anybody know what i have to do to a holley 94 to make it run with a mc culloch supercharger? i want to run bonnet style blowing the boost through the top of the carb. anyone have any experience with this?
Don't you havt to pressurize the whole carb??? I've seen pics of carbs enclosed in boxes that are pressurized. Do you know Matt Campbell in SB? old biker buddy.
metalshapes would be the person to talk to I think. I have a float from a 97 that either went to another planet or was crushed by some sort of supercharger...so new floats might be a good place to start?
Start here: http://www.vs57.com/ Mc Culloch made at least two generations of flathead blowers, the second with pressurized carbs. Pictures are on here somewhere as a starting point, along with lots of articles and links.
...and look at the competition carb kit--3 94's in a can. Somewhere on there are also pictures of the base flathead kits made in the early fifties.
From what reading I have done on this, you have to fill the floats with something that is gas resistant and encase the whole carb in some type of box so the whole thing is pressurized. Otherwise it will crush the floats and push gas down the carb flooding the crap out of it.
Metalshapes is running a 4150 Holley on his. I believe he didn't bother changing anything for a long awhile, they had problems with a sunk float up here in November around the Good Guys show. So, you would need to change the float to one of the solid plastic kind. I think he was running around 6-8 PSI of boost, so I think if you wanted to run more than that, you'd need to pressurize the whole carb. On another note, are you just using one 94? I'm not sure it would give you enough fuel for the supercharged motor. What motor are you using?
to run a boost through set up ya definately need to have the carb sealed,, also remember fuel preassure must be upped to however many lbs of boost plus the actual preassure you want to achieve the desired lbs, must compensate for the boost
i was gonna run a small block boost through set-up on my race car with a 4150 in a box and a vortech blower and 250hp of nitrous but decided the whole blow through was gonna be more trouble then it was worth, but from all i found the box is very necessary if ya are gonna do it
No carb box on here (pic from Street Rodder), and he got away with this setup for a few months before the primary float sunk. We'll wait for him to chime in, maybe he did other stuff, but I know I was surprised that it worked with the brass floats for that long.
i'm running 3 94's. i have pictures of cars that had similar set ups, just need to know what kind of mods the carbs need.
Will you be running one HUGE bonnet that puts all three 94s in the same air cavity? I would THINK that all you'd need was new floats. I don't know if they are available for 94s in the hard plastic type, but you could probably make some by hacking up the ones used on the Holley 4 bbls. That might not be possible at all, just thinking outloud. This is from the Turbocharging section of my "Super Tuning and Modifying HOLLEY Carburetors," by Dave Emanual... "When only the top portion of the carburetor (as opposed to the entire unit) is pressurized, a slightly differend technique is usually needed. Depending on the carburetor model, it may be necessary to seal those openings (such as around the throttle shafts) that connect a high pressure area (inside the carb venturi) to one of atmospheric pressure. This is done to prevent fuel from being blown out of the carburetor. One of the simplest methods of sealing the throttle shafts is to create an air seal using blower/turbo pressure. "The air seal principle is quite simple. High pressure air will always move toward a low pressure area. In a blower/turbo environment, atmospheric pressure constitutes the low pressure area and the clearance between the throttle shafts and body provides a path to that lower pressure. By simply adding equal pressure to the shaft-to-body gap, the pathway is effectively blocked, thereby preventing fuel loss. "Drilling small holes in the throttle body just below and on each end of the throttle shaft will privide an entry path for pressureized air, these holes should be approx. .060-inch in diameter and the drilling should be done on a drill press so that depth may be carefully controlled. After removal of the throttle plates and shafts, four holes should be drilled from the underside of the throttle body. Use care when drilling so that when the drill bit stirkes through into the throttle shaft bore, the other side is not scratched. Remove all burrs prior to reinstalling the throttle shafts. "Once the throttle body is drilled, a 1/4" to 1/2" sapcer plate shoud be drilled to match and crossdrilled to intersect the vertical holes. Tubes pressed into the crossdrilled holes will provede a convenient means for attaching pressure hoses from the turbocharger. (The crossdrilled holes may be tapped for threaded fittins if preferred). Naturally, the carburetor gasket should also contain properly located holes." They have a couple of diagrams of this spacer plate, but I don't think Metalshapes did anything close to that on his 4150... As for the crossdrilling in the spacer, from the looks of this diagram, you have 4 small holes that all connect inside the spacer, so you might need some kind of machine shop to do this part.
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