Clean 2.0 nova
14-01-08, 09:38 PM
This thread is only really to put down some findings of some testing I was doing regarding Digidash speed pulses, as I thought it maybe of some use to some.
I basically knocked up a squarewave generator to see how feasable it was to get the variable assistance on the electric power steering working, and also to get my MPG meter more accurate on my trip computer in the nova.
I think my EPAS is the early type and my trip computer is from a calibra turbo. It may also be worth noting that my digi-dash gave me a reading of 136mph at brunters, when the official timing gear gave 136.7mph - so my digi-dash must be a freak of nature - as it was accurate:eek: .
My Digi-dash type is 6 pulses/transducer revolution, you can tell this as on the transducers it says '6 IMP'. Because the transducer rotates twice for each revolution of the road wheel you get 12 pulses per road wheel revolution. Other types of digi-dash may have 6,8 or 16 pulses (think I read it somewhere). If your bored and good at maths you can therefore work out the rolling wheel circumference.
Test results 1 - square wave o/p V speed readings:
61HZ pulse = 22mph on dash, trip comp = 9
121HZ pulse = 42mph on dash, trip comp = 17
236HZ pulse = 80mph on dash, trip comp = 33
345HZ pulse = 120mph on dash, trip comp = 50
This gives average of 30HZ for each 10mph on digi-dash - as also found by DOM (migweb). The trip computer obviously requires a lot more frequency.
Test results 2 - Frequency set at 330HZ:
Digi-Dash = 114mph
Red switch flicked over (power off, then on again), dash = 44mph
trip comp = 48mph.
If I was to use a higher frequency transducer of say 15 impulses per transducer revolution, I recon I would get the following figures at 114mph (825HZ):
Dash = 110mph (red switch kept flicked over)
trip comp. = 120mph
I think this is close enough to use a 15 IMP transducer to get both running, or indeed I could add a 'stackable' '15 IMP' transducer just to run the trip computer and EPAS, and leave the '6 IMP' transducer for the digidash.
Test 3 - EPAS control.
With the EPAS wired in and revs signal applied straght from the engine, I could indeed vary the assistance using the pulsed signal on the EPAS blue/red wire. I found that if a '15 IMP' signal was simulated the assistance would back off around 20-40mph. Which i recon is spot on.
The fact that a 15 impulse transducer (30 pulses per road wheel revolution)works is not all that surprising, as an ABS ring (for a calibra at least) has 29 teeth. This could well be the standard for modern vauxhalls?
These findings are usefull as I don't have to buy a gay EPAS controller box thingy that doesn't give varying assistance for varying speed, usefull info for others aswell i'm sure.:thumb:
Notes:
6 IMP transducer P/No:90149083
Basically your not totally f'cked if you get a dash w/out a transducer, as you can tell how far out it is when using a stock transducer and determine the one you need by the factor of its error.
Does anyone no any p/no's for vauxhall 15 impulse transducers, stackable or not?
If anyone wants any more info please ask, as I don't know how clear I made it all:tard: , Iain
I basically knocked up a squarewave generator to see how feasable it was to get the variable assistance on the electric power steering working, and also to get my MPG meter more accurate on my trip computer in the nova.
I think my EPAS is the early type and my trip computer is from a calibra turbo. It may also be worth noting that my digi-dash gave me a reading of 136mph at brunters, when the official timing gear gave 136.7mph - so my digi-dash must be a freak of nature - as it was accurate:eek: .
My Digi-dash type is 6 pulses/transducer revolution, you can tell this as on the transducers it says '6 IMP'. Because the transducer rotates twice for each revolution of the road wheel you get 12 pulses per road wheel revolution. Other types of digi-dash may have 6,8 or 16 pulses (think I read it somewhere). If your bored and good at maths you can therefore work out the rolling wheel circumference.
Test results 1 - square wave o/p V speed readings:
61HZ pulse = 22mph on dash, trip comp = 9
121HZ pulse = 42mph on dash, trip comp = 17
236HZ pulse = 80mph on dash, trip comp = 33
345HZ pulse = 120mph on dash, trip comp = 50
This gives average of 30HZ for each 10mph on digi-dash - as also found by DOM (migweb). The trip computer obviously requires a lot more frequency.
Test results 2 - Frequency set at 330HZ:
Digi-Dash = 114mph
Red switch flicked over (power off, then on again), dash = 44mph
trip comp = 48mph.
If I was to use a higher frequency transducer of say 15 impulses per transducer revolution, I recon I would get the following figures at 114mph (825HZ):
Dash = 110mph (red switch kept flicked over)
trip comp. = 120mph
I think this is close enough to use a 15 IMP transducer to get both running, or indeed I could add a 'stackable' '15 IMP' transducer just to run the trip computer and EPAS, and leave the '6 IMP' transducer for the digidash.
Test 3 - EPAS control.
With the EPAS wired in and revs signal applied straght from the engine, I could indeed vary the assistance using the pulsed signal on the EPAS blue/red wire. I found that if a '15 IMP' signal was simulated the assistance would back off around 20-40mph. Which i recon is spot on.
The fact that a 15 impulse transducer (30 pulses per road wheel revolution)works is not all that surprising, as an ABS ring (for a calibra at least) has 29 teeth. This could well be the standard for modern vauxhalls?
These findings are usefull as I don't have to buy a gay EPAS controller box thingy that doesn't give varying assistance for varying speed, usefull info for others aswell i'm sure.:thumb:
Notes:
6 IMP transducer P/No:90149083
Basically your not totally f'cked if you get a dash w/out a transducer, as you can tell how far out it is when using a stock transducer and determine the one you need by the factor of its error.
Does anyone no any p/no's for vauxhall 15 impulse transducers, stackable or not?
If anyone wants any more info please ask, as I don't know how clear I made it all:tard: , Iain