Lotta fun with Megasquirt, Autotune, tunes while you drive Options

[DNHunt]

I downloaded a newer version of Megasquirt with autotune. It uses a wideband O2 meter to adjust the air fuel mixture to a target while you drive. The targets vary according to RPM and manifold vacuum. I have a high of 14 at cruise and a low of 12.6 at WOT. Megasquit keeps adjusting until the amount of fuel gives the desired voltage from the O2 meter. It speeds up tuning a ton. (IMG:http://www.914world.com/bbs2/html/emoticons/smilie_pokal.gif)

It's cool to see it changing without any key strokes on the computer. There are a couple things to consider (there always are). Tuning is only as good as the O2 meter and the air fuel mixture is just a number pulled out of the air. It will not tune the ignition side of the ECU. So, when I get everything sorted out and the engine well broken in it still goes on a dyno.

Dave

[yarin]

Wow.. those guys are certainly cranking out some amazing additions to their lineup. The router board should be a neat addition allowing for more input and outputs.

Things us 914 people can do:

External oil cooler flow control & temperature/pressure monitoring.

Cold start fan block servo. i just came up with this one.. instead of using the original heat-expansion cold start block off it can be connected to a servo or solenoid.

Fuel pressure info.

Then again one of the reasons i found the 914 so attractive was its simplicity (no power anything, simple, light, to the point).

Guys I have a question about my MS plan:

How reliable / easy would it be to implement spark advance/timing control using MS II triggered from a Pertronix type optical or magnetic pickup on a stock dizzy. Can this signal be used to trigger MS? I've heard several people experience a noisy RPM signal coming from the negative side of the coil.

Has anyone here run MS Ignition on a stock dizzy (advance locked) with a stock coil?

Here is the page for using the high current driver: http://www.megasquirt.info/ms2/vb921.htm

MS has a dwell parameter. Isn't the dwell set by either points or the slot in the optical pickup disc? Or does MS just read the first rise of the waveform and set its own duration?

I found this potential problem on the MS site:

"51. As we noted in step 50, there are two input circuits for the tach signal. One takes the square wave input from a hall sensor, optical sensor, or points.

This is also used if you want to trigger off the negative side of the coil, since the points control the negative side of the coil's primary circuit. However, you can only trigger off the coil's negative terminal if you are NOT trying to control ignition timing. " located in here: http://www.megasquirt.info/ms2/V3assemble.htm

Has anyone with a noisy tach input tried this?

"If you are going to use the negative side of the coil to trigger MegaSquirt (I.e., you are not using ignition timing control), then install and solder C12, the Ed capacitor (399-2017-ND, 0.001 µF, 102 marking}. Otherwise leave the C12 location empty - DO NOT jumper it. This is located above "Bowling" in the copyright notice. The value of this capacitor may need to be increased if there are noise problems with the tach signal - values up to 0.1uf will work. The 0.001uf value is a good starting point."

Thanks! I want to plan out my MS project and target any issues ahead of time before jumping into it.