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Old 05-10-2013, 11:53 AM   #21
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Originally Posted by Leafy View Post
It was a pain in the *** to find it but dealer price is like $700something. Mazda motorsports has it for less, but not enough less that I wouldnt want to just buy a motorsports electric power steering setup from Australia.
They're already started showing up in pull it yards in my area, Can probably get one for under $50.00 as they probably wouldn't even know what it was.
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Old 05-10-2013, 11:53 AM   #22
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Originally Posted by duffbuster243 View Post
They're already started showing up in pull it yards in my area, Can probably get one for under $50.00 as they probably wouldn't even know what it was.
Yeah the picture of it in the parts diagram it looks like a charcoal canister.
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Old 05-10-2013, 11:58 AM   #23
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LOL, you're right. Just tell them it's vapor emission part. Be sure to grab all the wiring though. I think if setup similar to original design and wiring, there shouldn't be any electrical issues with the pump running.
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Old 05-10-2013, 12:20 PM   #24
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Originally Posted by Leafy View Post
This is why its bad to disconnect the battery from a running car.
That's part of it. The other part is that an alternator looks like a current source, which is quite slow to changing its output current in response to a change in system voltage. So if the battery is low and drawing a lot of current, then you disconnect the battery abruptly, the current from the alternator will be momentarily be too high and the system voltage will spike; this can be as high as >35V. It won't be as bad if the battery is charged and drawing very little current, and the system electrical loads are heavy, to absorb the excess current.
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Old 05-10-2013, 12:29 PM   #25
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OK guys, my nifty amp clamp has arrived in the mail today, and I am thus able to provide some solid data.

The pump draws between 6.7 and 7 amps at idle, meaning with no steering input, regardless of whether the wheels are pointing straight ahead or not. (The fact that the pump would be "idle" with no steering movement regardless of the position of the wheels is common knowledge, but I wanted to put it out there, anyway)

With steering input, the current draw varies between 12ish to 24 A, depending on how fast the steering input is.
For instance:
Merely changing lanes on the freeway would be about 12 A, while driving the twisties would require about 16 - 18 A. parking lot maneuvers would require bursts of about 24 Amps.
Things get interesting if I hold the wheel at full lock like an idiot. It quickly climbs past the 50 A mark, reaches 60+, and maxes out at 65 A or so. The highest I have seen is 68 Amps.
That, however, is very brief, but I am very happy about my decision to install a high output alternator, nevertheless.

As long as full lock (not momentary full lock, but holding it there) is avoided, the system purrs along at a maximum of 24 - 25 amps at times of very fast steering input.

All in all, I am very happy with the results.

Oh, guess what.. Rear defroster (on the soft top) only draws 7.6 A. I swear I thought such a huge resistor assembly would be at the 30 Amp range.

And, this is the amp clamp I bought.. It's damn cheap, works great, and a must have for the sorts of answers I have been looking for.

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Old 05-10-2013, 12:46 PM   #26
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Good stuff.

Does the factory Peugeot the pump came from have a limit switch that turns power to the pump off when at full lock?

BTW does it look possible to mount the motor where the PS pump was?
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Old 05-10-2013, 12:56 PM   #27
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Quote:
Originally Posted by tpwalsh View Post
I thought this was due to the relatively big voltage drop when you're spinning the motor, and don't have the alternator running? With the car actually running voltage through most of the system should be 14ish volts, and therefore not have wacky dwell and PW issues.
Potentially, the transients caused by the pump's current draw rapidly swinging from "idle" to "full load" and back could have a similar effect to that of turning the headlights on and off at idle, greatly multiplied. The alternator cannot react instantaneously to load changes.

Placing some distance between the pump and the alternator (which is the primary current source for the engine electrical system while the car is running) will mitigate this.



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Originally Posted by JasonC SBB View Post
But load that changes from one second to the next - the alternator and its control system (bandwitdh) will handle it.
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Originally Posted by JasonC SBB View Post
an alternator looks like a current source, which is quite slow to changing its output current in response to a change in system voltage.
You can see the logical conundrum that I was in, from the apparent contradiction between these two posts.

The rise-time of the pump's current demand is an unknown.

The hysteresis and rise/fall times of the alternator's regulator is an unknown.

Thus, by buffering the pump from the alternator with a length of lossy cabling, and putting the battery between, them, we can offset this effect, particular when he takes the steering to lock and jumps the current draw to 60+A.




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Originally Posted by JasonC SBB View Post
The other problem with cabling the big load all the way to the battery is that there will be an error in the charging voltage setpoint at the battery, when the load is heavy, due to the voltage drops in the cabling between the alternator and the battery.
We already had that discussion. We specified the use of thinner-than-ideal wiring between the pump and the battery, to deliberately create some drop when the pump is in a high-demand state.

By comparison, the relatively massive cabling in the alternator - battery - chassis - engine loop should keep the voltage drop on that side of the system minimal.
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Old 05-10-2013, 01:00 PM   #28
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Originally Posted by JasonC SBB View Post
Good stuff.

Does the factory Peugeot the pump came from have a limit switch that turns power to the pump off when at full lock?

BTW does it look possible to mount the motor where the PS pump was?
Yes.

