View Full Version : Vortech Carb Enclosure Q

01-15-2007, 09:21 PM
I have a carb enclosure with a semi modified demon 750. It is on a 500" BBC with a YSI blower. It is running about 7 PSI with 28 degree total advanced locked out.

The problem is that after about 5200 the thing falls flat on its face. I have twin eliminator pumps, a boost refrenced regulator. The fuel pressure is steady about 15 PSI. I have a msd programmable 7/ 10 coil combo.

Any ideas? Is there something in the carb that needs to be modified? I know its not detonating nor is is lean or rich. The timming on the ground electrode looks to be on par.


01-15-2007, 10:17 PM
I'd say it's in the carb/enclosure combo. The hats are a much better way to go, especially at higher boost, but require more carb mods. That enclosure should work at that boost level but I am totally unfamiliar with the carb mods needed with an enclosure. I know mine did a similar thing before being modded correctly. I'd recommend CSU carbs or SD Concept Engineering for the carb mods.



01-16-2007, 01:56 AM
im with camcojb on this one.. as your boost increases the volume (not the mass) air the engine recieves is reduced, the carb is modded to compensate for this, if this compensation is off you rengine output will suffer.. id install a WBO2 or have somone run it on a chassis dyno and see what actually is going on

i mean there is also no idea spending a lot of money on carb guesswork if the problem is valvefloat.. this will be obvious once you get some hard data..

just my 0.02$

01-16-2007, 07:41 AM
I am pretty sure its the carb or enclosure. I ripped on it again last night. It has no problem hitting 7500+ in a hurrry with the nitrous carb and no blower and box.

I am going to try a CSU or the like for a carb with a bonnet when I bolt on the F-2, but I figured I would give this a try. The motor is about 724 on the motor and I was looking to see how much of a gain I would get with the Vortech and box. This set up will eventually end up on my 69, but figured I would try it on the 72 camaro first. I was hoping to get about 800 RWHP with the vortech, but it looks like it will reside on a more streetable motor.

Thanks for your input.

01-16-2007, 07:49 AM
Heres the 500" motor with the F-2 and the EFI manifold set up that will some day make it in the engine compartment. The only diffrence is the bracket is now polished and it has the lowering bracket.



01-16-2007, 08:41 AM
What a beast. Wow.

01-16-2007, 12:27 PM
hey PhilM, i had the Vortech supercharger and their carb enclosure on my 355 sbc and hit 7k regularly with 10+ boost and had no problems falling flat... My carb was built "specifically for blow thru" set-ups. What they did to it, i have no idea. Sorry, wish I had more details on what was done to the carb.

I am now going with a bonnet style top hat due to hood clearance issues on my new 388 sbc and have it set up for 15+ psi...

I think I'd look in the direction of the carb!!

01-16-2007, 01:42 PM
I know member Chrismoe on this site has one of those. I'm pretty sure his is doing ok. You might ask him.

01-18-2007, 07:21 PM
I was having a similar sounding problem with a 750 DP on my single turbo SBC Jaguar. I had to build a low profile carb hat to fit under the hood, and with it on it wouldn't turn any rpm or make any boost. I pulled the hat off after a short pull and found the carb was wet with gas above the venturies. The air flowing across the primary vent tube was drawing gas out of it. I welded in a deflector and now it's fine.