Doesn't need rehasing, BUT...
 

After hearing the success some folks (Ben) have had with gas mileage, I decided to revisit the AFR table issue I've back-burnered.

I had a totally FUBARED (complete with negetive numbers and 5 decimal places) my AFR table, my guess is it's an MS-II think... Anyway, so I tried to salvage it, and came up with this:

http://abefm.smugmug.com/photos/336710514_eEMxQ-O.png

Now I'm wondering if these are reasonable. Could someone comment? I took a lot out of the no-boost end of things, since I'm cruising on the freeway (granted, this is a california, 80-100 mph cruise) at <14:1 and it seems dumb. On the other hand, I don't want to burn any pistons.

Anyone like/hate what they see?

I run closer to 13.8 at 100kpa, and 12.8 when crossing in boost and 12.2 when at 10psi.
Why are your Y values in percent and not in Map?

no no no YER DOIN IT WRONG. You're still only going to be at 16:1 in cruise.

You really want to be a tad bit rich at the very low loads for smoothness. Don't be afraid to lean the bitch out in cruise areas. I'm like 19:1 at 4k rpm and 90kpa. The difference between my map and yours is probably 5 mpg.

I'm still getting ~30mpg with the top down and the a/c on, in all sorts of mixed driving, rush hour, boost, and big double tire trails tattooed to the road behind me.

really I wouldn't get leaner than 14:1 above 80 kpa. you dont need to. assuming you're stepping on the gas for a reason, it's better to have the power than not.

then I'd add a row below 20 kpa. or maybe change the 35 kpa row to 30 and the 25 row to 10 or 1 or something small. set the 1kpa row to 20:1 or some ridiculous overrun/engine brake AFR.

above 2500 rpm up to 80kpa, run as lean as you are comfortable with. probably start adding gas back in at 5000 rpm.

cruise, as you'll notice in logs, is primarily 25-80 kpa and 2000-4500 rpm. concentrate on that area and smooth into the rest of the map.

Ben: how on earth do you run 19:1?

I disagree. High speed cruise is >80kpa. The instant I step in it, accel enrichment comes in and adds the extra fuel required for response and power.

Not needed, there's an auto overrun based on MAP and TPS. Save the limited resolution.

I start adding fuel back in around 4200 rpm or so. I have no business with a lean cruise over 85 mph.

I agree that smooth is key. There should be small value changes between a cell and any of the other cells around it. Anyone who has ridden in or driven my car is amazed at how smooth it is, especially in the transition area between vac and boost. Really, if you didn't watch the gauge and couldn't hear the turbo, you wouldn't know it was happening.

I'm at 19:1 because I got some occasional studders at 19.5:1. :fawk: I just leaned it out until the car didn't want me to lean it any more.
Big gaps (.050"), COPs, and lots of timing.

just looked at a commute datalog. barely ever get above 80kpa and that's only when I'm over 20% throttle. ie, passing.

and yes enrichments will eliminate tip in leaning, that's no big deal.

High speed cruise for me is more like 45-55 kpa with elevation variations. I run 16:1 at cruise and allow overrun fuel cut to remove fuel when I let off the throttle. I like that better then setting the target table to really lean on the bottom row because of cell averaging. Averaging two cells from 20:1 to 14.7:1 makes for some weird driving characteristics so I leave my bottom row no leaner then 16:1, overrun does the fuel cut for me very well it seems.

I'm around 16.3:1 average at cruise, getting 29mpg. My car gets a little funny at around 17.2:1. What timing is everyone running at highway cruise at this AFR? I'm around 3800-ish rpm (3.90 torsen) and 38-ish deg's advanced. EGT's around 1250F in 2 cylinders (I only have 1 EGT gage, probe is in rear 2 cylinder's manifold).

did i miss something? what's the deal with the Y axis being percent instead of kpa? and how do you go 205% if it's TPS?

I saw that and ignored it, thinking it's just how the axis is labeled in MSII

this is more or less what i target:

http://www.boostedmiata.com/MS/afrtargets_mlvs.jpg

i'm getting something like 25mpg city only, never over 50mph.

Looking at my logs, it's in the ballpark of 4500 RPM (I'd say 4200-4700), and running around 55-90 kpa, mostly around 75-85.

A long time ago, I was running leaner, and when I went richer, I got better throttle response. I think I need to revisit the whole accel enrich thing.

Do you guys find EAE or the standard TPS/MAP-based one to work better?

The other thing I'm curious about is how is the top end? 32-36*, mostly around 34 is my advance. I've never felt comfortable with my EGT guage, what should I be looking for? I guess I don't know "when to stop", other than no more leaning when it bucks.

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Hey, Ben, post your AFR table, Y8s too. :-) I use overrun, but I do want to get this ballpark in other areas.

What I'm curious about is why stop running lean at higher RPMs? Are you afraid more total gas will heat the engine more? Out here in Cali, it's not unreasonable to cruise at 90, even 100 mph from time to time. 4500 is perfectly reasonable.

Clearly, not destroying the motor comes first, but I'm still wondering how you draw your lines in the sand.

as long as im cruising i don't mind being lean. But i have yet to cruise over 4.2K or so. I believe my targets table on my map has 15.5:1 until 5K. beyond that i blend in fuel simply becuase im probably wot at that point, or have more load.

you guys have NO idea how impatient I am about this!! :-) Speak to me!

http://abefm.smugmug.com/photos/337553637_y9PGT-M.png

Does that look better? I want to actually RUN something maybe tonight, depends....

