Well this must be Page-3..... the last!

Sept-6,2008
Summary.. if your 25+ year OLD 240/260/280 does not
feel safe at xx-MPH or any speed you should not drive it faster!

Road Tested my 280zx 2+2 up to 100MPH, see video



Included several Pix of my 1983 280zx 2+2.











Road tested and video'd both Z's Dash Speedo and My External
Speedo.
Marty schematic gave me a starting point. He used an Alarm
Clock display, his 510 truck used a magnetic sensor on drive
shaft for speed detection, his unit performs the basic MPH
function. Calibrating his unit uses external speed detector
local speed trap display.

If you are electronic knowledgeable, you'l note the differential
speedo input ,Lm324, from the Zs digital dash (thats the
reference. The double pole switch enables swtching
between MPH and KMPM, LEDs reflect your choice/switch
position.

The External Speedo has 1-inch High Intensity Red 7-
Segment3-character display, Not an Alrm Clock.
You will need to perform some guessing as to electrical
noise filter capacitors other than that shown in my
schematic.

I have about $300 into my box, and you mmay be able
to build it for less. Good Luck and drive safe even at
100mpph.

280zx schematic :


Drive Test 1 Videos:


Drive test 2 video:



Terrymac


Hi
This is my Page-2 on the 280ZX 's 85+ Digital Dash Speedometer .
I have completed the final phase on the digital speedometer, by
removing my Zs Dash and installing the speedometer interface
(making 2 solder conections to 2-wires) and adding a phone
Jack to connect the external speedometer.

The Basic Speedometer wiring diagram can be found at the following LINK

http://martybugs.net/electronics/speedo.cgi

During this past winter, I revised/modified Marty's Speedometer to enable
it to work with the 280ZX Digital Dash (marty's car was a 510-Datsun
Truch).

Progress ha been slow on the prof of Speedo working, as I had the Zs
frame modified (appears previous owner had front fender accident/
repaired, but did not have it suspension re-aligned ( Another $425).
Plus as I opted for Slotted-Drilled rotors when I reded the Zs under-
carriage (they warped within 1st 1K miles). You will appreciate good
rotors as you put the Brake-on to slow down from ~90-100MPH.


Revised New Pictures 8/31/08 are linked below.



Martys originl schematic for his 510 datsun

Video of my Digital Speedo Powered-On with engine running during
the night follows.


Pix of the Digital Speedo with Phone Jack connector
and DC Power Connector which plugs into Cigerate socket.




Will add another Video this week when I have a friend drive
the Z past 85 and I record the vdeo so you can see both the
Dash's speedo and the Red LED External speedo operation.


I've been asked "why add a 2nd Speedo...why not change out
your digital Dash with an Analog Speedo). The answer is
simple, I like the Digital Dash and I want to keep my Z as
Original as possible. I solder 2-wires connections inside the
Dash which does NOT modify its instrumentation, functionality
or reduce its reliablility.


I have spent most of this past winter/spring/summer building
my speedo to Answer 1- Question on my 280ZX ?

" how Faaaast in MPHs is 4500/5000/5500-rpm"


Terrymac

 

go ahead and wind back the miles while you got the cover off, huge investment!

if you figure out how to do it please post a thread with all of the materials and procedures...im tired of not knowing how fast i go on I75

 

TerryMac's stocks just went up! That is awesome!!!

 

zdriver, home of the $30 oil change and stock broking... this things getting BIG! ! !

 

at 85 mph you go back in time, so who cares after that point???

 

only if you have a Flux Capacitor and 1.21 gigawatts.

 

My electric car will have 1.8 Terawatts!
Million horsepower

 

My electric car will have 1.8 Terawatts!
Million horsepower

 

88MPH!!! we have to hit 88!!! We can only see 85
We just need 3 more milllesssperhoursz

 

Wow that's awesome man!! And yes..I do have an '83 n/a with the digital dash. How much would you charge to convert mine to more than 85mph? I am curious about this. Although I don't yet know the future of my Z. Also..I would like to have a custom color. If I do decide to keep it. Anyway let me know on price. But it will be a while though.

 

brilliant i say, brilliant!!!!!! we dont need stainless steal body panels on our deloreans we just need jigawatts!!!!!

 

So this new speedo is going to be an external unit that is used only after 85 mph is reached? or will it be grafted to the housing?

 

WildmaN.... thats a great question!

I working on Adding Kilometers/Mile to the Speedo-box.

My best guess on When a High Quality Speedo will
be available probably Late 2008 time fram.

