I thought springs are not just to support the weight of the car - check out Eibach or HR web site and see their different springs for the same car. I got red eibach sports springs from my 911 and they are far better than the blue or the OEM even with the same shox.
I was happy to get billy PSS9 as they specify the same part for the RS6/S6/A6, but if another make only state it is good for a A6 quattro then I would not get it - read what Grizz said about type approval and imagine what happens if you crash and cause damage/kill someone and they take you to court about having incorrect suspension for your car, or you carry your family around....
Never heard of Weitec so why would KW brand them differently - is it like Skoda owners thinking they have an Audi or a Lambo??? Stick to the tried and tested.....
RS6 coilover findings
The design of suspension systems is a little more complex than you seem to think - and as a Chartered Mech Eng I do have a limited knowledge in the area:
Damping is an independent variable not dependent only on the spring rate. The force exerted by a spring for a given compression (over it's normal working range) is about constant. The force exerted by a damper depends on the speed of movement.
Much of the work done by suspension components is to do with controlling the vertical movement of the wheels, not the car. Thus those seeking better handling frequently fit lighter wheels/discs to inprove the contact time between tyre and road. As a simple demo, take a wheel and tyre (inflated), and simply drop from a few inches - it will bounce straight back up to you as the tyre is a very good spring (and poor damper). The work of the damper is thus basically to control the wheel assembly as it bounces between the tyre and the spring.
The problem with wheels is that they go round - which means that they also behave as gyro's (that's why bikes work!) - so the sped of rotation (function of car speed and wheel/tyre size) is also a consideration - especially in a car capable of 185, compared with 140 say for an A6 - it's basically squre function so the gyro forces are about doubled.
Now throw in the rest of the steering geometry and components, and you will begin to see that there are any number of variables many of which will vary between models - small wonder the designers spend vast amounts of time and money trying to solve all the equations and get the best compromises (it's always a compromise in the end - there isn't a "right answer").
Turning to your main assertion that as the size/model no is the same in Bilstein, one should be able to apply the logic to all models - again there is a logical flaw in here. Bilstein may well have rated all the parts for the RS6 , and if the size is the same on other models then they will fit, and perform, though probably rather more harshly than one might want. However just because someone made a unit for the A6, doesn't mean it will translate UP to the loads imposed by the RS6. Think for a moment about the speed rating on tyres - one can use ZR rated tyres on a slower car, but don't try putting R rated tyres on the beast - they will fit, sure - but please don't risk my life near your car!
I appreciate you are looking to encourage people to think outside the box and to find alternatives, but I would counsel that you think long and hard before adopting cheap solutions in this area - it could be a VERY costly mistake - and I'm not talking money.
Dave
This would be true if the spring were always vertical, and the car stationery. However in practice the suspension legs are normally cambered, and the car itself of course is subject to roll. The spring (and damper) therefore does contribute to transfering the lateral forces into the wheel/tyre.A coilover spring is only there to support the weight of the car, not as is often mistakenly thought, to control lateral car movement.
The spring rate is not defined by the weight of the car - the static compression of the spring will be determined by the spring rate (ie how much it compresses at rest), but the rate can be anything you like - all that is needed is to adjust the height. For fast road use one tends to go stiffer - for rallying etc the softer and more compliant may well improve the handling.the damping range of the coilover is defined by the spring rate supplied (which is defined by the car’s weight),
Damping is an independent variable not dependent only on the spring rate. The force exerted by a spring for a given compression (over it's normal working range) is about constant. The force exerted by a damper depends on the speed of movement.
Much of the work done by suspension components is to do with controlling the vertical movement of the wheels, not the car. Thus those seeking better handling frequently fit lighter wheels/discs to inprove the contact time between tyre and road. As a simple demo, take a wheel and tyre (inflated), and simply drop from a few inches - it will bounce straight back up to you as the tyre is a very good spring (and poor damper). The work of the damper is thus basically to control the wheel assembly as it bounces between the tyre and the spring.
