Ecotec Negative Ignition Timing Values

[Dylan]

yeah some of the ecotec models were pretty lean in low rpm high load areas too... I never stuff with the maf or maf tables other than cleaning the element with carby cleaner. ... only touch PE commanded AFR and open loop values. never done a cammed ecotec with a MAF... they all go 808 by then.

as the MAF gets dirty, it leans out and uses more timing from what it thinks it less airflow... good combination

When you say you don't touch the MAF tables would that include the injector multiplier table?

[Jayme]

yeah I dont touch that either.... I dont generally sit there and do widebanding on stock ecotecs... just fix commanded AFR for WOT, do some logs with the narrowband and make sure the MV at WOT look right, and leave the rest alone. anyone of them that are modified enough to warrant tuning the whole thing, the first thing they do is throw MAF away and put an 808 on it ive never had to tune a modified ecotec on a MAF.

[vlad01]

yeah I dont touch that either.... I dont generally sit there and do widebanding on stock ecotecs... just fix commanded AFR for WOT, do some logs with the narrowband and make sure the MV at WOT look right, and leave the rest alone. anyone of them that are modified enough to warrant tuning the whole thing, the first thing they do is throw MAF away and put an 808 on it ive never had to tune a modified ecotec on a MAF.

I like your style lol.

[Dylan]

That's the go. If GM set the MAF up right it should do the work for you.

[Holden202T]

yeah your right there is more gains to be had from increasing the timing down low, im not sure if the gains was from my exhaust or just the softening of the throttle they do down low .....

I know stock ecotecs idle with fuck all timing, I dunno if that's some sort of emissions thing or what, but when I started with it, I pretty much just got the stock $12P BLCD and stuck it in and see what happened! it pretty much was too much timing and I think rich down low and lean up top, I used the knock sensor and brains to work out the timing retard required, and once I stopped getting knock and the fuel was pretty close I just tweaked as I found stuff. but the extra timing down low certainly made it spin off the line well

its been a while now but I recall that I actually removed a bit of timing down low to get it to take off without spinning as much ....

I also fitted a map sensor to my brothers VS (stock) and logged that for a few weeks then played all the logs back one after the other and was able to get a fairly complete map based timing map made from the MAF tune, which I then used as a base for putting the 91 octane tune into it ..... figure if people use the tune in a conversion that's a fairly safe starting point, then the 98 tune was there at the flick of a map switch if people wanted it.

it certainly went way better with the 808 and kitted up T700 than the stock vs pcm and auto, some of that was the auto, but certainly it was more toey and more responsive with the 808.

[Dylan]

Obviously a lot of work gone into it. Thanks for sharing

[Gareth]

That's the go. If GM set the MAF up right it should do the work for you.

why do all the training video's and books for gen111 tuning say to calibrate the MAF then?

Eg: Greg Banish's video...

Im sure if you change the stock intake pipe, air filter, engine pumping losses, etc.. then the MAF would require calibration to the new setup??? This confuses the hell out of me

[Jayme]

well im not saying you shouldnt do something there if you have modified things... ive never had to touch a MAF on anything except a bog stock setup, in which case the GM tables are fine...
in theory, the MAF measures grams of air... if its calibrated right from factory, you increase airflow through your engine, the MAF registers more air, extra fuel comes in... this is why MAF's are so forgiving to engine modifications. im not sure the circumstances the training books etc recommend to calibrate the MAF... perhaps modified engines with MAF's tend to not be the same as the commanded tables anymore, requiring recalibration?? anyways someone with more MAF tuning experience than me can comment.

[Holden202T]

Obviously a lot of work gone into it. Thanks for sharing

its easy enough when you do 700kms a week and work in IT who supply you a laptop and being that I work in IT I can also make changes at work when I get time then put the tune in before I go home so progress is made quickly

on the subject of tuning the MAF, I am by no means saying don't do it .... but that said, I have tuned plenty of worked 5ltr's and even modified V6's ..... and honestly some of the things people fuck with in the tunes is un-believable, and frankly, not necessary!

when I tuned the V6 sprintcar, I setup a base tune for methanol AFR's and the injectors he had, then at the end of the tuning session (on the dyno) all I had changed was commanded AFR table, VE table and Spark Advance tables..... that's all it took to tune this thing for different injectors, different fuel, different inlet and exhaust and more compression ...

you need to follow the KISS principal, if you adjust all the above and then its still got issues, then start looking at other stuff like IAC settings or AE/PE etc.

theres lots of things in standard tunes that can make big improvements, like the AE v's time I think it is, basically makes the motor really rich if you keep the boot into it for too long, probably for keeping things cooler and safe and also for making the motor more doughy so you back off or don't pick up speed as quick... and especially the timing they remove from low revs to make the motor nice to drive for everyone, but not getting the most for people like us

anyways will stop ranting heh!

[antus]

why do all the training video's and books for gen111 tuning say to calibrate the MAF then?

Eg: Greg Banish's video...

I think thats for modified engines to work around software airflow limitations. In our case we can meter more airflow if required with the1s bins, to the point where the maf hz wont go any higher... at which point you need a bigger maf, and then need to modify the maf tables to suit.

Essentially its a nasty hack, and has flow on effects through the rest of the tune. Maybe its passable if your not looking for OEM accuracy and can accept the rough edges, but in our case its far better and easier to run an operating system thats made for higher airflow.

And in the case of a gen3 if you start hitting limits your probably better off with an after market OS too.