This 1st box is a rough hardwired unit, Ver-2 will be
hardwired too but with improved packaging, and the
Speedo Display is currently RED, I would like to have
BLUE Display as well.

So far the $ cost of the rough box falls into $200.00
in electrical parts. With Ver-3 the components will
be on a real circuit board with No Wire-wraping.

This (my) Speedo will NOT Replace your current Digital Dash's
Speedo, it will connect to your Dash, and you will then
calibrate The External Speedo to match the Digital Dash's KMH
or MPH at say 10-mph.... The Speedo will then I believe Display your Z's Correct Speed above 85!

I need to complete THE Verification Tests, preferably on a Zx
with Digital Dash thats been removed and the owner is willing
to allow me to install the Speedo interface cable (a 2-wire
cable), the Speedo box is powered by the Z's 12vdc (I assume all
ZXs have functioning cigaret lighter socket).

I live in Fond du Lac, Wisconsin. If their is a ZX owner
interested in being the Verification Plateform give me a
email via ZDriver or my email address
(tryme.terry@yahoo.com)

Thanks for the Question.

terrymac

 

I still haven't quite figured out how you're going to accomplish this.

Are you saying that the correct speed above 85 mph will be displayed on the original factory speedo display, but will be controlled by the "external" unit you've devised?

Or will the factory speedo display stop at 85 and now you have to look at the external unit you've devised in order to see your real speed?

The ideal solution would be to have the external box "intercept" the speed signal and control the display on the factory speedo. Since you can switch it to use KPH, the display should be able to go up to 199 if you can accurately control what LED's are activated.

 

WildmaN...

The External Speedo uses the input to the digial dash, as a standalone
speedometer it measures How Fast you are driving. It does Not Control
the Digital Dash in the Z. But shows your speed beyond that on your
Zs Display which Stops at 85-MPPH, and 140 KmpH.

Terrymac

 

Ok, so it's an external speedo that you have to use over the 85mph limit of the stock speedo.

That's a great job, but I'm thinking it would be easier to just take the speedo cluster to a shop that can re-calibrate it to use KPH as MPH. You then have a 140 MPH digital speedo.

There's a guy in San Diego that has a calibration system that can go up to 150mph.

This is how I converted a Canadian 210 KPH analog speedo to use MPH which gave me a 210 MPH (factory) speedo w/ a 6 digit mileage readout.

 

You can have another shop calibrate your Mechaniical analog Speedometer.
But I like my digital Dash, And I understand how a computer controlled
speedometer worrks. As defined by the Stupod US Goverment. It performs
the speed meauring function just fine, but as you reach 85MPH the program
goes into a loop which forces the Display to show 85-MPH if Equal to/or
greater than 85. So you can modify the mechaniical input to the digital
dash but you will not see moore than 85 in the Display.

I like the digital system, but it would take alot of modification to the software
program to achieve what the Z drivers want " a Unlimited Speedometer".
you can do this as I have by using the same INPUT that the Dash uses.

See video I recorded... below



I need to havesome mechanical Alignment on my Z before I drive it to 85 Plus
and have a partner shoot the video.


Below are a couple of pics of the revised Speedo for he Z.

IMG]http://i251.photobucket.com/albums/gg286/terrymac22/100_0858.jpg[/IMG]

IMG]http://i251.photobucket.com/albums/gg286/terrymac22/100_0852.jpg[/IMG]

See next update in a week or two.

terrymac

 

Ahh. But you missed my point. The digital dash also has a KPH setting. All you need to do is re-calibrate the speedo to represent "MPH" when it's in the KPH setting. That will allow you to show your MPH up to ~140 as long as you can ignore the little "kph" next to the number and realize you're actually going "mph".

 

shady280 has a valid point, for Kilometers/hr, indeed it just a matter
of switching between two pots. Thats what my speedo schematic
has and supports.

 

Now I'm really confused. Shady hasn't posted in this thread so I'm not sure who you're replying too.

I guess my point was, if you set the factory digital speedo to KPH and have your factory digital speedo re-calibrated so it's measuring MPH even when it's displaying KPH, you've solved both problems with no additional components or interface.

 

Sounds like a good plan. Now for some reason I would think that the Odometer would no longer read correctly after the calibration. Am I right?

 

anyway you could just take an existing digital dash, hack it up and place your box in there?

 

You are correct, the odometer reading would be invalidated...

 

That would be my next suggestion.

 

Would it though? It seems to me that the odometer is physically connected to the speedo gearing (odo is to the left of the digi speedo, where the analog speedo / odo is). The stock digi dash KPH / MPH push button is only there for the digital speedo readout & gets it's signal from the speed sensor.