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digital spedometer


itsaprothing

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I have searched this and have had no luck so i'm sorry if someone else has posted this, i probably wasn't searching good enough.

 

i have a 1983 280zx and i noticed that the spedometer doesn't go past 85 even though i feel myself going faster. at first i thought maybe it's because it might have only 2 number spots but then i thought why doesn't it go to 99? I then decided that i'd press the button and switch to kilometers and it goes up to 160 i think or whatever 85 miles is in kilometers. something like that. so now i realize that it's capable of using 3 numbers. it just doesn't do it when i'm in the miles mode.

 

SO, the question. how can i make my spedometer go past 85 when in miles? I saw another 280zx with the non digital dash and the spedometer only goes to 85 so I realize that that's probably why mine only goes to 85. but just like people can buy the 140mph face plate from thezstore.com, is there something i can do to my spedometer to make it go past 85?

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You can try this mod, but I don't know that anyone has actually done it on a street vehicle. If you do try it, I would strongly suggest getting a spare dash to try it on so that if it doesn't work you still have a good one.

 

The other options are to find a '79 analog instrument cluster and swap it in, or any analog cluster and use aftermarket gauges. The downside is losing that cool '80s digital dash; the upside is getting a higher speedo and a much better tach that actually shows when you're at 6k instead of "6k +/- 500, roughly, maybe".

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it sounds good, but its kinda shady, I dunno if i want to do that.

 

has anybody done it to their car successfully?

 

and how does the finished product even look when it's back onto your car? and how bad does it mess up on the numbers? didn't he say that it messes up when you're going like 20mph or something?

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interesting idea, I'm sure if someone's good enough with wiring they can figure out how to make it work...

 

as for anyone who wants to modify a stock digi dash, I've got one someone can have for the cost of me shipping it to ya... I don't plan on using it as I greatly prefer analog

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  • 2 weeks later...

Anyone know how to hard wire a digital dash in?

As in run wires to a non working digital dash (works but converted to a turbo harness, and the dash only worked for first 2 minutes then the car lost all power to everything.,.... about 10 minutes later it comes back on... problem repeated about 5 times so I just converted to complete turbo harness..

So anyone know how to hard wire a digital dash (as in where the positive, negative, and maybe even the tach??? yes Ive searched to

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stprasinz,

You should have posted a few weeks earlier. My brother crashed my yellow ZXT and I just junked it couple weeks ago. I've converted from analog to digital for this car and I used the non turbo digital harness to start with. I remembered I had to run a couple extra wires for turbo related stuffs. If your digital gauge goes out that usually means something wrong with the gauge and not the wiring. This is the reason why people hates the digital gauge. I still have a couple of the digital clusters. One I used the method above to convert to 140MPH and the other still stock. The only one problem with the above conversion is at low speed it won't read the speed correctly.

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At low speed it reads incorrectly. If I remember correctly it displays slower then the actual speed at low speed. At 55 and up it displays close enough to the actual speed. Here is the theory behind this mod. Take the top speed in KMH devide it by the top speed in MPH. You have the ratio. Then use this ratio calculate the pulse per revolution on the chopper wheel. Then use electrical tape to cover up some of the holes on the wheel. The problem is you can't have even slots on the wheel. This will yield incorrect speed readings at low speeds. There is a way to fix this and that is to leave even slots on the wheel. This will yield the wrong speed reading accross the band. Use different speedometer gear to correct your speedo. Does that make sense?

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stprasinz,

You should have posted a few weeks earlier. My brother crashed my yellow ZXT and I just junked it couple weeks ago. I've converted from analog to digital for this car and I used the non turbo digital harness to start with. I remembered I had to run a couple extra wires for turbo related stuffs. If your digital gauge goes out that usually means something wrong with the gauge and not the wiring. This is the reason why people hates the digital gauge. I still have a couple of the digital clusters. One I used the method above to convert to 140MPH and the other still stock. The only one problem with the above conversion is at low speed it won't read the speed correctly.

 

Actually I think my cluster itself works properly... The thing is the whole car would shut off after about 2-3 minutes then would take from 1 to 10 minutes before it would work again......

 

I was baffles

 

especially since I used all the relays in my other harness.....

 

I was wondering about how to wire the digi dash in with none of the origanal wires... All I am worried about working is the speedo, and the tach......

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Look at the link above and on the 4th picture. The original wheel has 24 blanks or gaps in it. There is a photo electric eye on the wheel and it counts the pulse each time the gap passes the eye. The electronics in the gauge uses these pulses to display the speed. You can see in that picture that he covers 9 of those 24 gaps. Therefore the spacing on the wheel are not even. This will give the incorrect readings at low speeds. The right way to do it is cover up just 8 gaps. This will give consistent speed reading accross the band but it will be off (reading slower than actual speed). You can fix this by selecting different speedometer cog in the transmission. What you want is a smaller (less teeth) cog so that will cause the wheel in the gauge will turn faster. Now does this make sense?

 

 

If your gauge shuts down the first thing you want to check is the power to it. I have seen the connectors in the back of the gauge not making good contact to the gauge just like the famous problems with the turbo ECU connectors. Check this by wait until it shuts off and put your hand behind the gauge and wiggle the black connector. if that doesn't fix it open up the whole gauge and look on the circuit board for breaks or cracks. GL

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  • 2 years later...

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