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It would be interesting to install a O2 sensor with a gauge so that you could monitor air/fuel ratios on the fly and at different throttle positions while you drive.
I love this stuff!! Your passion for “tweaking” is awesome, and then taking your time to share it is more awesome.. THANK YOU! If “micro-tuning” was a 6-pack of Bud Light, you’d be a Budweiser delivery truck!! I think you may be reaching the boundaries of “micro-tuning”. I’m a little bit puzzled about your igniting timing and cam timing….. Generally, and what is typically changed/adjusted at elevations above sea level for naturally aspirated carb’d engines, to compensate for the lower oxygen and air density – slower combustion time - is advancing the ignition timing and advancing the cam timing. Raising the compression also seems to help with the loss of power at elevation. So you have adjusted your ignition timing back to zero and your cam timing is at 1 degree retarded? I’m interested in that adjustment and why that feels better to your butt dyno ? Gnarls.
...This is where we run into the limits of tuning the Aisan carb. Changing main jets yields significant changes but I haven't figured out how to do much else.
...less into the throttle on the highway maintaining speed and looking at the gas gauge I would estimate I burned a lot less fuel.... and get a more economical cruise with the same tip in pull.
... Chasing un-claimed throttle response and horse power.... .
I might have learned something that is a total game changer. I can't post it yet though I need to run more miles first .
...If this keeps up I can run this thing and the HAC gets a NO. .
I towed 2 round bales of alfalfa yesterday at about 1,750 lbs each. This thing is towing WAY better now. I pulled on this one hill probably 12 mph faster than before with the stock filter setup and previous tune. I can barely feel the 19' trailer unloaded. I will be towing again today. Kind of botching my mileage test towing but there is definitely more torque going on these days.
....but there is definitely more torque going on these days.
How many times are you taching it passed 5,000 RPMs!! Gnarls.
Well not much on the last tank. That's what is weird though, if I drive like I'm rally racing it does better on gas than when I am trying to be conservative.
Theory......The power valve is too rich.....1. Normal operation is good with current jet on primary bbl.2. Open it up a little and power valve comes into play. It just happens to be to rich, uses a bunch of gas to get up to speed.3. Then more throttle is applied and secondary bbl comes into play.... It's not too rich, uses appropriate amount of gas. You get up to speed quicker and then go back to normal operation. Just happen to use less gas overall than condition 2 above....Really need a wideband O2 sensor to see what's going on. It's somewhat possible to see what's going on with a narrowband by tapping into the signal with a digital voltmeter..
Aside from emsvitil’s excellent analytical input, and not assuming any errors, miscalculations, or environmental factor were NOT taken into account ....there are other factors that can affect gas mileage:The fuel – octane rating, gasoline sourceThe MPG calculation – accuracy of tank fill up and accuracy of odometerAmbient air temperatureRelative humidityBarometric PressureIncreased elevation from sea levelExact same test routeGnarls.
... The odometer is within less than 1% because I was able to use a speedo sender from a 4.37 geared 1st gen which just happens to line up perfect for 35s and 5.29 gears...
This is probably why Glen says that his Toyota gets the best MPG while driving it in the 3K rpm range. He swears by it. I tried a Salem to Portland trip doing this, got horrible MPG. But I am EFI too!
Another setting with the power valve (not the jet) would be the spring for how much vacuum it takes to close the valve.......
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