pulse generator Q

chappychapperton

Active Member
Hi,
Having a bit of trouble on deciding what to order for my electronic speedo pulse generator. I have a 70's C6 tranny behind my 302 and installed a new set of TPI tech quad gauge cluster and speedo. The quad cluster works great and I am just in the process of setting up my speedo. The speedo has a black and white wire coming from it that goes to the pulse generator. Now there are two types of generators, a 16PPR and a 8PPR. Looks like the 8PPR simply has a black and white wire and somehow uses gauge power, and the 16PPR has a black/white/red wire and uses 12v power for the sender. I would of asked the manufacturer of my gauge but they have gone out of business....... If anyone has any experience with either and if there is any difference that would be great. I am leaning towards the 16PPR just cause it makes more sense that it would work. Thanks.
 
I believe the 3 wire one is a Hall Effect Sender and it creates a square wave.
this is what my VDO gauges use
The 2 wire is a inductive sender and it generates a sine wave. This is used on a lot of GM's but needs to be converted to a square wave before going to the speedometer
Some aftermarket speedometers can be connected to both senders, but they are not connected to the same terminals
Don
 
You need to know what your gauge requires. The 8PPR and 16PPR are not interchangeable. The wrong sender will not work with the gauge. If memory serves, TPI tech use 8PPR senders. Where I work, we sold those gauges on a special order basis. I'm not surprised they went out of business. Classic Instruments, while being a little more money, are far better quality. The 8PPR senders only used two wires, the 16PPR senders use 3.
 
If you use the link below it should bring you to a wiring diagram for TPI TECH gauges. I don't know if they are the same as your gauges but it shows
a 4 pin connector with a black and a white wire to a pulse generator. As for the
ppr, they have nothing to do with the type of sender (2 wire or 3 wire). PPR is
the number of pulses per rev, sometimes it's rated as pulses per mile and is
determined by the number of teeth, grooves or slots in or near the sensor
This number of pulses is fixed and cannot be changed without replacing parts.
On VDO gauges, you can calculate the pulses per mile by using the PPR of your sender,your diff gear ratio and tire circumference then input this number(PPM) into your speedo. Job finished.
Hope this helps



http://www.hotrodders.com/forum/wiring-diagram-tpi-tech-speedometer-136899.html

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Thanks for the input on this.

What I have found out from searching the web is that you are correct on the fact that it doesnt matter if I have a 8PPR or a 16PPR generator. The TPI gauges actually have a program so you can pick either of the two and it will calibrate from there. I am going to order the dakota digital 8PPR (black/white with no red) pulse generator and calibrate my speedo to that.

I will throw an update in a few weeks to let you know how this all works out.

Thanks.