S13 Dash - Pulse Rates?

[Black 1via RB25det swap]

G'day Guys,

Anyone know what the stock S13/180sx dash pulse rate is for speed sensor signal?

Looking at getting a tailshaft Speedo from Bluewire Automotive but their speed sensor puts out 4000 pulses (not sure in what time frame) and apparently it won't work unless the S13 dash can handle that number or more.

[GTSBoy]

The S13 dash will require a +/- 1V sawtooth AC signal from the speed sender. It cannot tolerate a squarewave 0-1 or 0-5V signal. So make sure the Bluewire device can do that.

I can't tell you about the S13 specifically, but it is very likely to be the same as R32 GTR. In which case, there are waveforms shown in the GTR service manual for the speed sender's signal for various roadspeeds. Just download it and have a look see. The S13 one should be in the same ballpark for pulse rate at speed. Of course, there's always the possibility that it is a few % different or even a factor of 2 or 3 different. Is there are useful S13 workshop manual equivalent to the GTR one available?

[Dose Pipe Sutututu]

Another option that tends to work, is to use a 300ZX N/A manual speed sensor with the RB25DET gearbox.

Direct fitment (sensor wise) and just snip off the connectors and fit up a Deutsche connector for that added sex spec feel.

Not 100% accurate but you're about 5 to 10% slowest than the actual speed. I suppose to you mix/match wheels to game the circumference to get the desired reading.

[Black 1via RB25det swap]

1 hour ago, GTSBoy said:

The S13 dash will require a +/- 1V sawtooth AC signal from the speed sender. It cannot tolerate a squarewave 0-1 or 0-5V signal. So make sure the Bluewire device can do that.

I can't tell you about the S13 specifically, but it is very likely to be the same as R32 GTR. In which case, there are waveforms shown in the GTR service manual for the speed sender's signal for various roadspeeds. Just download it and have a look see. The S13 one should be in the same ballpark for pulse rate at speed. Of course, there's always the possibility that it is a few % different or even a factor of 2 or 3 different. Is there are useful S13 workshop manual equivalent to the GTR one available?

Awesome! Yeah I've just found the S13 workshop manual so hopefully it has something handy in there. 

[Black 1via RB25det swap]

11 minutes ago, Dose Pipe Sutututu said:

Another option that tends to work, is to use a 300ZX N/A manual speed sensor with the RB25DET gearbox.

Direct fitment (sensor wise) and just snip off the connectors and fit up a Deutsche connector for that added sex spec feel.

Not 100% accurate but you're about 5 to 10% slowest than the actual speed. I suppose to you mix/match wheels to game the circumference to get the desired reading.

Ive run out of options for using the direct fitting of a sensor into the gearbox now without ripping open the gearbox to examine the worm gear. I've got a 300ZX and an RB25DET speed sensor both of which are working outside of the car to make the dash work. When I put either of them in the gearbox, they make contact with the worm gear but I get no response from the dash which I can only guess is because the worm gear is rotating the incorrect way.

 

So now I'm investigating taking the shortcut of the tail shaft Speedo to save ripping open the gearbox and opening the next can of worms.

[GTSBoy]

To be fair, a GPS speedo to heads up display is probably the best way to do this sort of bodge.