j--rho

Hello,
I am thinking of buying a CLK55 AMG for use as a competitive autocross car that I could still drive to events. I know, I know, I'm crazy, it's the wrong car, etc., but please hear me out.

From initial research, it looks like the W208 (2001-2002) model is a bit lighter, and has a double-wishbone front suspension vs. the later car's struts. This has me thinking I'd want a 2001-2002.

Here goes-
1. What is the behavior of the traction control/stability control systems - can they be completely defeated? Sometimes they still try to do stuff, or turn themselves back on, when you're having too much fun.
2. The auto tranny, when in manual mode - let's say you start in first, shift to second, and then you're driving around and hit the rev limiter in second gear - will it let you bounce off the rev limiter in second gear, or does it decide to shift you to third gear no matter what?
3. In my class I will be allowed to roll the fender lips, and I have a lot of freedom over the suspension components. What is the widest front wheel and tire I am likely to be able to fit? What are the inboard "contact points" with wide wheels? Does going larger in diameter buy any additional inboard clearance to the control arms? I don't mind losing a bit of steering lock if it buys me more front tire width - I only need to be able to turn enough to get around the autox course. If somebody has a wheel-off picture of the W208 front suspension, that would be totally awesome.
4. For those that have actually weighed their cars, what did they weigh? I'm wondering how light I can get it. Starting with a minimally option'd car, I would be doing the usual stuff like removing the spare tire and tools, then installing a super-lightweight exhaust, headers, a lightweight battery, replacing the front seats with race seats, and doing a couple other little odds-and-ends.
5. What sort of numbers have people been able to put down with headers, cat-back, intake, and an ECU tune? I've seen low 13's stock so far, anybody gotten into the mid to low 12's?
6. I saw mention somewhere of somebody importing a clutch-type limited slip differential from AMG. Any more info on that?

Thanks in advance for the help guys!!!!!

Boosted9603

1. I am not totally sure, but it seems like the traction control still works a little when it is off. I suppose you could bypass it completely if you unplug the abs harness?
2. I've hit the rev limiter numerous times and it hasn't shifted.
3. Stock fenderwells upfront will allow a 235. With a smaller diameter you may be able to fit 245 without rolling. My 235x35x19 front tires put a little scrub mark on the front of the wheelwell inside.
4. 3720 with half tank of fuel, me in it, laptop and bag, video camera, and misc. other things.
5. I went 12.9 with my car being stock besides K&N filters, and a magnaflow. Just look at the recent threads and you will see that BlackOnBlackCLK ran 12.5 with full exhaust. https://mbworld.org/forums/clk55-amg-clk63-amg-w208-w209/265511-12-54-111-37-n.html
6. There is a Quaife differential available that would perform well.

hhseouljah

i can have a picture of the front wheel well/suspension for you later this week.

however, clk for autocross? hm? why not an m3? or an s4?

j--rho

As for why no S4 or M3? - The S4 is AWD which doesn't really float my boat, and the M3 has already been "done". I like to do stuff a little different, and the CLK's extra oomph V8 I find appealing.

A suspension pic or two would be really awesome. I'm trying to find out how much further a wheel could go inboard - the fender lip is the outer limit, SLA cars generally have good inner clearance. By sacrificing turning radius, a heavy fender roll, lots of negative camber, precise offset measurement, and custom wheels, I'm hoping I can fit a 265 up front. A 285 would be dreamy. That's one place the M3 is clearly better - besides a lot less weight on the nose, it can fit a 285/30-18 up front without too much trouble.

Thanks for the reply Boosted. Homemade headers, that's pretty cool. One of the pics showed a lower a-arm, that's a start there too.

The Quaife is not a bad choice, and certainly way better than nothing, not too expensive either. I'll keep my eyes open for a clutch-type though.

Was the 3720 with the spare tire and stuff in? With you and your listed gear out of the car, would you guess it'd be more like 3500?

Speaking of fuel level, has anyone noticed fuel starvation issues running the tank low on fuel, maybe at the track with sticky tires? Some cars can go down to fumes, others need 3/4 tank to keep from starving.

The tire mark on your fenderwell - was it "above" the tire in the top of the fenderwell, like from bottoming out, or was it "inside" the tire, like from turning at full lock, or maybe some combination of hitting a bump while turning?

Thanks again for the replies fellas!

