Mercedes CLK55 AMG Coupe

[fndrbndr]

I was playing around with the PI project, and decided to go to europe, since most of the cars have been little two-seaters (go figure).  I picked the CLK55 AMG pretty much randomly.  It's in C-class stock, and looks to be a bit of a pig at about 3900 lbs.  However, it's got a Mercedes powerplant, and I've heard such good things about German engineering that I decided to give it a shot.  It smoked my A850 ALS-spec Cobra Mustang on Suzuka at 771 PI, on DOT tires (up one width), 2800 lbs (full race weight).  The A850 was 3000 lbs almost exactly, running 432 hp IIRC (it's close if that's wrong), and was on full-width racing slicks.  Even the first lap beat the mustang ghost, despite the 'stang's considerable head start.  Obviously, there are two possibilities here.  One is that if they had a scoreboard for 775 PI cars (or somewhere in that ballpark), this would be one of the scoreboard cars.  It's possible that this is just the car's "sweet spot," and in much the way that you don't see many Golf MKII's in C or B-class races, but they're dominant in D, this is where this car really performs best.  But it's also possible that I've stumbled on a good all-around A-class car.  Right now, my A-class garage is basically a Shelby Series 1, A TVR Tuscan S, and the Cobra, which doesn't perform too well online, in all honesty.  The Shelby is a strong performer, and the Tuscan is controllable enough that its considerable power can be used to good effect on the longer courses.  However, it gets kind of boring going between just two cars when there are 300+ in the game.  I'll be building this to A850.  Build and tune are forthcoming.

[fndrbndr]

On the way over, I was thinking something through.  (I'm on campus right now trying to get my thesis uploaded for format review.  There will be alcohol tonight!)  I can either go up 80 points or go down 70 in taking the car to a "traditional" point.  Maybe I should be a bit more clear about why I'm going up instead of down.

1.  I'm good in B class.  I have the muscle-inc. cars when I run a power track, and it's rare that I run into people online who can consistently beat my 2000GT and the other Tiny Terrors in non-leaderboard cars.  If they can, it's because they're just better drivers.  I'm OK to losing to Serial, Snyder, etc. etc. etc., and more than willing to admit that it's mostly due to my own skill, not car choice.

2.  I've already mentioned the big ol' hole in my A-class repitoire.  I'm thinking this may help fill it.  It may even eclipse the standbys.  I've got a grip car and a speed car.  This, however, may be the flowing track car that I'm missing.

3.  This car is a porker.  I don't think I can keep the weight reduction and lose 71 pts.  I also don't think that adding 600 lbs back on (the next weight reduction package) will be competitive without a lot more hp and more tire.  I'd probably just end up with a heavier, more awkward car, and still end up back in A when it's all said and done.

4.  Bimmer and SPhilli seem to have a bit of an A-class rivalry going.  Frankly, Bimmer doesn't get to run "Heidi" very often with the Muscle, Inc. crew, and he's proud of the car.  I'd like to compete with those, and since this is a Benz, this kind of completes the "big three" of German cars, IMO. 

[fndrbndr]

OK, so the AMG didn't have a great night online.  Bimmer suggested more tire, more weight, and more hp.  I'll try that. 

Edit/Update:  I'm running about 2600 lbs on this car, and I think that may be hurting it. Bimmer's suggestion, put a little more clearly, is not to fear running heavy in a Mercedes.  Just make sure you've got the necessary torque and go with it.  I'll be trying that.  Sorry I still haven't posted a build, but this car is a bit tricky for some reason.  I don't know whether it's just that I'm trying something so far out of my comfort zone or whether the car is actually that difficult to put in respectable trim.  I think I'm going with torque upgrades and dropping a weight reduction level, which I think will put me about 3100 lbs.  That's very heavy, compared to what I usually drive, but should be manageable.

[Mike350h]

Yes, Heidi is very fast and does well on all tracks it seems.  Shpilli and I always rail Bimmer for taking her out because we don't have any thing to really compete with her......yet.  I've always wanted to build out a Merc. but my brother tried it and didn't have too much success.  I'm looking forward to the outcome of this build.  Good luck fndrbndr.

[fndrbndr]

Thanks.  I'm honestly starting to get a bit frustrated with it.  It showed so much promise in the PI project that I figured I had found a very strong car.  Even when I won races with it, it was down to consistency, not speed.  I won a race at Suzuka with the worst laptime by a full second.  It's just that all of my laps were within a few tenths of that time, and I didn't run off the track.  I've been working on thesis revisions, so I haven't given this a lot of time, but I think it will get faster as it gets more Heidi-like, adding some weight and horsepower.  I may also downgrade the tires a bit to make room. 

