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Astra GTE Digidash
givemethebighammer - 26/11/02 at 09:36 PM

Has anyone tried to link a vauxhall astra gte digidash to a ford (or any other manufacturer) gearbox ? The the electronic speedo sensor screws in to the gearbox where the speedo cable normally goes, so if it would somehow fit into another gearbox, it ought to work (in theory)

Maybe just a long shot ?


Stu16v - 26/11/02 at 11:02 PM

Only if the drive from the gearbox was exactly the same ratio as the Astra, for a given tyre size.
HTH Stu.


givemethebighammer - 26/11/02 at 11:50 PM

The tyre size is adjustable with a switch on the top of the digidash module. The gearing of the speedometer drive on the gearbox is another matter. Where would I find info on the drive ratios for Ford and Vauxhall gearboxes. I guess its not something that would be common knowledge ?


MrFluffy - 27/11/02 at 09:24 AM

I looked into the astra digi dashes a bit back, and found this site very usefull...
http://homepage.ntlworld.com/ben.copeland/Mk1%20Digi%20Dash.htm

Im still going to use one when I find one for reasonable money...


[Edited on 27/11/02 by MrFluffy]


givemethebighammer - 27/11/02 at 10:10 AM

Thanks for the link - I had already found this site. I still have yet to find out about the speed sensor problem. Will it or won't it fit into the speedo cable connection on a ford type 9 gearbox. If anyone has any ideas how to do or bodge this one I would be very grateful


Mr G - 27/11/02 at 10:28 AM

Yes this has been mated to ford stuff ok. I mentioned in the 'Running Gear' forum that joining the XROC forums will come in handy as alot of questions on diffs/driveshafts/hubs etc are asked on there... well I asked this on there only a few weeks ago.

If i remember rightly the answer came back that the sensor fitted ok - you need a three piece speedo cable like the orion ghia one which has the trip computer sensor normally on it.

Fitz at TOP BOSS TUNING put a 4 pot ASTRA GTE dash in his 24v cossie powered sierra.. (He was going to put a 6 cylinder carlton/senator digidash in but went back to analogue instruments as he said it was distracting)

www.topbossperformance.co.uk

If you do join the xroc forum pm graceland for info





www.xroc.net/forums



Cheers

G


Stu16v - 27/11/02 at 05:51 PM

I am fitting a digidash to my car. The Astra speedo drive goes round twice per wheel revolution ( I know, I've got one).
I also own a Westy, so I wired the dash in that using a speedo transducer out of a Daewoo Nexia, which also has a cable drive output. After checking to ensure the transducer gave the same reading as the Astra, when the Westy was doing 80 (off road of course) the digidash was only reading twenty mph! So by v. rough calculations, the RWD Ford output runs at quarter of the speed. Whether the Ford transducers off the later Granadas would offset the difference I dont know, but apparently there are three different output signals available to account for different gearing.
I am now playing with building my own sensor to run off the driveshaft, progress is good, but am unable to say whether it will definately work.
P.s. the switch on the digidash recalibrates the speedo for different tyre sizes that are fitted on the Astra (185/60x14 as opposed to 185/65x14 IIRC). But the overall difference is very small anyway, so dont rely on that.

HTH Stu.


theconrodkid - 27/11/02 at 06:20 PM

could you not use an after market type transducer and aim it at a hub or other rotating part and adjust the number of choppers on said moving part?


Mr G - 27/11/02 at 07:09 PM

I cannot believe that the gearing for the drive is that way off. This is a popular conversion seen in alot of cars other than vauxhall.

Does the daewoo unit definately give out the same amount of pulses as the proper astra unit?

As ive got no idea what type of signal is set I can't comment more but i remember that the dash and transducer must match and only a fair comparison can be made with gearbox drive difference if an astra transducer is used.

I think i'll have another sniff around and see what I find. Thanks for the info Stu.


Cheers

G


Stu16v - 27/11/02 at 07:16 PM

Conrod kid, possibly, but then you need a signal amplifier as the signal sent by the standard one is a lot stronger. I did try it on my mates Westy with an aftermarket sender and it wasnt having any of it!

