240km/h Speedos

[dguy]

I'm posting this mostly for a certain someone who mentioned that his speedometer thinks it's a helicopter rotor above certain speeds   , but it may be of interest to anyone else who wants to "upgrade" that old 140km/h speedo.

http://www.fiero.nl/forum/Forum2/HTML/038149.html

[GoFast85]

I have an 85 kph that I would like to send out. If we can get a few together we can cut the costs. Any interest

[dguy]

For those who are interested, there have been a few updates to this thread.

The guy in B.C. who was considering doing entire speedo conversions appears to have de-tuned the project for a few reasons, and is now only planning on producing a near-match overlay for the speedometer, scaled up to 240km/h.

People wanting to do the conversion would have to obtain their own recalibration crystal.  Details, including a possible value for the crystal can be found at the link at the top of this page.

[2ML67]

Actually I am working on modding my gauge package to accept the 97 GTP gauges I have. If this works I will have a much higher speedo plus a tach with the lower portion being a digital readout for boost as well.
Just remember Fiero's can not reach or exceed 200kph so it really would be for looks only to have such a speedo. Afterall there are laws against doing such speeds and we all know laws are meant to be obeyed. Dan

[FieroBUZZ]

Just remember Fiero's can not reach or exceed 200kph so it really would be for looks only to have such a speedo. Afterall there are laws against doing such speeds and we all know laws are meant to be obeyed. Dan

Did you actually get away with that, you sneak?  Did he trot out all the specs on an iron duke?

[Boy-z]

kEVIN AND i MEET A GUY AT THE cORNWALL CAR show and he was saying that the cluster from a 1989 Mazda 626 has the exact hookup for the Fiero he said the plug was identical I don't know what you think off that but if there is one at the juck yard I guess it is worth  a look.

[dguy]

Resurrecting an old thread due to something I found recently on Pennock's.  

The guy in B.C. who was working on the 240km/h overlay is apparently targeting the back-lit instrument panel, and mine ain't.  So I've wandered off in another direction...

I stumbled across this link a few minutes ago.  Free downloads of the faces for both the imperial and metric original gauges, in a variety of colors, apparently for both the back-lit and side/indirect-lit crowds.

All you need to do if you're converting from the 140km/h speedo is replace the stock crystal with a 4.43MHz crystal, have a good quality print of the new face made, and stick it down.

[GoFast85]

I just ordered and received the package. The crystal that I received was not a 4.43MHz crystal. Will get back to the forum tommorow with the crystal that is the replacement size.

[dguy]

Hmmm...  nicely done, but I think I'll stick with something that prominently shows km/h instead of MPH with some squinty numbers stuffed in there as a token gesture to the metric system.

I may measure my height & weight in inches & pounds, but I drive in km/h.    


...although suddenly I feel like doing a photoshop job on that overlay I found, and changing the scale a bit.  

[GoFast85]

Have the crystal sizes.
On a stock 85 mph speedo the crystal size was 6.331 MHZ
The unit supplied for the 150 mph speedo is 7.37 MHZ

No way the 4.43 will work with the 85 mph (140 kph) speedo to 150 mph (240 kph) speedo. Do you have the link for the incorrect crystal

[dguy]

Have the crystal sizes.
On a stock 85 mph speedo the crystal size was 6.331 MHZ
The unit supplied for the 150 mph speedo is 7.37 MHZ

No way the 4.43 will work with the 85 mph (140 kph) speedo to 150 mph (240 kph) speedo. Do you have the link for the incorrect crystal

Huh?     Oh hang on, I see it.  Bad wording on my part.  I never meant to imply that the 4.43MHz crystal was appropriate for a 150mph speedometer.  What I should have wrote, was this:  

All you need to do if you're converting from the 140km/h speedo to the 180km/h speedo...

My apologies for any confusion.  


The widely believed-to-be-true formula for calculating the "size" of crystal that you need for a speedo conversion, is 534 / desired max MPH.  I've seen it mentioned in a few places, but the one I happen to have bookmarked is here.

Now if that formula is accurate, the crystal supplied with the conversion kit you bought is, well, roughly double what the formula says you need.    Then again I know SFA about how crystals behave in circuits, so you may still have an accurate speedo with that (possibly) doubled value.

Where did you purchase your kit from?  I'd like to get in touch which whomever put it together and ask them why the crystal they're supplying is roughly double what the popular calculation says that it should be.  I'm leaning strongly toward making my own speedo face at this point, and am trying to gather as much information as possible...

[GoFast85]

I just gave rsphaff on Pennocks a blast . He is still   working on   ;)nudge nudge. He is just pulling our legs. The fellow who sent me the package did me a favour and not actively involved in Fiero's. Dan will be putting it in for me so if it works then we will know. We will talk more on this at the monthly meeting this weekend. Why would anyone want a 180 kph speedo because for the same amount of work you can get a 240 kph or also a 190 mph one. Is it my member is bigger than yours situation  

[aaron88]

yah... well my speedo will go to 250 then.

Aaron

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[GoFast85]

Aaron -- You will have to paint your car yellew then  

[aaron88]

Paint? ...Yah, with a roller...that's my style.  I might just as will get some stripes on there while I'm at it.  Never mind, I don't like stripes.

Aaron

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