Boosted9603

Yeah I'd say 3500 is a safe be with my stuff and me out of it. I'm 180 and my crap I had in there could easily be 50 lbs. That was with the spare and everything in it.
No fuel starvation ever felt in my car and I've run it pretty low.
The tire mark was in front of the tire at the front of the wheelwell. I am not sure at what point it rubs there because I've never felt nor heard the rubbing.

blackbenzz

Cool project!

Your options with the LSD are Kleemann (phantom grip style) and Quaife (ATB). The better option is Quaife.

I have a CLK55 with a supercharger, water to air heat exchanger, and other things that make it heavier but also have the brembo front bbk, fiberglass bumpers, headers/exhaust, and took out the spare. On the scales at the track with me in it and ~1/2 tank I remember it weighing 3575lbs. I need to reweigh it since I dont remember exactly. I'm sure with some ltw seats, battery, c/f hood, fiberglassfenders, sunroof delete, resonator delete, remove rear seats, etc etc you can get to ~3200ish wet with you in it or 3k lbs with little gas and you not in it. If you go extreme with weight reduction you can probably get sub 3k

I also have a CLK430 (no sunroof) with fiberglass fenders, c/f hood, and exhaust that should be pretty light. I will get it on the scales and let you know how much it weighs.

j--rho

Thanks for the further replies guys. Under my ruleset I wouldn't be going quite that far with the weight reduction - just the seats, headers/exhaust, battery, intake. I will also be doing new wheels/tires, springs/shocks, and swaybars.

How much weight did you save going to the big brakes?

If the car is around 3450-3480 stock, I should be able to get it close to or under 3200 on fumes, without driver, as I expect the stock seats and exhaust are very heavy.

No worries about weighing the car on my account, but I am interested to see how light others have gotten their cars, and if anybody has already weighed some of the stock components I'm planning to replace.

da_guitarist

fyi, there's a good buy on a 55 in the forum now

H-MAN

I have a W208 55 and can answer 1 and 2. I have autocrossed my car and think you will have a great time with it, you will definitely be the only guy around in a benz. I ran with a vette and boxster in A-stock and even with those guys on race tires it was neck and neck between us. There was a guy in Australia who back in 2001 or 2002 bought a new CLK55 and used it as his tarmac rally car. He gutted the car and installed a cage, it looked great. I may have a few pics of that car somewhere.


1. You can shut the traction control off and it stays off. With TC off, I have felt some initial TC if i only have very little wheel spin (.5-1 sec tops) but if I stay on the gas I could spin the tires all day long.

2. When using the manual mode for the transmission it will not shift to the next gear even if you hit the limiter. However I think it's faster to run 0-60 or 0-100 with the transmission in D than shifting it manually. I use the manual for dropping down gears for corners.

H-MAN

Great car, looks like it came to a bad end

j--rho

Hey guys,
Thought I'd bring this back to the top again. I stuck with the Viper for one more year but it's time to start thinking about what to do next year.

I have a few lingering questions, all for a 2001-2002 W208-

1. Brake assist - the symptom would be, you brake hard for a corner, come off the brakes to turn-in, but the brakes are still on, because the car thought you were in a panic stop. Does this happen to you? Does turning traction control off disable it? I'd like to keep ABS active.

2. What's the lowest speed or RPM where it'll let you go to first gear in manual mode? For instance, my Tundra manu-matic won't let me downshift to first above 25mph, even though the truck will do 45 in first, presumably to keep me from blowing the rear tires off. Does the CLK have a similar limit? We have some pretty tight corners in autocross and it would be nice to get in the gear I want on entry, instead of suffering the delay of having the car downshift on exit.

3. Still haven't been able to find a picture of a W208's front suspension in a wheelwell view. We know there isn't much room outboard (are the fender lips rolled from the factory?) and I'm curious what the inboard limit is, and if maybe going with a larger diameter wheel would increase inboard clearance. Within my ruleset I have some freedom to modify control arms to increase clearance.

The class I plan to race in allows 285's - while I don't expect to be able to fit a 285 up front (rear I don't think will be a problem), I think the car is going to need at least a 255 in front to be competitive, 265 would be better. This car will have a bunch of negative camber, high spring rates, custom built wheels, and I won't need to turn anywhere near full lock, so with those compromises I'm hoping I can fit more up front than the 235/245 limit provided by conventional wisdom, at least as I've researched on this board.

As the car's competitiveness hinges on the rubber I can fit up front, any pics of the front wheelwell and its interference points (the more and higher res, the better) would be much appreciated!!!

