AMGod

No sweat. Here you go.

C55 vs. C32

AaronC

I dunno dude. All I know is I have friends that have driven my car, and have test driven the C55. They said the same thing I did. One even said that the C55 felt "mushy" to him.

AaronC

Eric beat you to the punch. Check my response.

AMGod

On a short track like Hock, 2 seconds is a lifetime. Equally, 15 seconds at the Ring is a lifetime in the race world. I agree it is the sum of all parts; however, the C55's available increased power under the curve is the main factor, IMHO. Wonder what a pullied/chipped C32 would do?

AaronC

FWIW:

http://www.edmunds.com/insideline/do...ticleId=103424

AaronC

Also:

http://www.autoweek.com/article.cms?articleId=101130

AMGod

I think you're on target with the tire analysis. Looking into the lower data in the link the 55 does to better in lateral G's at a lower speed and better in slalom and evasive. I may have to dip into the euro version 55's suspension part bin just to make me feel better.

Vomit

The issue is not whether the wheels are 17" 18" or 19"

The issue is sidewall height/stiffness. To achieve the same tire height, a 17" tire will have taller sidewalls than the same height of tire on a 18" wheel or a 19" wheel, which is great for comfort and bad for handling. If you deny the truth of this assertion, try to picture a 30" tall tire on a 5" rim. The tire would have 17 1/2" of sidewall. Your car would ride like it was on a cloud, but I would not recommend turning the steering wheel very fast! Now take the same 30" tall tire and put it on a 20" rim. The tire would now have 5" of sidewall. Your car will ride much harsher (because of less "padding" between the wheel and the road), but will corner much better (because of less sidewall flex).

To say that it makes no handling difference whether a car uses a smaller or larger wheel is absurd. I invite anyone (Erik?) who believes this to slap a nice set of 13" wheels on his car, with stock-height tires, and we will take a run around a track.

AMGod

I think it has more to optimizing the slip angle rather than just looking at sidewall height. 7% slip is suppossed to be optimal. If you look at the sidewall height on F1 cars, then you will see my point.

Erik

You do not honestly think that was my point do you....?

Vomit

My point was that, all other things being equal, a tire of a certain height with a shorter sidewall will corner better than a tire of the same height with a taller sidewall.

Perhaps I should have added, as someone previously mentioned, that this principle applies more to street tires (which tend to have relatively weak sidewalls) than it does to full-blown race tires (which have sidewalls built like brick ****houses).

Remember: the question is whether the taller sidewalls on the C32 than on the C55 help to explain the track difference, not whether it is possible to build a tire with a tall, low-flex sidewall (such as on Formula One cars).

I am sure that, given enough money, you could build my hypothetical 30" tire on a 5" rim which would outperform the 30" street production tire on the 20" rim, but this is not really the point, is it?

Vomit

"I have seen several comparisson of 17-18 and 19" , we are NOT talking about any huge difference here."

Did I miss something?

Erik

Aaron

Most you what you write is OK, I do belive we see this the same way.

Regarding the Pirelli, my guess is they use Asimetrico.

You claim that those Rosso tires are not even close is very supprising.
In every singel, and I mean every test made in Europe, among top of the line street tires for Sportscar or fast saloons, the Pirelli ends up on top.

A friend of mine put on a set of Falken on his E46 M3, the tires was nice on the streets, but totaly useless on the track. He had to change into Rosso and are very happy with them. Huge difference.

But both you and I know that street tires are not made for track use. they have to much negative profil patterns, run a few laps and most of them are totaly useless. I personally drove a lot on Dunlop SP9000, a very good tire but totaly useless on tracks. 1 reasson was the very open pattern and very soft tire side.

I later used R to Dunlop Supersport Race and the difference was amazing.

Yes 2.8 sec on a 45 sec lap is a LOT, I agree.... I did not read all the numbers correct, so forgett my coment about beliveing it should have been more.

Personally I did lap my car with R tires app 2 sec faster with engine problems ( 80 Hp down on power) and no risc taking, than I did with a ***** to the wall driving with normal street tires. This was on a 70 sec track.


But back to the main topic, will the tire size going from 17 to 18 make up for the difference between this 2 cars.

I do not think so, but thats my opinion based on a "few" laps on a race track. I may be wrong.

And yes I know the CSL use R tires, so does several other sportscar to day.
Also the AMG DTM CLK (Dunlop Supersport Race ) used that when they tested it on the Ring and Hockenheim.
The Porsche GT3RS ( Zero Corsa), Modena Challenge,( Zero Corsa)

But to make full use of such tires the setup ( springs/shock and alignment) must be adapted to that kind of tire.

Erik

Yes you did, I did not talk about 13" tires.....

