Well,tonight I pulled the crystal out of my '84 Canadian 140 Kph speedo,it was a 4.194304 mhz crystal.

I replaced it with a 3.686 mhz crystal and installed it in my '84.

I put my spare radar unit in the fiero and went for a drive, the results are as follows:

Speedometer---------------Radar reading
30 mph-------------------16 mph
40 mph-------------------21 mph
50 mph-------------------26 mph
60 mph-------------------32 mph
70 mph-------------------Missed this reading
80 mph-------------------42 mph
90 mph-------------------47 mph
100 mph-------------------51 mph
110 mph-------------------57 mph
120 mph-------------------62 mph
130 mph-------------------70 mph
140 mph-------------------74 mph

Joe, what gives?

Where did we go wrong, could there be a difference in the Canadian speedo that throws it that far off or is the math wrong.

Ogre, anyone?

Let's get this figured out.

------------------
'84 SE 2.5l
'85 Coupe 2.5l now getting a 3800
'86 SE 2.5l

[This message has been edited by fierohoho (edited 09-12-2001).]

That 4.19.... that is in your 140kmh speedo is the same freq that is in a 85mph speedo.

Like I said...I haven't tried this yet.

There seems to be another difference between 85/120 speedos but I don't know if the # on the TexasInstruments chip makes a difference.

I'll hopefully be able to figure this out this weekend.

------------------

Did you get your car in my book yet????
http://www.animatedconcepts.com/fierobook.htm

Steve:
I think that should be the same as an 85 MPH.
If a hash mark for say 100 KPH (62MPH) is at the same point as on a USA speedo then it should read the same.

Having read that I'm not sure if it made sense or not.....

Gary

You sure you weren't picking up the speed of the ricer behind you? I be quite now.

I think what I'll do is use the 140Kph speedo and solder in a couple if wires with clips on the ends where the crystal goes.

Then next time I get to Mpls. where the electronics supplies warehouse is I'll pick up a whole bunch of various crystals so it will be easier to take the car out, see how the speedo reacts with different crystals without having to re-solder a crystal in one at a time.

Unless Joe can come up with something before I make the road trip of course.

Joe, would it help if you had the chip numbers out of the 85mph/140kph and the 120mph speedo's, I could get you both?

------------------
'84 SE 2.5l
'85 Coupe 2.5l now getting a 3800
'86 SE 2.5l

Sorry I haven't replied...phone circuits have been tied up for days.

I'll try to figure this out later today.

After finishing my speedo ground I tried my conversion. Failure.

I started with a 120mph speedo and put the 2.??? crystal in. Zero was now at like 30mph. No good. I put the crystal in my 85mph and zero is zero.

I hooked my VSS upto my drill The Milwaukee runs about 48mph. I put the new crystal in and it is nearly DOUBLE. So the equation that I found on the internet was wrong...sorry, just posting what I found

But we are on the right track. We just have to go the other way....get a higher crystal for higher MAX speedo. I will work on some sort of equation. I will be soldering leads onto the speedo for easy swapping too.

------------------

Did you get your car in my book yet????
http://www.animatedconcepts.com/fierobook.htm

Fierohoho,
I tried that formula a few years ago when converting my first v-8 Fiero and it does not work.
I ended up using a 200 MPH speedometer and the correct crystal for it was a 7.3728 MHz. Oliver's pages have some information about the Fieros speedometer at: http://home.t-online.de/home/O_Scholz/speedo.html
There are a number of electronic experts on this forum. Maybe a new thread would get one to post the real formula.

Before starting a new thread I think we'll let this one ride to see if I or Joe get the crystal tests done first.

I have the stuff to make the test easier, now I just need to get the crystals.

Hopefully an electronic guru will stumble on this and lend a hand.

Joe, thanks for the tip on the higher crystals, I wasn't sure which way to go so now I know, should save a few bucks.

I never thought about a drill on the VSS.

That would save some road tripping, I'll do that and when I get close I'll throw the radar in to get an accurate reading by 10mph increments.

Would it help you if I posted the outcomes of the 10mph steps for each crystal when I do them?

------------------
'84 SE 2.5l
'85 Coupe 2.5l now getting a 3800
'86 SE 2.5l

I had a discussion SPECIFICALLY with oliver scholz about this topic. Maybe he can respond.

