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RE: TR3 Engine Stutter and SU tuning

To: triumphs@autox.team.net (Triumphs List), tr3driver@comcast.net
Subject: RE: TR3 Engine Stutter and SU tuning
From: spamiam@comcast.net
Date: Sun, 06 Mar 2005 01:03:59 +0000
Randall,

Based on an SU discussion on the TR7/8 list I have been thinking about the 
question of the spring strength and fine tuning of the needle.

If we could see the air pistion while on the road, we could tell if it was just 
reaching the top limit of its excursion at maximum air flow.

WHen we know the piston is moving correctly, then a wide-band o2 sensor will 
tell us the mixture.  With the piston position information linked to the 
mixture info, then we should be able to determine which "stage" of the needle 
is responsible for each mixture condition.  The profile can be fine tuned in 
that manner.

I am in the process of making some sketches of an electro-mechanical doodad to 
measure the piston position in place of the dashpot.  Yes, the damping effect 
will be lost in its current incarnation.  I could add some other dashpot device 
the the electro-mechanical device to restore the damping.  Maybe a shock 
absorber from an RC car....

Anyway, this thing could be connected to one of the multichannel wide band O2 
sensor devices to record the real-time measurements.  I was considering 
adapting this little computer-type device called a BX-24 to take the position 
readings and apply the mathematical formula to convert it to piston travel 
measurements and display it on a little screen on the passenger seat.  It could 
be programmed to read the O2 sensor too....

This should take most of the guesswork out of the spring/needle/dashpot oil 
questions.

-Tony

>Date: Fri, 4 Mar 2005 18:56:59 -0800
>From: "Randall" <tr3driver@comcast.net>
>Subject: RE: TR3 Engine Stutter
>
>> Don't know if
>> they are fully optimized but I don't have many options.
>
>Huh ?  With dozens of needles to choose from (not to mention modifying your
>own), plus a bunch of different springs to try with each needle and of
>course the endless debate over what fluif to use (which of course depends on
>what spring & needle you use), you should have a dizzying array of options.
>
>Out of curiosity, what are you running now ?  I think I've got a similar
>problem with my Sports 6, except the DPO got the carbs from some sort of
>Volvo ...
>
>Randall




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