that much overlap to cause low vacum probably is not optimal for your setup.So why crutch the problem?