Calling Coyote X, Megasquirt XFI file

[blownintegra]

I want to try to tune mine on the old motor to get a good base, and then tune for the new motor to try to get some additional mileage. Shoot, if I do that and get a boattail, I may see 60? who knows?

Thanks for the head start!

[TELVM]

Originally Posted by Coyote X

yep I am using ms1-extra. The file I posted is the one currently in the car. The VE table has been using auto tune with the wideband.

( Most probably you already know, but just in case: ) You can configure Autotune to better suit the RPM and kPa scales you choose. For the scales in your VE table I'd suggest these adjusts in your custom.ini:

#else ; Actually only good for DualTable and MSnS-Extra.
   table = veTable1Map
      allowAutoTune          = on
      corrector              = egoCorrection
      xLimits                = 1000, 4500
      yLimits                =   19,  100
      zLimits                =   10,  200
      xRadius                =  149
      yRadius                =    3
      initialStartupInterval =  1.0
      updateInterval         =  0.5
      proportionalGain       =  0.5
      lumpiness              =    6

Also it is important to disable the 'Acceleration Wizard' before activating Autotune, a high value (something like 1000) in 'MAPdot Threshold (kPa/s)' will do.

I had it set to 18:1 for a large part of the afr table ...

Some people will cry and yell on reading that, but many engines can safely run that lean (sometimes even leaner) at partial throttle. However above ~75 kPa (depending on engine) it can be hairy not to run stoich or richer, pistons and valves can get the nasty habit of melting.

Of course the higher EGTs from such lean mixtures call bye-bye to the catalytic converter, and the NOx emissions skyrocket (sins these which could mean eternal damnation for some ecosouls).

Cut fuel 95% on lifting the throttle pedal ...

You can completely cut fuel 100% on overrun/coasting when no throttle pedal, no problem.

YouTube - Consumo 0.0 en retención (Toma 2 :-)

... and 0% acceleration enrichment for pushing the pedal down (had to push slowly to keep it running).

That's relatively easy when accelerating off a stoich AFR ... but from 18:1 it is a real challenge without accel enrichment. You could consider trading a bit of accel fuel enrichment for a huge gain in driveability.

Removed the idle so the car would not even attempt to idle and just die as soon as the clutch was pushed in.

(This must be some advanced esoteric hypermiling technique I've not yet been initiated in ... )

[Coyote X]

I have an EGT so 18:1 wasn't that bad and I went to 14.0:1 above 80 kpa

The acceleration enrichment at 0 was just for that 118mpg run. If I totally lifted my foot off the pedal it cut the fuel 100% but if I just raised my foot a bit while the pedal was going upward it cut the fuel 95%. It would make you realize quickly when you were moving your foot and force very easy changes to the throttle position. I guess I could have left it and trained myself to operate the throttle slowly but I would rather drive like a maniac most of the time.

Normal settings for driving are a lot more sane with an actual idle and everything else normal. I typically turn on autotune after the car has warmed up and the o2 correction goes over 5% a few times to get the table dialed back in perfectly. I don't remember the exact settings I had but it had at least 1 second settle time I think, so acceleration enrichment didn't bother it. I also had a lot bigger step interval. I have been running it for a good while now with a computer mounted to the dash so I have gotten pretty used to getting it dialed in.

[TELVM]

In practice I discovered Autotune is influenced somehow by the Accel Wizard, no matter how high we set 'updateInterval' and 'proportionalGain'.

[blownintegra]

All of you guys are very knowledgeable with Autotune. I have been looking for where this is in the settings. I do not seem to see this anywhere. Can you all help me locate where the "autotune" setting is?

thanks,

Mike

[TELVM]

Two ways to do it.

1) Go into your C:\Program Files\MegaSquirt\name of your project\mtCfg\ folder, then open custom.ini file with notepad. Scroll down to:

[AutoTune]

2) Open Megatune and click on File => Configurator => name of your project => custom.ini . Scroll down to:

00028 [AutoTune]

[blownintegra]

Okay, and there is no additional key to get this started a la hondata?

you just connect a wideband and let it go?

thanks!

[TELVM]

To activate Autotune, go Tuning => VE Table 1 , then type CTRL+A.

This of course after you have created a coherent AFR targets table for VE Table 1 for Autotune to reference, v.g.:

[blownintegra]

telvm,

you seem to know how to a lot about megatune. I can't get the timing or fuel right.

