ColorChange

I am taking my E55 to the track because my Porsche TT will not be in yet (May 14 event, late May tt delivery). What do I need to do to the car to get it ready?

1. New brake fluid?
2. New brake pads?

What pressures should I run (I have the Conti's)?

Any issues to look out for (overheating, oil pressure, etc.)

Thanks

saber

ColorChange,
1/4 mile racing or laps?

ColorChange

Laps Laps Laps, DE stands for drivers education.

Renn 208

Since your car's brand spakin new, there shouldn't be too much to prep for the track.

Usually, I would check all of the rubber bushings for cracking, look for play in the wheels, pad and rotor condition, etc. But you should be fine out of the box.

Things to consider after the DE weekend would be: check pads and rotors, engine oil condition, tires.

As for the pressures, it depends on the track and your setup. Just watch your roll line and if you have a pyrometer, make use of it.

ColorChange

Renn:

Wow, stock pads and fluid will work? I am surprised and impressed. No cooling issues, etc. Hmm. I shouldn't have a problem adjusting tire pressures a the track. Any recommended starting points?

Renn 208

Well, it really depends on how hard you plan to push your car around. Since this sounds like your first DE in this particular car, why not go with it out of the box and learn it's limitations? If you do, you'll know first hand what it might take to push it even further. Sure you could jump right to it and get some track pads, but I usually like to know how things baseline before deciding on changes.

Oh, and you probably already know this, but after you've finished a hot lapping session and have come off the track, try to stay off the brakes as much as possible, lest you get some pad deposits on your rotors, or promote uneven cooling.

eclou

I would start at 32lbs cold F&R, watch the outer blocks to see how far you are scrubbing, then add or bleed to keep the scrubbing right at the edge of the block. You might see some chunking and feathering of the edges too so don't be surprised.

ColorChange

Actually I do have DE experience in my Countach. I plan to push the car quite hard. That is why I am surprised the stock pads and fluid can handle it. Can they if you take it to 9/10?

Eclou, I'll be sure to chalk them. I heard other people saying they start at 35-36 cold and then get close to 40 hot. Slightly higher on the rears. Too high?

eclou

Maybe a couple # more on the rear at most. Remember they will heat up more quickly than the fronts from cornering, the fronts will heat up more quickly from braking. Depends on your track configuration

Dr Chill

These are the mods I feel necessary if pushing your car hard for several 20-30 minute sessions (any longer and you'll cook your brake system).

1) Castrol SRF or reasonably similar brake fluid-stock fluid is DOT 4 but with lower boiling points
2)race pads
3)brake ducts

Additional recommended changes

1)braided steel brake lines
2)racing compound tires


Stock calipers and rotors should be adequate.


After a few laps your dash will read in big red letters "Brakes overheated! Use caution." This is due to a temp sensor in the brake fluid. If you are running SRF, the fluid will outlast the brake pads and rotors. If you continue driving hard, the brakes will fail and give very little warning since electronic brakes do not give feedback like hydraulic brakes. After 20 minutes of hard lapping, you will smell burning brake pad when you exit the car. After adding ducts, the warning came on a little later and I no longer smelled burning pad. I pushed my last session to about 35 minutes and when I entered the pits, my pads were on fire and required a shot of fire extinguisher.

The stock pads are ok for street use but not for any serious track use. Nobody makes a race pad for the supercharged AMG cars yet as far as I know, and I've spent many hours researching this. Pagid will have a pad out very soon but you can have the old compound stripped off the used set and any one of many companies can add a race compound to the backing plate.
Did you know that MB chinzed out and gave us 2 left rotors in front and back (or maybe only rights)? If you look closely at the rotors on each side, you'll see that they are indentical instead of mirror images of each other. Instead of venting air into the vents and out the crossdrilled holes, on one side, the air goes in the opposite direction. This was a cost saving measure MB took when subcontracting Brembo to manufacture the rotors. Anyway, the rotors should be usable and are a lot cheaper to replace than 2 piece Brembos.


I have acquired several r compound tires and can't wait for the next track event. This will likely make the biggest difference in stopping ability. When the pads are finally in, I will finally feel confident to avoid a serious braking issue out there, because I like going faster than Vipers and Porsche TT's.

ColorChange

Jah:

Thanks a lot. I thought the brakes would need some work.

I will go with the SRF (that's what I use in my other cars, expensive but the best).

What pads do you recommend?

What ducts? Are you talking scoops or do you need to run actual ducts? Where do I get them?

Will the Conti’s hold up? What pressures (cold and hot, front and rear) do you run?

Is there any easy way to know out the understeer?

