Choosing Aftermarket Ecu's

[petert 554]

I spent some more time on the dyno today fine tuning my new engine. I spent condiserable time holding at each load point (the important ones anyway) and confirming the mixtures. After that I decided to do a power run vrs mixtures to see the outcome. To my surprise there was still a nasty rich - lean dip at 500-5500 as it came on the cam. Inspection of the fuel table at 100% throttle opening shows 5000 had a value 85 to produce 12.9:1 and 5500 had a value of 102 to produce 12.9:1. Hold them steady at those points and the mixtures were fine. However, on the power run, where you move through the points, there was spike to 13.4:1.

 

The only way to solve the issue was to add another axis at 5250. If your software doesn't allow you to add an axis, then there's no chance of ever improving on that type of situation.

 

Then take a look at the ignition table, in particular from 2500 to 4000 at 100% load. Load in this case is by manifold pressure. Those values were originally 24 degrees. However, while I was watching the torque readout, I used the + and - keys to adjust the timing. It was surprising how much the torque INCREASED by a decrease in a few degrees. The resolution for a highly tuned engine is important. Notice in this case it's to a tenth of a degree. Again, that's what you pay for.

 

I also concentrated on 3500 - 80%, to check the cruise timing. I had this value originally at 30 degrees. As I held the + key down the Nm just kept on climbing, until they peaked at 36 degrees. I didn't have time to do the full table, so I filled in the rest at 36.

[huckleberry 0]

Interesting read. In a different thread there were different opinions about this item.

A lot of people (incl. me) don't map and just don't know how it works and don't know what ECU would be best for them. Looking at the difference in price I only believed there had to be some difference, just dídn't know what. And with 'what' I mean what difference for the actual output between two same engines with just different ECu's.

[SPGTi 2]

Another important consideration for the cost consious is how quickly a system can be mapped, as a saving in initial purchase price can be eaten up by mapping costs very quickly.

I have seen Omex, DTA, KMS and Megasuirt being mapped. The mapper was more used to the Omex and DTA systems but the speed and ease that the tables could be corrected for the Omex and DTA enabled half a day on the rollers compared to full days for the other systems.

 

Steve

[petert 554]

I didn't think this had loaded due to an internet slow down, so went to the club, and thus hadn't added the screen shots. Here they are:

[Sandy 189]

It's amazing how much harder it can be to get an accurate and satisfying map on different ECU's. They all seem to do similar stuff on paper, but the reality of creating a precise map quickly is something else.

The compensations are hugely important to keep an eye on I find, if you're not keeping an eye on them they can corrupt your values during the process and after. Some ECU's display the compensations clearly and some don't.