For those of you running a down draft Weber. Have you noticed any benefit from running the fuel inlet to the top port instead of the side port?

I am using a Mallory comp 140 fuel pump and Mallory 4309 regulator with all -8 fuel fittings and lines up to the regulator. From the regulator to the Weber is -6. the car is a 51 mm IDA Weber. And I am debating on using the top or the side port to feed the fuel. I see most of therace cars that use Weber's use the top port, but still others use the side port. this card is setup for blow through if that makes any difference.

 

There is benefit to it as ive tried both set up. For blow-thru, do you think your carb hat will clear the top inlet fitting?

 

I like the idea of running the side port so the pulsing fuel isn't pushing right on the needle and seat. With the side port it'll have to make a few bends to take the pulse out of it.

With that said never ran a top port. Mel what's the benefit?

 

There is no benefit from running a top port entry, keeping steady consistent fuel flow is more important and -6 is more than enough, I have seen 1,500hp twin turbo cars running -6 fuel inlets.

 

no fuel starvation above 11k rpm despite i have been told not to use carter 7psi pump on a bridge. Im using the side port as return btw.

 

i tested mine, which was new, and if you're making big hp, the pump is probably borderline.

the box says 72GPH, but installed in the car its more like 35...

 

bridged motor has been taken out. After approx 1k miles, coolant has been seeping and leaking out of the rear rotor housing but motor is still strong despite the smoke. havent taken it apart to inspect the damaged area.

 

I have the tall secondary venturies (the things that look like a battle axe) which are the same height as my velocity stacks. So I welded a plate to the top of the stacks and built a n plenum on top of t b at. I should have enough room to fit A -6 because of this.


are you running the return there because you are running a returnless regulator, or do you believe it's better to run a return from there instead of the regulator?

 

Im running returnless regulator. since i added a return on the carb, i never had a problem with flooding. I also have a restrictor on my return line to regulate the flow back to tank. If something happen to your float or needle and seat, gas will overflow out of the carb or into the motor.

Idk about the effect on a blow thru.