Lotta fun with Megasquirt, Autotune, tunes while you drive Options

[DNHunt]

I downloaded a newer version of Megasquirt with autotune. It uses a wideband O2 meter to adjust the air fuel mixture to a target while you drive. The targets vary according to RPM and manifold vacuum. I have a high of 14 at cruise and a low of 12.6 at WOT. Megasquit keeps adjusting until the amount of fuel gives the desired voltage from the O2 meter. It speeds up tuning a ton. (IMG:http://www.914world.com/bbs2/html/emoticons/smilie_pokal.gif)

It's cool to see it changing without any key strokes on the computer. There are a couple things to consider (there always are). Tuning is only as good as the O2 meter and the air fuel mixture is just a number pulled out of the air. It will not tune the ignition side of the ECU. So, when I get everything sorted out and the engine well broken in it still goes on a dyno.

Dave

[nsyr]

Sounds great. i have ms2 v3 that i will be using in my suby conversion and i am a bit nervous about the tuning. seems like this will help with not getting things screwed up.

[Tom Perso]

Hey Dave,

Nice to hear that - I upgraded the firmware on my MS v2 to that same level. It will be interesting to see how well it works. I plan on using an Innovative Motorsports LM-1 O2 sensor.

Tom

[DNHunt]

Andrew

Play with it on the stim first to see how the gauges work and stuff. When you get it in the car get the thing running then play with it at idle. Mess with the constants such as opening time and pulse width modulation etc all at idle. Play with the VE table and the tuning screens. The worst that will happen is it will die. Play with afterstart enrichment and warmup enrichment. When you feel comfortable take it on the road and do some tuning. Save the files as you make changes cause you can always go back. Get a good wideband O2 meter and pay attention to it while tuning.

Tom

The auto tune is pretty slick. It's tough to use it at high RPM and low vacuum cause you just don't linger there for very long, but, it will tune cruise very quickly.

Dave

[bd1308]

so what if you dont have any data for the high RPMs....

does it guess?

b

[DNHunt]

Britt

Autotune will tune it BUT, I quess I'm not willing to gamble with that part of the fuel map. I like to start with lots of fuel there, like a reading of 11:1 with the O2 sensor. It runs like a dog with that rich of a mixture. Then I datalog some accelerations and look at the datalogs with the MS viewer. I look for places where the MAP and RPM match my VE grid and then I back out a little fuel at these spots. I repeat as necessary until I like the way it feels and the air fuel ratio is safe. The final tune will come on a dyno.

Dave

[Hydra]

I've just received my MSI v3, i'm right in the process of assembing it, and it's gonna go on my EJ20 suby conversion, from what i've read on MS's forum autotune is still somewhat unreliable, did you run into any problems? i've read about guys saying sometimes it leans out the misture a bit too much etc...
Now for a small highjack, how are you guys running ignition on your suby engines? is any of you using MS'nS extra for ignition with the wheel decoder software? i'm planning on running ignition straight from MS (using 4 VB921 high current ignitors) , and would really appreciate any help i can get... i'll be going for COPs if all works out well, with a bespoke laser-cut 36-1 wheel, and running ignition directly from MS appears to a real PITA, on the forum they say it's a difficulty 10 on a 10 scale...
So from your experience guys, am i being too crazy trying to run injection AND ignition from MS?
thanks.
Nick
p.s: how many people on 914club are using MS? any idea anyone ?

[lapuwali]

I'd use something with less teeth than 36-1. With the 8-bit processor (i.e., not MSII), the interrupt load gets pretty nasty with too many teeth. An Electromotive 60-2, for example, is way too much. By the time the interrupt code completes one round, the next tooth is already triggering another one at high revs. The 16-bit processor in the MSII can cope, but the 8-bit processor has a hard time, and is operating pretty close to the limit as it is. Later extra code revisions may make it impossible to use that many teeth.