------------------

Fieroworld! Home of my 87 GT and 85 GT
Justin C.
Engineer, Designer and
Technical Trainer for Nortel Networks Business Products.

I can't find an easy equation to figure this out. The crystal feq isn't proportional to anything. Brian has posted the magical 200speedo freq. Thanks. RadioShack.com does not have that one. They have and 8.00. Anyone know of another source for them?

Thanks
Joe

Allied electronics has the crystals
http://www.alliedelec.com/

If we knew the rest of the circuit I could come up with something. Since I have not had it apart I am not sure of anything. Does anyone have the schematic traced out? If not can anyone get it? If the chip is indeed in the circuit the number would help as we could look it up and find the information on the formula. Any data sheet would have these calculations.

*BUMP*

Hey guys... any headway on this one?

Not for me...just what I found out and already posted. Nobody locally sells crystals so I have to wait for them to be shipped

Hey Minn...I hear they sel EL sheets. Have you lookend into sticking your printed guages on one of them?

Like I said here is a source for the crystals!!!
http://www.alliedelec.com/

Won't have a day off till Monday.

I plan on hitting the cities to do some shopping so I hope to pick up the crystals I can at the electronics surplus store.

I'll start with the next one up from the 4.194 that I took out.

Doesn't look like I'll need to go over the 8.00Mhz crystal for my 140 unit so that should be easy.

Are the crystals only made in certain freq's or can you get just about anything if you look around?

falconhulk, I will try to draw a schematic if I get a chance and post it, DO NOT hold your breath that it will be a work of art but I'll try.

fIEROHOHO,
I have looked at many of the electronic surpluss suppliers in Mpls./St.Paul area. There supply of crystals is limited. What ever you cannot find you can go to Chris Electronics Distributors at 2023 west county road C2 in Roseville (1-800-356-6599) to fill in your supply. They have a great stock.

Thanks Brian, Is that place set up like a home depot where you just browse or do they have an order counter? I may poke in Monday to check it out.

No, they are a warehouse. So you can call them with all the frequencies you can't find anywhere else and check to see which they have in stock. If you go to MPC in Eagan (952-681-8099)I know they had a number of frequencies in their bins three or four months ago.

Well I made my trip to the cities today and hit the electronics warehouse for crystals.

Brian, thanks for the address/phone and info, but I didn't make it down there, I'll keep that info for future needs though.

I picked up the following crystals to play with and when I get them tested I'll post the results like I did before:
4.000
5.000
5.068
5.185
6.000
6.144
7.372
7.500
8.000

Hope to try them out on Wednesday.

[This message has been edited by fierohoho (edited 09-24-2001).]

I hope you realize that changing the crystal will also affect the odo and trip. I'm not sure what you are trying to gain here.

If the plan is to make a 140 MPH speedo (or another for that matter), you want to leave the crystal alone so to the odo an trip are correct and then change the fullscale of the speedo using the resistor posted here and on Oliver's site.

quote Originally posted by terryk: I hope you realize that changing the crystal will also affect the odo and trip.

No, thats why I'm using a radar to check the calibration. If the adjusted speedo reads 60mph and so does the radar the odometer will run run at 1 mile per minute or 60 miles in an hour, I would expect them to work evenly (but not accurately) no matter what the crystal.

[/QUOTE] If the plan is to make a 140 MPH speedo (or another for that matter), you want to leave the crystal alone so to the odo an trip are correct and then change the fullscale of the speedo using the resistor posted here and on Oliver's site.[/QUOTE]

I guess I missed the part where a resistor was mentioned in this thread and Olivers site given by Brian had no mention of any resistor changes.

As I recall (correct me if I have this wrong people) the 200mph speedo upgrade which is sold as a kit comes with the new face and a crystal to match the new face, so I guess the crystals are the place to start.

While I am the first to admit that I am not an expert in electronics there is a good indicator from my first attempt that changing the crystal is a good place to start in trying to turn a 140Kph speedo into a 140MPH speedo without redoing the face.

If this doesn't work then we'll know, maybe we will run across someone who has or can figure out the correct solution.

At the least it's fun playing with Fiero stuff.

.

[This message has been edited by terryk (edited 09-24-2001).]

I bought a 200MPH Speedo kit a few years ago for one of my cars and all that was in the kit was a crystal and a new stick on face....

