I went with the Audi Club Potomac Chapter to Virginia Int'l Raceway in Danville VA. We were there the two days after the Rolex Grand Am races were run. As always, it was great fun. VIR is a 3+ mile roadcourse with long straights and great turns.

The C32 was great. Other than atrocious, unrelenting understeer, the C32 was fast and fun. (More on the understeer below.) I found that lowering tire pressures (33 lbs) actually improved grip because the tires were heating up and causing hot pressures over 40 lbs.

Power was awesome. I hit almost 130MPH on both straights, which is a good speed considering how gingerly I was coming out of corners. I put to shame several Audi S4s (B6 - V8 models) and two Subaru STis.

Brakes were phenomenal. I used EBC Red Stuff ceramic pads, and they held up very nicely.

As to the understeer, what do you folks think of the following solutions:

1. H&R rear stabilizer bar. Stiffer than AMG stock, and should get the back rotating.

2. De-staggering wheel/tire setup. I would basically mix/match my winter tires so that my summer set was all 8-1/2" with 245s and my winter set will be 7-1/2s with 225s.

3. Moving the battery to the trunk. A relatively easy step, but kind of radical. It's not unprecedented. Lots of higher end tuner cars do this.

 

i would suggest two things:

1. getting an adjustable front and rear sway bar setup...this way it allows you to have more control between different tire/wheel combinations....

2. if money is not an issue, get a full coil-over setup like the Bilstein PSS9 setup, gives you even more control to fine tune for the track and for daily driving....very well worth it if you are going to be tracking the car on a regular basis

 

Having spent many track days with SMGC32 driving the heck out of the C32 I can give some pointers on what the car needs to reduce the understeer. I say reduce because it will always be there regardless of what you do

1) Get either a set of PSS-9's or Carlsson RS coilovers. These will allow you to set the car to your tastes with ride height and shock valving (compression and rebound go up together so there is only one adjustment). Setting the front at about 6 and the rear at about 3 (9 being the softest setting) makes the car fairly neutral.

2) Get some good R-comp street legal tires such as RA-1's, Michelin Pilot Sport Cups, or maybe a set of Falkin Azinis 615's (long lasting but very sticky and stable). Order them in 245 and 255 and mount those on stock rear wheels all the way around. Or if you want go for new wheels contact CCW and get some custome made wheels and stick the largest possible tire on the car. Just remember that a coilover strut tube is thicker than stock so a wheel and tire combo that works on a stock suspension might not fit a car with coilovers.

3) Get the car alligned and have them use the crash bolts to make it have the most negative camber up front possible. Also remove a bit of the factory toe-in because that will help the car change direction. Just allign the toe to just outside factory spec going closer to a zero toe set-up.

These things really make a big difference and should make the car more fun. Once you get going you will want to upgrade brakes so realize that a set of 18 inch wheels might be a good idea for they allow you to use a 14 inch stoptecbh or brembo kit. The factory brakes dont take the abuse we throw at the car and I doubt they will last very long at VIR once you really start cooking with gas!

Finally about tire pressues. Start out with about 34 psi up front and 32 in the rear. This allow you to dial out a bit more understeer. Your tire temps will quickly rise to 45 or so up front and 40 or so in the rear at a moderate pace. If you really get moving your tires will hit 50+ psi after every session unless you start at 30 psi or less cold. The car is very nose heavey and has a great deal of understeer so you need to run a lot of air up front. Moreover, if you run anything less that 45 hot your front tire will roll over onto the sidewall and wear all the writting right off the tire. This car is a great car and could really kick butt at the track if it just had 3+ degrees of front negative camber. The basics are all there.

 

no, it's not unprecented, the w202 c36 has it in the trunk as well..

 

Trouble is that there is no room for a battery and a spare tire in the trunk. I personally would buy a motorcycle battery and use that for track events and just replace the factory battery in its OEM location. The motorcycle battery has enough power to start the car but it wont work well long term so change back to the stock battery once you get home from racing.

You can also purchase an optima battery for they are about half the weight of a factory version as well.

Running around with no spare tire seems great until you actually need a tire (a real blow out or a tire that will not seal with fix a flat) and you have no option other than a 200 buck tow. The thought of being on a road trip with no spare is crazy in my mind. MB does so really cheap and stupid things these days.