The problem with wheels is that they go round - which means that they also behave as gyro's (that's why bikes work!) - so the sped of rotation (function of car speed and wheel/tyre size) is also a consideration - especially in a car capable of 185, compared with 140 say for an A6 - it's basically squre function so the gyro forces are about doubled.
Now throw in the rest of the steering geometry and components, and you will begin to see that there are any number of variables many of which will vary between models - small wonder the designers spend vast amounts of time and money trying to solve all the equations and get the best compromises (it's always a compromise in the end - there isn't a "right answer").
Turning to your main assertion that as the size/model no is the same in Bilstein, one should be able to apply the logic to all models - again there is a logical flaw in here. Bilstein may well have rated all the parts for the RS6 , and if the size is the same on other models then they will fit, and perform, though probably rather more harshly than one might want. However just because someone made a unit for the A6, doesn't mean it will translate UP to the loads imposed by the RS6. Think for a moment about the speed rating on tyres - one can use ZR rated tyres on a slower car, but don't try putting R rated tyres on the beast - they will fit, sure - but please don't risk my life near your car!
I appreciate you are looking to encourage people to think outside the box and to find alternatives, but I would counsel that you think long and hard before adopting cheap solutions in this area - it could be a VERY costly mistake - and I'm not talking money.
Dave
Just read Dave's post, summed very very well but I'll post my pre-writen thoughts anyways (it was a long, long meeting)...
All your points are valid and well made Ceveman. The only things I can see that you're missing is that the C5 RS is, in pure marketing speak, 33% more car than the C5 S.
The output is 33% more, 450bhp plays 340bhp, torque 560 plays 420, standard wheels 9x19s play 8.5x17?, brakes 365/335 vs 321/256.
So, the questions are, do you think the manufacture made these considerations when designing these suspension kits?
Are the materials and tolerances used in these kits up to dealing with 33% more car?
Yes, the unladen weights are similar between the S6 and the RS6 but are the entry breaking and corner exit forces going to be the same?
Can they handle a rebound at top speed - ick!!!
Last question… These companies are in the business of shifting units, so why would they not just increase their market scope and slap the C5 RS into their application lists? My thought is; the C5 RS was be a bridge too far for their research, testing, materials and budget scope, hence the price OR these suspension units were released prior to the Beast’s launch and were therefore never tested. Of course there could be a million other reasons....
All your points are valid and well made Ceveman. The only things I can see that you're missing is that the C5 RS is, in pure marketing speak, 33% more car than the C5 S.
The output is 33% more, 450bhp plays 340bhp, torque 560 plays 420, standard wheels 9x19s play 8.5x17?, brakes 365/335 vs 321/256.
So, the questions are, do you think the manufacture made these considerations when designing these suspension kits?
Are the materials and tolerances used in these kits up to dealing with 33% more car?
Yes, the unladen weights are similar between the S6 and the RS6 but are the entry breaking and corner exit forces going to be the same?
Can they handle a rebound at top speed - ick!!!
Last question… These companies are in the business of shifting units, so why would they not just increase their market scope and slap the C5 RS into their application lists? My thought is; the C5 RS was be a bridge too far for their research, testing, materials and budget scope, hence the price OR these suspension units were released prior to the Beast’s launch and were therefore never tested. Of course there could be a million other reasons....
No matter where you go, there you are.
When i was looking in too kits 3.5 years ago the only kit was the pss9 kit , I spoke to KW at length about a kwv3 kit . Although they did a kit for all the other A6 range they would not sell one for a rs6.
Several months later they called to say they had finished the kit and it was in testing ..
End of the day you pays your money and takes your chances ..
Several months later they called to say they had finished the kit and it was in testing ..
End of the day you pays your money and takes your chances ..
