On Sat, Mar 22, 2003 at 12:11:36PM -0800, Randall Young wrote:
> > I just realized that the HIF 6 in this application seems to have a
> > vacuum port that is plugged off. If it leads to where I think it does,
> > it gets the vacuum from between the butterfly and the piston, which
> > means that it would "measure" the amount of vacuum that the piston is
> > exposed to. Am I reading this correctly?
>
> Unless a HIF is quite a bit different than the earlier models, the piston
> gets it's vacuum signal directly from the venturi, which should be quite a
> bit more than the vacuum between the piston and the throttle plate.
I thought that that vacuum, was what sucked the fuel up, but that the
backwards facing ports in the bottom of the piston were past the
bridge and in the area between the bridge (venturi) and the throttle
plate.
>
> > I've been experimenting this week with using the green spring rather
> > than the yellow (12 oz rather than 8oz), it seems to work pretty well,
> > except for sometimes when trying to accelerate from a very low load
> > situation, in which case the car just doesn't want to do anything,
> > except possibly die.
>
> Have you tried heavier oil in the dashpot ? That's it's function, to richen
> the mixture when you open the throttle suddenly.
It slows down the piston movement and I'm running 85/140 in the
dashpot. I've got some stuff that is heavier, but then the piston
drops very slowly too. A heavier spring (as I understand it) increases
the velocity of the air through the venturi, increasing the vacuum to
the jet and also "stretches out" the profile of the needle so that at
the same airflow, you are "lower" or thicker on the needle.
>
> > If I were a little less restrained on my
> > sanity/time/research budget I'd experiment with a progressively wound
> > spring on the carb piston. But if I were going to that much bother,
> > I'd probably do better with a closed loop fuel injection system.
>
> Why not use a needle with a faster taper ?
I'd like it to move easily at low loads, but the piston hits full
movement way before I've got full airflow through it. I also want to
keep the mixture as lean as practical at low loads as it seems to make
a 20-30% in fuel economy.
Kai-
(combining responses here)
No, most people do not have the difficulties that I have had. I made a
few dumb mistakes, and a couple of really clever mistakes, exacerbated
by my doing every thing I could to make sure that everything was
perfect. I suspect that in my zeal to understand everything that is
happening, I might also be a bit more vocal about discussing it. I
also have enough vanity to think that enough people are interested.
I know that there are other folks besides you and I with supercharged
british Iron. Would there be enough interest to set up a mailing list
(probably a yahoo group) for others that share our
afflic^H^H^H^H^Hinterest?
Larry
--
I've found something worse than oldies station that play the music I used to
listen to. Oldies stations that play the "new" music I used to complain about.
lrc@red4est.com http://www.red4est.com/lrc
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