Ok Guys I'm hoping to get some help with aftermarket gauges in my '70 Fury with the Ram V10 swap.

I'm using the '96 Ram PCM and below is the output specs for all the gauges. I was thinking about using the stock cluster out of the Ram but it doesn't fit or look good in the Fury's dash so I want to run aftermarket gauges. The oil, temp, fuel & volt gauges will not be an issue because I can just use mechanical gauges by adding some fitting to the engine. The speedo will not be an issue either because many aftermarket speedo's use adjustable Hz signal to set your speed. The big issue is the tachometer. The spec below shows 125 Hz at 3000RPM for the V10. If the V10 had a single coil like the V8's I could use a standard tach hooked up to the coil but the V10 has 2 coil packs, one for 6 cylinders and one for the other 4 cylinders. Have any of you V10 guys installed an aftermarket tachometer? Anyone have any ideas?

Thanks

 

I would think you could still use a coil pickup just because there's is two doesn't change the amount of sparks for rpm

 

There are two coil packs.... one has two coils, the other has three. Both packs get constant power, and the PCM fires the appropriate coil at the appropriate time, (one coil for two cylinders, so, the cylinder on compression gets a spark, and the cylinder on exhaust also gets one.) Seems to me though, that just monitoring one of the coils, and doing math from there, *should* be able to make an aftermarket tach read properly......

 

Ahh that part does make it a little more confusing. I may be a little foggy here on a coil pickup but basically every time a spark is fire down the wire there is pulse sent to the tach. So actually you would have twice the sparks to actual RPM could one not calibrate the tach back to compensate this?

 

Maybe, lets talk this out. Ok a vehicle with a 4 stroke V8 and standard distributor and single coil will fire the coil 4 times for every rotation of the engine. So the tach is set to read 4 pulse on the neg side of the coil as 1 rotation of the engine. In theory if said engine was firing on the power stroke & the exhaust stroke (this would not be possible with a standard distributor BTW) the cold would have to fire 8 times per rotation.

So your standard automotive tach has 3 settings, 4 - 6 - 8 to cover the typical engines sold in cars. So 4 cylinder would read 2 pulses as 1 rotation, 6 cylinder would read 3 pulses as 1 rotation and the 8 cylinder would read 4 pulses as 1 rotation.

So lets look at the wiring diagram for the V10 below. OK 5 coils total in 2 packs. All coils have the same power source and each coil is provided a ground by the PCM individually. Because the V10 fires on both the power and exhaust strokes each coil will fire 1 time for every rotation of the engine. So if I spliced into the negative side of one coil I would need a tach that could read 1 pulse as 1 rotation.

 

Check out the links...

 

Thanks I was looking at both of them on youtube and think that is the way to go. Has anyone on here used either of these adapters on there vehicles? I like to Dakota digital one because it is tach and speedo adjustable. I plan to change gears from 3.23:1 to 3.55:1 and I think with this adapter you can adjust it and not change the gear in the trans.

 

What year trans are you using? The gears in the ones that use 'em are pretty cheap. 25-30 bucks, and it's a two minute swap.