My home made 140 MPH speedo

Originally posted by EricCoolCats:
Jeff, if you wouldn't mind that file would be something we could throw in the article on COOL CATS. joefriday and I are in contact and as soon as his preliminary testing is also done, we're going to make an official page on the site so anyone can do it. Your electronic info is invaluable!

BTW, for everyone else, you can print your own speedo and instrument cluster faces via my site here: http://www.coolcats.net/media

I made a whole bunch of T-Bird logo faces for everyone. If you'd need something custom (logo, numbering, etc.) drop me a line ([email protected]) and I'll be happy to do that for ya.

Check your E mail!

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Jeff Korn

88 Turbo Coupe: Intake and exhaust mods, T3 turbo at 20 psi, forced air intercooler, water injection, bypass valve, Ranger roller cam, subframes, etc., etc.. // 86 Tbird 5.0 (original owner): intake, exhaust, valvetrain mods, 100 HP nitrous, ignition, gears, suspension, etc., etc.... // 91 Escort: Bone stock winter car // 02 Taurus Vulcan(wifes car)

Hey Jeff,

Sure if you can send that spreadsheet I'll see if I can make a PDF file.

[email protected]

I'm more of a vector than raster type of person. Plus the files sizes are tiny with pdf.

Thanks

I'm wondering if the errors present below 50mph are constant across the speedometers, or vary with each. I already know that they are pretty inaccurate to begin with, since my speedo and odo aren't even in sync with each other on either car.

I'd be willing to ship another speedo to Jeff K for testing and comparison if he is willing to do the work of another test. That way, if the errors ARE constant, some of us who are great with graphics can make accurate speedo faces.

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Mike Walsted - NATO member
1986 5-speed TurboCoupe and 1985 5-speed XR7

[This message has been edited by Walsted (edited 12-18-2003).]

Originally posted by EricCoolCats:
Jeff, if you wouldn't mind that file would be something we could throw in contact and as soon as his preliminary testing is also done, we're going to make an the article on COOL CATS. joefriday and I are in official page on the site so anyone can do it. Your electronic info is invaluable!

BTW, for everyone else, you can print your own speedo and instrument cluster faces via my site here: http://www.coolcats.net/media

I made a whole bunch of T-Bird logo faces for everyone. If you'd need something custom (logo, numbering, etc.) drop me a line ([email protected]) and I'll be happy to do that for ya.

Eric- What did you use to do the gauge faces? Where do you have the overlays made? I want to come up with something when I do the speedo calibration in the 83 TBird. Then I suppose I can do one in silver..so the cluster I swapped into my 80 XR7 (in preparation for the future 2.3T swap [Image: tongue.gif]) will match the original silver w/ black one.

Chuck


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Any connection between your reality and mine is purely coincidental..
83 TC Clone, 87 Ranger (soon to be 2.3T), 84 XR7, 80 XR7, 86 XR4 and 62 Mercury Monterey
NATO Member

Woohoo to Jeff!

That's the type of confirmation I've been looking for. Obviously, my "turn a drill and time" methods left a bit to be desired. Now, I'm having a bit of trouble understanding the last part of your first post Jeff. Could you put in layman's terms this part:

"BTW, as long as pulse voltage to speedo is over .2V RMS, speedo will read correctly independant of pulse voltage."

Does that mean the crappy low speeed accuracy can be fixed? I don't mind a speedo that will read higher than actual speed, but to read up to 7mph LESS than actual is scary, and it'll probably get us all in trouble with the cops. I also wonder about the accuracy from speedo to speedo for these cars. It really is a shame you didn't try the stocker first before the conversion, but hindsite is always 20/20 eh? Now Jeff, as everyone else who's done this conversion has NEVER had it installed and tested in a running, driving car, would you be so kind as to try it out in your TC for a while, and post back on what you think? Tell us if it's durable and note if there's anything funky going one. Also, tell us what you think about gauge illumination at night! In theory, the converted speedos are IDENTICAL to the motorsport unit from a hardware standpoint, but we all now how far theory gets us. We need a road test!

BTW, thanks for props, but I gotta bow out of the spotlight: this would have never happened if it wasn't for a group of several dedicated individuals. Turbocoupe50, Masterblaster, Jabobia, Eric of Coolcats, Thunderchicken, and more (I know I'm forgetting a few, sorry!)shared information freely with me that was absolutely essential in figuring it all out. They all deserve credit in my book.

Thanks Jeff, for giving us a great scientific test-out. Now, get your arse out there and drive with it!

Joe

Joe.... I tried using pulse input voltages between 0 V and 8 V RMS (root mean square). If the pulse input voltage to the speedo was greater than .2V, it would indicate a speed for whatever frequency I was putting in. Speed indication did not change for a given freq. when voltage went from .2V to 8 V. If pulse input voltage was under .2 V, the speedo didnt work... needle just stayed at zero. The cutoff from working to not working was quite sharp.... either it indicated a constant speed or nothing.

