Hi Guys, I have a R32 engine in my golf mk1, and i want the original rev counter to work. I understand that it needs a -ve signal to work, but i'm not sure on how to get it from a R32 engine? Can any of you help ?
Hello there, first question is what type of R32 it is, MK4 or MK5? The MK4 ecu has a tacho pin you can use with an low->high & 6->4 cylinder signal converter such as this: http://ashlocktech.com/Home.php MK5 outputs via can-bus so need a can-bus module, this guy sells one which works: https://www.facebook.com/haldexcontroller/ Iast I heard with the unit above you also need a low->high signal adaptor same as the 20v boys use, chris bellman, james e looms and william skelton on facebook all do those. but he might have modified his units to output a proper mk1/2 type negative spike signal, see what he says!
So, I search the CANBUS converter thingy, and that looks like an option, however it is a bit expensive so I have something else in mind... I notice that there is two wires from the altenator, L and DFM, L is to the lamp in the cluster, connected and working... DFM is for the ECU, but not necessary, some also call it W. And then I thought about the rev counter on a Diesel, could that work with the DFM signal from the R32 altenator ? That would an easy mod... Any inputs ?
Older diesels use the W terminal for rev counter yep, you would need to change the alternator for a diesel type with W signal or its possible to add the W terminal with a bit of modification. the W signal still wont drive petrol clocks though, so again you'll need an adaptor. plus depending on the belt/pulley setup not all alternators turn at the same speed so sometimes will need calibration to match up. Heres an adaptor which accepts a W signal: http://www.dakotadigital.com/index.cfm/page/ptype=product/product_id=128/prd128.htm another option is to tap into the negative pulses from ecu to the coils, similar to the old skool vr6 method: https://clubgti.com/forums/index.php?threads/vr6-rev-gauge.98913/ however some have found this messes with the engine running so YMMV
