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Old 10-27-2011, 05:56 PM   #1
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Default MegaSquirtSanta - Custom Modifications / Firmware

Ho ho ho...

It is nearly Xmas time and MegaSquirtSanta needs to know what you boys and girls would like in your Megasquirt 2 for Xmas.


I've already added and freely released firmware mods for:
  • AC Idle Up (both duty and rpm)
  • Battery Volt Idle Correction (duty up/down)

*coming soon* I'm busy putting the final touches on this set...
  • Graceful Off for AC Idle up - keep RPM spike to a minimum!
  • MAT correction for Idle
  • Clutch/Neutral PE0 switch to lockout PID

What else should I be looking at to enhance this mod?

PS - so far nothing has been removed or harmed in the making of this mod !!

G (aka MegaSquirtSanta)

Last edited by gslender; 11-01-2011 at 06:20 PM.
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Old 10-27-2011, 06:51 PM   #2
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I hope this isn't an xmas only thing and come easter you'll be the xmas easter bunny etc etc.

As for feature request, how about a proper non-linear injector compensation table a-la MS3 rather than the static value we get in MS2 that's then adjusted linearly via voltage.

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Old 10-27-2011, 07:28 PM   #3
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MegaSquirtSanta gives many times a year!

I'll look into that "non-linear injector compensation table" feature, but may require some thinking behind what is broken in the MS2 version and why the MS3 option is that much better.
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Old 10-27-2011, 07:33 PM   #4
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(Posting from my phone.)

Ms3 uses a table ms2 static x change per voltage change.
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Old 10-28-2011, 05:29 AM   #5
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i.e. linear vs non linear.

No injectors that I know of are linear in operation, particularly at low PW/DC.
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Old 10-28-2011, 07:14 AM   #6
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I'm all for anything that smoothens idle! Anyone got a screenshot of the injector compensation table?
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Old 10-28-2011, 08:30 AM   #7
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based on this

Attached Thumbnails
MegaSquirtSanta - Custom Modifications / Firmware-28102011132500.jpg   MegaSquirtSanta - Custom Modifications / Firmware-rx8injectorlatency.jpg  
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Old 10-28-2011, 09:08 AM   #8
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Cheers frank.

Merry Christmas gslender
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Old 10-28-2011, 09:11 AM   #9
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Hey frank are those rx8 injector settings there?

Edit: d'oh! Typed before I looked

I suppose if it were done, just a single table for all 4 injectors (to save space) would be acceptable. No need for individual injector trim. Right?

Last edited by Greg G; 10-28-2011 at 09:21 AM.
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Old 10-28-2011, 10:37 AM   #10
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The latest 3.1.4 beta MS2 code uses a default injector battery voltage correction curve with a scale factor, instead of the linear correction in 3.1.1 and older code versions. Just wanted to mention that one's already been improved a bit, although it's not as sophisticated as MS3.
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Old 10-28-2011, 12:03 PM   #11
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To expand a bit on Matt's post, the new non-linear correction seems to be able to match published data for dead time for most (all?) injectors. It requires adjusting the 2 parameters (dead time @ 13.2V and correction factor) but it's not very difficult using a worksheet.

What MS2/Extra doesn't have that MS3 does have is a small pulse width curve which is where the non-linearity of injectors needs to be corrected for when using large injectors. This is what will affect idle quality under normal conditions.

This is also not something you can guess and it must be measured to be of any use. So having the option available is only a small part. Being able to characterize the injectors is the major part which may not be accessible to most users.

Jean
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Old 10-28-2011, 01:30 PM   #12
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Another possible candidate is robs' tps dot smoothing. Might be applicable to mapdot as well.

http://www.msextra.com/forums/viewto...p?f=91&t=42233
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Old 10-28-2011, 03:21 PM   #13
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Quote:
Originally Posted by jbelanger View Post
To expand a bit on Matt's post, the new non-linear correction seems to be able to match published data for dead time for most (all?) injectors. It requires adjusting the 2 parameters (dead time @ 13.2V and correction factor) but it's not very difficult using a worksheet.

What MS2/Extra doesn't have that MS3 does have is a small pulse width curve which is where the non-linearity of injectors needs to be corrected for when using large injectors. This is what will affect idle quality under normal conditions.

This is also not something you can guess and it must be measured to be of any use. So having the option available is only a small part. Being able to characterize the injectors is the major part which may not be accessible to most users.

Jean
True, but for this community at least there's not a large range of injectors used.

They only need to be measured once and the community benefits as a whole
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Old 10-30-2011, 09:46 AM   #14
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What do you guys think of MAT based pwm idle duty correction? When my engine is hot, I notice the idle valve duty is higher, by about 1 duty point per 5 degrees F. This is because the air is less dense at higher temperatures. Yes the closed loop duty will make up for it, but I figure if we already correct it (by a user definable factor), it will leave the closed loop code less to do, and allow us to run lower pid values.

My question is, what will the baseline value be? I suppose it's normal operating temp. Shall we say 100F? Duty would be added above the temp at a user definable rate. Below that, no correction is applied.

Last edited by Greg G; 10-30-2011 at 11:21 AM.
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Old 10-30-2011, 02:12 PM   #15
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Idle valve duty hystersis, based on RPM. Should hopefully be a simple tweak to the current PID code and would be very useful.
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Old 10-30-2011, 11:50 PM   #16
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The MAT based idle valve correction would also probably help address the hot restart issue...
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Old 11-01-2011, 10:45 AM   #17
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Map / EMap fueling strategy ( Exhaust Manifold air pressure )

VSS input
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Old 11-01-2011, 02:47 PM   #18
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Quote:
Originally Posted by PeteNMA View Post
Idle valve duty hystersis, based on RPM. Should hopefully be a simple tweak to the current PID code and would be very useful.
I'd like to see this as well. On my setup it seems like there isn't enough granularity to hit the targets the code is trying for. I'd rather it be "good enough" and stable than oscillating back and forth and causing transients,
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Old 11-01-2011, 04:57 PM   #19
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I thought hysterisis was already in? or am I confusing it with the mariob code mods?
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Old 11-01-2011, 05:12 PM   #20
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Quote:
Originally Posted by richyvrlimited View Post
I thought hysterisis was already in? or am I confusing it with the mariob code mods?
Mariob put it in, but it never made it into the mainstream releases. It helped when I was using his code but the lean spike fix and AC idle up improvements were better. If I could get one release with both that would be awesome, though.
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