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[igofar]

Just a quick question regarding SERT tuning and AFR adjustments.

Without a dyno, how does a tuner choose where to set the AFR value?
Can you just base it on best "feel" during road tests?
I am sure on a dyno, you could adjust and then check for an increase in power.....

I know closed loop bikes only operate in closed loop when the AFR value is set to 14.6:1 and you can get some adjustment by varying the CLB tables.

What values are some of you guys running?

I am thinking a value of 13.8 in the open loop cells and trying to have the bike in closed loop under most cruising conditions
would be a good way to set up the AFR table....

Any comments?


Brad

[WVULTRA]

Brad:

Without using a professional Tuner, the TTS System is really geared for the "home tuner"!  Their new V-Tune Software takes most of the guesswork out of the equation.  From their files:

VTune Overview
The VTune program enables a tuner to quickly optimize a calibration's VE table on a particular vehicle.  There are four key operations which must be run in sequence as follows:

First, a MT7 calibration must be installed into the vehicle.  These calibrations have been specifically set-up to work with the VTune software.  Note that VE tuning is only effective for AFR cells that are set to exactly 14.6 AFR value.  For tuning purposes, the AFR can be temporarily set to 14.6 over a wide range of engine load.  Refer to the Appendix section Closed Loop Operation for more information.

Next, DataMaster-HD is used to collect VTune data while riding or dynoing the vehicle.  This REQUIRES that the VTune data type be selected for recording.  The procedure for this is outlined in the appendix section Recording VTune Data for detailed information.

The DataMaster VTune Data File and the associated MT7 calibration file are then processed by the VTune software.  This process analyzes the data to generate a corrected VE table for the vehicle.  This corrected table is automatically merged into the MT7 calibration file and saved as a new calibration file.

Finally, the new "merged" MT7 calibration file is programmed back into the vehicle.

This process is repeated several times, and each iteration will zero-in a little closer to the optimum VE table value.  When the values do not change more than 5% between iterations, the optimum table has been generated.  In our experience, this takes three iterations.

NOTE: After the final iteration, the user must reset all AFR cell to the factory original values.  This is required to prevent the vehicle from running too hot due to lean mixture operation.

Even though it mentions "a tuner", it can easily be done by a rider doing Data Recordings while packing the laptop.

 

[bikerboy53]

Igofar,

The SERT manual actually gives some guidance on what the AFR should be for a few different conditions. On page 92 of my manual it recommends:
12.8 : 1 Peak power AFR
11.0 : 1 Severe loads AFR
14.0 : 1 Cruising under light load

Your guess of 13.8 wouldn't be bad for some conditions, but not for heavy loads or peak power.

Once you know the AFR you want, the hard part of tuning is getting the VE tables set correctly for your bike. If your bike "fits" one of the canned maps then you can start with one of those and tweak the AFR tables to suit. The SERT Manual also gives some advice for determining whether your bike is running rich or lean.

I bought a digital AFR meter, Wide Band Oxygen sensor, and Aux box from Innovate Motorsports to measure the actual AFR and determine correct VE values. It takes a lot of work to map everything correctly though. And the instrumentation costs as much or more than a good dyno tune. But it does give you the ability to find out what you have for AFR and tweak things on your own. After a few "bad" dyno tunes I finally gave up and started doing it myself. 

[bikerboy53]

Actually, the VTune sounds like a pretty good (and fairly painless) way to determine VE values. I think those guys at TTS may be on to something really good!! 

[WVULTRA]

Actually, the VTune sounds like a pretty good (and fairly painless) way to determine VE values. I think those guys at TTS may be on to something really good!! 

bikerboy53:  I totally agree!

From a very respected Tuner (Doc 1) on using the TTS Data Recordings to set VE values:

If my VE was synchronized to 14.6 all the way up to 90% TP (or 90kPa which ever came first) and I changed the whole fuel table requesting 13.5 I would get 13.5, if I requested 13,8 I would get 13.8 so if I request 14.6 at the cruise area and 13.5 in mid range, and 12.8 under a load I will get that AFR in those respected areas. Now the only place I can not tune or synchronize the VE with the 02 or 14.6 is the 100% TP range because it will not go into closed loop nor can I set it at 14.6 so the 100% TP column has to be set the conventional way with the AFR sniffer from the Dyno. (or you can play with the and do 3rd gear runs on the road and use the dyno calculator to see if you are getting more power or less power making changes and run the same way again to see what your changes are doing.

 

[miker]

Ditto!  I am at an average 13.9 mid postion and cruise...plugs look fine if not a on the little dark side, oil temp has not exceeded 230 under any condition, etms not active..2-1 exhaust.  Good luck.