Help me make a CA/SOHC KA Tach work on a SR!

[kazuo]

Okay.

So I have a digital gauge cluster. I like my digital speedo. I like my HUD. No analog clusters for daddy.

Anyway, as we all know, CA/SOHC KA tachs do NOT work on a SR20DET. I had a SOHC vehicle. Tach no worky.

They didnt have digital gauge clusters on SR20's in Japan.

I need to get this tach from a CA18DET cluster working in the SR20DET.

I have been told I can run a wire from some place or another to the tach and make it work, OR I can take the circuit board off the back of a SR tach and screw on a CA18 face.

The problem with method one is i dont know what wire(s) to run, or where.

Problem with method two is the analog/digital tachs are different sizes, so im not sure if switching the circuit boards and faces will result in inaccurate tach readings.

Any ideas?

Thanks in advance :)

[autobahNESSA]

buy Auto Meter!!!!
haha

Just run without a tach. Not like u need it in S.F. Traffic.

what happend to the idea of switching the faceplates?

[kazuo]

I want a tach, NOT a ricemeter! Dammit. :P

Ya I DO need a tach dude... I like being able to look and see what I'm idling at. =)


But as far as switching the faceplates... I guess I'm just gonna try that today, cus nobody seems to have any clue on what the bets way to do this would be.

:P

Originally posted by bayarea240
buy Auto Meter!!!!
haha

Just run without a tach. Not like u need it in S.F. Traffic.

what happend to the idea of switching the faceplates?

[AKADriver]

If the angle between 0 and 9 is the same on the HUD and non-HUD tachs, then using the non-HUD board with the smaller HUD face should be fine.

Considered just getting a '91-'93 240SX HUD tach? yeah, it only reads to 8k...

[DuffMan]

Switching faces alone is going to be inaccurate. If you switched faces, and then did some soldering on the board, you might be able to make it accurate but I havent figured out what resistor needs to be changed.

As far as running it off a different wire, I tried running a CA18DET tach off a KA24DE CAS signal. The tach twitched when i revved, but stayed at zero. I think the result would be the same with an SR.

This is my theoretical solution to the problem: The KA24E tach and CA18DET tach have the same part number on the circuit board. I'm betting that they work with the same type of tach signal. My idea is to take the KA24E ECU mount it somewhere in the car and feed it power and a CAS signal. Then attach the CA tach to it and it should get the right signal. It's only a theory though, I havent tried it yet.