Fuelish Thoughts and a Question or two

[Ron R.]

Some background info:

SPF GT40
Windsor 393 making 565 bhp at the flywheel on an early dyno pull, expecting closer to 600 bph when the webers are sorted.
SW 240A x2
one FISPA filter/regulator (from an alfa or fiat, not original to GT40) see attached picture

I figure that my motor will probably need half inch fuel lines (-8 an). I would guess that the SW 240as working together can supply enough volume, but I just don't see any way that the little FISPA filter/regulator is going to flow enough by itself (I'd guess, from memory, that the inlet/outlet has an ID of about 1/4 to 5/16 inch).

I'll need a regulator with the webers, should I just give up on my hopes to keep things original looking by using the FISPA, or could I try to find another one and run them in tandem?

I've thought about trying to hog-out the inlet/outlet, but I just don't think I can improve the flow enough to solve my problem. Secondly, I don't know how that would affect the regulator function of the unit.

Finally, I don't need a return line. What are you carbed guys doing with the second bung on the fuel tank....plugging it up or using it to run a vent?

Thanks

(Sorry its posted in the wrong forum, but I can't change it now.)

 

[Rich E.]

Ron,

I can't remember if we talked about this but are you going to run a filter in the sponson just off the tank then pump, pump, filter, weber's or filter off tank, pump, filter, pump, weber's? Us carb'd guys don't need a return so the second bung on the tank is capped. I'm not sure if webers need a return but if they do and you don't want to plum it back to the tank you could always run it back to the pumps and just use a check valve.....Just an idea.

Rich.

P.S. I'm running -6 and don't have any fuel supply issues and my windsor based 427 makes similar HP. -8 will be more than enough IMO.

 

[Alex]

If it were me I'd use a proper pump/filter/regulator setup - taking that one and hacking it up screams bad idea to me (since this is your engine and fuel we're talking about).

-6 line can support around 650hp n/a (of course this is very generic because things would change if you had 10000ft of line and 10000 90* bends in it, but within reason...).

Us carb'd guys don't need a return so the second bung on the tank is capped. I'm not sure if webers need a return but if they do and you don't want to plum it back to the tank you could always run it back to the pumps and just use a check valve.....Just an idea.

Whether or not you use a return line depends on the type of pump you're using.

 

[Ron R.]

Guys,

I was planning on running the two pumps in series (they each have integral filters), followed by one (or two in parallel) FISPA filter-regulators. I've measured these, and the id of the inlet/outlet is about a quarter of an inch (-4 an). I think we call all agree, that would be too small. I understand that the Gt40 version of the FISPA has larger inlets, but I don't know how much larger.

I'll probably temporarialy run a modern filter and regulator, and then see what happens with the FISPAs after I get done cleaning them up.

Rich, I don't need a return line, so I'll just cap the second fitting on the tank.

I plan on doing the install the week of Halloween (finally!), so after I've established a baseline, I'll start mucking about with the vintage stuff.

Thanks, Ron