Mr G, the Daewoo unit was used in tandem with the Astra sender, and both dash's were reading exactly the same, thruogh the range tested. It would be interesting to find out how others have done it, may save me some hassle! But the trouble is, people 'customizing' a road car dont have to have the calibration checked by SVA. Bugger!


stephen_gusterson - 27/11/02 at 10:05 PM

it would be fairly easy to make up a circuit to divide or multiply pulses to give you the right ratio.

If people were interested in sufficient numbers, some hardware/software guy could do a converter quite easily.

There must be a few on here.


ATB

Steve

(a hardware / software guy)

[Edited on 27/11/02 by stephen_gusterson]


Stu16v - 27/11/02 at 10:29 PM

Cool, Mr Hardware/Software guy....mate....good buddy.....creep creep etc, etc
I have a mate who knows a little of whats going on in the sensor. This is the bit where I start to loose the plot a bit, but it may make more sense to you.....
As in my previous post above, I found that the sensor in the standard Astra (the model most VX digidash's come from) turns exactly twice per wheel revolution. The sensor itself (OK I didnt find this out, my mate did) has six tiny magnets inside, as one goes past, the pickup it turns the current in the signal wire on, as the next goes by, it turns it off. Now we are working on the theory that if we strap/glue twelve magnets on the Rear driveshaft output shaft, and using the original pickup which seems surprisingly intolorant to how far away the magnets are, with a wheel of similar rolling radius we will have an accurate speedo. Does this sound practical?
The other option is to find out exactly how many pulses a Ford speedo sensor kicks out per wheel rev. and as you say, have a pulse converter to correct the pulse, and maybe the type of signal too.

Cheers, Stu.


givemethebighammer - 27/11/02 at 10:51 PM

Checked the XROC Forum:
quote

"dojj - easy enough to modify the pulse generator from the senetor or astra to make it work on sierra - you just need the short speedo cable from an orion ghia (mk2) which has the fuel computer as this is a 3 piece cable and the rest is jsut a case of finding the right wires and pluggin them in as appropraite"

Sounds fairly straight forward - what's the worst that can happen, famous last words.

Think I am going to give it a try.

thanks, hope I didn't open too bigger can of worms here.

What about a Maestro digidash ? sorry just a thought


johnston - 28/11/02 at 12:15 AM

first i dont know anythin bout them

but can they not be "re-programmed " by the same guys can can "fix" the mileage on them?????

or wat about a sensor for a trip meter like u get in a rally car????? some goin to the box some go in a split in the cable


wayne916 - 10/1/03 at 07:46 PM

If the speedo transducer from the astra is a pulse count ( I read earlier it was 6 magnets with an pick up coil), and one rotation of the wheel turns the sensor twice, I would be prepared to build a variable multiply/divide micro based circuit and sell on if any one is interested, I am fitting a MK2 dash to my V8 hybrid Landover


Mr G - 12/1/03 at 03:30 PM

I'm still interested in finding out how people are getting on with fitting one of these dashes.

What is the situation with the drive take off on vauxhalls. Does it come from the gearbox diff? I'm not clued up on fwd boxes etc.

Using a box to sit between the wrong amount of pulses coming in and converting them seems a good idea. I did find a 'max power' type site where someone had fitted an astra lcd dash to thier mk4 escort but i can't find it again! I was going to email the person and ask what they had done to modify the transducer and get it working.



G


Stu16v - 12/1/03 at 10:03 PM

Mr G, yes, it is basically driven off a nvlon gear on the side of the diff, which drives a worm gear which in turn is connected to the transducer. The Mk4 Escort is the same, and I think the VX transducer will screw straight on to the Escort gearbox IIRC. Dont know if the Escort speedo drive has the same gearing though....But there again, I doubt if the bloke with the Escort had to go through SVA
Wayne916, are you able to make something to multiply pulses as well as decrease with your 'magic box?