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RSTPerformance
08-22-2006, 05:39 PM
Ok, I said I would post our experience for others to gain a bit of knowledge, it might be useless knowledge, but hey you can enjoy the procrastination or ignore the post ;) ... This is my initial opinions with only using the Bilstien’s once on one car.

First I have to talk about the Audi... The cars are very heavy up front and require massive amounts of camber to really handle well. We drive the crap out of the cars beating them to death at every event and I don't think anyone can argue that we get the most out of every part on the cars. The end results with the suspension design in an Audi in regards to the struts are major side loads on the strut shaft. If the strut can't handle the side load things only get worse as any play in the strut shaft changes toe in/out dramatically, in turn causing poor handling and an even greater side load on the strut multiplying the wear and its effects. In addition to that the side load (based on our experiences) it also damages the struts compression and/or rebound valving.

Now the Companies:

Koni-

Great company to work with for several years. They helped us with the cost and development of our suspension since day one. Huge kudos’ goes to them and if they have an application that works for your car I certainly wouldn’t tell you that they are a not a great company to work with. For us their recommended product didn't work. We tried several things over a 5 year span to make their product work and when all was said and done this summer I was not comfortable with their next suggestion. I felt we would still have a strut that would fail after a 1 day race weekend. I told them my concerns and asked for another option. That other option was going to cost us well over $1,200 per corner just for the strut insert. They did help us a lot so it was tough to look elsewhere but we just could not afford or justify spending that much money when we were not certain that even that super high level product would work or not. We decided to look elsewhere and see what options were available to try.

Bilstien-

We contacted several companies all recommending Bilstien or other "new companies." We would have loved to work with a new smaller company but we had a 3 week turnaround deadline and nobody could meet that except Bilstien. We talked with Bilstien and spelled out our problems and concerns. They guaranteed us that they had a product that would work. After talking with them and discussing the option that they had for us we asked the price. It was then a done deal; we were going to give the Bilstiens a try. After last weekends race at Lime Rock I am confident that the Bilstiens replaced what was once the "weak link" in the suspension and that the Bilstiens were now the strongest part of the suspension. After 2 days of long sessions we did not notice any fading from start to end (something we certainly noticed with the Koni's). Despite being a bit slower than other weekends the tires felt like they "gripped" the track surface much better. Most importantly though is that the strut seemed to handle the side load and the Toe is staying where we set it and is "tight" not all loosy goosy if you know what I mean.

Bilstiens data/setup vs past Koni data/setup:

The first issue we encountered was that tire pressures normally were set with the Koni's to start around 29-30psi and would come up to around 40-41psi at Lime Rock. With the Bilstiens they only came up to 35-36psi. This was odd but decided that the tires were not coming up to the same pressures because the struts were actually working? We increased the pressures the car handled much better which resulted in more consistent faster lap times.

The other issue that we encountered was that the car seems to need more camber than it did previously. We are already running at unthinkable amounts and I can't imagine going any higher but I am confident that with more camber we should be able to get the car to handle considerable better, maybe gaining .5 – 1 second a lap. (Maybe I am dreaming) Next project is to get that additional camber out of the front and test out that theory!!!

We were about 1 second off the pace in the beginning of the weekend but at the end of the weekend we were only .5 seconds from where we wanted to be. Other contributing factors besides the two issues above could be a result of running on well used tires vs. new tires.

Anyway we are very pleased with how things have turned out with Bilstien. We now have an affordable well built strut insert that I think will handle the massive amounts side load, time will tell. I am confident that we can run the cars in the mid to low 1.04’s at Lime Rock lap after lap once things are completely figured out which will keep us in the hunt with all the “top dogs”!!! I loved the Koni's and the thought of all the adjustments but as quoted by everyone we talk to… "All the adjustments in the world are useless if the struts don't even work."

Raymond "new Bilstien believer" Blethen
RST Performance Racing
www.rstperformance.com

Conover
08-22-2006, 06:10 PM
Thanks for the write-up. I thought that the Bilstiens might be the answer. Now your all set to enter some Enduros, eh?