Erik

Vomit

O.K., maybe I exaggerated a little

Erik

Forgott 1 thing. That S4 has an V8 with 344 Hp..... It will destroy the C43....

reggid

you have neglected to consider that not all roads are flat and having stiffer sidewalls can be a downfall on bumpy surfaces!

AaronC

I did alot of research on Max Performance tires recently, and every source I could find said that the Rossos were no where near as good as the others. They are on par, handiling wise, with the old Pilot Sports. The PS2 is a far shot better then they were.

In the end comparing Max performance tires is kinda like talking about batteries.Which is better, Energizer or Duracell. Everyone has an opinion.

Zeppelin

I have to believe that AMG improved on the C55 suspension over the C32. The C32 has pathetic understeer in stock form. I have never driven a C55, but it would have to be faster than a C32 on a road course. 18" vs. 17" tire debate would account for very little difference.

You don't believe the suspension could make the difference consider this. My C32 which has been through 2 years of suspension tweaking is faster than a C32 on 18" R compound tires with KW Coilovers and Stoptech brakes driven by an instructor. This is on a high speed road course.

My car has stock brakes, stock 17" wheels and street tires, stock shocks with H&R springs, custom swaybars, custom camber correction. Driven by me with only 6 track days under my belt. Cost of these mods $350. My car is 10 seconds a lap quicker now than when stock on a 1:38 second a lap track.

FrankW

i think tire compound makes a difference and the camber correction would make the car corner a lot better than someone relying on coilovers.

that said, the C55 has approx the same weight over its front suspension vs the C32 which the supercharger makes the engine top heavy and the stock spring setup really sucks and makes the car understeer a whole lot. I don't track my car, but I've taken the car to the canyon before and after I put in the RENNtech springs. It made the world of difference in the way the car handles and how you can push it a little harder because the front end pushes less taking a fast turn.

Erik

The 360 CS, ( Challenge Stradale) does have R-tires, the 430 has normal street tires.
Thats and Aplle and Orange comparisson.

Erik

The correct suspension will do a lot, IF the driver is good enough to take advantage of it. IMO very few people are.

About you drive faster than the instructor in a C32 with R tires and lots of suspension mods, I say you are a very talented driver.

With only 6 track days, you have probably picked up a lot during those days, so my guess is that the 10 sec improved time is mostly due to you better driving.

Not saying your suspension mods is unimportant....

Well done.

AaronC

The C55 is more noseheavy then C32, 55%F/45%R vs. 54%F/46%R, despite the engine itself being lighter. The reason for this is becasue the V8 in the C55 had to be mounted partially forward of the front track. Certain mags have commented on how the C32 handled more neutrally becasue of this.

green_IZ

Depending on the conditions, a C32AMG can be tested faster than a C55AMG and vice-versa! I have a C32AMG with the same rim (18")and tire style that is stock on a C55AMG and I have raced my buddy's C55AMG and have won by only a marginally leap ahead. " You Win Some & You Lose Some, But You Live To Fight Another Day"! As an example, in this article, the C32AMG tested faster than the C55AMG!

THIS IS AN EXCERP FROM EDMUND'S WEBPAGE:
For the past three years, the ultimate C-Class has been the C32 AMG. With the engine bay stuffed with 349 horses' worth of supercharged V6, this compact sedan offered performance that bordered on the obscene. Let us quantify that statement; as we discovered in our test of the C32, the baby Benz could slingshot from zero to 60 mph in just 5.4 seconds and blast down the quarter-mile in 13.8 seconds. And this was under poor traction conditions. In other words, this innocuous compact sedan could lay waste to practically anything else on the road. And it wasn't just impressive in a straight line, either, as the AMG-massaged suspension and brakes endowed the C32 with the moves to match its track star performance.

So if it was so great, why is the 2005 version called the C55? As many of you enthusiast types have probably guessed, the numbers indicate a new engine. In place of the force-fed 3.2-liter V6 is an AMG-built 5.4-liter V8 (why it's not called the "C54" escapes us, though we do like the look of the double fives better). Kinda runs contrary to the "If it ain't broke, don't fix it" philosophy.

We're willing to bet the reason for the change is that Mercedes doesn't want to be bested by countryman Audi, whose top-dog A4 sedan, the S4, now packs a V8 beneath its hood. We can almost hear the conversation in the Mercedes-Benz boardroom: "Vell, if Audi offers a V8 in its little A4, how do you zink it vill make us look if ve don't have vun in zee AMG version of zee C-Class?" Or, maybe they spoke in German (wink, wink). Anyhow, since Mercedes already had a nice AMG V8 in its parts bins, company execs evidently figured "might as well put it in the C-Class."