You also don't really need the resolution the 36-1 wheel gives you. Subaru themselves use under 10 teeth (it's an odd wheel, and I can't remember the exact number of teeth), and I know of plenty of very high rev bike ignitions that use (for example) 8-1 or even 6-1 successfully. Hell, Suzuki used to only have one tooth on their ignition wheels. With only one tooth, your maximum error at 8000rpm is 2.5 degrees, which is still going to beat the average distributor. With a 4-1 wheel, you're under one degree in max error at the kinds of revs a Subaru will see.

EDIS uses discrete components or an ASIC in their ignition box, and it probably uses 36-1 because it made their implementation easier, and EDIS takes all the load off the MS processor for the precise triggering of the spark. I know fiid is using EDIS to trigger his car (turbo Soob 914) quite successfully, and it's a lot simpler than a COP setup.

So, if you haven't already made the wheel, try an 8-1 or a 4-1 wheel instead of a 36-1 wheel, and the code will be a lot more stable. Alternatively, using the EDIS setup and your 36-1 wheel is proven and stable.

As for doing both, you don't really have an option on the later Subaru engines, as there's no distributor.

[DNHunt]

The MS 1 8-bit processor is full to the gills. They are out of memory. I'm using MS 1 on a v2.2 board running MSextra 024s13 code just to buy time. I have the board and components for MSII and V3 in the garage, but it doesn't have the features I want yet so everything is gathering dust. CAN is on the way with a router board just like the Carerra GT.

I kept the dizzy on my rebuilt engine so i can run a second wheel; right now it just has pointer to TDC #1. Sequential injection and COP is on the way.

Dave

[airsix]

QUOTE (DNHunt @ Jan 14 2006, 08:25 AM)

The auto tune is pretty slick. It's tough to use it at high RPM and low vacuum cause you just don't linger there for very long...

Dave, that's what big brakes are for. (IMG:http://www.914world.com/bbs2/html/emoticons/biggrin.gif) Second gear, hard on the gas, hard on the brakes. Ease it up from 30 to 50mph and you got it. (IMG:http://www.914world.com/bbs2/html/emoticons/wink.gif)
-Ben M.

[fiid]

I'm still using MSTweak for my tuning. From what I've read, the autotune stuff works reasonably well, but what I really want is to have it work against an AFR target map (which MSTWeak doen't do either.... (IMG:http://www.914world.com/bbs2/html/emoticons/sad.gif) ). I need to aim for richer AFRs as I start to pass 150KPa (IMG:http://www.914world.com/bbs2/html/emoticons/smile.gif).

I wish it would stop raining - I need to drive my car... (IMG:http://www.914world.com/bbs2/html/emoticons/biggrin.gif)

[yarin]

QUOTE (DNHunt @ Jan 14 2006, 05:09 PM)

The MS 1 8-bit processor is full to the gills. They are out of memory. I'm using MS 1 on a v2.2 board running MSextra 024s13 code just to buy time. I have the board and components for MSII and V3 in the garage, but it doesn't have the features I want yet so everything is gathering dust. CAN is on the way with a router board just like the Carerra GT. I kept the dizzy on my rebuilt engine so i can run a second wheel; right now it just has pointer to TDC #1. Sequential injection and COP is on the way. Dave

Are you talking about installing a wheel spun off the distributor? Has anyone done this?

Where can i find more information about running custom wheels for spark? I was considering doing the ford EDIS but haven't commited to it yet.

What are my other spark options with MS II v.3?

Thanks

[lapuwali]

Actually, you probably don't want to use MSII just yet. It's real bleeding edge, still. The MS1 extra code is actually more advanced and more stable at this time, simply because it's been around longer.

MS1v3 with extra code and EDIS is the most widely used and most stable setup right now, closely followed by MS with a distributor and simple advance control from MS. These are more than adequate.