Bildon
08-23-2006, 06:25 AM
:023: Nice write up.
I told you so :P

924Guy
08-28-2006, 01:21 PM
Awesome... :happy204: :happy204:

I've been a Bilstein believer since I put them on in 2002!

They're still on the car. Should probably get 'em rebuilt one of these days... :D

Eric Parham
08-30-2006, 12:06 AM
Glad to hear that the Bilsteins are working out. I switched to them while autocrossing (before I even discovered road racing), and never looked back.

On your front camber issue, I still think you need to make the outside rear work harder. If your car/cage is stiff enough, the rear can help plant the front so you might not even need as much front camber as you've got now, nevermind more. So, what types of rear swaybars are available or adaptable to the Audi?

RSTPerformance
08-30-2006, 05:58 PM
Have to give more props to Bilstien. At Bilstiens request I gave them some feedback on tire temps, tire presures, and the cars handling. They identified why they thought we had different data results as compaired to the Koni's. They told me why and what the results are from the different dampaning rates. They offered some suggestions, and we will be working with them and giving feedback. I can only say that the prime indicators (tire temp, tire presure) show that improvements can be made to the car, and starting out at the same point we had left off only means we are going to get faster!!!

It is companies like this that truley do make champions, with todays conversations I am even more convinced that this is a great company that will only help the ITB Audi's to greater sucess :)

Raymond :035: Blethen

Eric- not much available for rear bars... need lots of fabrication. I made a bar but I have a fear that it may cause the rear pick-up points to rip out of the car... how can that be fixed without raising eyebrows? At anyrate you are correct, we do need to get the rear to do a bit more.

kthomas
08-31-2006, 09:22 PM
Bilsteins, or something that used a lot of Bilstein parts (RR ShockTek's), have won about 4 of the last 5 ARRC's for ITS.

Daryl DeArman
09-01-2006, 03:37 PM
I have been out of the IT loop for quite some time. Was wondering, since Raymond mentioned big side loads, if anyone in IT has used or uses DMS struts?

Raymond,

If you want to find out how much of this change can be attributed to the side loads that the strut cartridge can handle without failure or if it is because of different dampening rates, I discovered a wonderful company to work with (excellent turn around and value).

brenner (http://www.brennerfabrication.com)

Send him one koni and one bilstein have them both dyno'd and find out what the real difference is. He only charges $25/shock, you get nice pretty data chart, a follow up call to discuss results, great guy! He is in Fort Bragg, CA. Knowledge is power--so they say.

Eric Parham
09-02-2006, 11:12 PM
Raymond, although my preference would be to stiffin the rear of that Audi with a balanced combination of stiffer springs and swaybar, I think you should see about the same improvement in steady-state cornering even if you do it all with stiffer rear springs alone (assuming your rear shocks are sufficient). It may make trail-braking over bumps more challenging, for example. If it helps cornering but hurts braking or some other basically non-cornering stability issue, at least you'd then have the right reason for fabbing a $tiff rear $waybar. If you can swing a dry test day, just keep upping the rear spring rates until the car is almost undriveable, and then back off 25-50 lbs (or don't) ;) If you do it basically without swaybars, I'd be aiming for rear spring rates approaching those of the fronts, which, in turn, should be about the same as the front corner weights (I know, apples and oranges, but not far off). If you eventually do go for a stiff rear swaybar, look for rear WHEEL rates approaching those of the fronts.

RSTPerformance
09-03-2006, 12:13 PM
thanks for the info guys!!! looks like we will have some stuff to do this winter. I am toying with the idea of changing around spring rates for the ARRC... Different traks certainly take different spring rates I have noticed. Lime Rock we need a much "softer" rear end than at any other track.

Also thanks for the link. Most of the Koni's are basicaly junk (or need rebuilding I should say), but I think we may be able to find one that is still good. After we have a few races (the rest of this season) on the Bilstiens we should be able to get one bilstien and one koni that have similar useage on them and compair the two of them on a dyno... -thanks for the link!!! To bad the UPS guy will make more money on the shipping than the actual test :rolleyes:

Raymond