MarcusF

1. Turning off ESP does not disable ABS. Keep in mind that brake assist is driver adaptive. Also, here’s a quote from the 2001 W208 press kit - "As soon as the driver eases up on the brake pedal, normal brake control resumes."
2. With the transmission in drive, if you're at full throttle, approaching a turn, release the gas and grab the brakes, the transmission won't upshift. It will downshift as speeds decrease.
3. Sorry, I don't have any photos of the front wheel well, at the angle you want, here at work.

j--rho

Thanks for the reply Marcus.

In regards to #1, I was told this might be a problem by some test-driving friends I have. They noted experiencing this problem when testing some AMG cars back around the time the CLK55 came out. They may have been testing with TC on, or maybe it didn't have adequate time to adapt to their driving. Or maybe it was those overly optimistic marketing people again...

For #2 - the ability to downshift is what I mean. Let's say I'm going 55mph in 2nd gear, and need to slow down to 25mph for a corner. I'd like to be able to brake, and while slowing down through 55mph-50-45-40-35-30-25mph, be able to move the manual shifter thingy over to make it downshift to first. If it won't let me downshift above 25mph, then it won't go to first gear in the braking zone;and would instead (presumably) downshift to first on the way out of the corner when under heavy throttle.

If I could get it to first gear on the way in, I don't lose time when the engine kicks down on the way out. Every tenth of a second counts!

A simple test would be to go out on the road, put car in manual mode, accelerate to ~50mph in second, lift off the gas to decrease speed, then keep quickly blipping the lever over to initiate a downshift, noting the speed at which it eventually lets you downshift.

On a related note, does anybody know if the transmission/shift parameters are adjustable via the ECU? Might be another way to go about it...

neilbo75

LOve the first picture! Second makes me wince ... Chappy, here it is - the fabulous, mysterious Australian rally car. Now we know why Affalterbach doesn't like to talk about it. Notice the 208 F1 safety car 18 inch "aero" 2 peice AMG wheels.

You're asking some good questions, j--rho. I can chime in on a couple:

--The car will not fuel starve. I almost ran out of gas on Nurburgring last summer without any problems.

-- ABS is not completely defeatable, without going under the hood and doing some sabotage work.

--Brembo BBK will save 5 or even 10 pounds on each front corner. The stock AMG rotors work well but are heavy.

--I haven't noticed any "brake assist" issues.

Hope you do your project - sounds cool.

Chappy

That W208/55 was short-lived in that race IIRC.

Chappy

To the OP: Biggest tire size I've seen up front is 245s.

I've autocrossed and tracked my CLK and never had an issue with the brakes....but I left-foot brake, so I try to make my transitions as smooth as possible.

Chappy

Next time I pull the CLK out, I'll play with the downshifting and keep an eye on the speeds.

j--rho

Thanks much Chappy. A lot of the searches I've done here have pulled up your posts, lots of good stuff there.

I can see how on the W209's, inboard clearance would be limited by the strut. Wondering what it is that limits inboard clearance on the W208.

MarcusF

These are the gear ratios and speeds in gear for a CLK430. There is less than 2% difference in the final drive ratio on a CLK55, but the transmission gear ratios are the exact same.

Since Hollywood traffic is an endless stream of zero to forty (on a good day) to zero, I tested it on my mind numbing commute today. I was able to downshift my 430 to first at 30 and at 25 by tapping the shifter.

Chappy

We've got a good community here....folks from all over the world.

Since you're possibly looking at a trick suspension setup, you may want to do a search on "speedybenz" as he has done some significant work to his W202. The W202 has (basically) the same suspension as the W208 - just not sure what the clearance differences are in the front wheel well.

Additionally, the CLK55/W208 AMG comes from the factory with rolled fenders. You may have some luck pushing beyond the conventional information here with 255s....please keep us updated on your progress!

Chappy

Spot on, as usual Marcus!

j--rho

I found a couple pics in this thread:
https://mbworld.org/forums/wheels-ti...rabus-out.html

To you guys that have poked around in your front wheelwells, does this pretty much look like the front of a W208? Looks like the knuckle and upper ball joint are the pinch points. What's the most wheel backspace people have been able to run up front with 25" tall tires on 18" wheels? A width and offset combo would be helpful in lieu of a backspace measurement. If a 235 fits ok with zero camber in front, I should be able to fit a 265 with about 2.5 degrees negative camber. Maybe even more with some offset bushings in the lower control arm and a shortened upper control arm. Neat stuff.