Unit 20
0151 3366888
The northwest's only dedicated 'RS' repair centre.
http://www.facebook.com/pages/unit-20/104343529619713
0151 3366888
The northwest's only dedicated 'RS' repair centre.
http://www.facebook.com/pages/unit-20/104343529619713
Guys,
Thx for your lengthy replies, you make a lot of sense. I agree that my somewhat layman's speculation was somewhat crude in reality, and I thank you for clarifying the matter. Interesting debate and nice to know that we can have open discussion without things turning silly.
Bilstein PSS9 it is then, although I think I'll buy them from the US and save £500!
Cheers fellas,
Mart.
Thx for your lengthy replies, you make a lot of sense. I agree that my somewhat layman's speculation was somewhat crude in reality, and I thank you for clarifying the matter. Interesting debate and nice to know that we can have open discussion without things turning silly.
Bilstein PSS9 it is then, although I think I'll buy them from the US and save £500!
Cheers fellas,
Mart.
You're right, it was a healthy discussion but I think our opinions were out of genuine concern rather than full-on debate. If it's worth anything to you, If I was to do it over again, I'd save the money, fit H&R's, ARB's and new control arms (if it's a high miler or advised by the fitter). Obviously, don't forget the new Audi top mounts and leave money in the budget for a full geometry approx 2-3 weeks after fitting everything.
Having said that, I'm in a 'loon so I don't load up the rear much at all, making the H&Rs more suited, in theory.
Best of luck Mart.
Having said that, I'm in a 'loon so I don't load up the rear much at all, making the H&Rs more suited, in theory.
Best of luck Mart.
No matter where you go, there you are.
Re: RS6 coilover findings
Hey Caveman, are you still in here?
if so, how did your purchase from the US go for the Bilstein PSS9 ? were they the Bilstein B16 's?
And what about in this late year of 2017, anyone have any other conclusions on the above discussions?
Can anyone suggest a good place to get some Bilstein PSS9 's? Iv'e an old beast 2003 C5 RS6 Avant which is in dire need of new suspension from the old factory fitted which are giving me a balooning ride!
Thanks in advance if anyone has ventured back into this discussion cave
if so, how did your purchase from the US go for the Bilstein PSS9 ? were they the Bilstein B16 's?
And what about in this late year of 2017, anyone have any other conclusions on the above discussions?
Can anyone suggest a good place to get some Bilstein PSS9 's? Iv'e an old beast 2003 C5 RS6 Avant which is in dire need of new suspension from the old factory fitted which are giving me a balooning ride!
Thanks in advance if anyone has ventured back into this discussion cave
2003 RS6 C5 Avant Black on 19's
Re: RS6 coilover findings
Go to MRC or Unit 20- both will supply and fit. (BTW that recommendation is valid for every single RS6 garage/service question).
I have Bilstein PSS9's and i've had them for 6 years after the DRC failed and i did a deal with the warranty company
which was negotiated by my supplying dealer Fontain Motors who i always found to be excellent.
On their softest setting they are still slightly harder than i would like them to be for gentle cruising.
On their highest setting they are still slightly lower than i would like them to be (very slight wheel rub on full lock).
They are comfortable enough to transport a fully loaded RS6 with 5 adults and luggage space full from London to the Alps.
During a little test around the left hander from the M26 eastbound onto the A21 southbound (its a very very scary corner),
we found my RS6 could comfortably corner faster than my friends 996 Carrera on standard suspension.My friend is an experienced
racing driver and far,far more talented than me and remarked that he could not safely stay with the RS6 around the bend.
This is the best information i can give you based on my experience with Bilsteins.
I have Bilstein PSS9's and i've had them for 6 years after the DRC failed and i did a deal with the warranty company
which was negotiated by my supplying dealer Fontain Motors who i always found to be excellent.
On their softest setting they are still slightly harder than i would like them to be for gentle cruising.
On their highest setting they are still slightly lower than i would like them to be (very slight wheel rub on full lock).
