Hey guys,
One feature that I always wished the stock ECU had that I like a lot with the AEM EMS (AEMTuner) is TIMING TRIM PER GEAR and FUEL TRIM PER GEAR. I could live without the fuel trim per gear but the benefits of being able to globally add or remove timing in particular gears is really helpful.



Roadspike had briefly looked into this for me once and made a good point that the BARO TRIM table may be edited to allow for 5 gears (2nd-thru-6th). He also mentioned that it looked like that table was not actually active and had no effect.

Is this something one of you genius' would be willing to try to create? I can test it on 9653 or 9417 roms.

Adding the timing trim and possibly the fuel trim per gear would really make me love the stock ECU more than AEM that much more


-Jamie
(aka Jack_of_Trades)

 

Yeah I thought about this a LONG time ago, but figured without proper 3d mapping pre gear it was kinda useless..

and 3d mapping per gear is really user-UNfriendly...

in saying that with V7 all the barebones are there for timing per gear...

 

I actually prefer just a simple single variable trim value rather than an elaborate 3D map. That's how AEM is setup and it works quite well. Also, I have some significant timing jumps sometimes and I wouldn't want an interpolated 3d map making those timing jumps and larger. I would rather just raise or lower my entire timing curve globally.

I totally wish I knew how to edit to code myself I peeked at the baro trim code in IDA PRO but I literally have no idea how to change the lookup from baro to the gear lookup like you have for boost control. I clicked on the subroutine location and I can see that both lookups are in there but I don't wanna play with fire.


Hopefully one of these smart chaps would be willing to lend a hand.

-Jamie
(aka jack_of_trades)

 

well dorp me an email and I will see if I can whip something up for you.

modifying the IAT or Baro compensation is probably the easiest... I dont think the Baro table has anything in it..

 

Email sent, thanks!


Also, I actually like the IAT TIMING TRIM table so I would like to keep that if possible.



-Jamie

 

Very interesting idea! Subscribed!

I always wanted more consistent AFR throughout the gears, but how is the timing affected by gears?

Higher gear -> Higher load -> Lower timing?

 

If you tune a vehicle in a lower gear, it may knock in higher gears since the duration that it sits in each load cell is so much longer.

If you tune in a higher gear, the lower gears are generally less aggressive than they would allow.

• Fuel trim per gear
• Timing trim per gear
• Boost per gear

This would be about as flexible as you'd ever need it to be to get the most out of each gear.

Here is an example. I had an Evo 8 with AEM EMS that was strictly for 1/4 mile racing. He ran a MBC and it was tuned for 4th gear since that is the gear it will be in for roughly half of the track. I then did pulls in 2nd and 3rd gear as well to see how the power was in each gear. The results were roughly (this is all off memory so don't take it as gospel):

2nd gear: 440whp
3rd gear: 490whp
4th gear: 505whp

After adjusting the fuel and timing trims for 2nd and 3rd gear:

2nd gear: 480whp
3rd gear: 515whp
4th gear: 505whp

To test it out, we did three 1/4 mile simulation pulls (waited 20 minutes between each pass) with no trim adjustments and looked at the average WHP, ET, and MPH. Then we did the same with the trims adjusted and did three 1/4 mile pulls again. I forget the exact results (I will dig them up later) but the average whp was about 20-30whp more and he shaved an average of .3 seconds off his times.

If we get this implemented in the stock ECU, I will gladly do as much A/B dyno comparisons as I can for everyone.


Here is a snapshot of what I was thinking about:



For the load activation, I stole one of the MAF COMP vs. COOLANT TEMP tables. I will let the guru's set it up the 'correct' way since I know there is more to it than that lol.


-Jamie
(aka Jack_of_Trades)

 

Wow. thanks for the detailed explanation.

I thought lower power at lower gear was due to less boost build-up, and it was pretty much solved by Tephra V7's gear dependent boost solenoid setting.

But I learned there are more margin at lower gear if I run pretty much knock free at higher gears.

Now I can also understand why you said timing compensation is better, because current AFR varying pattern (leaner at lower gear) is actually helping this issue already.

It is interesting indeed! Modded stock ECU keeps evolving thanks to you guys like tephra and you! Thanks!

 

Mitsubishi have implemented 3D acceleration spark maps on some models and yes they can be tuned for very good results.

 

Great idea ! I had the same observation with the performance in different gears, and from the logs I coud see the timing and AFR differential .

 

I have made a few maps that used different ECU controlled boost/load levels in each gear so I could sort of tune each gear separately but it makes for a choppy map and wouldn't be street friendly.

I'm looking forward to trying this setup out if the ECU gods can achieve this.


-Jamie
(Aka Jack_of_Trades)

 

You should look at the mazdaspeed roms.

They have pretty much everything mappable per gear. Boost/Ignition/fueling/cam timing/etc

It actually makes your brain hurt a little. In all honesty, while the tuning/data geek in me thinks it's awesome, the tuner side of me thinks it's too powerful for it's own good.

 

Good idea.
hope this can be done and ported to the 9055 rom.

 

IDK really. If they can tune one gear, it's pretty simple to give each of the other gears a nudge and tweak if they feel it's needed.

-Jamie
(aka Jack_of_Trades)

 

Yea your idea with the "compensation" per gear would be a nice and simple way to do it.

The Mazdaspeed tables having nothing simple about them. They are all 3D for each gear and have a bunch of 3D compensation tables on top of those... It's a cluster**ck.