Questions about MS3 soft rev limiter
#26
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On AFR safety limit cut, MSExtra recommends a short spark cut before fuel cut to not further lean due to the sucking off of the wall puddle. No comments on cats or using that on other fuel cut situations. So, I have recently set up AFR safety for 0.02 seconds of spark cut before fuel cut.
I have not had AFR safety cut occur for some time, however, because EAE.
I am still using the soft rev limiter fuel cut. I recently changed the Soft Limit zone from 200 to 150 RPM, and that works well still.
I have not had AFR safety cut occur for some time, however, because EAE.
I am still using the soft rev limiter fuel cut. I recently changed the Soft Limit zone from 200 to 150 RPM, and that works well still.
#27
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On AFR safety limit cut, MSExtra recommends a short spark cut before fuel cut to not further lean due to the sucking off of the wall puddle. No comments on cats or using that on other fuel cut situations. So, I have recently set up AFR safety for 0.02 seconds of spark cut before fuel cut.
I have not had AFR safety cut occur for some time, however, because EAE.
I am still using the soft rev limiter fuel cut. I recently changed the Soft Limit zone from 200 to 150 RPM, and that works well still.
I have not had AFR safety cut occur for some time, however, because EAE.
I am still using the soft rev limiter fuel cut. I recently changed the Soft Limit zone from 200 to 150 RPM, and that works well still.
#29
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Would you mind my asking you for the rest of the settings you have there?
I'm guessing you let the rpm come down to a few 100 below the cut so you're not railing the limiter?
What's the load and RPM you have for the settings.
Wait is 0.02 secs. How long do you kill spark for?
I'm guessing you let the rpm come down to a few 100 below the cut so you're not railing the limiter?
What's the load and RPM you have for the settings.
Wait is 0.02 secs. How long do you kill spark for?
#30
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I will attach my settings, yes, along with some logic: They weren't all what I had remembered.
No Warning output as I have limited I/O. I do, however see warnings on my T/S when driving as I have that annunciator on. This can occur on a punch because, before new exhaust gases gets to the O2 sensor, and I suspect some sensor response time, the AFR table (the target one) will see a lower AFR target than the car was just running. Hence, immediately you will get an AFR error, even if the AFR itself has not gone lean, just remained where it was supposed to have been, and was, the moment previous.
That is why there is the Wait For. I have mine at 1.5. I had thought it was shorter. The EAE should respond quickly enough to not need a 1.5 second delay.
The Kill spark For, I said above as 0.02S, I really had a 0.04S. But I have rethought that. 0.08 allows (2) injections per cylinder at 3K RPM with no spark before fuel cut. Idea, according to Matt Cramer, is to allow some cooling of the cylinders, as they were just run in a lean condition for at least (in my case) 1.5 seconds.
I may re-think my wide zone at 80kPa and 3K, as there is really no reason for that area to get out of control, and 0.9 + my target of 14 would be getting kind of lean (but still not dangerous.
The 0.4 at the higher kPa: I have target at about 11.7, so 0.4 would be at 12.1. Not yet where things are disastrous (as I understand).
Anyway, that is were I am at this time.
One other note: AFR safety is something that should come in when there is something wrong that should be addressed. Clogged fuel filter, bad injector, too much alcohol in gas, bad O2 Sensor calibration. It is not something that should happen and then you just keep on, like a rev limit.
No Warning output as I have limited I/O. I do, however see warnings on my T/S when driving as I have that annunciator on. This can occur on a punch because, before new exhaust gases gets to the O2 sensor, and I suspect some sensor response time, the AFR table (the target one) will see a lower AFR target than the car was just running. Hence, immediately you will get an AFR error, even if the AFR itself has not gone lean, just remained where it was supposed to have been, and was, the moment previous.
That is why there is the Wait For. I have mine at 1.5. I had thought it was shorter. The EAE should respond quickly enough to not need a 1.5 second delay.
The Kill spark For, I said above as 0.02S, I really had a 0.04S. But I have rethought that. 0.08 allows (2) injections per cylinder at 3K RPM with no spark before fuel cut. Idea, according to Matt Cramer, is to allow some cooling of the cylinders, as they were just run in a lean condition for at least (in my case) 1.5 seconds.
I may re-think my wide zone at 80kPa and 3K, as there is really no reason for that area to get out of control, and 0.9 + my target of 14 would be getting kind of lean (but still not dangerous.
The 0.4 at the higher kPa: I have target at about 11.7, so 0.4 would be at 12.1. Not yet where things are disastrous (as I understand).
Anyway, that is were I am at this time.
One other note: AFR safety is something that should come in when there is something wrong that should be addressed. Clogged fuel filter, bad injector, too much alcohol in gas, bad O2 Sensor calibration. It is not something that should happen and then you just keep on, like a rev limit.
#31
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Thank you for that explanation.
I definitely understand that this is a fail safe, but I think it's a good idea to have it in place for someone like myself learning how to tune.
Now to go read about EAE at some point.
Appreciate the help DNMakison!
I definitely understand that this is a fail safe, but I think it's a good idea to have it in place for someone like myself learning how to tune.
Now to go read about EAE at some point.
Appreciate the help DNMakison!
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