Mega Jolt and rev counter

[Jonny XKE]

I did a search for this under upgrades but couldn't see anything so apologies if this has already been covered. My rev counter seems to read too high. I wonder if this is due to the mega jolt. It reads around 4K rpm at 80mph. Any ideas?

[Heuer]

Nothing to do with Megajolt, the rev counter is driven by its own generator in a closed loop. You are actually lucky as most rev counters under read because the generator magnets under read. Of course the revs to mph will depend on gear ration and diff ratio but as I assume you would have been in fourth gear at the time then it would be down to the diff ratio. Do you know what it is?

You could of course just plug a laptop into the Megajolt and you will get the actual engine rpm from that to compare with the rev counter. Details of how to do that are in the Megajolt support thread.

[Jonny XKE]

It's a 5 speed box with a USA spec diff so 5th should be like UK 4th I'm told.

[Jonny XKE]

Laptop is the way to go .. forgot about that option