Individual Cylinder Lambda Question

[jcolley]

I have a client who has 4 LTC-Ds running cylinders 1-8 on an LS7. In the M1 Tune Help, it recommends having a bank collector lambda reading as opposed to averaging individual cylinders, but no basis as to why.

Given the client has already forked over for four LTC-Ds, I'd rather not sell him a 5th LTC-D for the merge collectors if it's not a really valid reason.



Anyone have any idea why it's preferred?

[stevieturbo]

so you are actually tuning each cylinder for lambda ?

[Stephen Dean]

Hi,

Can you tell me where in the M1 Tune help is this mention thanks.

The way that the exhaust Lambda works in the M1 is that if you have individual cylinder lambdas, it will average each of the banks to generate the Exhaust Lambda Bank x Collector value, and then the Bank Collectors are averaged to generate Exhaust Lambda Collector. To use the Fuel Closed Loop function, the M1 needs to see the Exhaust Lambda Bank x Collector value.

[jcolley]

Hi,

Can you tell me where in the M1 Tune help is this mention thanks.

The way that the exhaust Lambda works in the M1 is that if you have individual cylinder lambdas, it will average each of the banks to generate the Exhaust Lambda Bank x Collector value, and then the Bank Collectors are averaged to generate Exhaust Lambda Collector. To use the Fuel Closed Loop function, the M1 needs to see the Exhaust Lambda Bank x Collector value.

I played around a bit today and saw it averaging the cylinders allocated to a bank, so figured that much out, just trying to figure out why an actual sensor would be preferred.

One thought was, does the averaging process take into account the individual cylinder lambda diagnostic state to verify it is working before considering the value in both the numerator and denominator of the averaging process? I would assume so, but haven't gone into Build to see if I can find it.

The reference in M1 tune help is on the "Exhaust -> Lambda -> Bank 1 -> Collector" Page

[jcolley]

so you are actually tuning each cylinder for lambda ?

Correct, 8 LSU 4.9s on this V8.

[Stephen Dean]

Hi,

With the individual cylinder Lambda's, the M1 will use the reported value from the sensors if the sensor diagnostic is reported as Ok, if the diagnostic goes to any other value, then the sensor is removed from the calculation and the Bank Collector value is averaged over the remaining sensors.

The Bank collector was preferred over the averages as it is a more common sensor to have in place compared to individual cylinders.