MSefi.com read only forum (Jan.15,2018)

I must be dumb, but how do I set my MS II to straight AN. I cant find a straight AN option anywhere. Im running MS II V3. The engine is a 355" Chevy with converted vintage Hillborn injection and no MAP signal at all due to the Individual runners. Please help, Ive searched here and in the manuals for hours.

Thanks,
Tony

It's set under the injector control screen.

The way MS2 B&G code handles alpha-N is that it uses the Alpha-N MAP table to generate a psuedo-MAP signal that is plugged into the speed density table.

Matt Cramer wrote:It's set under the injector control screen.

The way MS2 B&G code handles alpha-N is that it uses the Alpha-N MAP table to generate a psuedo-MAP signal that is plugged into the speed density table.

Matt, thanks for responding

The only options under the injector control that I can find are "2" speed density to AN blends or speed density only (three choices total). I'm tuning on the Alpha Numeric table under "other tuning" and it's working OK but the gradiations are too few to get rid of some problem areas. I saw on another thread where the poster said that I should be able to change the "kPa" column to Throttle position on the VE table and tune on that much finer grid. I just can't figure out how to do this.
Thanks
Tony

You'll want to check what code version that guy was running. I don't think there is a way to do this in B&G firmware, although I haven't been able to find a manual section on B&G alpha-N tuning myself.

Matt Cramer wrote:You'll want to check what code version that guy was running. I don't think there is a way to do this in B&G firmware, although I haven't been able to find a manual section on B&G alpha-N tuning myself.

So what you're saying is that I'm tuning the right (only) way using the AN table under the "other tuning" menu?

Tony,

You set the alpha-N table (N refers to rpm, not 'numeric'; alpha refers to the angle of the throttle opening) and then tune using the VE table. The alpha-N table translates the throttle position to a pseudo-MAP value that is used for the VE table: http://www.megamanual.com/mt29.htm#ra

If you want pure alpha-N, then arrange the alpha-N table so that the MAP is always the same as the TPS (i.e. the 100% TPS row has all 100 kPa in it, the 50% TPS row has all 50 kPa in it, etc.). Then the VE table will be RPM (on the horizontal axis) versus TPS on the vertical axis (though it will say MAP, it will actually be TPS in percent - you can change it to say TPS% in the INI, if you like).

However, the table is there because the effective wide-open throttle generally occurs at less opening with low rpms. For example, in my engine, at 2000 rpm I get 100 kPa intake manifold pressure at just 25% throttle opening. Opening the throttle further doesn't increase flow at all (since the engine is already flowing everything it needs). So in my case, I would have 100 kPa in all the 2000 rpm table entries for the alpha-N table above 25%. Then the fuel is more likely to match the actual airflow of the engine.

But you can do it however you like. Alpha-N is an advanced option, intended for those with lots of tuning experience, in-depth knowledge about their engine combinations, and very good ideas about what they are optimizing for and how to accomplish that.

Lance.

Lance, thanks for the response. You've helped clear matters up a little. I'll try a couple of things based on some tips here, and report back. The car is running very well already, I'm just refining the A/F. Here's a short video of what I'm doing, if you're interested.


http://youtu.be/XxJD5StLDH0

I tried to make the kPa values match the relative throttle position, but the throttle position dot wouldn't go to the right place, and would change heights every time I adjusted the kPa Value on the left column of the VE table. Why does the throttle pedal (TPS) move the kPa column anyway with the engine stopped? I'm very confused.