Lighting: I made the speedo face out of heavy semi gloss paper, the kind of paper the wife uses to make birthday cards and such on the computer. Used a HP712C ink jet to print it using the highest contrast and resolution I could set. After the ink dried, I hit it with a few coats of clear laquer (I think it was Plasti-cote brand). I used Joes idea of sanding the old speedo face off until I hit the green plastic, and glued the new face on with high strength clear trim adhesive. Sprayed the adhesive on my finger, and spread it spread it on the plastic face. I reassembled my spare cluster with the new speedo, and lit it up with the stock lighting on my workbench. Speedo is a little darker than tach, but not by much. I dont think most people would notice it unless I pointed it out to them. Also, when comparing the "blackness" and "glossiness" of the speedo face and tach face under room light, they seem a pretty good match. After I reassembled the cluster with the 140 speedo in it, I asked the wife and daughter if they could see any difference between the color, glossiness, etc of the old tach face and new speedo face, and they both said they couldnt tell any difference.

Accuracy: I dont think inaccuracy at lower speeds will bother me much. Lots of my driving is higher speed anyway where my particular speedo, at least, is accurate. The TC sees lots of highway miles on trips... IMO the TCs are one of the best, if not the best interstate cruisers ever built. Even though the wife has an almost new Taurus (2002) with nearly every option, we still take my TC on road trips.... the TC has more comfortable seats, rides just as good or better, has WAY more power, and gets better gas mileage than her Taurus. When driving around town in city traffic, I rerely look at the speedo anyway.... I just drive with the flow of traffic most of the time.

It is supposed to be 40 deg here over the weekend, and the snow has stopped falling, so I hopefully will get a chance to put the new speedo in over the weekend and see how it performs on the road. I will also take the old 85 mph speedo and check its calibration. I may even pop a 33 nF cap in the old speedo, print out another 140 mph face, and tape it on, and see how the calibration works out on that one. I will keep everybody informed.

A closing thought.... The 100K resistor that sits next to the 33nF cap seems to be important in the calibration. I am guessing that resistor and the 47 nF / 33 nF cap together control calibration. I am thinking that, if the speedo is off due to changes i tire size, rear end ratio, etc, it might be possible to make fine calibration changes by adjusting the value of that resistor. Maybe remove the 100K resistor, and in its place, put in a, say, a 95K resistor and 10K trimpot in series, giving an adjustable resistance of 95K to 105K.

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Jeff Korn

88 Turbo Coupe: Intake and exhaust mods, T3 turbo at 20 psi, forced air intercooler, water injection, bypass valve, Ranger roller cam, subframes, etc., etc.. // 86 Tbird 5.0 (original owner): intake, exhaust, valvetrain mods, 100 HP nitrous, ignition, gears, suspension, etc., etc.... // 91 Escort: Bone stock winter car // 02 Taurus Vulcan(wifes car)

[This message has been edited by Jeff K (edited 12-19-2003).]

I agree on the resistor. Anyone with a canadian 200 kph already has the correct capacitor, but the resistor next to it is 110K, instead of the 100K in the 85's and 140's, so it definately has something to do with it. I suppose experiments will have to be made in order to find out its true importance.

Jeff, with your equipment, I believe it is now possible to make a higher reading speedo (I'm talking above 140mph). After you get done testing out your stock speedo, and then its 140 conversion, try another time, only using capacitor that is even lower than .033uf (seeing as how the stock 85mph is .047uf, is seems logical the lower uf=higher top speed),and using your pulse machines, make a mark on the face where 60, 120, etc, etc, come in at until you peg the speedo out. Hey, if you can find out which capacitor will work for a 200mph speedo, perhaps the stock Canadian face markings will be accurate enough to work in mph? Although I don't know how many of us would really need a speedometer to read higher than 140mph, given this opertunity it seems almost daft not to try.

Joe

Joe, I will play around with different resistor and cap values and see what happens. I may try changing the resistor to a 200K ohm or so pot and see what kind of speeds I can get the speedo to max out at. Probably not to practical, as most driving would be done using a small part of the dial range, but can you imagine the shock value of having, say, a 250 mph speedo in your car? [Image: smile.gif]

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Jeff Korn

88 Turbo Coupe: Intake and exhaust mods, T3 turbo at 20 psi, forced air intercooler, water injection, bypass valve, Ranger roller cam, subframes, etc., etc.. // 86 Tbird 5.0 (original owner): intake, exhaust, valvetrain mods, 100 HP nitrous, ignition, gears, suspension, etc., etc.... // 91 Escort: Bone stock winter car // 02 Taurus Vulcan(wifes car)

Jeff, I've had some people report to me that aftermarket speedos usually require a 1K resistor soldered inline to read accurately below 30 mph. Maybe that's something that would work in your situation too.

Sorry to steal the thread here, but Eric:

How much do i have to reduce the guage overlays on your site to make them work?? they came up on my comp way too big. And how do you remove the old face to put the new one on? Any Ideas as far as Material use for the overlays? I was thinking vinal type materials, since there is a place in town here that prints vinal graphucs and also does custom work.

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87 Tubocoupe, Light Regatta Blue, All Options incl. Leather; 2.5" exaust, Dynamax super turbo mufflers w/3"chrome tips, MSD 6AL, Blaster2 Coil and wires, Homemade adjustable boost valve.

"May the fluids under the hoods of the beleivers flow forever"