I don’t plan on tracking it after this so I plan to leave the bake lines in place. I would be willing to upgrade the rubber and then put the Conti’s back on after I eat the new tires. Big difference with maybe pilot sports?

eclou

Pilot sport Cups would be the way to go. Run same size all corners - 265/35/18. If you are just planning on running this once, I wouldn't bother modding the car. The most dangerous driver on the track is the guy in the unfamiliar car. Just learn the characteristics and be happy.

ColorChange

eclou:

Is that what you run on the street? How do they compare to the Conti's and in wet weather? How much better are they on the track?

And yes, I will take it easy as I do with any new car before I start to crank it up.

The Pilot Sport Cups sound great. Why do you recommend equal sizes all around?

eclou

Pilot Cup Sports are amazing tires. Street legal (but noisy) with near-Hoosier grip on the track. Many racers get 50-60 heat cycles out of them. I get about 10 cycles out of Hoosiers. They have better wet traction than Hoosiers, but nothing like the Contis for the street. They are a Track tire with street capabilities, similar to the Yoko AO32R but MUCH better.

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eclou:

I'm worried about running equal sizes screwing up the stability management system. Any concerns?

eclou

Why? Outer diameter is still the same. I doubt there would be any probs.

Blocktrader

To add to what Dr Chill was saying, the sensor will go off no matter what fluid you have in the car. The SRF just gives you more insurance. I came in two laps after the light and saw no problems. I have a second car to drive while one cools off though. Chill was staying out longer after the light came on. I would recommend a spare set of wheels because the clear is going to take a beating from the hot brake dust if you stay out long. I think 265 tires on the front would make a huge difference in the handling. As it is the car pushes alot. One important driving note about this car. If you start to run wide you cannot tighten the line trailing the throttle like you can with most other cars, so don't come into the corners too hot.

Blocktrader

The stabilty management appears to allow the car to push as much as the car wants. I would imagine it just reigns in oversteer. You couldn't say for sure because there is no way to get the car to oversteer the way it sits. (aside from tire spin induced which is reigned in even if you are going straight) Either way, my only concern would be that the stability system might kick in and make the car push no matter what you do. I can't see any downside to running the bigger tires up front.

P.S. To answer your question about the Conti's, the shoulders will not look pretty after your done. Mine have a few chunks gone in front and they look rough all the way around. If you are keeping the Conti's on the car run alot of pressure. Take a guage and pump. I think you can find quite a bit of improvement playing with the pressures. Despit the few issues the car is a joy to drive on the track. You come out quite relaxed.

ColorChange

Hey Guys, thanks.

I am thinking of getting PS2's and running those at the track and on the street, and then reinstalling the Conti's after that so that the track doesn't chew up the Conti's. Reasonable?

Anyone else running 265's all the way around?

eclou

PS2's are a lateral move. Personally see that as a waste of $$$.

FIXEDupW209

hey the ducts chill is talking about are custom fabricated ones made of carbon fibre. he says they really doa good job. I would do a quick search for you but i do not have time right now but you will find it without a problem. That should help out cooling a little.

Dr Chill

If this is just a one shot deal, leave the car stock. The brake fluid will hold up ok and you'll use up about 35% of your brake pads after about 4 or 5 20 minute runs. The Contis will lose chunks of rubber and you'll probably wear the lateral tread down to the steel belts. DO NOT STAY ON THE TRACK MORE THAN 5 TO 8 MINUTES AFTER THE WARNING APPEARS ON THE DASHBOARD!!!!!

I tried 28, 32, and 35 lbs inflation and found 32 to be the best compromise between speed and traction. The tires really heat up and the warm pressure will exceed 40 lbs even if you start at 32.

My ducts were custom made for me by Mosler Automotive-maker of the MT900 Photon.

ColorChange

Thanks Dr. Chill:

The ducts look great. Nice job. So many eople make the mistake of going after bigger brakes when more colling will do the job most of the time. I did a similar mod on my Lambo for the track.

It still makes sense to me to get PS2's or comparables to protect the Conti's (which are fine for the street, but will get eaten at the track). WIll the PS2's (or other tire you can recommend) hold up?

OK, stock pads but I will still put in SRF brake fluid to be sure.

Dr. Chill:

I'd like to call and talk if you could PM your e-mail.

tim@colorchange.com

eclou

You have 3 choices for tires that will survive the track and still be street legal. Yokohama AO32R - do not come in 18", Toyo RA-1, Michelin Pilot Cup Sports.

You can try Goodyear F1 Supercups, Dunlop SP9000's, Conti's, Bridgestone S03's, Pilot Sports, AVS sports, etc. They will all be badly worn because the car is 4000+ lbs.

Dr Chill

Burn up the Contis on the track because several better tires are out there.