coozer
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 posted on 2/9/08 at 12:18 PM |
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Electric PAS
I have a nice Epas column that has a 100amp motor on it.
If I attach it to my 7 will the battery (redtop 25) be OK.
It only pulls full amps when your parking or turning the steering standing still. With the weight of our cars it may be less than that.
What do you reckon??
Steve
1972 V8 Jago
1980 Z750
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Paul TigerB6
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| posted on 2/9/08 at 12:31 PM |
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Fit a nice lightweight bike engine in there - with only 60kg of engine / gearbox you wont be needing power steering!! 
Sorry - couldnt resist!! 
On a more serious note, your engine will be running so you will be hopefully taking some / most of the current draw from the alternator. Do you know
the output of this at all??
[Edited on 2/9/08 by Paul TigerB6]
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Davey D
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| posted on 2/9/08 at 12:41 PM |
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i ran my S14 200sx on a varley Redtop 25, and everything ran fine, so dont worry about it ;-)
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02GF74
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| posted on 2/9/08 at 01:15 PM |
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is will suck power from your engine.
why on earth do you want PAS is a light car such as a 7?!?!?!
A larger steering wheel or going to the gym will fix that.
I manage to turn the wheel on a landrover with hooooooge mud tyres and 13 inch steering wheel no probs - ok, on a long journey my shoulders ache a bit
but that is a good think, no?
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Paul TigerB6
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| posted on 2/9/08 at 01:18 PM |
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quote:
Originally posted by 02GF74
is will suck power from your engine.
why on earth do you want PAS is a light car such as a 7?!?!?!
As its an electric PAS system, it doesnt have a PAS pump to drain power from the engine. Do agree though that power steering isnt required though -
even if the car has a huge lump of Zetec in the front!!
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02GF74
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| posted on 2/9/08 at 01:26 PM |
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quote:
Originally posted by Paul TigerB6
quote:
Originally posted by 02GF74
is will suck power from your engine.
why on earth do you want PAS is a light car such as a 7?!?!?!
As its an electric PAS system, it doesnt have a PAS pump to drain power from the engine.
So it pulls electrons out of thin air?
If it is electrical, it will draw current and the alternator will supply current.
Something has to power the alternator (clue: the engine).
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smart51
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| posted on 2/9/08 at 01:49 PM |
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I used to design electic PAS systems, so I know a thing or two about them.
They draw minimal current when you're not doing any steering. They draw current in proportion to how hard you are steering. They draw current
for a certain time then reduce the assistance they give. This varies from manufacturer to manufacturer. "Ours" were quite good. The one
on the honda civic pool car we had was pretty poor.
Full power is quite a lot, say around 80A. That's when the vehicle is stationary and you're trying to turn the wheel at super human
speed. One the move and doing normal steering you're typically less than a quarter of that.
Apart from not really needing PAS on a seven (do you have a huge V8 or something?) I'd worry about the feel and more importantly stability.
ePAS are tuned to suit the vehicle. Most have several tunes to suit different versions of the same vehicle to adjust for heavier engines and wider
tyres, for instance. If you take the ePAS from a Micra or a Corsa, will the tune suit your car?
Lastly, most ePAS unit expect CAN messages from the rest of the vehicle, notably the ABS so it knows the speed. It might not work at all without the
right CAN nodes.
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Paul TigerB6
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| posted on 2/9/08 at 01:54 PM |
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quote:
Originally posted by 02GF74
If it is electrical, it will draw current and the alternator will supply current.
Something has to power the alternator (clue: the engine).
The EPAS steering column operates via a torque sensor on the column itself, and in turn an ECU which then drives the motor. This means that it gives
the most assistance where its needed, ie parking, and very little (if any) in normal high speed cross-country driving. I cant see this sort of system
having such a drain on the available power from the engine that Coozer is going to have a sleepless night over how much slower he is going to go!!
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MikeRJ
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| posted on 2/9/08 at 02:27 PM |
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quote:
Originally posted by smart51
I used to design electic PAS systems, so I know a thing or two about them.
In that case could you explain something I've wondered about for a while:
With the power off, if you turn the steering wheel does the motor also get turned? I'm presuming not as the drag of a highly geared down
powerful electric motor would be pretty high. If it doesn't what kind of mechanism does it use?
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BenB
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| posted on 2/9/08 at 02:29 PM |
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Isn't that a bit anti the whole notion of a lightweight car with good feel??
If you put on PAS, add brake servos, ABS brakes etc etc etc you may as well go the whole hog and replace the engine with a 8 pot pig-iron lump and
replace the glass fibre with sheet metal....
.... and you end up with a Volvo... 
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coozer
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| posted on 2/9/08 at 09:44 PM |
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Ok guys, I ask as we manufacture them at my work and have 4 different types. As my company is the one who designed it in the first place I know all
about how it works.
I'm only asking about it as I can get my hands on them for nothing...
New Toyota one has a 3 phase motor and it needs a CAN wiring loom to work but we have older one's (corsa) that don't.
I only fancy putting one on because I have some and nobody else has done it, oh, and my steering is quite heavy
1972 V8 Jago
1980 Z750
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smart51
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| posted on 3/9/08 at 08:26 PM |
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quote:
Originally posted by MikeRJ
quote:
Originally posted by smart51
I used to design electic PAS systems, so I know a thing or two about them.
In that case could you explain something I've wondered about for a while:
With the power off, if you turn the steering wheel does the motor also get turned? I'm presuming not as the drag of a highly geared down
powerful electric motor would be pretty high. If it doesn't what kind of mechanism does it use?
The motor is permanently connected to the column through a gearbox. With the power removed, you have to turn the gears and the motor to turn the
wheel. This will of course make the steering quite heavy but then have you ever driven a hydraulic PAS car that isn't working?
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DarrenW
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| posted on 5/9/08 at 07:54 AM |
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i would have thought you will have the knowledge base available to make it work in a fashion Steve but the bit i would have thought you will have
difficulty in is tuning the steering ECU for the MNR? Do you also have access to the tuning software?
Id imagine fitting it wont be that hard of a job if you can get hold of any associated sensors you may need. Is it also possible that if it doesnt
work too well you can just remove the motor and gearbox and revert back to manual steering quite quickly?
Id be concerned that the Corsa column may be over assisted out of the box and loose you some steering feel. Based on the last folly this wouldnt be a
good thing. Lets hope you dont have to rely on help from the Japs ref tuning it!
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DarrenW
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| posted on 5/9/08 at 08:02 AM |
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What type of sensor does yours use Steve? Optical or inductive? If optical take care to keep it scrupulously clean. A competitor of yours uses this
type and they have to be assembled in a clean room. having never seen a clean room at your place id guess you either buy them in complete or use the
inductive type.
Of all the types available id think the Corsa one is the best place to start. No harm in trying to do it. If you succeed you may be able to offer the
intelligence to some manufacturers to open up a new market for little sports cars.
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smart51
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| posted on 5/9/08 at 06:33 PM |
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quote:
Originally posted by DarrenW
If optical take care to keep it scrupulously clean. A competitor of yours uses this type and they have to be assembled in a clean room.
Ahem. Shhh! I didn't tell you this. The bit that is assembled in a clean room is sealed so you don't need to worry if you don't
open that part.
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coozer
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| posted on 6/9/08 at 02:54 PM |
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Torque input, so if the car is light the steering only gives assistance when you run the wheel and bend the input shaft that in turns tells the ecu
how much torque is being input. That make sense? ie the heavier the steering (parked) the more assistance it gives..
1972 V8 Jago
1980 Z750
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