There is a VE table, and a spark table but i can't figure out the numbers and what they relate to. Thus I am tuning in the blind. Can you tell me a good start for distributor settings and which is advance and which is retarded? Also, same with the fuel?

Please note, my VE table is in % not in lambda like yours. I am more familiar with that style. Also, it said something in the ignition that anything between 15-22 will not work???

Thanks,

Mike

[TELVM]

I'll try to help.

Originally Posted by blownintegra

There is a VE table, and a spark table but i can't figure out the numbers and what they relate to.

To simplify, the values in the VE table represent the amount of fuel MS feeds at a particular rpm and MAP pressure. This is dictated by the volumetric efficiency (capacity of ingesting air) of each particular engine. At low rpm & low MAP the engine process little air and demands little fuel. At high rpm & high MAP the engine process lots of air and demands more fuel. So generally speaking the numbers in the VE table should increase following a 'northwards' and 'eastwards' pattern thru the table, decrease in a 'southwards' and 'westwards' pattern.

You really need a wideband oxygen sensor to tune a coherent VE table. You write a value in a cell (say 1100 rpm & 30 kPa), then test it by putting the engine at that combination of rpm & MAP and watching what AFR the wideband display shows, then correct the value when necessary (a higher number in the cell for richer, smaller for leaner). To begin with in 'fail safe mode' I'll aim to 14.5 from the bottom of the table up to ~75 Kpa, then progressively enrich at higher MAPs until about 12.5~13.2 (depending of engine) at 100 kPa (WOT in NA engines).

Naturally aspirated engines with moderate compression ratios/camshaft timings (the usual street car) can tolerate relatively high levels of error in the AFR setting for some time without serious danger, but only at partial throttle. Above ~75 kPa MAP a too lean mixture can quickly destroy the engine, so start tuning the 'southwestern' zone of the VE table first, staying away from WOT and high rpm, and only venture 'north' and 'eastwards' after you become confident about your tuning ability.

... which is advance and which is retarded?

As the mixture doesn't burn instantaneously after the spark, but needs some (small but measurable) time to burn completely, gasoline engines ignite several degrees before the piston reachs Top Dead Center (TDC, its maximum elevation inside the cylinder). This allows the flame front time to adequately develop for when the piston reachs TDC a few degrees and miliseconds later.

That's ignition advance. When we say 'ignition advance' or 'spark timing' is 20º, the spark is firing when the particular piston in compression phase is 20º short of 360º in angular and a bit short of max elevation in linear. A timing of 22º is 2 degrees more advanced than 20º. A timing of 17º is 3 degrees more retarded than 20º. The more before TDC we ignite, the more advanced the timing, and viceversa.



As happens with the amount of fuel, the engine demands different ignition timing at different combinations of MAP & rpm. This is trickier to tune however, as only a dynamometer or an experienced 'seat of the pants meter' can tell the correct ignition advance. Too much an advanced ignition timing can destroy the engine, so it's safer to begin with lower values and increase only after confidence.

In the Megasquirt Spark Table the number in each cell represents the degrees in ignition advance added to the base timing. So if base timing is say 10º, and the cell value is 17º, the real total advance at that combination is 27º.

Can you tell me a good start for distributor settings ...

Sorry, I'm not familiar with your engine and blind numerical advice could do more harm than good. Read this for advice on ignition advance tuning with MS1-Extra:

MS1 Extra Tuning Manual

Also, same with the fuel?

Read this for advice on VE table tuning with MS1-Extra:

MS1 Extra Tuning Manual

Please note, my VE table is in % not in lambda like yours.

Please note the table I posted above is an AFR targets table (8x8) in volts, not a VE table (12x12) in fuel. Autotune looks at the AFR target table (which we previously fill with AFR targets, expressed as wideband voltage) for reference to correct fuel values in the VE table.

So if for instance the AFR target table commands 'maintain a 14.7:1 AFR at 2000 rpm & 50 kPa' (expressed as say 2.5 volts wideband in the 2000 rpm & 50 kPa cell in the AFR targets table), autotune will automatically correct the 2000 rpm & 50 kPa cell in the VE table with the amount of fuel that yields 14.7:1 as read by the wideband (say 39, or 45, or 61, or whichever for the particular case).

Info on how autotune works: MS1 Extra Tuning Manual


I'll try a search tomorrow to see if I cand find Megasquirt VE and spark maps for a Metro 1.0 like 3-cyl yours.