Fuel issue, lookin for some advice.

[sverbus]

I've got a 434 in a '70 nova that is pretty stout. 700'ish inch cam with ported and blended Dart Pro-1's with the big 230cc and 2.08int/1.60exh valves.

I run a Dart Intake ported to match Felpro 1206 gasket which in turn matchs the heads. It's a 13:1 motor with a steady diet of 116 Torco Race fuel. Powerglide to Ford 9" and 4.56 gears.

Fuel cell in the trunk and battery in the trunk as well. I run a swich up by my steering column that activates the fuel pump which is a Holley Blue pump mounted behind the license plate. I have -6an line running the length of the car up to a Holley Regulator, and then -6an line to the bowls of the Demon carb.

The Demon is a 820 Downleg Race Demon.

my problem is that that when i start to creep upwards of 5000+ the fuel pressue starts to drop considerably. I go from 7.5 psi to around 5 and then I let off.

I think I have afew problems:

1. First off, I think the line is to small coming up to the bowls on the carb from the fuel cell. I'm thinking -8an line all the way up. (I alredy run a canister type filter)

2. I think im getting voltage drops due to insufficient wiring and poor planning. I'm going to rewire the entire battery/charging system and rewire my fuel system and ignition. I currently run a Mallory Hyfire 6 system with a Mallory Pro coil and MSD pro-billet distributor. I think the ignition is robbing the car of power elsewhere.

Im planning on putting a power distribution block under the dash to take the main power wire from the battery to. Then run my constant power wire to my Mallory Box, and then a wire to my accesories and also a wire to the starter. In the trunk im going to use the current wire that activates the fuel pump to go to a relay, and then run the relay right off the battery and then straight to the fuel pump. No voltage drop then eh?

My question is do you all think these are good solutions? Im hoping that the holley pump is big enough, if not i'll sell it and go with the Holley black pump.

Sorry to make this so long, but these are the things that I had my dad to help with when I lived at home, but now that my wife and I live far away and everyone's busy as hell, I'm going to rewire all of it myself.

Sorry again for length.

Scott Verbus

[CoMax Racing]

I think you definatly are on the right track. I would use a #8 line for the main line from the rear to the front. #6 line from the reg to the bowls is ok. You also want to use a relay to power your fuel pump.(not just a wire from the switch to the pump)

One other thing is the Holley blue pump is very old technology, there are so many better pumps out there that flow better and use less amperage. I would go with something with a g-rotor style pump, not the old vane style the Holley pump has. Barry Grant builds a nice pump.

Hope this helps

[sverbus]

Thanks for the input CoMax...Another idea I have is that should I run a return style setup and use my existing -6an line for the return, or run a dead-head system?

And I didnt put it in there but I planned on putting a relay in the trunk for the pump..

I was going to make a little aluminum box to put all my distribution blocks and relays in to keep the protected.

Thanks,

Scott

[CoMax Racing]

A return system is always more desirable over a non return system. The biggest reason is its way easier on the pumps. You are not asking the pump to basically try to build max pressure all the time. By returning fuel to the cell the pump stays alot cooler. The #6 line for a return will be fine.

As far a mounting your relay, I think you said you were going to mount it in the trunk,great idea, put it as close to the pump as possible to minimize voltage drops.

[jones_performance]

line is to small and so is the pump.

my setup is
-12 from the cell to the pump/filter (magnafuel prostar 500 combo), -10 from pump to front of car to regulator, -8 to carb. my pump is a bypass style also. i just use the bypass at the pump and run a normal regulator (magna fuel 2 port to be exact)

also if i take the line off the carb and let it droop towards the ground fuel will gravity feed from the cell.