 

Thanks for all the ideas. Some follow up:

1. I could not find an Optima battery sized for this car. I think it's a "group 49" which is the size of a microwave oven. Could I use a smaller one and use some foam shims around it?

2. Regarding inflation, I was able to go as low as 33lbs up front without rolling onto the sidewall. That was the best result for me.

3. Stabilizer bars (adjustable) will be the first investment. I still use the car 363 days/year on public roads, and I like the ride as-is. I had a set of uber-firm KW coilovers on my A6 and it was a brutal ride on the street.

4. Before I go with a big-brake-kit, I'll probably explore ways to improve brake ducting either on a permanent basis, or some track-day hack job. Even though there are bigger brakes available on the market, the rotors on the C32 are probably bigger than you would have found on a full race Porsche 15 years ago.

5. I've got a spare (did the "mod" to add it back), but pull it out at the track.

PS: I put a lot of money into my old A6 2.7T, and while it was fun and rewarding, it was the source of great stress and expense. I'd like to keep the car nominally stock, and limit modifications to "dumb" parts like wheels, tires and stabilizer bars.

 

I've done bars on my Audi, at it was fairly easy. Is it easy on the C class?

 

I'm talking from my experience with a W202, but I think all should translate to the W203. Try 5mm then maybe 10mm wheel spacers just up front. Making your rear track to front track ratio narrower then spec in the rear tends the car towards oversteer from understeer (the W202 at least; I know from experience). Yes to the mention of increasing negative camber. However regarding toe not so. I run speedybenz's suggested values and they are really great; 1/16" total in the front and 1/8" total in the rear. Castor matters a lot too, and affects you in the turns to pivot the car, but I can't remember what mine are set to now. I think you want just about max castor, but don't quote me on that. I had a raceshop, not the dealership, align my car following speedybenz's recommendations. That with his suspension kit is an incredible step-up in turn-in ability and balance of the car.

 

The factory dials in large amounts of toe to make the car track straight and true at speed but this makes it more slow to transition.

I just had my E55 alligned and it now has 2.5 degrees nagative camber and the toe was set just outside of spec and it actually will turn in now where as before all that car watned to do was go straight.

You are correct on caster but a W203 has a camber and a caster bolt to make adjustments. You can not really adjust it all that much and its either no bolt or bolt added.

So yes have the car alligned by someoen who knows about tracking the car (some dealership allignemnt guys know about this stuff) and go from there. The bolts are about 8 bukcs each and u need a camber and caster bolt for each side.

 

As for the KW set-up on yout Audi I can relate because the C32 on a stiff setting with the Carlsson RS is very firm. But honestly when set to the softest setting the car is softer than stock and when set firmly it is very firm. The softest and firmest settings are just to far in either direction so 1 is never used and neither is 9.

From having melted around 20+ sets of tires on 2 C32's I can say that the car MUST be lowered for track use. First it gets that heavy motor out of the air (lower the center of gravity) and it also creates .5 degrees of negative camber (maybe .25 since strunt cars have almost no camber curve over its travel range -- W0202 cars with wishbones are a different story). Driving the car with just RENNtech springs was amazing. The car no longer had such massive understeer and it actually rode far better than stock.

So if you do not want to go for coil-overs I would buy a set of RENNtech springs. Having been around for design and testing I can say 100% they are not just re-painted H&R springs as a forum member has tried to state. THe spring rates are set to work best with the stock shocks and the car is worlds better than stock. Coilovers are just a better option performance wise sicne you can firm up the shocks for track use and go back to a softer setting for streets. Also you can corner ballance the car with the Carlssons while springs leave that issue on the table.

Tire pressures are more a factor for how you drive. If you are not chasing the clock you likely do not need to have as much air in your tires (given the camber challanged nature of the car). I wore michelin off my first set of tires in my local canyons and I had 40 psi in my tires.

As for adding bars, I have always worked from this approach. Bars are for fine tuning a well set car but they are not the best method of patching up a poorly set car. In stock form the bars are actually fairly large and goin bigger may not be the best plan in the book. I think RENNtech springs will serve you much better than a set of bars but both together could be better. Same goes for the Coilovers. You just dont want to go to firm on the bar because the car could start skipping around the track.

