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Old 10-08-2009, 04:45 AM   #1
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Default Finally, a decent tune .... next step, spark

Here is my latest and greatest .msq file: http://www.snarc.net/evan_hr_69.msq .... 69 is always a fun number.

Some things I realized while tuning tonight, that I didn't realize in the past 14 months of having a 'squirted Miata:

1., I had mostly ignored the bottom row (20 kPa) of my VE table, instead letting MLV's VE Analyzer make suggestions with a minimum MAP of 30 .... I've been doing that because Paul taught me all along that MLV/VEA doesn't do well at idle, which should be tuned manually .... he's correct .... but what I didn't realize is that the non-idle cells in that row (everything above 1,000) were super-rich and were ******* with the cells above them, since MegaTune interpolates. So tonight I leaned them out, and now my car runs much better when it's just puttering along at relatively low RPM (2000-3500) in third and fourth gear. Now it feels like an ordinary car in that scenario, not a diesel truck!

2. I had a giant lean spot in the lower-right corner of the table, not counting the bottom row and right-most column. That explains the jolt I felt when I stepped on the gas from low/medium RPM in passing gear on the highway. I added some fuel there, now life is smoooooooth.

3. I now realize why my car had so many misfires .... not because there wasn't enough spark, but because there was too much fuel.

4. I learned those three things not by datalogging and then trying to comprehend the line graphs, but by opening MegaTune's VE table, and keeping one eye on that with another eye on my wideband .... who needs to watch the road, anyway? That's how I started to realize what my car was doing and why it was doing it.

So .... I don't know if this post helps anyone else, but maybe some other people can learn from my mistakes.

Meanwhile, now that I finally have a logical fuel table, I suppose it's time that I learn more about tuning the spark table.

First major question: is it vital that the RPM columns in the spark table are the same as those in the VE table? I assume yes, so we can compare apples-to-apples.

Second major question: is there some tool for tuning spark, equivalent in usage to MLV / VE Analyzer?
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Old 10-08-2009, 05:29 AM   #2
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Second major question: is there some tool for tuning spark, equivalent in usage to MLV / VE Analyzer?

Yes, it's called a dyno.
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Old 10-08-2009, 08:47 AM   #3
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lol

yeah, dyno time.
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Old 10-08-2009, 12:51 PM   #4
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so the up-side to being unemployed is having the free time to get a good tune. oh, and to have Uncle Obama pay you while you are doing it. where do i sign up?
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Old 10-08-2009, 12:53 PM   #5
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I'm so waiting for them to lay me off. mt.net helps me achieve this goal.
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Old 10-08-2009, 04:07 PM   #6
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Originally Posted by evank View Post
I learned those three things not by datalogging and then trying to comprehend the line graphs, but by opening MegaTune's VE table, and keeping one eye on that with another eye on my wideband .... who needs to watch the road, anyway? That's how I started to realize what my car was doing and why it was doing it.
Oh, yeah, same thing, only safer... On MLV, have you turned on the "tuning panel" I think it's called? It shows you the spark and fuel tables and where you are, along with a history of where you've been, and shades the cells proportional to how much they are sharing with their neighbors.

You're right, I learn a ton by watching that. I generally autotune the whole map, then block select and "undo" the bottom row, or see what the changes are and decide what I want to do about them.


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First major question: is it vital that the RPM columns in the spark table are the same as those in the VE table? I assume yes, so we can compare apples-to-apples.
No, it really isn't. On MS-II I don't even think they are the same size. :-) It'd only be easier on a steady-state dyno.


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Second major question: is there some tool for tuning spark, equivalent in usage to MLV / VE Analyzer?
Of course they are all right. I use a knock sensor, and added like 5* degrees everywhere and pulled it where I got the computer pulling timing. This only works because the computer records knock AND prevents most damage.

It's not the BEST tune, but the car was way faster than it was on my super conservative map. But, after roughing out fuel, dyno time really is worth it.

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so the up-side to being unemployed is having the free time to get a good tune. oh, and to have Uncle Obama pay you while you are doing it. where do i sign up?
That's not really contributing, is it? If you want to start a politics thread go ahead, let's talk about cars here.
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Old 10-08-2009, 04:23 PM   #7
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sorry abe.....wasn't trying to ruffle your feather. i was just busting my buddies stones.
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Old 10-08-2009, 05:28 PM   #8
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:-) Ah, that is entirely encouraged. :-P

BTW, 2,500 hp at 7 psi is pretty good. Do you have an intake?
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Old 10-08-2009, 05:50 PM   #9
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oh, i see your gripe.....signature has been modified. keep in mind that the dyno numbers were before MS, intercooler, and clutch/flywheel.
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Old 10-08-2009, 06:02 PM   #10
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Actually, it was just the missing decimal point. :-) It said 2544 hp or something silly. Who's clutch?
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Old 10-08-2009, 10:58 PM   #11
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Quote:
Originally Posted by evank View Post
1., I had mostly ignored the bottom row (20 kPa) of my VE table, instead letting MLV's VE Analyzer make suggestions with a minimum MAP of 30 .... I've been doing that because Paul taught me all along that MLV/VEA doesn't do well at idle, which should be tuned manually .... he's correct .... but what I didn't realize is that the non-idle cells in that row (everything above 1,000) were super-rich and were ******* with the cells above them, since MegaTune interpolates. So tonight I leaned them out, and now my car runs much better when it's just puttering along at relatively low RPM (2000-3500) in third and fourth gear. Now it feels like an ordinary car in that scenario, not a diesel truck!
I found that I only hit the bottom row (above ilde) during shifts, and running a tad rich on the bottom row makes for smoother shifting. When I go lean on the bottom row, I occasionally get a little bucking while shifting. YMMV.
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Old 10-09-2009, 10:27 AM   #12
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Who's clutch?
1.6 ACT Streetlight 1 piece chromoly lightweight flywheel and a stage 3 clutch. so far it has been great. i was really concerned about using a puck type clutch......but to my suprise it has a very light pedal and manageable engagement.
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Old 10-09-2009, 02:11 PM   #13
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Good to know, I've avoided them - especially ACTs - myself. I've had a SPEC brand stage 2/3 hybrid (pucks on one side, full face on the other). Feels like stock.
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Old 10-09-2009, 02:13 PM   #14
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Quote:
Originally Posted by John151 View Post
I found that I only hit the bottom row (above ilde) during shifts, and running a tad rich on the bottom row makes for smoother shifting. When I go lean on the bottom row, I occasionally get a little bucking while shifting. YMMV.
I think what he's getting at is since the rows are averaged when you are between them, if one if very far off, over time (and multiple auto-tunes) your VE table will drift in the opposite direction in the row adjacent.
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Old 10-09-2009, 06:05 PM   #15
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I think what he's getting at is since the rows are averaged when you are between them, if one if very far off, over time (and multiple auto-tunes) your VE table will drift in the opposite direction in the row adjacent.
I got that. He was "super rich", and is now going lean. I am just saying that my experience is a tad rich in those cells works well for me.
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