Larry, what about a linear encoder, or rotary encoder with bellcrank? I
would think that you could get one on the piston and a rotary encoder on the
throttle and log the two in reference to each other. I can't imagine it
would be that hard. Being a computer nerd, you could probably even whip up
an RS232 app that could log it all to a laptop.
James Nazarian
71 MGBGT V8
71 MGB Tourer
-----Original Message-----
From: owner-mgs@autox.team.net [mailto:owner-mgs@autox.team.net] On Behalf
Of Larry Colen
Sent: Friday, April 30, 2004 3:56 PM
To: Dave Wood
Cc: mgs
Subject: Re: Fuel injection
On Fri, Apr 30, 2004 at 11:28:05AM -0700, Dave Wood wrote:
> Larry,
>
> Did I understand you to say that you are running a blower on your MG with
> SU's? I've been curious why all of the Blower advertisements that I
seen
actually that's a single SU. It's the kit from http://www.hi-flow.com
although the Moss kit also has a single SU.
> required replacing the SU's with a single Weber. I may be mistaken, but I
> would be surprised if the stock SU needles would do the job properly with
> the addition of forced air. Perhaps there are some recommendations for
> alternate needles to help with the leaning out you mentioned.
The problem only comes in when the piston slams open when you hit the
gas from partial throttle. I suspect that the blower creates a lot
more vacuum than the system was designed for. Only having one carb is
nice because I can custom tune the needle, the trick is figuring out
where on the piston I am at any given time. I tried making a widget
that'll indicate piston position, but I didn't have precision enough
manufacturing abilities. What I need to do is make a better device for
measuring piston rise, and also mount a voltmeter to measure AFR in
such a position that a camcorder can record both of them.
On the dyno, I noticed that I hit full piston rise a lot earlier than
I expected. My noted got destroyed when brakefluid spilled on my
logbook, but under full throttle, you get full piston rise, pretty
early, even if you do block off one of the piston vacuum ports, and
increase spring tension.
These are some of the surprising things I was learning by running the
O2 sensor.
By the way, my goal is a reliable 110 hp to the ground, on 91 Octane
street gas, in my MGB. There are some very interesting things going on
with this project. If you are interested enough to help out with the
research (especially if you are in the "Bay Area") do contact me off
the list at the address below.
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