Everything there is to know about MegaTune Auto-Tune

Forum for discussing Tuner StudioMS tuning & datalogging software.
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Read the manual to see if your question is answered there before posting. If you have questions about MS1/Extra or MS2/Extra or other non-B&G code configuration or tuning, please post them at http://www.msextra.com The full forum rules are here: Forum Rules, be sure to read them all regularly.
sohc96neon
MegaSquirt Newbie
Posts: 3
Joined: Tue May 04, 2004 2:14 pm

Post by sohc96neon »

Quick question. What do I change to get the auto tune to work. I have the rpm broken down at 1000rpm segments an my map in 10kpa segments. When im watching the screen it auto tunes untill approx 300rpm over my rpm bin. It will either say outside tunning window, or outside vertex? Im happy with the results sofar, It has only changed my map around 2-5% in the area it works. Any ideas what parameters to change? Thanks

Tom
176HP, 147TQ
MegaSquirt'N neon code 14.03@99.7 All motor on street tires
Scott
Running MegaSquirt
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Joined: Sat Apr 03, 2004 10:38 am
Location: Colorado Springs, CO / USA

Post by Scott »

T3Bunny wrote:Isn't the programing language differant for the MS-2 though?
I believe the programming languages are different by choice rather than necessity. The idea being that more people are familiar with C than with ASM so development, like has happened with the Extra code, would proceed even more quickly with more people contributing. (It's hard to imagine code changes happening more quickly though, I can't keep up as it is.)
whittlebeast
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Post by whittlebeast »

McNugget

Be careful having the 02 range anywhere near 100%. When your VE map moves from an area the is requiring 50% leaning and then moves to a point on the VE map that needs more fuel, it would take a comparatively log time to step from -50 all the way to +75 that is required at the new spot.

I use about 15% authority and use autotune until I seldom see the 02 driven fuel % GEGO correction go over about 5%. Remember that the AE will slam the GEGO correction to 0% If it just came from +95 o2 correction, you are in for a real surprise. High power tuning can ONLY be done using Target AFR and having different target values for cruse thru High load. Using a narrow band for this can be done but is sketchy and should only be done to home in slowly on the high-speed settings. I use the rule never allow the o2 to swing thru stoch when on the power. If it does, immediately add a few clicks more fuel in that area and retest. This is not the time for a top speed test or a quick test at the 1/4 mile. That feel in your gut when you get a look at the pistons will be your most memorable part of the evening.

When ever you are tuning with Autotune, drive very smoothly and move your right foot as little as possibe to give MT time to find the patterns. Turn your AE down for triggering and amount during this phase. High speed foot movement and the holes in the fuel dilivery are later tuned with AE AFTER the VE table is close ( +/- 5% most of the time) IF using the late versions, I have had far better luck tuning AE with the RPM driven AE.

Have fun tuning

AW
efahl
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Post by efahl »

sohc96neon wrote:Quick question. What do I change to get the auto tune to work. I have the rpm broken down at 1000rpm segments an my map in 10kpa segments. When im watching the screen it auto tunes untill approx 300rpm over my rpm bin. It will either say outside tunning window, or outside vertex? Im happy with the results sofar, It has only changed my map around 2-5% in the area it works. Any ideas what parameters to change?
Tom,

I'm not sure what behavior you want to change? It sounds from your 2-5% changes that you are already near a pretty good tune. Do you want it to move faster? (Faster == less accurate, slower == more accurate by virtue of the auto-tune algorithm.)

If you increase the radius parameters, which would allow tuning farther from a vertex, then you will be changing the wrong vertex (typically four are involved at any given time, but auto-tune only changes the nearest one). The radius parameters try to minimize this error by only tuning when the nearest vertex has overwhelming influence.

If you change the limits, then you don't change the accuracy or speed, just the region that is valid for tuning. If you want to auto-tune with MAP over about 80 or 90, then you almost certainly need a wide band lambda sensor.

Look at the bottom of your car1/custom.ini file and read the descriptions there, see what looks reasonable and then ask here to verify if you need to.

Eric
sohc96neon
MegaSquirt Newbie
Posts: 3
Joined: Tue May 04, 2004 2:14 pm

Post by sohc96neon »

Eric, Thanks for the tips. Im currently running a wide band and the wot has been set using a dyno ,so I dont need it to tune there. My main problem is with having a big cam in a 4cyl it wants lope at low rpm cruising and the afr goes from 12.8-15.5. Ill try and change the parameters and get it to correct past my rpm bin.

Tom
176HP, 147TQ
MegaSquirt'N neon code 14.03@99.7 All motor on street tires
Mike Bonkalski
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Joined: Tue Sep 07, 2004 12:34 pm
Location: Geneva, Illinois

Post by Mike Bonkalski »

Dumb question... Will auto-tune work with Alpha-N?
'71 Porsche 911 Targa RS
'02 Saab 9-5 Aero
whittlebeast
Helpful Squirter
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Post by whittlebeast »

yep
hudsonhawk
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Post by hudsonhawk »

Autotune rocks. In just 2 quick drives I was able to make a VE table that is good for about 80% of my driving. Just need to start on the upper MAP areas.
'72 CJ-5 w/'83 AMC 258 running a late 80's GM TBI controlled by MegaSquirt.
McNugget
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Post by McNugget »

Ay, thank you again!
tyrone27
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Post by tyrone27 »

u have to have a wide band to use this? can u have a narrow band?
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