Tuning {A0009}

[lplott]

For you guys running FI: How did you tune {A0009} after running the AutoVE? The Custom OS makes {A0009} very rich and I am curious (before I start this process) how you are tuning {A0009} to its optimum (as lean as possible without KR, is this a good parameter/goal?)

Lonnie

[ringram]

you can use autotune method with % error from what afr you want vs what afr you are running. (ie) you can create a map with a calc pid which divides the data by 12.5 or whatever.

(eg) actual = 13, afr calc pid = actual/12.5 = ben factor

If you want different afr at differnt boost you will need to make other maps, but Id say this was a reasonable method, so if you havnt got a WBo2 yet, now is a good time to ask santa for one.

[caver]

Hope I didnt misunderstand your question.
Once the autove is done properly then commanded = actual.
Therefore you enter your desired afr into the table and its done. Just need to double check your final mixtures.
From my experience best power for na motors at wot is around 13 to 13.2 afr blown needs to be around 12:1 I run low map values at 14.63 thereafter blending it to the desired wot settings.

Course you can still enable PE mode and command afr based on rpm

[lplott]

Caver: That was about what I was thinking. Start out A0009 really rich (maybe 11:1) as the tutorial says. Log the WOT, monitor KR, make a small adjustment (0.1) to lean out WOT, blend the MAP, log again, monitor KR, etc.

Keep this up till I get to 12:1 or KR starts. Richen up by 0.1 and montor for a while to ensure KR doesn't return.

During this process monitor the spark PIDS to make sure timing isn't being pulled for reasons other than KR.

This will probably have me running a little rich, but better safe than having new cigar ashtrays.

Thanks for the help,
Lonnie

[dfe1]

Something to keep in mind-- if you're running catalytic converters, an exceptionally rich mixture (like 11:1) can toast them. If you need to run that rich, you'd be smart to remove the converters until you have finished tuning.

[lplott]

dfe1:

What is the richest you would recommend with the CATs installed? 11.5:1 ? I really do not want to toast them, Random Tech High Flows.

Thanks,
Lonnie

[GMPX]

Something to keep in mind-- if you're running catalytic converters, an exceptionally rich mixture (like 11:1) can toast them. If you need to run that rich, you'd be smart to remove the converters until you have finished tuning.

Interesting dfe1, I have seen stock LS1's running in the 10's with the factory tune (cat protection, cmd AFR's in the 11's).
But then I have also been told the std converter does not like getting hot, which is why cat protection exists.

Cheers,
Ross

[dfe1]

In my experience, it isn't so much the air/fuel ratio that's critical, it's the amount of unburned fuel in the exhaust that causes problems. When experimenting with air/fuel ratios, it's difficult to determine at what point the amount of excess fuel becomes critical because it differs with each engine, and with placement of the O2 sensor. A ratio of 10.5:1 in one engine may not cause problems while an 11.5:1 ratio in another will cause converter overheating. I've also seen problems from excessively lean mixtures when they result in intermittent misfires. Retarded timing is another factor. (You can easily see this with EFILive-- just look at B5901, Spark retard to assist in converter light-off on start-up.) Pulling the spark back increases exhaust pollutant levels so the converters get hotter quicker. Since B5901 settings are only active for 80 seconds or less after sart-up, there's no potential for overheated converters.

The important point to remember is that the intensity of the reaction initiated by a catalytic converter is directly proportional to the amount of hydrcarbons, carbon monoxide and oxides of nitrogen in the exhaust. Many times, excesses of these compounds occur when not expected-- mild acceleration, deceleration, and throttle transitions. Even though the system may be operating in closed loop during these conditions, momentary lags in fuel correction can result in blips of excess fuel reaching the exhaust system. Usually these "indiscretions" are of short duration and don't cause any harm, but during repetitive testing they can stack up enough to be a consideration.

At wide open throttle, there's enough air flow to keep the exhaust moving rapidly through a converter, so to a degree, the potential for damage is lower than if excess fuel is being dumped in at idle. With the low air flows associated with idle conditions, it doesn't take much in the way of excess fuel to get a converter to glow red.

I didn't mean to alarm anyone, I just wanted to point out that there's a risk when arbitrarly throwing a bunch of fuel into an engine. You should be safe if you keep wide open throttle AFRs between 11.5:1 and 13:1 and keep WOT bursts to five or six seconds until you get the tune sorted out.

[lplott]

Thanks DFE1. I hadn't considered what all that extra fuel would do to the cats.

I get the LC-1 bung installed next Monday, and if the weather stays nice (in the 40s), I should be able to start the Idle Transition tuniing.

Let the fun begin.

Lonnie