----- Original Message -----
From: "Greg Monfort" <wingracer@email.msn.com>
To: "Bricklin" <bricklin@autox.team.net>
Sent: Wednesday, March 08, 2000 2:57 PM
Subject: Fw: onto fuel
> Unless you plan on doing some sustained full throttle
> runs, the large lines and hi perf pump are
> superfluous since a daily driver normally only needs
> 0.5*HP/6lbs, or ~27GPH. Well within an OEM system's
> ~40GPH capability. Production cars with carbs
> typically lean out under hard acceleration from fuel
> starvation, but since it's usually only for a second
> or two at a time, it's no big deal.
>
> I assume though there will be some serious WFO going
> on occasionally, so.....
>
> If the opening in the tank is too small, then the
> high volume pump will be trying to pull against a
> positive static pressure, causing it to bleed off the
> excess pressure that you bought it for. The last
> thing you want is a restriction.
>
> I'm not familiar with the pump you're using, but the
> line should be as large as it's inlet will allow, or
> 3/8" min for 250-375HP. The 1/2" pipe is a good
> 'catch all' size for street motors, just in case you
> do a performance upgrade later.
>
> Minimum fuel flow should be 0.23*HP (~75GPH for
> 325HP) for a dead head regulator, or 0.17*HP (~55GPH)
> for a return style regulator. The return line needs
> to be 3/8" min for 45-90GPH.
>
> Frankly, I'm surprised you didn't convert to high
> pressure electric. Less stress on the cam, much
> reduced possibility of getting vapor lock, less
> pressure drop from "G" forces, and it helps offset
> line frictional losses.
Yes, I agree. But in keeping with the design concept of the performance
mods, the elec fuel pump was dismissed. Hell, I could've gone with fuel
injection or a big block. But what I wanted to acheive here was a mod that
looked like it belonged in a 1975 car. It's as much asthetic as
functional(there goes my design background). One of the reasons for so
little chrome. I mean when you look under the hood, it still looks like it
belongs with the rest of the car, there is not a break in continuity nor any
"strange" components. For example, presently I am deciding whether to use
concours grade Ford hoses and lines(repros of the old stuff) or hi tech
materials. Another example is the radiator. Hell, I could've gone with an
alum aftermarket instead of a 4row using the same tanks, but again, does it
look like it belongs? There is little if any actual compromise in
performance in the real world for some of these items for the performance
goals of his project. I am not going for the upper limits. >300 Hp & 300 ft
lbs is highly respectible with driveability. As for the elec vs mech fuel
pump, I concur, but the differences you mention are minor, and with the
addition of syn lubricants, even lesser so. This car had syn since it
first became availiable and with now 8k miles on it everything coming out
looked practically brand new (cam, heads, etc). BTW, AC Delco now has a
new oil filter that is really something. The filtration is higher yet the
restriction is far lower than most I've tested. The check valve is very
precise also. At almost $10, it's not a cheapy, but there are far more
expensive ones out there. I was impressed.
The edel fuel pump puts out something like a 110-130 gph at standard
pressure. Stock fuel pumps are less reliable, less consistent, PSI is
unrealiable, with far less output. Vapor lock can be addressed with other
methods, such as location of lines, underhood heat factors, yada, yada,
yada. As far as G forces go, the carb is far more apt to be subseptible
than the line with the HO pump.
But I agree, the 3/8 -1/2" line to the pump may be the proper way to go.
Now, the best way to do this, hmmmm....
stephan
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