Hello,
I got a 95 F-150 w/ a 351W E4OD with a Vortec V-1 gearcharger. I bought this truck a year ago with all of these things already installed. Well, since this supercharger is geared up from the pulley, it seems like it would make a good amount of compression. So when the throttle plate is wide open or more than half, wouldn't the supercharger make a positive pressure (higher than atmospheric, therefore not a vacum). And then how come the vacum lines are not blown off? This is a conceptual question, and since I am new to superchargers, I can't figure it out. As of yet, I have not blown any vacum lines. What do you all think?
The vacuum lines are fairly tight and are generally fine at positive boost pressures for a short period of time.
The point at when the blower creates boost and when it comes on is largerly due to the pulley combination. The V1 and V2 kits utilize a bypass valve and they wont create any pressure under nomal driving conditions, only at, or close to, WOT. If you notice a loss in pressure, you could check to see if the belt is too loose.
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Matt C.
Supercharged, Intercooled and SCT/PRP tuned
The tee and vacuum hoses are fine under boost, as it's highly unlikely you're generating more boost than you've ever had in vacuum. The brass T's easily handle 100psi and the equiv vacuum. The lines I believe are rated for 50psi, and the equiv vacuum.
The brake booster has a check valve, so under boost the vacuum in the booster remains giving you several stops.
What becomes a problem is if while under boost you try and actuate your heater doors, AC doors, and so on, you'll have pressure instead of vacuum, or need to brake one and off while contuously under boost.
One solution is to put a check valve between the intake and the brass T.
ANother solution is to run all the accessories off a diesel engine's vacuum pump, fabricating simple brackets for it to fit into the 351W you have. Then no matter what boost you have, all your emissions solenoids, brake booster, climate control doors and so on, only see a vacuum. This pump draws so little HP you won't even notice it.
Then you can run boost as often as you want, and still have the rest of the truck be happy.