Lots of Chevy guys use the HEI distributor, which is essentially a wheel mounted in the distributor. Some use the HEI ignition controller (which can provide a tach signal for MS), but a few may also use the wheel decoder code, as well. There are quite a few OEM distributors that have a Hall effect or VR sensor wheel in the distributor, in fact. On a Type 4, you can use a Pertronix/Compufire/Crane system to trigger the MS using a locked 009 (no advance curve problems, as MS controls the advance), or a Mallory Unilite if you happen to have one already.

If you want to try your hand at some homebrew trigger, you can get Hall Effect or VR distributor sensors from GM/Nissan/Mazda/etc distributors, and try to rig something up.

My plan of attack this summer on my MS system on my Type 4 will be to go fuel only first, then either use the Unilite I have on the shelf as the trigger, or one of the many 009s I have lying around with a VR trigger and a 4 tooth wheel. I have little interest in trying DIS ignition right now, and mounting a crank wheel is just too much trouble. My goals are drivability and economy, not all-out power.

[Tom Perso]

I'm still up in the air with my ignition triggering. I have a good Mallory Unilite which is more than likely what I will use to start off with. Dave's crank fire's solution is elegant and seems to work, I just need the time to do something like that.

Plus, just getting the fuel delivery right first will be a challenge. I should only fool with one variable at a time.

Tom

[DNHunt]

The system I'm using is really working well, but I want to switch to the new chip to get more resolution in pulsewidth. That could pay some real dividends as the A/F mixture will steady out. Most people can't tell that it jumps around some with the MSI but, I can. MSII also offers a more sophisticated closed loop fuel control. MSII on the version 3 board will do what I am doing now with MSI but I want to let the more adventurous work the bugs out.

I would like to do COP eventually just because it can be done. Some weekend this winter I'll put the V3 board together and get MSII running on the stim in preparation for the code version I will want to run. I know that second wheel support is in the works with a version of code a couple of releases from now and the router board is being tested now.

I'm stuck with my 36-1 wheel since it's was part of the rotating mass Jake balanced (I've learned you don't mess with Jake's balance). So, whatever I do will involve a 36-1 and VR sensor. Of course that's not all bad because there will always be support for that configuration. I'm kind of looking at a Vanagon distibutor for the second wheel. I believe they are an optical sensor and fit right in. Otherwise, I think I have a dizzy with a pertronix in it.

I look over the MSEFI web site everyday and it is still hard to keep up. It's a rare day when there isn't some change to something. It's amazing what people are doing and since the MSII code is in C I expect it will develop farther. Being a more robust processor than MSI it has more onboard potential. Add to that CAN and slaving more boards and who knows what's up.

Time to start learning C

Dave

[stock93]

Dave,
Thanks for the post. I always like to hear about someone elses experiences with MS. I know the vanagon distributor through 82 used points. I don't know what they did when they went to watercooled.

John

[crash914]

I am still waiting for my MS2 chip....I guess I could download the latest megatune software and give it a go...

the auto tune looks like it should be the bomb...hope to give it a go in the next couple of weeks...

[Rocky]

Dave, heard and saw you buzzin Hwy 16 yesterday and today. Sounded real good! (IMG:http://www.914world.com/bbs2/html/emoticons/clap.gif) I was walking the dog on Cushman Trail both times. Nice break in the rain the last 2 days allowed me to break out my garage queen and put a couple hundred on the odometer. (IMG:http://www.914world.com/bbs2/html/emoticons/driving.gif)

Rain, rain go away...

Tim

[Gary]

Some pretty cool stuff going on over in the megasquirt forum. 2006 is shaping up to be an interesting year. Check out the microsquirt controller and GPIO board. The fast WBO2 controller looks very interesting but less mature...

[DNHunt]

Hey Rocky good to hear from you. I've been terrorizing the 24th St on ramp for tuning the FI. This thing is so loud I'm afraid to run through there to much. We need to get together soon.

I'm still drying out from last weekend at Bremerton.

Dave