Q45tech/Electrical people... Voltage multiplier

[elwesso]

So the point of this thread is to somehow trick my car into thinking its going the right speed..

What I need to do is device a device that will multiply the voltage of my speedo sensor output by 15% so that Im back where I should be.

What I tried first was to switch the speedo pinion gear. Q45 has 17 teeth, Twin Turbo Z has 18 teeth, N/A Z has 21 teeth.. Off by 1 tooth, not that big of a deal, thatd put me at 5% which is acceptable...

Turns out since the twin turbo Z has a smaller diameter pinion gear on the speedo sensor, you cant use it in the N/A transmission..

Theres things out on the market that do this same thing but they cost like $100 or so..

Since I dont really need any adjustability, would you think theres any way I could make something using common components like resistors, inductors, capacitors, diodes, even op-amps...?

I can hook stuff up, i just dont know enough about the intricacies of those things to get anywhere.

Essentially, the deal is. I need to build something to multiply the voltage by 115%.. So when my sensor reads 1.0 volts, it needs to output 1.15 volts..

[Q45tech]

The speedomter IC uses a frequency not a voltage to determine speed. Sure it then converts the frequency to a voltage to dive systems.

A frequency multiplier or a differnt speed sensor plastic gear is much easier.As the AT was used in 300ZX those gear fit as does the gear from J30.

3.694. 3.90, 4.083 are common choice from Nissan Dealer.

If you have TCS the conflict must be resolved to avoid codes.

[elwesso]

Remember im using 5MT from Z32.

The problem with the gear method is that instead of going to a larger gear (say 3.54-4.08), im going backwards (4.08-3.54).. I have the gear for a 3.694 however due to it being a smaller diameter, it will not work. The gear that it meshes with in the transmission is too far away for it to mesh properly..

What do you think i need to do to get this to work properly. I dont think i can compensate the difference mechanically, so i need to think electrically.

[Q451990]

Does anyone make custom gears? You might also try tearing down the speedo heads from a spare Q and spare Z cluster to see if you can swap some parts there... it's possible that at some point they go back to some common component that can be interchanged.

Heath

[elwesso]

Problem is with that is I need a gear with less teeth, and of course thats going to make it have a smaller diameter. I cant use a smaller diameter gear because it wont mesh with the gear inside the trans that drives the speedo sensor gear.

[Q45tech]

You can do it mechanically by creating a complex set of external gears to match transmission and speed sensor or adapt a frequency to frequency convertor.

http://tech.aus300zx.com/idial...n.pdf

4.645 Hertz per mph................................279 Hertz at 60 mph

Obviously getting speedo to read right is not getting ABS/TCS to sync.

http://www.dakotadigital.com/i...6.htm

[qsiguy]

$54.95 plus shipping from Aussie.

http://www.jaycar.com.au/produ...YWORD

Just get it and be done with it.

[MinisterofDOOM]

Wes, I might have the Yellow Box that Robert tried to get working on my Q all those years back still in my boxes of spare parts. I'll check and see if I can find it. As I recall, though, he had a problem with the speedo signal dropping off completely above 20mph or something like that. But it's worth a try, I think.

[elwesso]

Yeah I remember that.... Ill consider getting that one from the aussies...