Thread: Vac

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CAN I TEE OFF THE BACK OF MY 3310 FOR BOOSTER AND PCV AND THE BACK OF THE INTAKE THERE IS A SMALL VAC FITTING I GUESS I SHOULD RUN MODULATOR VALVE TO IT VAC ADVANCE TO PORTED FITTING ON THE SIDE OF THE 3310 THEN I JUST NEED TO PLUG VAC PORT AT THE FRONT OF CARB AND I SHOULD BE ALL SET I HOPE HEY JOHNNY CAN YOU GIVE ME SOME ADVICE ON THIS THIS IS HOW IT IS DONE RIGHT NOW NEVER FIRED MOTOR YET MY 55 IS ALMOST DONE MOTOR HAS BEE BROKE IN ON THE STANDNOT IN THE TRUCK...THANKS FOR ANY INFO ON THIS.......

Originally posted by short step
CAN I TEE OFF THE BACK OF MY 3310 FOR BOOSTER AND PCV AND THE BACK OF THE INTAKE THERE IS A SMALL VAC FITTING I GUESS I SHOULD RUN MODULATOR VALVE TO IT VAC ADVANCE TO PORTED FITTING ON THE SIDE OF THE 3310 THEN I JUST NEED TO PLUG VAC PORT AT THE FRONT OF CARB AND I SHOULD BE ALL SET I HOPE HEY JOHNNY CAN YOU GIVE ME SOME ADVICE ON THIS THIS IS HOW IT IS DONE RIGHT NOW NEVER FIRED MOTOR YET MY 55 IS ALMOST DONE MOTOR HAS BEE BROKE IN ON THE STANDNOT IN THE TRUCK...THANKS FOR ANY INFO ON THIS.......

you can not tee into the brake booster or the pcv system vac hoses. run a separate hose to each one.

Why cant you Tee off of those lines? I have done it with not problems that Im aware of. Not saying you're wrong, but I never heard that before. Im just saying that the vacuum source all comes from the same place, right?

there is a vac. on the brake booster all of the time. your pcv system is open, so if you tee your brake booster vac. hose into your pcv system then you wont have any brake booster. you cant tee your brake vac. off of your pcv hose, it wont work. i've never seen a brake booster vac. hose teed into a pvc vac hose.

this is what im talking about you cant do, in case we are talking about 2 dif. things.

I have a 86 gmc 2500 with the pcv and the brake booster runing off of the same source after a put a holly carb. I just ran a large size hose from the pipe fiting behind the carb to the tee, as to not create a restriction. I have had no problems for a year and a half with full braking or blow by

The PCV valve is not just a open vac hose (if it was it would create a vacume leak condition) there is a plate that is held closed by a spring that opens and closes rapidly to maintain a restriction and there for steady vacume

thanks guys i kind of figured it would be ok to tee off the back of the carb to both booster and pcv

I see what you're saying Mike, but that's the way mine is hooked up, and I have plenty of brake boost and everything works fine. I dont know!

a pcv system is a big vac. leak, if it could pull the brake booster down then it couldn't be sucking the fumes out of the oil pan at the same time. the brake booster has to have a constant vac. on it to work and a pcv system is not a constant vac. it can not pull the brake booster down and suck the fumes at the same time. i dont know what you're doing, but something ant working right. you cant tee nothing into the pcv hose but, you can the brake booster hose. if your hoses is run like that diagram looks, you wont have proper brakes.

right off the back of carb not like the picture run small piece of hose off of carb add a tee run one side to booster other to pcv

i agree you can hook it up that way, but you brake booster is not gonna give you the assist that you need to be safe. i.ve hooked them up that way and it didnt work for me.