[TR] zenith or su's ?

[Foster, Stan (HP IT)]

Quite a few of us have installed the low end wideband o2 sensors like the
Innovate LC-1 which sells for around $200 (sensor, cable, gauge). This kit
also has outputs to plug into a laptop for data logging although to be really
useful you would need further instrumentation to make the a/f data meaningful.
Just being able to see what the carbs are doing under different throttle
settings (idle, acceleration, WOT etc) is very helpful.

This whole discussion makes my 3xdcoe 40's look pretty straightforward
although I have been humming that old Searchers number "Needles and Springs"
for several days now..

Stan

-----Original Message-----
From: triumphs-bounces at autox.team.net [mailto:triumphs-bounces at autox.team.net]
On Behalf Of Randall
Sent: Wednesday, December 02, 2009 2:57 PM
To: 'Triumph List'
Subject: Re: [TR] zenith or su's ?

> They sell Air/Fuel mixture gauges that are cheap enough

Unfortunately, the cheap ones don't tell you what you want to know.  They
are only accurate right at Lambda = 1.0; which is neither best power nor
best fuel economy.  "Wide band" sensors are available, but are substantially
more expensive.

> If you could get a throttle position sensor or something like
> a rheostat hooked up to a rig like this it would be very informative.

But, throttle position doesn't directly translate to piston position.  You
can infer piston position from throttle position & engine rpm (with maybe
some correction for altitude/air density), but it varies with your
particular setup and how are you going to calibrate it?

These are exactly the same problems one faces when setting up a fuel
injection system.  You need to know the actual airflow into the engine to
know how much fuel it needs.

-- Randall