Any good resources for ECU tuning?

[armstrom]

My last tuning experience was with a standalone on an old-school 3S-GTE engine (no variable valve timing, no direct injection, no drive by wire, etc...) Back then you could perform basic tuning by editing two maps in speed density mode. Fuel injector duty cycle in ms and timing advance, both on a 2D grid of RPM vs Load (MAP). (Sure, there were more maps.. optional open loop mode, etc...)

Needless to say, the stock ECU is far more complex than this. I have read most of the excellent resources posted by @steve99 but I'm looking for something more general... basically, how does the basic fueling strategy work, how are the timing values calculated, etc... Presumably the experienced tuners in our community had some resources available to determine what each map does. I'm not looking for proprietary tuning secrets, just some guidance on how to get started with basic mods to an existing base map, I can figure the rest out from there I have not yet decided on ECUTek vs OFT (though leaning toward ECUTek).

Thanks!
-Matt

[steve99]

if you open tune in romtaider then open the map your interested in then click properties it will often give info on map

also check out the romraider site www.romraider.com


also see here

http://www.clubwrx.net/forums/tuning...r-tactrix.html



also google bad noodle tuning guide and see Wayno ,s posts

[steve99]

see here fore tune systems



http://www.ft86club.com/forums/showthread.php?t=106068

[armstrom]

Excellent. I was hoping you would reply. Of course I found your post on MAF scaling after my initial post despite it being right there in your signature :P. I'll check out all these additional links as well. Thanks!
-Matt

[Kodename47]

If you go with ECUtek, they provide some help pdfs with some decent info.

Bad Noodles guide is one of the 1st I read too.

[armstrom]

so, here's a follow-up question... how accurate is the MAF based metering once you have a "good" MAF scale? Presumably you scale the MAF once for a given intake configuration and then do not have to adjust the scaling for changes in boost or other changes that impact VE such as exhaust mods, cam phasing, etc... Is that correct? In speed density or alpha-N tuning you always had to adjust the fuel maps when you made a VE change (clearly, boost is "baked in" to the SD map, and Alpha-N on boost is a really bad idea for a street car ) Some systems even represent the fuel map as a VE value or offset rather than injector pulsewidth. I always preferred injector pulse width as it was easy to tell when you were up against injector limits before you log your next pull on the dyno.

So, is it safe to assume that once you have a verified good MAF scaling you can increase boost and simply verify that the ECU hits your target AFR in open loop?

If so it would seem to me that a simplified tuning session would proceed like this:
1) Compute an accurate MAF scaling by logging in closed loop mode
2) Set a safe fueling map and ignition map
3) Verify open loop AFR accuracy (presumably long term fuel trim provides hints to this)
4) Tune ignition map on dyno for max safe power across the rpm/load range. If street tuning use knock correction logging to adjust map... Though I always preferred the old-school method of a stethoscope on the block and a load-cell dyno

A more advanced session might start to play with cam timing, PI/DI ratios and DI phasing to eek out more power... correct?

Thanks again for the replies. I was half-expecting a "use the search" reply, but clearly I've done that and have not found any overview threads at this level... they were either all too general or too specific.
-Matt

[steve99]

Originally Posted by armstrom

so, here's a follow-up question... how accurate is the MAF based metering once you have a "good" MAF scale? Presumably you scale the MAF once for a given intake configuration and then do not have to adjust the scaling for changes in boost or other changes that impact VE such as exhaust mods, cam phasing, etc... Is that correct? In speed density or alpha-N tuning you always had to adjust the fuel maps when you made a VE change (clearly, boost is "baked in" to the SD map, and Alpha-N on boost is a really bad idea for a street car ) Some systems even represent the fuel map as a VE value or offset rather than injector pulsewidth. I always preferred injector pulse width as it was easy to tell when you were up against injector limits before you log your next pull on the dyno.

So, is it safe to assume that once you have a verified good MAF scaling you can increase boost and simply verify that the ECU hits your target AFR in open loop?

If so it would seem to me that a simplified tuning session would proceed like this:
1) Compute an accurate MAF scaling by logging in closed loop mode
2) Set a safe fueling map and ignition map
3) Verify open loop AFR accuracy (presumably long term fuel trim provides hints to this)
4) Tune ignition map on dyno for max safe power across the rpm/load range. If street tuning use knock correction logging to adjust map... Though I always preferred the old-school method of a stethoscope on the block and a load-cell dyno

A more advanced session might start to play with cam timing, PI/DI ratios and DI phasing to eek out more power... correct?