[bimmerlovere39]

I think it will get faster as it gets more Heidi-like, adding some weight and horsepower.

In the intrest of full disclosure, Heidi is running slicks and ~2500lbs...

I'll look back over my CLK55 today.  The post is in JEi.  I'm not running aero, and that may be on of the big differences.

[fndrbndr]

OK, I tried more weight and more hp.  The car stayed planted a little better, but wasn't really much faster.  I could hang with my ghost, but couldn't beat it, and felt that if I did, I just drove a better lap, and didn't have a better car.  I'm thinking I'm back to 2900 lbs (I'm 3600 at sport WR) and use aero to get some downforce where I need it.  Thanks for the insight in Heidi, btw.  It's helpful.

[fndrbndr]

I'm still not thrilled with this tune, but I guess I should go ahead and post something meaningful in here:

Power:  Race intake, exhaust, intercooler (just for the rarity bonus) and engine block; sport fuel system.
Platform:  All race, including weight reduction.
Tires: Goodyear 235/265 (max width) slicks, +1 diameter, Brabus Monoblock IV Multi rims
Full Forza aero package.

430 hp
455 lb-ft torque
2901 lbs

Tires 29/28
Gears FD 3.70, gears (2.89, 1.99, 1.51, 1.20, 1.00, .80)  (I think the only one I changed was sixth.  I like the others where they are, but needed a longer sixth gear for straights)
Camber -.7, -.7
Toe +.1, -.1
Caster 5.5
ARB 15.44/18.42
Springs 554.3/463.0
Ride height default
Damping 8.9/7.5
Bump 4.5/3.8
Aero 85/110 (needed to keep the rear planted)
Brakes 47% front bias, 90% pressure
Differential Accel 35%, Decel 25%

This car isn't perfect.  Frankly, I'm beginning to wonder whether it's even very good.  I'm running in the low 2:08's with it on Suzuka, which isn't exactly stellar.  I set a low time of 2:07.9xx, but I think that was driver-related.  Any suggestions?

[bimmerlovere39]

Any specific issues you need to solve?

From looking at the tune I'd probably have done the following different:

• Wheels: I'd keep the stock size wheels and run a lighter wheel type - they Brabus wheels look good, but they are seriously heavy.  Lighter wheels could help the car feel lighter.  A tire with a higher response rating might help, too.  I recommend Hoosiers.
• Toe: Try running 0.0 toe front - I find it can increase front end grip mid-corner.  To get the extra turn-in, soften the front ARB (try an 11/13.8 setup, maybe - if you keep current springs).
• Shocks: Hm... try going to 9.9 front, 10.0 rear rebound, and 7.0 front 6.9 rear bump.
• Springs: I'd probably run slightly stiffer, more even front and rear springs, maybe 600/550, accompanied with 11.5/12 ARBs
• Diff: Maybe a 40/40 unit?

Those are all purely from looking at numbers.  Let me know if they work.

[fndrbndr]

Running smaller rims means running heavier ones, unless you mean losing the width, which I can try.  Also, the Goodyears have more response than the hoosiers, if the tire ratings are to be believed.  I think you're probably onto something, though.  I'll give it a shot.

[fndrbndr]

2:07.056.  Same ballpark.

Edit:  I dropped the rim width and rim diameter, stayed with my goodyears, and added 8hp and lighter rims.  2:06.466.  Thanks for the tip; I hope I executed it correctly.

[fndrbndr]

I looked at the scoreboards and noticed this time put me at 54% on my friends list.  I can live with being middle of the pack, but it was going to take over a full second to catch Heidi on this track.  While that's not the explicit goal, I would like to be able to pull something German out when Bimmer, Philli, et al get into it.  Anyway, I ran one of my stronger cars, a Shelby Series 1, to get a comparison, and in 8 laps, ran a PB of 2:06.254.  The Shelby is just WAY stronger on the flowing section, so much so that its relative weakness in the straights isn't a huge issue.  Maybe this should have been a power car instead of a flowing build?  I don't think it can catch my TVR, though...

[Ske]

Running smaller rims means running heavier ones, unless you mean losing the width, which I can try.

Not if you lose some power. I don't really think it'd help this car that much, but it certainly won't make it worse in my opinion. Both the C32 and this one seem pretty slow for their PI, the C32 was a full 2 seconds behind everything else when testing for the new touring car series I'm joining (A-class).

[fndrbndr]

Yeah, I think I'm putting this one on the back burner.  It's decent, and it's consistent, and there's definitely something to be said for that.  However, it's hardly a class-beater, and it's definitely not a hotlapper.  Thanks for the help, and I'll still probably pull this out online, especially in the public rooms, where its consistency and size (read: unwreckableness) will be an asset.

[bimmerlovere39]

Unreckability FTW!