TTS mastertune question

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Oct 14, 2009 | 08:35 PM

ssls6

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Road Captain

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From: South Park, CO

TTS mastertune question

I'm buying a new 2010 ultra and have a question about TTS Matertune. First, if I update the lambda table to 0.965 in all the closed loop sections, does that cause the bike to run at an AFR of 14.17 : 1? What is the purpose of Vtune for lambda based bikes? If the ECM in closed loop mode drives to the lambda table, what is Vtune going to optimize?

Thanks,
Richard

Oct 15, 2009 | 10:47 AM

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Quote:

Originally Posted by ssls6

If the stoich AFR of the fuel is 14.68 (straight gas, no ETOH) setting the lambda to 0.965 will indeed give you an AFR of 14.17. Since that is no longer in closed loop, you will only get this AFR if the VE tables are calibrated correctly. FYI, 0.977 Lambda is the lowest you can go and remain in closed loop with the Lambda cals.

In order to calibrate the VE tables, you run the VTune program. VTune is needed for Lambda cals for the exact same reason as the AFR cals: To correctly calibrate the VE tables. Once the VE tables are correctly calibrated, the AFR or Lambda will track what you set it to for either closed or open loop mode.

Also, the better calibrated the VE tables are, the quicker the ECM adapts to any load changes, thus the bike will run smoother.

--Gary

Oct 15, 2009 | 01:44 PM

ssls6

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From: South Park, CO

Quote:

Originally Posted by Hogflash

Great answer, thanks. I didn't know if VE tables were needed since Lambda is a direct feedback mechanism for the 02 sensors. Without a Lambda table, you need VE and lambda to back calculate AFR. With a lambda table, what is VE needed for?

The documentation shows 0.965 as the lower limit for closed loop, good to know it is actually 0.977. I guess when I buy the software, I would have figured that out. I'm trying to get my head wrapped around this first.

Thanks,
Richard

Oct 15, 2009 | 01:57 PM

porterjet

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From: Cal., work in Saudi

I seem to remember that .800 is an unofficial recommended limit due to O2 sensor life. You most likely won't need to go that far anyway.

Oct 15, 2009 | 06:33 PM

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Quote:

Originally Posted by ssls6

Lambda is a different way to think of AFR, but is accomplishes the exact same thing as an AFR table so VE is still needed. To be more technical, Lambda is really controlling the unburned (free) oxygen in the exhaust, which correlates to AFR. This is what all O2 sensors measure, be they switching, narrow or wide band.

Whereas the older HD cals uses the O2 bias table to adjust the closed-loop AFR (rather crudely), the Lambda cals allow you to set this directly, with better precision.

--Gary