Thanks again for the replies. I was half-expecting a "use the search" reply, but clearly I've done that and have not found any overview threads at this level... they were either all too general or too specific.
-Matt

I have no experience tuning boosted stuff.


But for maf scaling and maf based fueling


collect data for closed loop wack that in the VGI tool and get the closed loop sorted.


collect data for open loop ie commanded afr vs actual afr and feed that through VGI tool.


do at least another round to check its all good after its settled in for a 100km or so


some people do open and closed all at once, this seems to work if your scaling is already pretty good, but I usually prefer to do it in two passes after getting closed loop sorted.


Yep with maf based fueling once you have your scaling correct you should be fine unless you change the diameter of the maf tube or upset the flow of air past maf sensor.


As you increase boost your going to have to make sure you don't exceed the limit of maf sensor ie push it past 5v.


If that start to get close then you can either make a new maf tube and rescale again ie go from the stock 2.75 to a 3" . Or get a forrester maf sensor and use it in your current intake will get you another 30% higher.


see here


http://www.ft86club.com/forums/showthread.php?t=106496




or go to speed density fuelling




.

[Kodename47]

Anything that impacts flow of air over the MAF sensor, both before and after it, will have an impact on the scaling. You will find that an NA MAF scale may be near enough, or not at all for a FI setup.

At the end of the day the fuel map isn't actually in AFR points and is just a base fueling table like many other ECUs. You can scale it close or use the main fuel maps to get the fueling you want. Closed loop operation is imperitive so fuel trims don't go crazy, but open loop is really up to you. Don't forget that changing the MAF scale alters the load calculations too.

What I would say is that your "plan" is pretty much good to go though.

[Wayno]

Originally Posted by armstrom

so, here's a follow-up question... how accurate is the MAF based metering once you have a "good" MAF scale? Presumably you scale the MAF once for a given intake configuration and then do not have to adjust the scaling for changes in boost or other changes that impact VE such as exhaust mods, cam phasing, etc... Is that correct? In speed density or alpha-N tuning you always had to adjust the fuel maps when you made a VE change (clearly, boost is "baked in" to the SD map, and Alpha-N on boost is a really bad idea for a street car ) Some systems even represent the fuel map as a VE value or offset rather than injector pulsewidth. I always preferred injector pulse width as it was easy to tell when you were up against injector limits before you log your next pull on the dyno.

So, is it safe to assume that once you have a verified good MAF scaling you can increase boost and simply verify that the ECU hits your target AFR in open loop?

If so it would seem to me that a simplified tuning session would proceed like this:
1) Compute an accurate MAF scaling by logging in closed loop mode
2) Set a safe fueling map and ignition map
3) Verify open loop AFR accuracy (presumably long term fuel trim provides hints to this)
4) Tune ignition map on dyno for max safe power across the rpm/load range. If street tuning use knock correction logging to adjust map... Though I always preferred the old-school method of a stethoscope on the block and a load-cell dyno

A more advanced session might start to play with cam timing, PI/DI ratios and DI phasing to eek out more power... correct?

Thanks again for the replies. I was half-expecting a "use the search" reply, but clearly I've done that and have not found any overview threads at this level... they were either all too general or too specific.
-Matt

Sadly, the best posts you'll find about generating a decent maf scale will all be made by a banned user jamesm. The process will be exactly the same regardless of using stock or larger injectors.

Injector ratios should be one of the first steps, before ignition timing.

How accurate is it? I'd say within +-1% if you leave LTFT enabled in OL, and within +-0.5% with it disabled.

LTFT only indicates accuracy in closed loop, not open. You can make open loop AFR as accurate as you like with any LTFT at all.

"Too general or too specific"? Honestly you're not going to get a good result if you're not willing to take advice from the existing specific posts on this platform re separating DI and PI, etc.

[armstrom]

Thanks for the info. Please don't misunderstand my meaning. I find the "specific" threads I was talking about to be very valuable. The general threads tend to be more along the lines of "should I buy OFT or ecutek?" or "who should I have tune my car?". I was trying to find some info to kind of bridge the gap. I'm more than willing to take all the advice I can find! I'm here to learn, nothing more.
-Matt

[aagun]

oft for non boost
ecutek for boost