what should vacuum be on stock L98?
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Supreme Member
Joined: Jun 2001
Posts: 3,175
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From: Bedford, Tx
what should vacuum be on stock L98?
what does the book say, and then what do most of you guys have? i remember mine being like 17 or 18 inches. also, could a vacuum leak make you loose some of your low end torque?
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- David
88' GTA 5.7L TPI MODS---> air foil, K&N, Shift Kit, 180* therm, TB bypass, Gutted CAT, Flowmaster 80 Series Muffler added to Unkown CatBack, Ported Intake
http://www.geocities.com/david_angel_16
------------------
- David
88' GTA 5.7L TPI MODS---> air foil, K&N, Shift Kit, 180* therm, TB bypass, Gutted CAT, Flowmaster 80 Series Muffler added to Unkown CatBack, Ported Intake
http://www.geocities.com/david_angel_16
Supreme Member
Joined: Dec 2000
Posts: 3,813
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From: California
That sounds good to me, plenty of vacuum to run. A bad vacuum leak(very bad) will cause your brakes to not work well because of a lack of vacuum for the booster. I had that one when I first installed my super ram.
As far as losing torque, there are much more obvious symptoms of a vacuum leak--such as a rough idle or even stalling. Spray carb cleaner or wd40 in a suspect area, and if your engine races at all, you have a leak.
What exactly is the problem, and what has been done recently?
As far as losing torque, there are much more obvious symptoms of a vacuum leak--such as a rough idle or even stalling. Spray carb cleaner or wd40 in a suspect area, and if your engine races at all, you have a leak.
What exactly is the problem, and what has been done recently?
Member
Joined: Oct 2000
Posts: 248
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From: nlr, ar
low mileage, proper tune engine 18-20" vacuum
high mileage, good tune 18-19" vacuum. vacuum
relation to low end is sorta related. check
to ensure your ignition timing is 6-10* with
the EST bypass disconnected. vacuum leaks tend
to induce more fuel than necessary. which will
effect the low end. do you have a loss or asking
to better your low end??
airdeano
high mileage, good tune 18-19" vacuum. vacuum
relation to low end is sorta related. check
to ensure your ignition timing is 6-10* with
the EST bypass disconnected. vacuum leaks tend
to induce more fuel than necessary. which will
effect the low end. do you have a loss or asking
to better your low end??
airdeano
Thread Starter
Supreme Member
Joined: Jun 2001
Posts: 3,175
Likes: 1
From: Bedford, Tx
well, over the past few weeks it feels like im loosing some on my low end, the umph just isn't there like it was before. and when it shifts into second and im still accelerating at about 1/4 throttle, i really notice a loss in low end power until about 2500. i recently ported the the walls in front of the EGR holes, and siamesed the walls in the plenum only (to get rid of the walls between the runners in the inside of the plenum), but i ran out of time and didn't get to do any work on the runners themselves. AND i am missing a bolt on the plenum, but i don't seem to be leaking air in, I NEED TO GET IT FIXED SOON. im wondering if maybe my TPS needs to be adjusted since i took my throttle body off. and i realized something wierd. before i took it off, the blades wouldn't open all the way horizontaly, you could look it. but once i took it off, i was playing with it, and next thing i know its open all the way.. i think i might have a missfire as the exhaust sounds kinda weird once i get in the higher RPMS. gonna replace the plugs soon.
------------------
- David
88' GTA 5.7L TPI MODS---> air foil, K&N, Shift Kit, 180* therm, TB bypass, Gutted CAT, Flowmaster 80 Series Muffler added to Unkown CatBack, Ported Intake
http://www.geocities.com/david_angel_16
------------------
- David
88' GTA 5.7L TPI MODS---> air foil, K&N, Shift Kit, 180* therm, TB bypass, Gutted CAT, Flowmaster 80 Series Muffler added to Unkown CatBack, Ported Intake
http://www.geocities.com/david_angel_16
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