Questions for Steve Cole, VE tables on DBW

[remington007]

After doing many V-Tune data records on DBW bikes i noticed there is no recorded data for the 1% column on the VE tables.
#1 Is there ever a condition the ECM uses this column? If not why is it there?
#2 Do i just blend the values used in the 2 and 5% areas like the 80 and 100% areas?
I cant find any info. on this in the tunners manual.
Thanks.

[Herko]

Not Steve Cole but the DBW TB's use blade angle for throttle speed control.
No IAC motor on the DBW TB's.
Look at Data Mode and hot idle and blade angle is typically in the 3.x% range.
The 1% column is not a player for in this condition.

Technique used here...start with VE's in the 1 and 2 percent columns the same and keep them the same when good VTune data dictates a change. I.e. when all is done the 1 and 2 percent columns will be a mirror image of each other. No blending here of these columns. Technique only.

[remington007]

Thanks Herko, That is what i have been doing. It still leads me to wonder what the 1% column is used for.

[Herko]

1.x% blade angle may be needed for larger TB's or if air enters from an unwanted source such as an air leak etc.
Might be a good thing to have VE's ready to meter fuel in this TP range if this occurs.

Maybe a way to simplify would have the lowest column at 2 or 3% and anything less would automatically mirror the 3% column like the ignition tables do when off the chart.

Have also done tunes where the 1-2 and 5 columns were kept identical. Turned out real smooth.
Tried this with success to keep from chasing a wagging AFR tail in the low TP areas during calibration.  JMO.

[Don D]

What happens when the TB is modified and a larger plate installed. Do the companys correct the idle airflow as it relates to TPS? Isn't this important?

[Herko]

The companies that mod don't set the idle RPM, the ECU performs this function. Yes, as mentioned above a larger TB could in fact result in a lower percent of blade angle to maintain the prescribe idle RPM. On a modded TB a small bleed hole or similar could be incorporated but with a larger butterfly disc (blade) wouldn't lessen this need? As we know larger blade disc = more circumference which creates more area per tenth of degree of increased blade angle.

On the TBW TB's there is an adjustable mechanical stop hidden under a sealed plug. Appears to be there to prevent wedging of the blade in the machined bore when the TB does it's initializing routine during power up. One I checked had .002 mech stop air gap whereas the cable operated TB's have .003 to .004

As far as whether it's important if meaning in terms of step counts etc. brings to mind of all the (unnecessary IMO) minutia about having an exact TPS voltage and exact IAC steps on the cable TB's.
Set a good air gap, make sure no unintended air is entering an engine and the voltage and steps would work out just fine. I never did have a guy call me and say his bike quit and local dealer said it was because it had more or less steps than the guy at the bar said it should have.

[Don D]

Thanks makes sense

"minutia about having an exact TPS voltage and exact IAC steps on the cable TB's."

This is a DTT phenomonom but with that system perhaps it is that important.