You need to know the 0.050 duration and the Lobe separation to give an idea of vacuum. the tighter the LSA the more the intake and exhaust is open together and dropping low speed vacuum and compression.
Vacuum Requirements
- Thread starter mashud46
- Start date
So I would need a canister with one input and 2 outputs? Or put a Wye in going to the booster and split off to the multiport?
You could do a "Y" or "T". I just like using two, I like the minimalist under hood look. So I would have 3/8 going to booster and the smaller going to other side for AC and under dash vacuum actuators and the switches, and then a "T" for the carburetor or any emission controls or EGR in use.
Thats not that bad of a cam. What is the initial timing of the engine? Can you shoot for 16-18 degrees initial and control the idle speed with the timing? If you can get the idle speed up by raising the initial timing, you can close down the throttle blades on the carb to maintain the idle speed you want and effectively create more idle vacuum as it pulls through a smaller restriction of the carb.
I don't mean to hijack the thread, but this info is helpful to the op, at least in principle.
Initial is 14°. 36° all in by 2700. 8° of ported source vacuum advance. Runs well, runs strong. Doesn't kick back on startup, doesn't audibly ping on 91 with 9.5:1 (probably closer to 9.2 actually). Brakes work as normal in stop and go traffic. Which as I said is at least in my experience 10-12" is the safe minimum for vacuum brakes to work effectively.
My cam specs for funzies:
Got the part number confused for duration.
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Looks like good cam. Basically anything under .500 and stock springs not a problem. Where you get up to 1.6 ratio getting near .520, you got to be careful with stock and you need to go screw in studs near that spec.
that was the goal. i've got comp 980 springs, guides cut down for positive seals, stock rockers and pushrods. with stock heads, this is the biggest (probably should've gotten a cam one or two models lower tbh) cam i can use.
Put a GAUGE ON IT AND SEE HOW MUCH YOU ARE MAKING PRESENTLY. ANYTHING BETTER THAN ABOUT 14" IS USUALLY GOOD ENOUGH UNLESS YOU ARE IN STOP AND GO TRAFFIC WHERE YOU COULD DEPLETE THE VACUUM QUICKLY. WE USE A FAIRLY STOUT CAM IN OUR 383 AND STILL GET5 BY ONLY USING AN AUXILIARY RESERVOIR. THEY ARE INEXPENSIVE AND IF IT ISN'T ENOUGH, THEN GO TO A DIVORCED PUMP SETUP. ONLY REASON I HAVEN'T USED ONE OF THOSE IS WE DON'T NEED THE EXTRA WEIGHT IN THE CAR. i DO KNOW PEOPLE WHO USE THEM IN STUFF SO RADICAL THEY SOUND LIKE A FUEL; CAR WHEN THEY IDLE. YOU WILL KNOW IF ONE IS NECESSARY IN YOUR SETUP BY BRAKING AND THEN BRAKING AGAIN SEVERAL TIMES QUICKLY IN SUCCESSION SO AS TO DEPLETE THE BOOSTER. YOU SHOULD NOT END UP WITH A HARD PEDAL WHILE DOING THAT.
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