On the subject of vacume. With the entire carb under the same pressure the vacume would come from the same place it always has, that is the air moving through the venturi of the carb. It would be like you increased the outside air pressure from 14.7 psi to 19.7psi.The vacume is created by moving air. I could be wrong but it seems logical and a long time ago. On my olds powered ford there was no need for any vacc ports as all the vac ran was the wiper and the olds fuel pump was a vac pump also. Besides with the McCullogh supercharger there is no reason that it couldn't be used as a pull through as it uses the same type of impeller as a turbo but driven by a belt.Besides why would you want to pull a gasoline and air mixture through a red hot turbo, that would blow the tops of the pistons off in a hurry ,that is if it didn't explode as it was being compressed by the red hot turbo. Think About It. Go to www.paxtonproducts.com and you can see what the company makes now based on the Mccullogh/Paxton supercharger. It occurs to me that thier current products could be used as a supercharger.
>Would any of those superchargers work for an EFI engine like
>Primary rig is:
>95' F-150 EB 300/6 5 spd with 4" Superlift, MSD, Ram Air,
>Gibson Exhaust, 32" BFG Muds
>THERE ARE SOME PICS IN MY GALLERY!! :-)
>88' F-250 Superduty 351 + c6
>95' Mercury Cougar 4.6L V-8
>80' E-350 300/6 and a
>3 spd column shifter. Top speed, 65mph, Go Baby Go!
>The newest addition to the Ford family is a 99' Mustang GT
You get vacuum just like you normally would on a carb engine. The whole carb isn't under pressure when you're not into the throttle. You're not running boost when you're cruising or idling or anything else where you would normally have a vacuum. Only when you open it up will there be any boost created, but even on an N/A engine you won't be creating much vacuum at all anyway when you get on the throttle.
Lets think about it for a second. You're running 1/4 throttle down the highway (where N/A you would be running 1/3 throttle). The reason you are using less throttle is becuase your supercharger is creating boost. When the compressed air hits the carb, the throttle blades stop most (3/4) of it. So lets say you are creating 5psi at that point. Thats 19.7psia (psi absolute) pressure. You're letting 1/4 of this through. You can't say at that point that you'll have 4.9psia through (which would actually end up as 9.8psi below ambient) but you can see how this would still have a vacuum one cruise and part-throttle operation. Only when you get to 3/4+ (depending on boost of course) throttle operation would you have above ambient pressure.
If you have a boosted setup and find that your power assisted brakes aren't working properly you can add a vacuum canister like the radical n/a boys do.
I want to do same upgrade; m90 to 300 EFI. Looking at space I am going to move vacume can and mount charger above passenger inner fender... Run pipe threw inner grille mount inter cooler behind outter grille. go threw inter cooler and terminate where factory ram air tube goes into stock air box going to insulate stock exhaust manifold. If any thing happens want to be as near stock as possible may goto 19 lb injector
-For inlet to > charger will run pipe possibly threw inner fender and land outside of truck pass through fender wel., put k&n cone filter there