But,
* You would have to retain the stock reservoir to make life easier for yourself.
* Why would you want to subject the electric pump and its plastic reservoir to the heat from the exhaust system?
* There are already a few readily accessible places in the engine bay, such as my chosen location, and behind the headlight on the driver side. You could even install it inside the front bumper. I have heard of a guy who installed it in the trunk even.

This pump unit is used by Renault Kangoo, Renault Clio, Citroen Saxo and Peugeot 106.

The only difference among these applications is the orientation. My application uses a horizontal reservoir. Others have identical pumps, motors and outlets, but they have different reservoirs that enables the installer to choose an upright orientation.

Here is a link for the manufacturer's website:
HIDROSAN STEERING :: HDS Steering Pumps :: Production, Maintenance and Services

You can clearly see the fact that same setup is used with different tanks depending on application in most cases.

Oh, I paid $216 for a new pump. That's 400 TL, roughly converted to $. The owner gave me the pump at wholesale price, because he was intrigued by my project, and wanted to help somewhat. Retail price is 1050 TL, which is roughly $567.
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Old 05-10-2013, 01:02 PM   #29
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I would figure the big driver of doing this was so you could fit a no-compromises turbo manifold and still have power steering. Basically you'd do it to have a PS pump be anywhere besides the stock location.
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Old 05-10-2013, 01:14 PM   #30
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Please take a look at the output settings and tell me if I have this right guys..

Basically, I want the pump off while cranking, and only come on about 5 seconds after the engine fires, and if the RPM is greater than 600.

This output will be connected to the "-" side of the relay trigger. Relay trigger "+" will be taken from IGN.

EDIT: whoops.... second condition at the bottom should read "seconds > 5.0" I will correct that.

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Old 05-10-2013, 01:18 PM   #31
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I'm wondering if anyone has made the slots on the steering pinion bigger to allow more fluid to pass through.

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Old 05-10-2013, 01:20 PM   #32
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Originally Posted by Godless Commie View Post
Please take a look at the output settings and tell me if I have this right guys..
I'd add maybe 50-100 of hysteresis on the RPM field, to prevent the relay from chattering.
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Old 05-10-2013, 01:25 PM   #33
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Originally Posted by triple88a View Post
I'm wondering if anyone has made the slots on the steering pinion bigger to allow more fluid to pass through.
Wouldn't that make the steering even lighter, like an old Cadillac?
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Old 05-10-2013, 01:26 PM   #34
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I'd add maybe 50-100 of hysteresis on the RPM field, to prevent the relay from chattering.
Thanks Joe

The relay draws .2 Amps. I don't think that would be a problem for the MS output.
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Old 05-10-2013, 01:34 PM   #35
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The relay draws .2 Amps. I don't think that would be a problem for the MS output.
Nor I, presuming that you're using sufficiently beefy transistors.

But a 60 amp load on a chattering relay is extremely bad for the relay contacts.
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Old 05-10-2013, 01:43 PM   #36
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Nor I, presuming that you're using sufficiently beefy transistors.

But a 60 amp load on a chattering relay is extremely bad for the relay contacts.
...not to mention the motor and the pump.

That's why I will add the hysteresis value you have suggested.

You know, this is proving to be great learning experience for me.
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Old 05-10-2013, 02:02 PM   #37
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Wouldn't that make the steering even lighter, like an old Cadillac?
Correct therefore less pressure from the pump is needed.
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Old 05-10-2013, 02:16 PM   #38
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My other thought was that the pump probably isn't needed when the vehicle is completely stopped and you are in neutral with your foot off the clutch.

You are fortunate that the NBs do not conjoin the clutch and neutral wiring like the NAs did- they come into the ECU on two discrete lines.

I might change the conditions which drive the output. Instead of RPM and time, use:

VSS > 0
*or*
Clutch switch = depressed.

Thus, when you are sitting at idle at a stop, the pump is off. When you depress the clutch to shift into gear, the pump comes on. Any time the car is moving, the pump will also be on.

Who knows- maybe this will make things worse, having the pump cycle on and off while at idle. But it addresses your earlier concern about having the pump run all the time during the winter months.
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Old 05-10-2013, 02:17 PM   #39
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Originally Posted by triple88a View Post
Correct therefore less pressure from the pump is needed.
Yes, but pump pressure is pretty much standard across the automotive industry.
Both the stock Miata pump and this one deliver about 85 bars, which is roughly 1200-1250 psi.
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Old 05-10-2013, 02:31 PM   #40
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Originally Posted by Joe Perez View Post
My other thought was that the pump probably isn't needed when the vehicle is completely stopped and you are in neutral with your foot off the clutch.

You are fortunate that the NBs do not conjoin the clutch and neutral wiring like the NAs did- they come into the ECU on two discrete lines.

I might change the conditions which drive the output. Instead of RPM and time, use:

VSS > 0
*or*
Clutch switch = depressed.

Thus, when you are sitting at idle at a stop, the pump is off. When you depress the clutch to shift into gear, the pump comes on. Any time the car is moving, the pump will also be on.

Who knows- maybe this will make things worse, having the pump cycle on and off while at idle. But it addresses your earlier concern about having the pump run all the time during the winter months.
I'm afraid I have not made my concern sufficiently clear about winter months.
What I was trying to say is, I would like the pump to be off till the engine starts. That way, I would not be draining precious current from the battery before cranking the car.
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