They are comfortable enough to transport a fully loaded RS6 with 5 adults and luggage space full from London to the Alps.
During a little test around the left hander from the M26 eastbound onto the A21 southbound (its a very very scary corner),
we found my RS6 could comfortably corner faster than my friends 996 Carrera on standard suspension.My friend is an experienced
racing driver and far,far more talented than me and remarked that he could not safely stay with the RS6 around the bend.
This is the best information i can give you based on my experience with Bilsteins.
Re: RS6 coilover findings
ohhh - we need to meet one day around M40
Want to check how it feels. I still have DRC and want tos see what's the difference when I will get rid of it.
Re: RS6 coilover findings
I'll PM you next time i'm up that way.
Re: RS6 coilover findings
Best will be Beaconsfield services
Re: RS6 coilover findings
Great post, interesting points! thanks for the thoughts. But feel not much wiser...
Apart from desiring the Bilstein B16's for my car as the car's bouncing diagonally like an elephant on a trampoline with 3 legs!
I noted some are talking about getting them from the US, but I came across this offer on Euro Car parts, can anyone enlighten a dark mind on this sort of stuff and help me avoid a no-go area, or would you trust the Euro-Car Parts to provide the proper part as they state here (Bilstein Suspension Kit (Coilover)Product Code: 938440850) http://www.eurocarparts.com/ecp/c/Audi_ ... 679&001280
Any advice very welcomed
Apart from desiring the Bilstein B16's for my car as the car's bouncing diagonally like an elephant on a trampoline with 3 legs!
I noted some are talking about getting them from the US, but I came across this offer on Euro Car parts, can anyone enlighten a dark mind on this sort of stuff and help me avoid a no-go area, or would you trust the Euro-Car Parts to provide the proper part as they state here (Bilstein Suspension Kit (Coilover)Product Code: 938440850) http://www.eurocarparts.com/ecp/c/Audi_ ... 679&001280
Any advice very welcomed
2003 RS6 C5 Avant Black on 19's
Re: RS6 coilover findings
Hey Carlson, thanks for the post, just noticed it after i just sent my earlier one!
Sounds good. I think it's definitely the Bilstein PSS9's then B16's i believe.
I don't really want the car too low either, just low enough, and also don't like too much of a hard ride, but do want it to handle well on the bends etc.
I was even contemplating doing the job myself!
Sounds good. I think it's definitely the Bilstein PSS9's then B16's i believe.
I don't really want the car too low either, just low enough, and also don't like too much of a hard ride, but do want it to handle well on the bends etc.
I was even contemplating doing the job myself!
2003 RS6 C5 Avant Black on 19's
Re: RS6 coilover findings
They are easy to fit. See my diy in the FAQ.
Daytona RS6 C5 Avant. Viper'd, Billies, Waggers, MTM box brain, C6 stoppers, xcarlink, R8 coolant cap (woohoo)
///M3 E46 | XC90 (V8, natch) | Passat GTE | RR Classic V8 flapper
"The major difference between a thing that might go wrong and a thing that cannot possibly go wrong is that when a thing that cannot possibly go wrong goes wrong it usually turns out to be impossible to get at and repair."
///M3 E46 | XC90 (V8, natch) | Passat GTE | RR Classic V8 flapper
"The major difference between a thing that might go wrong and a thing that cannot possibly go wrong is that when a thing that cannot possibly go wrong goes wrong it usually turns out to be impossible to get at and repair."
Re: RS6 coilover findings
Cheers Shoppinit, i was all ready to do it myself, but then I noticed that the warranty is only valid if a professional fits them. Anyway, I decided to get an Audi specialists to fit near me as had sold the mrs car and had a bit of cash what a difference! Far better than a failing DRC! I think I need to lower the backs a tad more, as the fronts look lower.
what a difference! Far better than a failing DRC! I think I need to lower the backs a tad more, as the fronts look lower.
2003 RS6 C5 Avant Black on 19's
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