John and all;
I believe Nick Arias solved this problem on their lakester by using non air
bleed nozzles. They had a very efficient scoop and good sealing around the
stacks so the air pressure inside the plenum was higher than the outside of
the throttle body. The nozzles were not flowing the same as the pressure
built up with increased speed. That's their story anyway.
Jim in Palmdale, having to put rocks in his pocket to walk to the shop (and
he's a big guy)
----- Original Message -----
From: John Beckett <landspeedracer@email.msn.com>
To: Butters Family <bbutters@dmi.net>; <ardunbill@webtv.net>;
<land-speed@autox.team.net>
Sent: Thursday, February 10, 2000 7:59 AM
Subject: Re: Tuning Mechanical Fuel Injection
> Kvach
>
> My experience is all non-supercharged so far. But I can tell you that
> there is a 'lot' of air being stuffed into a hood scoop, depending on
> design, at 200 MPH, and very hard to equalize air flow, inside the scoop,
> with an individual port Hilborn type injection. I didn't need a high speed
> by-pass, heck I couldn't get it rich enough and maintain consistent plug
> reading throughout the cylinders. Anyway I have the burned rear pistons to
> back up my theories.
>
> John Beckett, LSR #79
>
> ----- Original Message -----
> From: "Butters Family" <bbutters@dmi.net>
> To: <ardunbill@webtv.net>; <land-speed@autox.team.net>
> Sent: Thursday, February 10, 2000 1:42 AM
> Subject: Re: Tuning Mechanical Fuel Injection
>
>
> > I have some questions on mech. FUEL INJECTION is there any
> > relationship to high speed lean out and the forward faceing hat stuffing
> air
> > into the blower at 200+ mph. I guess you should know the answer to that
> > question if it becomes more of a problem or only shows up on the track
and
> > not in the dyno room??? Has anyone used the conventional Hilborn type
> > injection on thier blower to do say 90% of the fuel requirement and make
> up
> > the remaining 10% with electronic down injectors that is regulated
wih
> > O2 and EGT sensors. Seems like you woouldn't need those expensive high
> flow
> > electronic injectors and they could cycle better. Kvach
> > ----- Original Message -----
> > From: <ardunbill@webtv.net>
> > To: <land-speed@autox.team.net>
> > Sent: Tuesday, February 08, 2000 11:45 AM
> > Subject: Tuning Mechanical Fuel Injection
> >
> >
> > > Group, in looking more closely at the "Hemi Head Chevy Engine" article
I
> > > told you about earlier today, there is an illuminating technical
tidbit
> > > expressed for those like myself trying to get mechanical fuel
injection
> > > working properly.
> > >
> > > That's a sidebar in the article entitled "Iskenderian Dyno Report".
The
> > > chart under it reads in part as follows:
> > >
> > > RPM HP TORQUE BOOST BYPASS(jet)
> > >
> > > 5500 539 490 16# .105
> > > 6000 578 482 17# .105
> > > 6000 514 462 17# .090
> > > 6000 590 492 17# .110
> > > 6500 624 480 17# .110
> > > 7200 638 440 19# .110
> > >
> > > All the above involves this hemi-head 301 Chev running on alcohol with
a
> > > 6-71 blower driven 1-1 with a Hilborn injector on top of it. With the
> > > Hilborn bypass jet system, a smaller (numerical) jet size means a
richer
> > > mixture.
> > >
> > > Several interesting things here:
> > >
> > > l. The engine needed different bypass jet sizes to give max power at
> > > different RPM ranges. Something about the cam timing, etc., was
letting
> > > more or less fuel escape out the exhaust at different rpms. Assuming
the
> > > Hilborn pump delivers a constant increase in flow directly
proportional
> > > to increase in rpm(does it?).
> > >
> > > 2. When running mechanical fuel injection, you can only run one bypass
> > > jet during a pass on a speed trials course (despite availability of
'jet
> > > selectors' etc., no time to turn 'em). One bypass jet size is not
going
> > > to give you full power at all rpm ranges, blown or unblown, so you
will
> > > have to focus on the top end and hope it doesn't hurt the mid-range
too
> > > much.
> > >
> > > 3. The blower's manifold pressure increased at the top end because
the
> > > gas-flow through the heads could not keep up with the increased output
> > > of the blower. At 7200, even though the manifold pressure went up to
> > > 19, the engine torque was dropping down sharply.
> > >
> > > The spark lead was 34 for all the above tests on this hemi-Chevy. The
> > > heads had the plug electrodes at the combustion chamber surface(no
> > > cartridge fire setup like the original Arduns).
> > >
> > > Any comment from veterans with mechanical fuel injection experience??
> > > ArdunBill
> > >
> > >
> >
>
>
>
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