R33 Speedo Drive And Apexi Rsm Into R32

[=premo=]

The R33 speedo drive has three wire's, 12v, earth and signal. Im about to put a R33 gearbox into my R32 but I'm not going to bother with changing the speedo drive to suit the mechanical because the plastic bit in the back of the dash cluster has broken so many times and im sick of fixing it.

What I want to do is use a APEXI device like a RSM or AVC-R to use as a speedo. If I hook up the drive to 12v and earth could I then use the signal directly into a rev/speed meter?

Would I need to use a relay so the power going to it turns off when the cars not in use or will it not drain power unless moving?

Thanks,

Daniel

[=premo=]

no takers?

there has to be an eletronic's wiz out there that wants to answer this question.