Still working on this one, my "weekend" Mon-Wed, didn't work out exactly as planned but I hope maybe later this week for the results.
HoHo

Hey Hoho...
You are going for a 140mph sppedo, right? I'll buy whatever crystal you have that may give me a 200mph speedo if you want to sell it(them).

Thanks

Well, today is the day I test the crystals.

I finally got the setup done for the easy swap and will try and post the results tonight.

I'll post some poor webcam pics of the stuff allong with the results.

It's been almost a month since I bought the crystals, thought I'd go nuts because I couldn't find em but they were in the last place I looked .

Results tonight!!! HoHo

What a coikidink....I just found the crystal that Brian C. sent me(thanks!!!).

And at the end of the week...I'll be able to make guage faces!

fierohoho... can't wait to see the results. Document whatever you can (especially the degree between MPH measurements...)!

The setup pics come first then the results.

The first pic shows the end of an old speedo circuit board that I cut off and soldered wires to,

the second pic shows the leads I clip to the crystal,

the third pic shows the whole setup hooked to a 140KPH dash pod, the leads go inside and are soldered to the two board spots where the crystal was,

then all I did was pull the bottom off the dash exposing the speedo plug on the existing dash and unplugged it and pluged in my adaptor.

I hung the test pod on the passenger window, put the radar on the passenger seat and went for a test drive.

Next post has the results. HoHo

can't wait to see...

Well, here's the results such as they are.

The left column will have the speedos indicated speed in KPH and the right will have the radar reading of the actual speed.

8.000 crystal

30=36
40=47
50=59
60=69
70=81

7.500 crystal

30=33
40=44
50=55
60=66
70=77

7.372 crystal

30=32
40=44
50=55
60=65
70=76

6.144

30=27
40=37
50=46
60=54
70=64
80=73

6.000 crystal

30=26
40=36
50=42
60=52
70=61
80=71

5.000 crystal

50=37
60=44
70=52
80=59
90=66
100=72
110=81

4.000 crystal
50=29
60=35
70=40
80=46
90-53
100=59
110=63
120=69
130=76
140=81

Not the results I had hoped for.

I am now open to suggestions or any thoughts.

Rob, what did you mean by the degree between measurements, was it along the lines of 360 degrees for say a gage face setup?

HoHo

[This message has been edited by fierohoho (edited 10-17-2001).]

Well, if my math is right....it looks like the 8.000 crystal has split the mph reading almost in half.

Speedo reads 42.5mph @ 81mph so...
reads 129degrees where used to be 247degrees

So when truckin along at 81mph you are now at 129degrees on the speedo half of the speedo sweep(260degrees)

You made yourself a 162 mph speedo.

[This message has been edited by Joe Torma (edited 10-17-2001).]

Yup! Was looking for the degree change (based on a 360 circle) for altering the gauge faces.

If your measurements are all correct, I'll try to make a 160(165?)mph speedo face for the 8.000 crystal using specific degree changes for 10 mph increments. (Joe- you seem quick with the math... can you figure what that works out to be?)

quote Originally posted by MinnGreenGT: Joe- you seem quick with the math... can you figure what that works out to be?

Quck with math? hehe..one thing I've never been called.

Not too hard though...260(degrees)/Max reading=degrees per mph on dial.

So, If you have a 165 speedo...1.5757575 degrees between mph

Note...since I have changed my tire size, I will be taking this into account. I am going put a blank sticker on my guage and use my GPS--you could pace someone, or use radar --- to tell my how fast I'm going at 55 or 65. I'm going to put a mark where the needle is and calculate from that degree mark.

[This message has been edited by Joe Torma (edited 10-17-2001).]

Methinks we better keep this one alive.
Bump¹

------------------

^{Never pull your pants down in Cosco, the dang monkeys will getcha
AIM: KSSouter}

My readings should be accurate to (+-) 1mph.

What else could I do to help?

Rob, have you done a prototype "indiglo" face yet and if so how did it look?

Another thought I don't remember seeing in a post before...

...this is a picture of the back of the gage cover, as you can see it is orange.

In real life (not the bad webcam pic) it is florescent orange.

Apparently this accounts for the orange cast at night.

I know this is for the side lit gages but, not everyone has backlits, I was wondering what it would look like if it was repainted say a florescent blue?

Anyone tried this?

I have not as yet taken apart my backlit gage cluster, is the cover painted the same for the backlit as for the sidelit?

If it is it may help any "indiglo" look to repaint it to the blue.