I took a cell phone video of me driving home at 70 mph and 19:1, but my freakin SD card reader isn't working. :(

When I FIRST put in my MS, I was 18.5-19.5:1 all the time under ~50kpa, and it was fine. Then I richened up the whole map, and got better throttle response. I was comfortable down low with it.

I think I just need a passanger to bump things around in real time. But as targets go, they look alright? I'm more wondering when and how steeply to transition into a power-map up top (on both axis)

Abe's been bugging me offline for a copy of my AFR targets, so here they are:

http://img29.picoodle.com/img/img29/...nm_b2cbf46.gif

The car wants to idle in the mid to high 14's, and I threw that 13.5 cell down there at the bottom to give it a little extra oomph back when I was having some idle problems. That probably needs to be raised back up a bit...

I'm not running nearly as lean in cruise as some, principally out of fear. I only just started leaning it out and have been watching the EGT gauge faithfully. I think I've still got plenty of room to go.

Like others, I start enrichening at the higher RPMs simply on the grounds that if I'm 6,000 RPM to begin with, I'm probably more interested in power than economy. I also think I need to lean out the 100 kPa row just a few points, just haven't gotten around to it.

That seems like an awfully lean AFR to be able to idle.

I tune to this AFR target table

Edit. My 101kpa row seems a lil high to what some of you are running. When I was running the stock ECU with my UEGO I could see the factory had the thing at 11afr at WOT over 4000rpm, even saw some 10s. I didn't want to deviate too much from that so I settled on 13. Truth is I don't think I am ever at/near 101kpa. I'm either cruising or boosting. I get at least 27mpg city and I drive the car hard. This is my daily driver miata with the 2554. the other car is at least 30mpg

http://abefm.smugmug.com/photos/337580386_Ebr5q-M.png

Ok, that's what I got. How's my table-by-committee going now?

below 2000 rpm, your drivability will suffer. run it all 14-14.6 up to 100 kpa.

and same with 90kpa and greater up to, obviously, where you put safe in-boost AFRs.

And i doubt you want to run leaner than 12:1 anywhere at 15 psi.

Before you burn a new AFR map, please do some reading up on reasonable AFRs. This is getting out of hand.

That's kinda why I'm asking here - I see so many ridiculous numbers everywhere.... People making power I tend to respect tend to be in the low 12 AFR's in boost. I've seen people say you never want to be above 9 or 10. It seems most of the dyno tunes are in the 12.2 range.

the car does idle just dandy at 18 or 19, but I think you're right. Then again, I manually tweaked those cells. :-)


ex:
http://www.russmarshall.com/v/cars/c...geViewsIndex=1
blue and purple lines made the most power

Not arguing, just confused...

it's less about absolute power (remember, you run california 91) and more about street reliability and margin of safety. your map was in the 14s at moderately high boost. I'd call that risky for a california gas street car.

have you calibrated your WBO2 lately?

Yeah, I have, and you're right, the map was a bit generous. But it's all for naught. Remember how I said my tables were messed up? Well, not everything is messed up, and I have no idea why. Flashes aren't always sticking, MSQ's come up weird. I'm at a total loss, but with an all new computer and untested software and the old reliable stuff gone I don'[t know if it's my soldering or my software.

UHG!

Maximum power with gasoline happens at about 12.5:1 AFR. Any richer than that is just safety margin aka charge cooling by the evaporation of excess gasoline. IOW: PCPro.

I've been gradually (very gradually) leaning my table overall in recent weeks. I think I could probably loose another .5 or so across the board and still be in the safe zone, but as Y8s correctly points out, I'm ultimately willing to sacrifice a few ft/lbs for a margin of safety. It'll be interesting to see what happens in a couple of weeks when my car gets it first tankful of NC 93 octane.


Sucks that you couldn't make it up tonight. Chris & I explored some really interesting beers, including one Russian Imperial that, despite being 10% ABV and quite strong, had just a touch of creamy sweetness about it- it was rather pleasant.

thread jack: joe, i tried some allagash dubbel the other day. very tasty, very belgique.

also there's this one rogue hop beer (I think) that's $39.99 for a 12oz. what's up with that?

Some time ago, I leaned out the top end, richened up the bottom, and (how many times can the car get unimaginably better? Does it get worse inbetween these? each time it gets better it seems it can get no better) got so much faster! I was shocked. So keeping the top end reasonably lean is a Good Thing. Seems like 12.0 is as low as you really want to go?

Damnit, I know. Turned out good - and a friend's (Leo) MS up and died on him as well. His I just turned on, everything looked great, put it back on the car and called it good (tweaking accel enrich so it wasn't a wash coming out).

My own box... I dunno, I could flash it, but it seemed any msq I wrote to it would start to upload, then somehow it would corrupt where it stores the information about reading system voltage. Then it would refuse to write the rest of the pages since the voltage was too low. Very odd. Different combinations of old MSQ's and MT 2.25 p1/2/3 and s19's left me really confused.

I took the MS out, resoldered all the pins on the CPU socket, reseated the chip.. I'm not sure what CAUSED the errors and corrupted so much stuff that had worked reliably before... But it seems to be good again as long as I don't load an MSQ from the last month or two.

So it's all up and working. The car seems to be fine, except for a small part right at 4200 rpm, where the table is pretty flat and I don't see why, but it's bucky and bouncy. It certainly takes more throttle to get down the road, but I imagine it is saving gas, and the throttle response is good. It still seems to be the transition into high RPM at low load that is a bit odd.

And, as an aside, I figured out my idle is doing something weird. My "integrating, decaying derivative" is decaying WAY too slow.. :-P