Speed pulse adjuster/corrector?
 

Anyone know of any off the shelf kit or item then can tweak the speed pulse signal?

I want something that can adjust (speed up or slow down) the pulse incrementally.

I think the Apexi RSM may be able to do this because it has a function called 'speed pulse adjust', but I'm not sure if it just changes the speed the RSM displays or also the speed pulse output it passes on to the ECU. The RSM can also de-limit so it's obviously capable of conditioning the speed pulse by clipping it.

why?

Can't help you with that, But any chance of you answering F1's question?

It's for my Skyline GTST. I want to convert the speedo to mph but this mean the ECU get the wrong speed since it gets a feed from the speedo.

is there no convertor like on classic's they use a small gearbox inline from the gearbox to the clocks this slows cable drive down by the correct amount thus de-limiting import scoobs