On the topic of brakes you are correct they are fairly large stock but again driving style and pace dictate what you need. We make the big brake kit fade a bit when driving at the streets of willow going counter clockwise and thats was on pagid orange pads. Pagid blacks are about ideal for the front fo the C32 when driven hard. You will quickly see your rotors crack and the calipers turn gold if you really push a stock C32 set-up. But if that does not happen to you you likely wont need an upgrade. Our silver stoptechs were bronze like a STi or 350z after 2 days at the track and the hats were a dark dark red (not black).

Hope this helps. Go chase down evo's and STi's in your C32... they hate being made to pull over for a benz. Great fun!

 

Thanks. I'll definitely look at Renntech springs rather than a fatter stabilizer bar. It doesn't hurt to drop the ride height a bit from a visual perspective.

 

For some reason AMG with SUV spec springs in the front of the C32. It rides well but who needs a fist and a half of fender gap on a sports sedan. The C55 sits far lower as do C230's so going a bit lower is a good idea. Going to a C55 shock or something of that nature could work well with the RENNtech spring since you ideally want a firmer shock when you recuce ride height. This is all in an ideal world but RENNtech springs alone are great as well.

 

I think I've finally found an online hangout!!! After a few years at AudiWorld (a great site) I struggled to find anything comparable for my Benz. Nice to get clear, objective and thoughtful answers and suggestions.

 

With 35,000 miles on the original shocks, would it be dopey to NOT replace them with the springs?

 

VIR is a great track. I've been on VIR 2 days each with a C32 and with the C55. Both cars ran about 133-135 mph going up the hill on the back straight just before you have to look at the corner worker station on the left. Probably pushing 150 down the other side if you can keep your foot in it, before having to brake for the left turn. Both cars had negative camber bolts, but only get about -1.5 degree if that. The C32 was running Michelin Pilot Sport Cups, and 225-45/17s in front and 255-40/17s in rear (at that time they did not make a 245 Pilot Sport Cup). Much understeer to say the least. On the C55 I ran 245-35/18s on all four wheels with Hoosier tires. The car performs so much better with much less understeer. Probably some of this is attributable to the narrower sidewall of the 18 inch tires, but you will probably get a great deal of the understeer out if you put the 17x8.5s that come on the rear of the C32 on all four wheels. I run higher pressures however, than they are talking about: about 40 cold in front, 37 in the rear. The lower pressure in the rear also takes out some of the understeer. If you are on street tires, I would think you would want somewhat higher pressures on such a high speed track.

 

you got it right there

I have a C230k I use to go around to and from work and the front shocks got weak at 25k.

I would either get some C55 shocks because they are the firmest available. The Koni yellows are actually softer than a new C32 shock and there is no sport from Bilstein so C55 shocks really are the only way to go.

Or if you are going for springs and shocks you might just want to do the Carlsson RS kit and set it to 8 (being very soft) for street use. The car will feel like stock only much more controled.

Find someone selling their used C55 parts and then you dont have to pay retail on the shocks. Or PM me and I will see what I can do too.
But yes shocks get weak and if you plan to take the strusts out of the front might as well replace them while it is all taken apart. Thats my logic at least... if its taken apart replace what you can and get it over with.

Another guy we go to the track with did put C55 shocks on his C32 (which had H&R springs) and he said it made the car a fair bit firmer and it felt very nice at the track.

 

Yes we used to run 40 and 37 as our starting point pressures but we kept chunking the heck out of the dunlop race tires we were using. The rubber just started flying off the tire at the end of the day and all that was left was cord... no rubber from the centerline out. Kind of scary being that we were chasing a 400 hp evo at the time and about to pull him over.... We were faster!

Anyhow with 40 as the starting point we were well over 55 psi after a session of driving and that was just too high. starting around 36 means you are around 50 after a session and that still is a bit high but not totally insane.

All depends on the track and driving style too. Tire temps for our local highspeed track showed driver side fronts to be working very hard and not having enough camber.

 

The cheapest and easiest way to get your car to handle better is new R compound tires. In all my cars and on all the tracks I have been to the best performance gains come from sticky rubber. That is the only part of the car to make contact with the ground and is the most important.

