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Servotronic SUCKS!

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I didn't realize how much I hated it until this week.

This week, I picked up another BMW to go with the M5. An '04 X5 4.4 Sport. :1:

And man, does the X5's non-servotronic steering feel nice! It's hefty during parking, it's hefty during low speed and it's hefty during high speed and feels so consistent, progressive and perfectly weighted.

The M5's on the other hand goes all luxury car light at anything below 60km/h, which is most of city/daily driving. I hate the inconsistency.

It's perfect at anything above 60km/h, though. Oh, and I drive exclusively in sport mode, so it's always set to 'heavy'.

I can see why they have it, but it makes no sense on an M Car. The M5 and the X5 4.8is both have servotronic, but the lesser X5s and regular 5s do not. They have it backwards!

Leave the wimpy steering for the regular drivers; give the hardcore heavy steering for the M and IS buyers. They're the ones who know the difference and they're the ones who don't mind having to put a teeny bit of muscle in their driving.

Is it possible to get rid of the servotronic in our M5? Can I retrofit something from the regular E39 5 series?

Or am I alone?
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The rack and pinon steering from the inline 6 E39s (which is wonderful) did not fit with the V8s. This is why BMW did not use the R&P steering in any of the V8 E39s, so I doubt very much it can be retrofitted.

The servotronic irecirculating ball steering is, however, better than the standard recirculating ball steering in the E39 540 (which does not have the sport mode).

You get used to it. The next E60 M5 will have R&P steering.
 

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Discussion Starter · #3 · (Edited)
Hmm, I'm not sure that's my problem with it. I didn't say it was imprecise, or lacked feedback, or anything like that.

I'm complaining solely about the weighting. I don't like that servotronic is a speed-sensitive assistance, as opposed to the engine-speed sensitivity of the regular line.

I googled it and on the Audi S4, VW Phaeton, etc., you can pull a fuse and it will disable servotronic assist altogether, setting it at the heaviest setting ALL THE TIME.

That's all I'm asking for. Does anyone know a quick hack like this? I don't mean permanent sport mode, because even in sport mode, as soon as you dip below a certain speed, it gets all light.

I want the heaviest weighting (minimum assistance), even at low speed. In other words, the steering weight you get when driving at 100km/h in the M5, I want that weighting ALL THE TIME.
 

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Under the drivers wheel well there's a black plastic junction box. There's a cable that looks like a coaxial cable in size entering into it from the top. That is the cable for the servotronic steering. It has some white plastic on the plug end. Unplugging it will remove the servotronic from the system, and in my experience, not throw a code.
 

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basil said:
Under the drivers wheel well there's a black plastic junction box. There's a cable that looks like a coaxial cable in size entering into it from the top. That is the cable for the servotronic steering. It has some white plastic on the plug end. Unplugging it will remove the servotronic from the system, and in my experience, not throw a code.
How does that affect the steering?
 

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or you can just drain the power steering fluid.. you'll get a pretty heavy steering feel then.. but after a month of driving, your biceps will be the size of watermelons... :haha:
 

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We used to disconnect the power steering on an E30 when we did 12 hour endurance races. It felt better when driving fast, but it is tiring, and it would get old quickly on the street, where you have to do things like drive slow and park.

Steve
 

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Discussion Starter · #11 ·
Thanks for the response, Basil! Sounds EXACTLY like what I'm looking for.

However, I tried sticking my head under the car with a flashlight and couldn't find this box exactly.

Could I trouble you for a picture of this with a description?

I assume you've tried this yourself? How does it feel? Does it feel like the regular line BMWs do?

Any other repurcussions I should know about?

Thanks a million!!
 

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I also think Dinan offers a software mod to do this or something like it and I wonder if you asked them nicely if they would perhaps make you a sw mod to just affect the steering program. I tended to agree with you until I put pilot sport tires on my car and found the best pressures for me. Now I get good weighting all the time, without the sport mode. Or, maybe Ive become wimpy :wroom:
 

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basil said:
Under the drivers wheel well there's a black plastic junction box. There's a cable that looks like a coaxial cable in size entering into it from the top. That is the cable for the servotronic steering. It has some white plastic on the plug end. Unplugging it will remove the servotronic from the system, and in my experience, not throw a code.
Interesting, I might give it a try:wroom:
 

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OpLock,

You need to remove the wheel to see it but you might feel it by feeding your arm over the top of the tire and then down, rearward of the axle line. It's on the inner wheelwell. I was going to take pictures next week.



It feels like sport mode or a little heavier. I think it is heavier than sport mode because after a lengthy time driving with it unplugged I felt that sport mode was too easy. However shortly after hooking up the servotronic and before I could get used to it something happened in my p/s system. I had some minor bodywork done and as soon as pulled away from the body shop I could feel the heavy steering as if the cable became unplugged again - but it isn't. Of course the dealer thinks nothings wrong...


I came to this knowledge by having the cable reconnected by the stealership for $200. I wasn't sure what the dangling wire was for until then (a loose end from a second engine install). Right now mine is hooked up but my p/s pump may be going so I'm getting very little difference in boost between the two modes.
 

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basil said:
Under the drivers wheel well there's a black plastic junction box. There's a cable that looks like a coaxial cable in size entering into it from the top. That is the cable for the servotronic steering. It has some white plastic on the plug end. Unplugging it will remove the servotronic from the system, and in my experience, not throw a code.
Great info, Basil!

BTW, what happened to the first engine?

David
 

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Discussion Starter · #16 · (Edited)
It feels like sport mode or a little heavier. I think it is heavier than sport mode because after a lengthy time driving with it unplugged I felt that sport mode was too easy. However shortly after hooking up the servotronic and before I could get used to it something happened in my p/s system. I had some minor bodywork done and as soon as pulled away from the body shop I could feel the heavy steering as if the cable became unplugged again - but it isn't. Of course the dealer thinks nothings wrong...
Great information, Basil.

However, I'm a little apprehensive to do this now. It seems like you're having PS problems.

Are these related to this unplugging mod? Does disabling servotronic somehow cause more wear to the PS system?
 

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My p/s issue seems coincidental but I can't say for sure. The dealer says there's nothing wrong...sometimes I wonder - what's the point... (defeatist smiley)


I'm having a differential swapped out tomorrow so time allowing, I'll unplug my servotronic wire and see if I can detect any changes.


David, The first engine is a continuing story for another time.
 

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If the $tealer still thinks nothing is wrong with the steering, perhaps you and a fellow board member could pay them a visit with two M5s so they can drive those one after the other and hopefully notice the difference in steering.

David
 

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DavidS said:
If the $tealer still thinks nothing is wrong with the steering, perhaps you and a fellow board member could pay them a visit with two M5s so they can drive those one after the other and hopefully notice the difference in steering.

David
Did they give you the "It's normal for an M-car" line??? I find them doing that alot lately
 

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"We tried and tried but we couldn't find anything wrong." I'm sighing just writing this.

They had another M5 in at the time I think. I thought to ask them to do that but I didn't have any faith that it would be compared in the end.

Anyway, I took some pictures of the connector for the servotronic and the junction box. I need to check something before I post them.

Cheers
 
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