Target AFR tables

[Steve Arndt]

Max,
Have you tested it? 15.2 isn't very far from peak temps. I am tuning for 16:1 in that range.

Pile,
What is your idle timing like? DO you have a separate map for idle timing?
At 1000 rpms and 50 kpa you are giving it 24.2 degrees. What are your idle values? My base idle timing is 10 once warmed up. My cranking timing is 2*.

Steve

[supaninja]

Hey panel, that's a old fuel map, I'm running about 15.5:1 right now with a bunch of timing, 44 deg. at WOT (I'm NA still) 12.5:1 and 35 degrees. My motor likes it, don't be scurred to run a little leaner if you got control of your ignition, it's the distributor advance curves that limit how lean you can run at cruise.

I want to see alred's fuel and spark maps, he's getting 50mpg's and runs some stupid fast times on the quarter.

[Piledriver]

has a ~6 point table, Idle timing is separate function, it gets auto tweaked to maintain idle speed.
It varies from 40-10btdc, below ~10 btdc changes make no discernible difference other than driving cht up..

I have fuel+ignition cut set to kill instantly, kicks back in just above idle speed, helps fast shifting.

I'd like to see Erics tables myself, but there's more to it than just the ECU programming, I'd probably be @~50mpg there with him with smaller heads and a tighter deck. 2L 914 heads on an almost stock 1.8 were ridiculous, but handy.

[supaninja]

I got small heads and tight deck too, without barely trying I hit 40. I wish I had more time to play with the tune.

[Max Welton]

Max,
Have you tested it? 15.2 isn't very far from peak temps. I am tuning for 16:1 in that range.

I've been running that way for about two weeks. My CLT is in the head so, while it doesn't read accurate CHT, it does show trends nicely.

But in my logs, my cruising AFR has been in the mid 15s. I didn't have a second baro (and where I live, it matters) so it was hard getting it to behave consistently. So I used ego quite a lot, which tends to chase a bit.

I added my 2nd baro just yesterday, so I've been retuning. If it gets more predictable, I may change the lean region to 15.5. When my AFR goes much over 16 I get a bit of lean-misfire.

Max

[supaninja]

16.1 is where I lean-mis too, 15.5 is nice and solid with enough overhead.

[subwoofer]

I thought the BSFC was lowest at 15.4 rather than 15.2, but I am planning to do much the same for my WBX. But I will use table switching to avoid landing in-between the lean target and the full power target.

[subwoofer]

16.1 is where I lean-mis too, 15.5 is nice and solid with enough overhead.

According to the aircraft boys, it does not actually misfire, but the cylinder-to-cylinder output gets out of balance - thus a really rough running engine.

[Max Welton]

16.1 is where I lean-mis too, 15.5 is nice and solid with enough overhead.

According to the aircraft boys, it does not actually misfire, but the cylinder-to-cylinder output gets out of balance - thus a really rough running engine.

I just know my butt-dyno doesn't like it.

Max

[supaninja]

ya you can hear the difference, engine tone changes and it clearly gets "rough".

Max- LOL

[panel]

I want to see alred's fuel and spark maps, he's getting 50mpg's and runs some stupid fast times on the quarter.

I'd like to see Erics tables myself

Here ya go.......

http://www.msextra.com/forums/viewtopic ... ce#p277302

[Piledriver]

Does he stop by here anymore?

[nic]

Here is mine.

2332cc 42mm inlets cb quick tune setup.

Any advise on the table would be appreciated!

[Frank914]

Hi Pile,

could you please so kind and post your AFR and Ignition Table again.
I'm running almost the same engine in my 914 and it would help me with my tune.

Thanks and best regards,
Frank

Here's what I'm currently at, 1.8l T4, 2L 914 heads, Widened Vanagon plenum w/2L runners, web 73, EMW/Bursch/Bugpack muffled Tri-Y exhaust, full sequential w/LS2 coils and Pulstar Iridium plugs
(just to try them. They DO kick amazingly hard with these plugs) for fun.
Running Gslenders latest (v2.6), biggest change here tuning wise was using the MAP oversampling/averaging code from MS3. That change eliminated my max VE changing from ~115>85 in ~500 RPM@4200-4700 RPM.

(and fixing my AFR sensor install, was throwing AFR readings off .5-4+ full points, this was essentially reverse engineered from what my ass dyno said was good and was really running for ages)

14.1 is ~stoich with local E10, vs a heated NB I ran breifly as a test.
'include AFR target" turned OFF.

EDIT-reposted pics with out the rpm scale cropped off...

NA, running fixed fuel pressure.
65 MPH and ~60 MAP @~3200 RPM is cruise.
Idles ~45-50.

AFR target:
Piles-Square-afrtarget.jpg


Timing: Not as scary as it looks. EGT/CHT say this is about right for this motor.
This engine also seems to be "knock proof" as I ran it for quite some time 27 degrees advanced due to some "extra" timing marks on the fan I installed... CHT and EGT were much cooler then
Piles-Square-advance.jpg

VE1: (MLV/VEAL set on "very hard" has been in the noise for awhile)

Piles-Square-ve1.jpg

[Piledriver]

Here's a project backup, custom dash and all...
You need to change the suffix to .tsproj to import.
(had to change to load here, its probably .tgz or such, compressed in any case.)

You need a decent ignition, I use ls2 truck coils with the advanced IDEAL brand SS mounts.
(securely hose clamped to the intake runners )

When I could get irdium pulstar plugs I reliably ran 22:1 afr at cruise.
I eventually only ran them in the summer as the motor overcooled under ~70F weather.
Nothing else I tried allowed better than ~18.5:1 reliably.(no detectable misses)
They stopped making them of course.

running at 22:1 chopped~75f off cruise cht in 100+ degree OAT.