Retrofit dynamic steering

[Adamantium]

Hi all,

Just started a dynamic steering retrofit but can’t find any evidence of those being done before.

My car is a 2015 UK B8.5 S5. I’ve just bought a steering column from a 2014 RS4 and a steering control module. Already have ads, dynamic suspension, sport diff, just wanted to complete the set..

The column is a relatively easy install. The wiring is being done for me by a guy who has already retrofitted adaptive cruise adaptive headlights, hill hold assist, lane assist, side assist and main beam assist plus several other things.

Am just wondering if any concerns immediately spring to mind.

[MME1122]

Very interested in this, I was going to ask my mechanic what he thought about trying to add it.

Is the RS4 column the same part number? How much were the parts, if you don't mind me asking?

[Adamantium]

There seem to be a lot of part numbers.

I originally searched for this one:

8K0419502AB

But ended up buying

8K0419506BB

One thing I have determined is that A5 and A4 are interchangeable. It looks like RHD and LHD are too.

I can’t work out what’s going on with the numbers. Those ending in 506 and 502 seem to be interchangeable, but only those with the second letter suffix B seem to be dynamic.

I paid £420 but prob paid a premium because it came from an RS4. There are a few in Latvia the on ebay for 320 euros.

I also picked up a dynamic steering module for £85. Needs wiring from footwell to left side of boot, but there’s multiple up wires being run that way anyway for all the other retrofits.

[hyetiko]

I tried to install a true rs5 dynamic rack when I needed to replace my steering rack on my 2016 s4. What I found out was the rack itself is different but rs5 and s4 are interchangeable. You also need a module that connects to the interior wiring harness. The last piece of the puzzle is a new steering column that also has a different module on it, that is what made it too hard of a swap and costly. I may be wrong about the steering column but that is what Audi told me.


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[JettaGetUpandGo]

The last piece of the puzzle is a new steering column that also has a different module on it, that is what made it too hard of a swap and costly. I may be wrong about the steering column but that is what Audi told me.

That's really unfortunate. When my steering rack fails (not if) I was hoping to upgrade to the RS5 rack and dynamic steering.

I'll be watching this.

[Adamantium]

I have just determined that the rack is different for dynamic and normal steering but am not phased by this. I do need to find out if RS4 and RS5 are interchangeable.

Forgetting about dynamic steering for a minute, are there other differences between RS4/S4 and A4 steering racks? The ratio for example?

[Adamantium]

FYI the steering column is the most obvious swap - there’s a bloody great gearbox on it just before the UJ that connects to the rack. The racks appear identical.

[Adamantium]

RS4 and RS5 are interchangeable.

Still don't know if the basic rack is different from an A4/A5.

Have managed to buy the same rack that came with my RS4 steering column, but will see if we can get it to work without it.

[Adamantium]

I now have some more information if anyone is interested that's makes sense of the above.

I found an old thread on here: https://www.audizine.com/forum/showt...u-need-to-know!

Taken form that post:

S4 w/o the driver assist option has the following steering characteristics:
Comfort mode: Fixed ratio at 15.9:1 and speed sensitive high level of boost.
Auto mode: Fixed ratio at 15.9:1 and speed sensitive medium level of boost.
Dynamic mode: Fixed ratio at 15.9:1 and speed sensitive low level of boost.

S4 equipped with Dynamic steering:
Comfort mode: speed sensitive variable ratio from 9:1 to 18:1 with comfortable boost at highway speed. Suited for long highway journeys. Precise, but comfortable at highway speeds.
Auto mode: speed sensitive variable ratio from 9:1 to 18:1 with progressively less boost at higher speeds. Suited for daily driving. Precise and tight at higher speeds, precise and easy to maneuver at parking lot speeds.
Dynamic mode: fixed ratio at 14.3:1 with dynamic boost for most predictable dynamic driving. Suited for dynamic driving on the track or on mountain/canyon roads. 14.3:1 is a much more direct ratio than the standard steering which has a ratio of 15.9:1 at all times.

The key point is that when in dynamic mode, and also when the electronics are off, the steering column just behaves like a solid shaft with no difference in input and output speed - i noticed this from playing around with the one I bought yesterday.

This means that the only way to achieve a final steering ratio of 14.3:1 is for the steering rack to have a different native ratio - which explains the 1N8 designation in the rack too. I suspect that dynamic steering cannot be coded with a stock rack that doesn't identify as being dynamic, otherwise those variable ratios from comfort and auto mode would be from 10:1 to 20:1. It also confirms that dynamic mode on dynamic steering cars is faster than dynamic mode on non dynamic steering cars with ADS similarly enabled to reduce assistance.

Only question is if you need both rack and column to make it work. You do need the controller in the trunk and the loom in between. It looks like there's one loom running front to back from column to controller probably with additional wiring running from controller to body control module, battery and local earth.

Crucially for some reading this, what I reckon it does mean, is you can fit just a dynamic rack and get a real benefit that many people would be happy with, even without the variable ratio feature.

[Adamantium]

Finally got it all in and working.

To anyone using this for future reference, you can’t make up your own dynamic steering loom as I did. The correct resistance is critical probably for the measurement of steering angle. It gave rise to overload warnings, sometimes when stationery.

Luckily I managed to find an oem loom from a breakers yard and problem solved. Does mean it’s an expensive retrofit.

In my case, (all from breakers)

RS4 dynamic steering column -£400 (seems this was cheap)
RS4 dynamic steering rack - £200 (this was definitely cheap)
Dynamic steering module - £80 (average)
Loom - £300

[windowguy]

Thanks for sharing your info on what you have done to get it working. A lot of times the thread does not get updated with the final outcome. Enjoy your new steering system.

Rob.

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[Adamantium]

Just re read my own posts and noticed a mistake. I said that the dynamic steering module was in the trunk. I thought it was in the vicinity of the active suspension module, it isn’t. It’s actudlly in the drivers side (in my case at least) footwell. The carpet needs to be cut to accommodate it.

When all is finished I’ll try to post some pics.

[Andrew8999]

Unknowingly, I had to replace my rack and pinion in my S4 with dynamic steering but I was sold regular rack. I took me sometime to realize that it was not the correct rack - only when I turned the steering wheel to max left and right I received fault codes. I will purchase the correct rack and pinion. Hopefully I didn’t damage any thing?

[wrxkyle]

has anyone tried just slapping in the dynamic rack with no change to steering column, and coded it as a normal rack and tested it? all most people want is the tighter steering ratio.

[IllusionalTA]

The modules aren’t happy, and the cars looking for the active steering control module, I accidentally bought a dynamic rack for my non dynamic car.. 😿

[John336]

The modules aren’t happy, and the cars looking for the active steering control module, I accidentally bought a dynamic rack for my non dynamic car.. 😿

Even if you use your old control unit and transfer it inside a dynamic rack (8 torx bolts)? Do you get an error then when turning the wheel to full left/right?

[S5noob]

Just re read my own posts and noticed a mistake. I said that the dynamic steering module was in the trunk. I thought it was in the vicinity of the active suspension module, it isn’t. It’s actudlly in the drivers side (in my case at least) footwell. The carpet needs to be cut to accommodate it.

When all is finished I’ll try to post some pics.

What coding changes did you need to do to get this working?