You want to save tires and do it the right way start at 30psi, get a pyrometer (one with a needle, around $50) and pull over after your 2nd or 3rd lap and check the tire temp at outside, middle and inside of tread, plus get psi reading. Keep doing this on for all 4 tires until you find the right psi to start with for each tire based on the tire you use and the conditions on the track and the weather. All those things contribute to tire temp. Make sure you log all this to a notebook and keep the data so when you return you can check your log and see if the conditions match and you will know were to start from. This is time consuming, but will save you tons of money on tire wear. If done right you can get a set of Hoosiers to last 6-8 track weekends. The basic idea is to have the temp be even across the surface in all 3 places and not have the psi exceed the hot temp from the tire manufacturer. Which is usually 40-44 psi depending on tire.

To remove body roll and get the *** end to rotate a nice set of beefier sway bars usually does the trick.

If you want turn in to improve get some camber plates and start off with around -1.5 to -1.6 degrees of camber up front but know the more camber you have will affect straight line performance. Depending on track layouts the camber can be shifted to one side or the other to improve turn in for mostly right or left turns.

Coil overs are expensive and can take a long time to "tune". They can also make your daily driver a bit rought to get to work in. I recommend them over springs if you just feel you have to do something. Unless you are Michael Schumacher sway bars, tires, and brake pads will get you there. The other stuff is a bit more serious. If you do more track time than street driving go for the coil overs and camber plates. Then you have full control over height, damping and rebounding, and camber/toe. Good Luck

 

Thank you. I'm not quite ready for the R-compounds, but the rest seems do-able. I'm lucky to get 2 or 3 track days per year, so dedicated track tires/wheels are not worthwhile yet. My next set of summer tires will be more track-worthy.

 

You can always buy track tires and then have them mounted at the track or for the track event. Bobby Archer usually goes to all the events I attend in Texas and only charges $40 a wheel to unmount street and put on race then remount street tires. Maybe someone at your tracks offers this service?

 

i was running same day 5th ring was.....my 2nd tire trialing event in c32

tried yoke a048 on my stock 8.5" front. ps2s in back. amazing diff almost fixed the understeer. also- the treadwear was very acceptable. no cording. the car is gripping now no sliding so no abrasion.

next time round a048s 255/40 all round, 2-3 mm spacers in front. i have h and r sways ready to go in.

 

I'm shocked that the Tech Inspector let you run with a mix of R compounds and Street tires.

It must have been obvious from the 19" in the back and 17" in the front. I certainly wouldn't recommend that combination. I'm glad you're still in one piece.

 

Questions about your tires/wheels.

1. Your front wheels look like 8-1/2" rear AMG wheels (I know that lip after having refinished my own). Did you run 255s on the front? Did you experience any rubbing?

2. Are your front wheels painted, or is that brake dust? If so, then WOW that's a lot of brake dust. What pads did you use, and how did they hold up?

 

yes the fronts are the 17x 8.5 35mm ET OEMs. sorry i didn't make it clear in prior post the tires are yoke a048 235/45-17 same OD as the rear 265/30-19. no rubbing at this size. my inner rear fenders are trimmed somewhat to remove any possibility of tire to metal contact.

after reading extensively i discussed setup with tirerack before ordering. i checked out the steady state and dynamic cornering before i hit the track -just as a precaution. this also served to heat cycle the tires.

as i said before i may try non staggered setup either 255/40 or 245/40 17s may even play with different compounds. i even think the c32 could benefit from reverse stagger, achievable by width or compounds ( same size all round but run softer compound up front). hey- the yoke a032 is very attractively priced like 150-160 in the sizes above. the 032 does not have the tread width like the 048 tho.

pads are porterfield rs4. amazing braking power with the new found front grip. i did not experience fade but this was a faster track. and no that not brake dust! i painted rim flat black. the rs4 does not create much dust but i do know 1st hand the dust will eat wheel finish if not cleaned off often.

all this said i may never track the c32 again as i am getting close to fully prepping a dedicated track car(s). the mini i picked up yesterday was a total hoot - like a gokart. maybe i'll drop in a full race engine with a 5 speed straight cut box..

good luck. pm me if you have any ?s.

 

I have a set of C32 OE wheels with Michelin Pilot sports for sale, if you're interested. R compounds will cost you another $650 thru TireRack. I had good luck with Khumo's at VIR.