Starting a thread containing some good info on neg split and Megasquirt.
First I just want to ask is it possible to run neg split with an MS1, MS2, and/or MS3?

I have been reading into this and would love some info from MS guys.

Thanks
Keith

 

I don't think it was possible with MSnS-e 1, MS2-e it definitely is, and it will be for MS3 as well

 

I am currently running a MS1 and would like to try doing some negative split. Anyone confirm for sure that it is not possible with the MS1?

Also what are the timing limitations of the MS1?

 

It is not possible with ms1. MS2/extra and MS3 will do it.

Ken

 

What are the timing limitations of the MS1? I read somewhere else that with the MS1 you cant go more than 20 deg advanced on trailing, which is why you cannot run neg split. Anyone confirm that?

 

On MS1 you can only do split between 0 and 20 degrees (note that this isn't "advanced", it's actually "degrees after leading."

You can't do less than 0 because there is only 1 timer for ALL ignition outputs, and that one timer is multiplexed.

On ms2 and ms3, we use a timer for dwell and a timer for spark for leading, and the same for trailing, so a total of 4 timers controlling up to 8 outputs.

There is no chance of us adding negative split to the ms1 because while I'm sure given enough cleverness someone could figure out a way, James, Phil and I have no time/motivation to work on MS1.

Ken

 

Ahh so for the trailing to fire before the leading you would need to enter a negative value... Are the settings for timing the same for MS2-3 where the trailing table is actually degrees after leading? I will be upgrading to one of those sooner or later.

 

The settings for ms2/ms3 are the same for the trailing table.

MS3's later alphas has a special rotary mode selected by choosing "rotary" for "stroke"

Ken