Of course, we're sure that this transplant wasn't exactly a drop-in proposition — we're talking 5.4 liters here (the S4's V8 is "only" 4.2 liters). You'll have to look hard, however, to be able to distinguish the C55 from the C32. The grille and headlights are slightly different (less horizontal bars on the grille and a switch to clear-lens headlights) and the rear end now has a discreet trunk lid spoiler and quad exhaust tips (as opposed to the previous dual outlets on the left side). With its low nose and raised rear, the C55 looks as if it's crouching and ready to spring forth at any moment. Trust us; in this case looks are not deceiving.

Changes to the cabin are equally subtle, yet worthwhile. A sportier, three-spoke wheel replaces last year's dowdy four-spoker, the instruments are larger, there's flashier metallic trim, and the updated center stack now houses a Harman Kardon audio system (versus last year's Bose unit). Lastly, the optional navigation system is now DVD-based (meaning it uses a single DVD for U.S. mapping as opposed to the multiple CDs that the previous unit required).

Upon firing up the C55, we noticed one thing about the engine switch that gladdened us — the low, full-throated rumble of the V8. And looking at the cold stats, the V8 packs even more of a wallop than the supercharged V6, belting out 362 horsepower (versus 349) and 376 pound-feet of torque (versus 332). As before, the powerhouse is hooked up to an AMG-tweaked five-speed automatic transmission, with manual-shift capability and two modes (comfort and sport) for automatic operation. This year, however, drivers can (in addition to moving the gearshift lever side to side) change gears via a pair of buttons mounted behind the upper steering wheel spokes — flick the left one to downshift and the right one to upshift.

At the track, the C55 turned in slightly slower times than the C32 we tested a couple years ago. The raw numbers came in at 5.6 seconds for the 0-60 dash and 13.95 for the quarter. Still quick, but one would rightfully expect that the V8 would be a few tenths quicker, not slower. As we have stated before, there are many variables that come into play when testing a car for acceleration — the track surface, weather conditions (cool air is better than warm) and driver differences.Putting all that power to the ground is tricky, as it's so easy (with the traction control switched off) to make the rear Pirellis go up in smoke. If we chose to take say, eight runs, we're sure that the times would have come down, but we feel that three runs are easier on the car and better represent "real world" numbers. But let's not split hairs; this is one fast car any way you look at it.

Speaking of the real world, during our week with the car we thoroughly enjoyed the C55's performance. Although it can be fun to change gears yourself, we found that with the tranny in the sport mode it does a fine job on its own. Downshifts come ultraquick and changes up, even under full throttle, are virtually imperceptible. With so much power readily available, the C55 seems to pull as strongly from 50 to 80 mph as it does from 20 to 50. Plant your foot down at 75 and the jetlike rush of acceleration is thrilling (and dangerous to your license). As before, the top speed is electronically limited to 155 mph. Of course, here in Los Angeles, we're overjoyed if we get up to 50 mph on the various "freeways." Fully up to the task of reining in the C55 are a massive set of easily modulated disc brakes that require only 118 feet to haul this Benz down from 60 mph.

Once the C55 was done burning up the track, it was free for the weekend. We took the car on a 200-mile round-trip up the coast, running from Los Angeles to Carpinteria, a small, charming seaside town that seems worlds away from the overpopulated and stressful environs of Greater L.A. During this little road trip, we discovered that, as expected, the C55 is a blast on a twisty road, thanks to its rock-solid chassis and quick, well-weighted steering. Slicing through the canyons, the Benz felt hunkered down, finely balanced and eager to eat up the road. The Pirellis stuck to the asphalt like gum to Reeboks and apart from a slight dead spot on center, the steering's turn-in response was crisp and linear.

What we didn't expect from the C55 was such a hospitable ride on the superslab. Although the suspension is definitely on the firm side, it did a fine job of absorbing the jolts of broken pavement and expansion joints. A lack of wind and tire noise, coupled with the C55's appetite for high-speed cruising, made the miles melt away and had us wishing we had taken a longer journey. Obviously, the seats had to be comfortable for us to feel that way, and they were with their firm but perfectly contoured design that kept lower back pain (this writer's/runner's Achilles' heel) at bay. We also found the navigation system easy to use (we figured it out without having to look at the manual) but wondered why the climate control had 12 fan speeds when six would do just fine.

The real question here isn't how many fan speeds are enough, but how many cylinders. We had no complaints with the C32 and its muscular supercharged six — it was more than fast and refined enough, even for our picky staff. So is the V8 better? In terms of the soundtrack it provides to this AMG performance, yes, but otherwise we'd call it a draw. We know the real reason why Mercedes replaced it, but we're not complaining.