Everything there is to know about MegaTune Auto-Tune

[Mike_Robert]

AW, very true! The TE units, in my personal experience, have firmware variables the advanced end user can fool with to adjust the averaging, etc. The actual WB sensors are fairly fast acting but this makes the usual A/FR displays that lots of folks use seem to jump around a lot which is unacceptable to the marketing people. Experimenting with this facet of the WB unit I use took a while but I am now able to clearly log/see the short tipin transients, etc., that are tough to tune out if you're getting .5 second averaged WB data.

-Mike

[McNugget]

What firmware are you running? Do you have the EGO correction parameters set to limit the RPM for EGO correction? Do you have a wideband lambda controller and sensor? (This is really necessary for doing any medium- to high-load auto-tuning.)

Hi Eric,
I use 025x1 and the 2.25b627 MegaTune. I have no wide band

My Ego correction parameters are set to 32 cycles and a stepsize set to 1. The Limit is set to 100% so it can do everthing with the VE table.

So you meen I should do a rolling road and set the parameters with the help of some professional... ?! Yeah that would be a great idea, but its very expensive.

Timo

[efahl]

Andy, did he give you a sense for how big the latency can get? I'm wondering if my default 1.0 second between adjustments is enough. Maybe the code should watch RPM and VE, trying to scale the time depending on volume flow...

Eric

[muythaibxr]

AW, very true! The TE units, in my personal experience, have firmware variables the advanced end user can fool with to adjust the averaging, etc. The actual WB sensors are fairly fast acting but this makes the usual A/FR displays that lots of folks use seem to jump around a lot which is unacceptable to the marketing people. Experimenting with this facet of the WB unit I use took a while but I am now able to clearly log/see the short tipin transients, etc., that are tough to tune out if you're getting .5 second averaged WB data.

-Mike

I've noticed maybe 2-3 tenths of a second lag on my friend's techedge, but I can still see everything that happens. What did you do to speed your techedge up?

[T3Bunny]

The amount of room left for new features in extra is ZERO They are now sharing bits for start up features with a feature in traction control as they will never happen at the same time. Thatss how full its getting.

Andy, I am probally oversimplifying this... But can't we just use another processor? I am having trouble finding the specific one we are using now in the Digi-Key catalog.... But down towads the bottom of the HC908 page there are some choices that seem to be very closely compatable, but with more room. Looks like we would just need an adapter to plug it in.

Where do we need to increase the size? Is this the flash, ram or eprom?

[McNugget]

This is what MSII is for

This CPU has much more room and is BTW much faster.

[efahl]

T3Bunny wrote:

> Where do we need to increase the size? Is this the flash, ram or eprom?

RAM. If you could adapt a 908 with 768 bytes of RAM in there, Extra
could conquer the Solar System.

--
Eric Fahlgren http://www.not2fast.com/



Posted by email.

[Scott]

To easily find the processor we are using, go to http://digikey.com/ and paste "microcontroller" into the search box. Then choose microcontrollers. Then choose "Freescale" from the Vendors list (far right side) and 40-DIP from the Package/Case list and click Apply Filters. At the bottom if the list is the processor we use, MC68HC908GP32CP, identified by the FLASH memory type.

If you go back (or open another tab) and choose MC68HC908 from the controller series list and choose a suitable number of A/D channels from the I/Os list, you'll find several possible substitutes for the processor we are using. For example:
MC68HC908AB32CFU
MC68HC908MR32CFU

All that was just to show you an easy way to find substitute options for parts at DigiKey.

My opinion is as was stated earlier. That's what MS2 is.

Sure it's possible to build an adapter board. At first glance, it even looks like a simple thing to do, but there are a lot of little details that have to be covered to make a different processor work. Also, if someone were to go to the trouble of doing so, they would be duplicating the MS2 efforts of Bruce and Al, and at the same time they would be undermining the development of the MS2 embedded software. I believe the effort spent on another processor should be focused toward the MS2 rather than fragmented from the existing one.

[T3Bunny]

....Also, if someone were to go to the trouble of doing so, they would be duplicating the MS2 efforts of Bruce and Al, and at the same time they would be undermining the development of the MS2 embedded software....

Your right with this! Thanks for the Digi-Key tutorial! Thats a lot easier than the paper catalog once you figure out how to use it.

Yeah, the question was more to gain an understanding of it all than anything else. I figured if it were as easy as just popping in another cpu, somebody else would have done this.

Isn't the programing language differant for the MS-2 though? (Sorry for taking this thread off track....)

[efahl]

So you meen I should do a rolling road and set the parameters with the help of some professional...

Timo,

No, you don't need to go to the dyno shop to get the high output regions of the VE table done, but you definitely should NOT use auto-tune with a narrow band sensor for that part of the table, you'll end up with broken or melted pistons. In order to use auto-tune for WOT tuning, you must be running a wide band lambda system (sensor and controller), with an appropriate EGO correction algorithm that allows you to set specific AFR targets (i.e., MSnS-Extra or MS-II). If one of these requirements is missing, then you must rely on seat-of-the-pants and experience.

Do use auto-tune with any algorithm and any sensor to tune the low-power part of the table, it will get you to stoich (or AFR targets) quite nicely, which will give you a starting point from which to extrapolate the high-power part.

Eri