Sport Steering Rack

[Error404]

nice

[terrybullwon]

Now maybe time to play with the Ackermann Angle?

[Error404]

have to say I really don't know enough about it or the standard set-up to start messing, also the rack location on the bulkhead is rather fixed (for me at least) so any changes would have to be made at the steering arms. Have you done much with yours James?

[andy10v]

Well done mate. Be interested to hear how you get on, with fitting and use.

Jamo why doesn't my computer come up with that instead of a boring error message?

[geryS2]

woaw, impressive !

something that could change one of the few weak points of an S2


could you give the quote to do the swap ?

we could do a group buy for this , might be interested

Cheers

[Jamo]

Well done mate. Be interested to hear how you get on, with fitting and use.

Jamo why doesn't my computer come up with that instead of a boring error message?

These are better, view quick before I have to moderate myself

http://static.pagenstecher.de/upload...4/error404.jpg

http://viacomit.net/wp-content/uploa...7/error404.jpg

[macspring]

Error,

Well done, proper commitment to the cause, no wishy washy, "the car for sale is too far for me to visit".

Didn't realise that an ABY/ADU rack was standard at just 2.6 turns lock to lock. Given your efforts why didn't you think of getting them to reduce the turns to say 2.2 ? Just curious.

Thanks.

[Error404]

I thought about it a lot previously, but now I personally think 2.6 turns is enough on a road car, I think anything more would be too much. I think a lot of people mistake the lack of steering feel for a lack of steering response, the steering (on my car at least) is as sharp as I want it. 2.6 actually is very quick by general standards.
The cost involved in a shorter rack is pretty scary, a custom pinion output shaft and rack need to be machined. A variable ratio rack would be the way to go IMHO if you wanted to follow that route, so the steering is less sensitive in the centre of the rack, and gets quicker the further it is turned. A lot of modern cars are set up this way

[macspring]

I agree, 2.6 is pretty quick for a road car. Cost is always an issue for once off, or low volume runs.

The variable rack is I presume commonplace on new cars and aids lock to lock parking. Newest car I'm exposed to is 2004.

When I had the Mk 1 Golf, I bought TSR p/s kit and the car was transformed and a joy to drive, especially after having it so long with say 4 turns lock to lock, and then to go to say 3 turns lock to lock and power assistance. In those days it was based on the Mk2 power steering equipment from a Mk2 Golf or say a Passat, and the rack was from a Nissan Bluebird with custom mounting brackets.

A friend of mine used a Toyota rack to good effect on his Mk 1 Golf.

The point I'm leading to is that if a more suitable rack from a more modern car was identified as a suitable replacement for a B4 S2 std rack, it would be the way to go as it will in breakers and will be cheap and may have the variable ratio as one goes from lock to lock.

The identification of a suitable rack with the right feel and ratio for easy mounting as a replacement of the oem rack is / would be no easy task, unless we're all very lucky and someone has a good idea for a possible candidate rack ?

While electric water pumps can sometimes be useful for certain situations, what about the idea of electric power steering racks, do these come with an ECU that could be reprogammed ? Definitely way ahead of myself now.

[djh]

Looking forward to getting it fitted, hopefully I'll get started on Monday. Going to give it go with the engine in situ, I guess we'll see how easy that isn't!

The way I look at it, lots of people splash the cash on big blowers, massive brakes and trick suspension, but really i think the steering is the weakest part of the car.

You should be able to do this resonably well as you don't have the battery tray in the way anymore, its just the lines and actually getting it to free off from the steering column. It might be easier to remove that inside the car and then work in the engine bay, thats how I would do it and it should make it come out quicker than trying to wrestle with it in the bay. I've removed a few of these now and thats the way forward.

[Error404]

The point I'm leading to is that if a more suitable rack from a more modern car was identified as a suitable replacement for a B4 S2 std rack, it would be the way to go as it will in breakers and will be cheap and may have the variable ratio as one goes from lock to lock.

