More resolution in the future

dr.occa · Post by **dr.occa** » Thu Sep 09, 2010 5:13 am

Any chance of getting a little more resolution in the near future? What I have in mind is possibly getting at least a total of 18 columns of rpm detail.

Post by **brentp** » Thu Sep 09, 2010 1:24 pm

The megajolt2 family is currently slated to support a 12x12 map- but this was picked arbitrarily and can be changed. How would a bigger map make things better- specific example? Should it be a square map, or one rectangular, with a greater emphasis on RPM bins? Remember too, you can change the bin bucket values, providing finer grained resolution in certain areas of the map.

Thanks,

dr.occa · Post by **dr.occa** » Thu Sep 09, 2010 10:06 pm

my reasoning is actually pretty simple minded. i've mapped out as best i can the aw11 ecu ignition table from jeremy ross' work and uses 18 columns of rpm resolution. i wanted to emulate it and tweak the timing table for my hi-comp setup.

the timing tables show interesting dips at various spots with slight differences among the 8 map lines.

Post by **brentp** » Thu Sep 09, 2010 10:44 pm

Interesting. with the 32 bit processor and ample RAM / Flash the limit of the ignition map is more of a human management issue (so many numbers to edit). I think some software tools to edit / smooth / manage ranges of the the map could help alleviate that. Also, I wonder if the AW11 ECU does interpolation between bins?

Spockie-Tech · Post by **Spockie-Tech** » Fri Sep 10, 2010 6:56 am

I'm guessing Hi Res tables are more of a "Sales Feature" than an often useful one.

Very few people I've talked to about Megajolts etc seem to understand the idea of interpolation, and if you have an engine that has a genuine need for that fine grained variation in the ignition map then you probably have a pig of an engine with poor breathing characteristics or a specialist race motor with an power band an inch wide.

A good driveable motor with a wide torque curve shouldnt need too many wiggles in the map to allow for multiple inconsistencies in the cylinder pressures across the RPM range.

However, if its easy to do in the software and you have the bytes to spare, you could have an low/med/hi-res option to switch maps between 8, 16 or 32 point (or non power of 2 numbers if you like

) just so you can keep the tuners who think having a 16/32 point map is "obviously" going to better than a mere 12 point map happy, but not forcing those with less picky needs to not have a wall of numbers to edit.

You could enter in a nice basic 8x8 map, then switch up to the higher res modes and have the intermediate numbers already interpolated and filled in for you to tweak if required.

Post by **brentp** » Fri Sep 10, 2010 3:27 pm

In the v1 RevA megajolt (ha) there was no interpolation between the map values, and under certain conditions you could actually feel this while driving. The interpolation really makes for an effectively much bigger map, but one where you can edit only *some* of the points

I like the switchable maps- it clearly needs to be able to gracefully downgrade / upgrade for many practical reasons, one being the simple sharing of ignition maps.

dr.occa · Post by **dr.occa** » Fri Sep 10, 2010 4:27 pm

brentp wrote:Interesting. with the 32 bit processor and ample RAM / Flash the limit of the ignition map is more of a human management issue (so many numbers to edit). I think some software tools to edit / smooth / manage ranges of the the map could help alleviate that. Also, I wonder if the AW11 ECU does interpolation between bins?

according to Jeremy Ross' findings, the AW11 ecu DOES interpolate between the various ignition maps based on several conditions received from its sensors.

i've attached an excel file of the aw11 ignition map based on the extracted info from the factory MAP ecu.