I've done some searching through the forums, but can't seem to find all the information necesary. It is apparent you need to change a crystal on the 85mph speedo's board, but what frequency does the crystal need to be? 4.45 MHZ? Also where would I find one of these crystals, and does it need to be a specific size? Is this all that needs to be done?

I haven't looked at my speedo yet, but if anyone has done this already, I would appreciate step by step instructions, as would alot of other forum members i'm sure.

Thanks in advance,
-Shaun

*cough*shamelessbump*cough*

damn, and someone just posted the answer to this last week...in the GFC...
someone was asking about changing an 85 speedo, and someone posted the speed/frequncy ratio...

Yes, I read that post. was 534 / speed i believe which brought me to the conclusion of 4.45MHZ but I didn't know if I just had to replace this 1 crystal? Also are they plug and play crystals or is soldering involved? Stuff like that.

what if you are running a 4banger how do you make the tach accurate???

cause i will be updateing my dash to the back light models

quote Originally posted by 4BanGinFun: what if you are running a 4banger how do you make the tach accurate??? cause i will be updateing my dash to the back light models

Get the 4cyl Dash Cluster. they are cheap

Why not just get a 120 mph speedo? They are pretty cheap. And you can swap in your odometer to keep the correct mileage.

nevermind

[This message has been edited by dguy (edited 03-17-2004).]

From what i've read the speedos are plug and play so 4 banger or v6 doesn't matter, the tach will be correct.

quote Originally posted by Steve Normington: Why not just get a 120 mph speedo? They are pretty cheap. And you can swap in your odometer to keep the correct mileage.

Because the cars electronics are calibrated for an 85mph speedo (from what I've read). Just dropping in a 120mph speedo would give you incorrect readings.

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No the 120's are plug and play from what i've read. They would work like a charm, but they're expensive.

Fieros are not electronically calibrated for 85 MPH speedometer. All Fiero speedometers are designed to accept a sinusoidal input from the VSS at 4000 pulses per mile. The speedometer itself determines how to display that on the dial face. Therefore all spedometers are plug and play in all fieros.

The only complication is if you are swapping in a 120 mph cluster containing a tach from a V6 into a L4 car. The tach will either have to be recalibrated or more easily, you simply swap the L4 tach board onto the back of the V6 tach. I've never done the board swapping but I've been told it will work.

The tach can be recalibrated by modifying the RC circuit by swapping a capaictor, resistor or both. When I did mine I changed one capacitor in the tach to recalibrate it. Since my car is an auto it doesn't really matter all that much if the accuracy was perfect. I hope this helps.

- Jonathan

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quote Originally posted by Steve Normington: Why not just get a 120 mph speedo? They are pretty cheap. And you can swap in your odometer to keep the correct mileage.

Because if you make your own you can make a 160mph or 240mph or whatever you want. I have heard that there are plenty of people unhappy with the 120mph version and wish that they had one that could read higher.