The identification of a suitable rack with the right feel and ratio for easy mounting as a replacement of the oem rack is / would be no easy task, unless we're all very lucky and someone has a good idea for a possible candidate rack ?

While electric water pumps can sometimes be useful for certain situations, what about the idea of electric power steering racks, do these come with an ECU that could be reprogammed ? Definitely way ahead of myself now.

I don't think its necessary. The rack ratio is linear in our cars, unless you find a variable ratio rack I would not go any quicker with a car that will be used on the road. We already have a quick ratio rack that fits nicely, VAG have kindly done most of the work already - all we need is better steering feel, which is what I'm trying to do with this mod

From what I have read the ABY steering ratio is 14.5:1, so the steering wheel turns 14.5deg for ever 1 deg of wheel angle.
So at 2.6 turns, the steering wheel travels through 936deg. at a ratio of 14.5:1 that gives the road wheels an angular range of 64.5deg - sounds about right.
Calculating back, if the coupe quattro is the quoted 16.8:1 then (64.5 x 16.8)/360 = 3.01 turns - again this is about right.

So if you had say a 2.2 turn rack, the ratio would be (2.2 x 360)/64.5 = 12.3
IMHO without variable ratio that would be unpleasant to drive at motorway speeds, it would be too easy to over-steer.

[mcandmar]

2.6 seems spot on to me too, go any higher and the force required to steer increases, and in turn you lose a bit of steering feel and precision. Drive a B3 car like my CQ20v and the steering is lighter and much more precise mid corner, its like having steering in high definition. Only draw back is you have to wind on more lock for the same steering angle. The biggest difference for me in the real world is turning into side roads, as in 90 degree turns.

For example if you drive straight ahead with both hands on the wheel then cross your hands winding on half a turn of lock for a 90 degree turn, in the CQ your just a little bit shy of where you want to be and usually have to add a bit more steering lock to get you on course. With the S2 rack its just right allowing you to quickly dial in lock to flick the car 90 degrees and drive away in one smooth operation. Ideally i would like to have the best of both worlds and hopefully thats what Error with achieve with the above modification.

For comparison our 993 has a steering ratio of 2.47, BUT even with the very light front end and power steering its very physical and will make your arms ache after a few laps on track. Having played about in a grass field i found catching the car on opposite lock very tricky, you have to be super precise on how much lock you dial in so you dont over correct. Do the same antics in the CQ and its all arms and elbows in the air as you try to wind on opposite lock fast enough, there is a happy medium. What is really interesting is the balls out light weight 993 RS model they ditched the power steering and ran a rack ratio of 2.73. Why? Steering feel and precision is more important.

Anyhow im starting to waffle on, back to you error

[Error404]

all good discussion
i think the point about precision is very important, this is the benefit of a variable rack, you get a 16:1 or 17:1 ratio in the middle of the rack, and something maybe 9:1 or 10:1 at the ends of travel - a nice compromise. I think people often confuse the lack of steering feel with a lack of steering response.

Now, I'm also working on another solution to the lightness of the stock steering.
It's a mod to the PAS pump housing which allows the spring preload of the flow control valve to be adjusted, which will allow the baseline pressure of the steering system to be adjusted. This will have a similar effect to the stiffer torsion bar in terms of reducing the response to steering input, but it will do nothing for steering feel. Too low a baseline pressure and the steering will just feel laggy. I have used an inline flow control valve to prove the concept and there are significant improvements to be made. It will be a cheaper and easier mod than changing the torsion bar.
I just need to get the drawings over to Kev to get a prototype machined.

[mackenzie50]

Really good to hear this line of R+D..I don't drive as fast as I used to (ancient old git) but I still value great handling and steering...so I like this way of seeing and making improvement in the beast(s)..whether S2 or CQ!

[Error404]

Rack now fitted. Few more jobs to do on the car, will be taxing it at the end of April. Looking forward to testing it