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Rob Stevens wrote: The ecu could work the latter out if it had both driven wheel speed sensors fitted, perhaps Allan will add this some time for S80 users?

I already queried Allan about this when the shaft speed appeared, and to be honest still unsure of the reply. This was over a year ago I asked

He replied that "shift cut is normally used on a sequential box, not an H pattern. If you have a sequential box you will use a gear pot and therefore will not need to measure gear this way. There is method in the madness"

To me, the sensible option would be via wheel speed, although yes there is a possible chance of inaccuracy during wheelspin of one wheel.

But if you measured a single driveshaft on say a fwd car, that same problem would happen anyway.

the only way to get a truly accurate relationship between shaft speed and gear/engine rpm is to monitor propshaft speed, or in case of fwd, actual diff input shaft speed ( ie mainshaft )

I still have not managed to take action.....

I've just fitted a left undriven wheel speed sensors to my s100 and it works fine to calculate gear by shaft speed as well as speed. I did have a problem to start, when i ticked the box, use left driven speed input in gear position settings it wouldn't work. Instead I linked the wheel speed input wire over to pin 14.

Forgive me if I'm wrong but the 2 main reasons dta did it with a shaft speed sensor is to allow s60 users to have full traction control, because they only have one wheel speed input and allow h pattern box's to calculate the gear without a pot.

Also the gear position indicates the correct gear every time even though it's connected to the front wheel, even round tight corners and with wheel spin. My car is 4wd so there aren't actually any undrivrn wheels.

Also if your calculating gear by rpm and using a wheel speed sensor, remember to multiply your gear ratio by the final drive ratio when filling in the table.

Greetings from a Greek user. I am using a DTA S60 ecu and i am having problems with the calculated gear and calculated driven speed. I have connected the undriven wheel speed to the front wheel (I a have a rwd nissan 200sx) and i get a correct reading to the undriven wheel speed. Gave it gear ratio, measured the distance per gear that DTA asked for but i get no reading at all at driven wheel speed nor calculated gear.
Any ideas?

Your gear ratios need to include the final drive if you use a wheel sensor for the shaft speed. The sensor would need to be on your prop shaft for those gear values to work.

It should still calculate a gear though, just the wrong one.

Do you have a shaft speed input? It needs it to calculate gears, you could link the wheel speed sensor pin (2) over to the shaft speed sensor pin (15) which would work but wouldn't be 100% accurate when the wheels start spinning. Otherwise just fit a rear wheel sensor or prop sensor.

As above, you need to do gear ratio x diff ratio for the results to be correct.

And I'm sure I needed to close the window and re-open when I did mine as table entries went strange.

I dont think control needs to be active......but it may.

In Diagnostic display, are you getting valid pulse counts from your wheel speed sensors ?

For gear by rpm I'm sure you need to copy the undriven wheel speed signal over to the shift cut input and tell it to use that, weird I know.

Rob Stevens wrote:For gear by rpm I'm sure you need to copy the undriven wheel speed signal over to the shift cut input and tell it to use that, weird I know.

I'd have been using that on my S80 anyway, so never tried without. So very possible.