Tuning GX31

[joaocaleira]

Hi,

Im doing a project at my college with the goal of doing a transition from carburetor to EFI, on a Honda GX31. I have a ECU with Megasquirt MS3, and as my knowledge about tuning with TunerStudio MS is quite limited im having some struggles with tuning my engine using the VE, AFR and ignition tables. Basically i would like to implement several operating modes to the engine. One to make it produce the maximum torque possible and other to decrease the engine consumption to the minimum, at certain rpm intervals. Implementing first the modes with the standard engine ignition system, and then with variable ignition. Would like to be shared with some opinions and tips on how to do this with TunerStudio MS. Thanks

Regards

[old guy]

Do a search for "Honda GX35" on this forum. There are a few threads on this engine which is probably similar to a GX31.

[joaocaleira]

My doubts are not specific for this type of engine, but I would like to know for example how I can decrease the engine consumption through the VE, AFR and ignition tables.

[Matt Cramer]

AFR targeting: It's likely to make best efficiency run slightly lean, but this typically isn't practical at high loads. Particularly on an air cooled engine; these need some extra fuel for combustion chamber cooling for reliable operation. This may be a balancing act between efficiency and detonation at high loads.

The VE table needs to be whatever it needs to hit the AFR targets.

Timing needs to be determined empirically by whatever puts out the most torque at any given RPM and load point.

[billr]

I gotta ask... will you be doing this using a steady-load dyno? Without such a dyno, the fine optimizations you are trying to research will probably be impossible to find with any accuracy.

[joaocaleira]

I gotta ask... will you be doing this using a steady-load dyno? Without such a dyno, the fine optimizations you are trying to research will probably be impossible to find with any accuracy.

Basically i started my tests with the carburetor configuration, using a load cell to measure the torque. The goal is to basically prove that the performance of an engine increases when you re using a EFI system. So now i assembled all the EFI system, with a MS3 and the load cell also. The goal is to, since the engine with the propeller runs from 1600 rpm to 2000 rpm, run:
lean from 1600rpm to 2000rpm
Rich from 2000rpm to 3500rpm
Lean from 3500rpm to 4500rpm
Rich from 4500rpm to 5800rpm

First with the standard ignition, and then with variable ignition.