guitarjunkie28

just use a bosch 044 with a -8 feed.

Jeff20B

It's carbed. Thanks anyway.

j9fd3s

the pete halsmer 4 rotor fc uses 3 bosch 044's, they pull from the tank thru a pre filter, then they feed into a common rail, another filter and then it goes up front to the engine, with what looks like a -8.



all the roadracing setups are overkill for the street

Jeff20B

Would two Carters be overkill? You'd think so, but it's carbed, so maybe not. Check out this idea.



16 gallon fuel cell

two Carter 72gph 8psi pumps



The fuel cell has two -8 fittings at the sump. Easy to plumb each to a Carter fuel pump. Then run dual 3/8" hardlines or a single 1/2" hardline to the front.



I figured supplying each Weber with its very own 72gph pump wouldn't be any more overkill than what the 2 rotor guys do with a single pump and a single carb. A plus here is both pumps cost only a little more than the single 100gph pump, and will flow 144gph together.



I've never done anything like this before, and don't know anyone who has, but this feels like the correct way to do the fuel system on this project. I followed similar reasoning while building the fuel system for my 20B; albeit that was for EFI, but the results were as expected. I bet the 23A will get plenty of fuel too. Please feel free to critique.

j9fd3s

yeah that sounds good. if its not enough, its not too much bother to add another 2 pumps

RONIN FC

Lets say, 500 HP x 0.5 (lbs fuel per HP)= 250 lbs (fuel per hour)

250 Divided by 6 lbs( 1 gallon of fuel) = 42 GPH



Overkill on gph will surely require a return line or you will just be heating fuel more.



I would do 1 pump, 1/2 inch line(No braided hoses) to a Holley regulator, The Holley regulator has 2 outlets, one to each carb.

Jeff20B

Ronin, is that 42 GPH per pump if using two? If so, that'd be 84 GPH single. I'd better step up to the 100 GPH unit then.



So I should get the 100 GPH pump with 1/2" hardline and a Holley reg, and use both outlets; one to each carb? That will be cheaper.

heretic

The only time I've seen a real need for 1/2" fuel line is when the fuel pump is bolted to the engine, far away from the tank.



The most you could possibly need is 3/8". I have built much heavier cars that will HURT at the dragstrip using 3/8" line and no pressure loss at full scat. You will probably not be making that kind of power. If you have future nitrous plans, then just run a complete separate fuel system for the nitrous.



5/16" line doesn't even become an issue until the ~400hp level in EFI trim.

RONIN FC

Thats 42GPH per 500 hp



Like Heretic says, you prolly dont need 1/2", but why not do it? Any decent pump should handle it.

Lynn E. Hanover

Well, lets see what you need.



The highest BSFC (Brake Specific Fuel Consumption) you would see would be around .683. In a 12A that would be a 12 to 1 FA ratio. With EGTs in the 1,500 area. Well rich of peak and no danger of any problems at all.



So for 450 HP you would see 450 X .683 = 307.35 divide by fuel weight (6.10 LBS) to get 50.38 gallons per hour. So the fun is going to cost you a bit in fuel costs. Of course the max power is just for very short periods.



Two pumps would be plenty. A 3/8" ID fuel line would be plenty.



The liquid vice electrical analogy is a good one. Voltage = pressure, Amps = volume, resistance = cross section.



For the IDFs the problem is in the carb. The Weber needle seat is too restrictive so I would go to a Gross jet .350 or .400 needle set. (actually two ball bearings) . There is a plastic filter that sits above the needle set under the brass plug, and that screen is way too fine to get the fuel flow you need. Discard it. Not only your case but everyone.



The hole in the bowl cover below that screen is too small. Drill it out and chamfer the edges at both ends.



Run the float high enough to make the boosters drip. Then lower it until the dripping just stops.



The fuel inlet fitting hole is metric. Use the correct metric to AN fitting. It is suprising how big a fire can develop when that fitting pops out because the engine builders helper screwed in an American fitting into that hole................. Don't ask.



I would get a fuel cell unless you have the skill to safely modify and add a fuel pickup in your existing tank. I use two 7 GPM Carters pulling through the metal fuel filters with push on fuel hoses. It isn't as sexy as all of that anodized AN stuff, but they are cheap (about 4 bucks). They are chrome plated. They work great. You can change them in 45 seconds. You must filter fuel before it goes through a sliding vane pump.



Then into each pump then out of each pump into a "T" fitting then into a large 16 micron fuel filter, then up to the front through a 5/16" ID piece of SAE fuel hose double wrapped stainless with a cloth cover.



The pressure regulator (A cheap Holley) close to the carb. A 1/4" fuel line from the regulator to the carb

(about 10") the other outlet to the fuel pressure gage isolator, then to the gage in the cockpit.

Insulate the regulator. If it gets hot it will go crazy and take you with it trying to tune the engine.



I run 6 pounds of fuel pressure, but most Weber people run less than 4 pounds. Run the car up to top RPM in a high gear (high load) and watch the fuel pressure through the whole run. Better yet have guest watch the gage,

to be sure that you fuel pressure does not change during the pass. Dropping fuel pressure means the carb will be leaning out. You will notice this when one of your pumps starts to wear out. Or you foul a filter.



A sad day for me. I washed the first gen GT-2 car, (real factory Pport) it leaves with the new owers in the AM. It still looks good.



Lynn E. Hanover