Making speedo work in an engine swapped car.

[BG0041]

Hello,
I don't know if this is the right section, but I don't see a more appropriate one.
So- I am thinking of swapping a Volvo 5 cylinder(B5204T5) mated to a BMW 6-speed gearbox (GS6-53DZ) into a Lada Riva.

I have planned almost everything, but I can't figure out how to make the speedo work.

The original one is connected to the gearbox, but both the Volvo and BMW from which the drivetrain components are gonna be from, use wheel speed sensors.
The problem is that the Riva never had ABS which means there's no way to get wheel speed readings.
And the gearbox and diff don't have any sensors in/on them.

Any ideas?
I would like it to be a daily driver.

Edit: I don't have any of the parts, it's gonna be a summer project. I got my info from the internet.

Edited by BG0041 on Thursday 3rd May 13:59

[gareth_r]

Usual disclaimers...

Speed sensors count pulses from either magnets or something ferrous (like a nut or a bolt head). I guess the more pulses per revolution, the more accuracy?

You can buy an aftermarket magnetic or ferrous speed sensor, and an aftermarket digital speedometer or multifunction gauge to plug it into, fit the sensor to read from the propshaft/UJ/diff flange/hub/wherever, then calibrate the speedo to display the correct speed for the pulses per revolution/diff ratio/tyre diameter.

(or use a GPS speedometer, but the legality would be questionable)

Edited by gareth_r on Thursday 3rd May 15:04

[Turkish91]

Surely a retrofit GPS speedo is available? Not entirely sure how enduro bike speedos work but can't be that tricky to wire up, albeit probably wouldn't have an ODO to clock up onto.

[gareth_r]

A factory fitted speedometer from another vehicle would need a box (such as the SpeedoHealer) between the speed sensor and speedo so that you could calibrate the reading.

[stevieturbo]

BG0041 said:

Hello,
I don't know if this is the right section, but I don't see a more appropriate one.
So- I am thinking of swapping a Volvo 5 cylinder(B5204T5) mated to a BMW 6-speed gearbox (GS6-53DZ) into a Lada Riva.

I have planned almost everything, but I can't figure out how to make the speedo work.

The original one is connected to the gearbox, but both the Volvo and BMW from which the drivetrain components are gonna be from, use wheel speed sensors.
The problem is that the Riva never had ABS which means there's no way to get wheel speed readings.
And the gearbox and diff don't have any sensors in/on them.

Any ideas?
I would like it to be a daily driver.

Edit: I don't have any of the parts, it's gonna be a summer project. I got my info from the internet.

Edited by BG0041 on Thursday 3rd May 13:59

A better question might be..."how do you convert an electric signal into a mechanical signal for the OEM Lada speedo ? )

Really there isnt anything difficult and there are multiple options. Creating a simple trigger is easy, whether from the discs/flanges, propshaft, gearbox flange, whatever.

Whether you then want to fit a suitable electronic speedo to the car or adapt to drive a cable...again, there are options.
This converts electric to a cable drive.

http://www.abbott-tach.com/cablex.htm

Or another

http://www.dakotadigital.com/index.cfm/page/ptype=...

But creating an electric signal is as simple as pointing a suitable sensor at a ferrous metal "tooth" that relates to road speed

It would probably be easier if you could fit an electronic speedo to the car as well though

[psi310398]

gareth_r said:

Usual disclaimers...

(or use a GPS speedometer, but the legality would be questionable)

Edited by gareth_r on Thursday 3rd May 15:04

According to my garagiste, there is a legal requirement to have a speedo fitted but none to have it work.

I can't see why an additional GPS speedo, possibly a He Man HUD thing wouldn't do the job.

[BG0041]

Thanks for the suggestions.
It really helped.
I am thinking of using the driveshaft to measure speed. (ring around it+ sensor)

[gareth_r]

psi310398 said:

gareth_r said:

Usual disclaimers...

(or use a GPS speedometer, but the legality would be questionable)

According to my garagiste, there is a legal requirement to have a speedo fitted but none to have it work.

I can't see why an additional GPS speedo, possibly a He Man HUD thing wouldn't do the job.

I should probably have said "might be questionable".

However, what is legal and what passes an MOT and what passes an IVA test are three different things.

[LordLoveLength]

If you used something like this http://hobbycomponents.com/motors-and-servos/824-n...
directly on the back of the speedo head you could do away with the cable completely.
Then a frequency to voltage converter like this https://www.ebay.co.uk/itm/Frequency-to-Voltage-0-... to drive it.
Worth a try for a few quid?

[psi310398]

gareth_r said:

I should probably have said "might be questionable".

However, what is legal and what passes an MOT and what passes an IVA test are three different things.

My Alfa Spider passes its MOT every year with a non-, or more exactly, semi-functioning speedo.

[gareth_r]

psi310398 said:

My Alfa Spider passes its MOT every year with a non-, or more exactly, semi-functioning speedo.

That's because the speedometer is not part of the MOT test.

It is, however, a legal requirement under the Construction and Use regulations, and the speedo is tested for Individual Vehicle Approval (which, strictly speaking, would be required if the Lada's bulkhead or transmission tunnel had to be modified in order to fit the Volvo engine and BMW gearbox).

[BG0041]

LordLoveLength said:

If you used something like this http://hobbycomponents.com/motors-and-servos/824-n...
directly on the back of the speedo head you could do away with the cable completely.
Then a frequency to voltage converter like this https://www.ebay.co.uk/itm/Frequency-to-Voltage-0-... to drive it.
Worth a try for a few quid?

I do have some experience with Arduino and purchasing from Aliexpress, but I first need to see how it would work and what calculations I'd have to put in.

[stevieturbo]

gareth_r said:

hat's because the speedometer is not part of the MOT test.

It is, however, a legal requirement under the Construction and Use regulations, and the speedo is tested for Individual Vehicle Approval (which, strictly speaking, would be required if the Lada's bulkhead or transmission tunnel had to be modified in order to fit the Volvo engine and BMW gearbox).

But the Alfa was probably expected to be broken even when new lol.

And legal requirements etc will depend where in the world he is.

Either way, not an overly difficult thing to resolve.

[Mr2Mike]

Plenty of kit cars have aftermarket speedometers operating from a magnetic sensor on the propshaft. A biased hall or inductive sensor could be used to sense the bolt heads on the propshaft/diff flange, though you would need to mount the sensor on the diff and route the wiring appropriately.