shaun8850

So I have an H/C/I setup, all Trickflow.. I have a S/C pushin 8psi...My problem is that at idle I am only pullin 6-8 HG (cold idle) warm idle I get only 10HG.. If i put a canister on it will that increase my vacuum at idle.. A tech was saying it wouldn't I need a Vacuum Pump.. I have looked for any possible vacuum leaks with no such luck.. Also why is it that when I am driving say 1800-2000 RPM my gauge reads 20HG of vacuum?

Also anybody with a S/C...have you experienced a drop in boost pressure at very top end of RPM?

I need to fix the surging idle. I have new IAC, EGR delete, I have done all the tests, TPS volts ok, reset base idle, etc... So if anyone has some input please share~

mjr46

what cam do you have in it??

shaun8850

TFS-51402000

See I thought it was a mild cam, 499 Intake 510 Exhaust.. Didnt think the cam would effect the vacuum that much..

mjr46

your valves may be adjusted improperly or other things if bottom end is worn faulty rings can cause issues.....read this article it will explain all about vaccum related probs and cause and effect relationships
http://www.atlanticz.ca/zclub/techtips/vacuum/

shaun8850

Well I hope that isnt the problem... I have a fresh balanced 306, I think I am bringing it to work and putting a Fogger on it to see if im missing a leak..Cuz I couldnt find anything..

mjr46

then I doubt the ring issue is prob....but good idea to do the smoke test..we have such a machine and cuts troubleshooying down to next to nothing when trying to eliminate vaccum leaks

Joel5.0

Anything below 13" Hg. with a Stg 1 in your setup = something mechanical is wrong..... second Mjr's suggestion to revisit the valve train.

shaun8850

the heads came setup..would roller rockers get loose and do that? Or do I have to bring the heads to a machine shop?

projectresto83

Make sure your pushrod length is right and your rockers are torque correctly

TrickFlowTech

I agree with this. It sounds like the valve adjustment is off. You should have plenty of vacuum with that combination.