Thread: Anyone running holleys on their superchargers?

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Yes. With the telltale hole screw out, theres a wee dribble of gas. I've had the carb apart a number of times, an have switched to a centre hung float chamber.

TyphoonZR, At idle and cruise throttle, there is enough vacuum to hold the valve closed.

Do you have a photo of your 350 carb? It must be a little old. Like said above you can adjust PV and jet sizes. In addition, I have owned Holleys since the mid 70's, all sorts, rebuilt and new, and sometimes they just will just not work right. That's when I go buy a new one.

Are you maintaining fuel pressure?

Kitz

Originally Posted by kitz

Do you have a photo of your 350 carb?Kitz

Here are some pics, Datsun 1200 Club
Datsun 1200 Club
(You can see the nitrous nozzle in the plate between the carb and the blower. And yes, the nozzle had blank jets blocking the holes up)

I'm not sure about the fuel pressure. But my old carb (a two stage weber 32/36, same as the holley used on the 2 litre pinto motor) didn't have this problem. And the holley has a larger bowl.(Can hold more fuel) My old carb used to lean out when I first got this engione running. Thats why I upgraded the tank pickup and fuel lines to 3/8, as well as fitting the holley blue and a mallory reg. Thats a BIG fuel supply for a 93CI motor. (Even a supercharged one)

That all looks good to me. The tapered spacer helps keep the carb level when under power; that's what I was looking for. If the fuel pressure is right (6-6.5 psi) then sounds like the carb needs to be tuned a tad richer with combos of main jet and PV.

It sure is helpfull to have an O2 meter when doing these things. Not including welding the parts for this are ~$100 from Summit, and you can make it permanent or temporary.

Good Luck, Kitz

Thanks.
A friend had loaned me his wideband A/F meter, but the O2 sensor was faulty. I'm hoping to get a good one off him in the next couple of days. Then, (weather permitting) I can see for sure what the A/F ratio is.


I think it's always going to be a work in progress. Maybe I should just sell it and buy a honda civic. No bloody way!!! lol

Sometimes the PV just doesn't work right on a blown motor. One of the local gys ran into that last year. He finally used the Holley PV blocker plugs and some richer secondary jets and it runs great now.

Manifold reference is the way to go but it is possible you have a vac leak as noted.

I got it all dialed sweet on saturday. Ran the wideband A/F meter, and fiddled with the idle, and the mains. I also had a problem with the accelerator pump check needle. the shaking of the motor was unseating it, and I was getting accelerator discharge nozzle dribble. bought a fangled kit from Mclendon carburator to remedy this. took quite a bit of fiddling around to get this spot on. (had to keep the needle seated, but also had to have little enough spring pressure on the needle to allow the pump actuator arm spring to overcome it so the pump could discharge.
Ended up with an Idle mixture around 12.7:1, and it runs about 12:1 at wide open throttle. At cruise throttle when doing the speed limit the mixture hovers around stoich too.
The larger carb has really made a difference to the available power up top too. The power curve used to begin tapering off about 6000, but know it pulls like crazy all the way to the red line. It was well worth the perseverence.