well about 3 weeks ago i switched to richmans non seq setup, removed air pump, works good, no boost issues anymore, just curious before going non seq my vac was aprox 19in at idle 800-1000 due to no air pump running a bit rich, no pfc yet, after non seq completed i'm seeing around 13in vac at idle, is this normal? i have removed all solenoids/vac chambers, car runs fine, boosts good, even good compression, just curious if anybody with non seq has seen this?

 

The vacuum should be the same as before unless you have a leak .If your compression is the same and the car is leak free and the idle is set up the same then the vacuum should be about the same . My Rich Mans modification involves alot of welding,over 1 1/4 lbs of welding rod and a great deal of reshaping ,porting and blocking ports ,and reworking the rear Y pipe . All four cast hot parts are worked on ..After all of this work the flow and spool up is better and the vacuum should be as high as before .

 

Do you have a stock or chipped ECU? If so, if you remove the air pump, the car will idle rougher and have rougher on/off throttle. The ECU is expecting air pump air to fudge the O2 sensor's numbers and compensates for it. Take that extra air away, the fudge goes the wrong way, giving rougher idle, lower vacuum, etc.

Only real fix for it is to either put the air pump back on or get a PowerFC that will let you disable O2 feedback.

Dale

 

still stk ecu, boost turned down until i install pfc. idle is a little rough due to no air pump, not really worried about rough idle as it will be snowing here in 2 months & it will be parked. then it gets pfc, rebuild etc......... definetly no vac leaks. is there anyway to verify good vacuum at a diferent rpm? would it be accurate to compare it at say 2000rpm or 3000rpm. if so does anybody know there readings at a certain rpm? this is really not life or death as i will be rebuilding soon anyways, just curious, also can't remember vac readings before non seq with air pump removed & lumpy idle. thanks