Originally Posted by Improviz

..........and dramatically improves acceleration, or compare the acceleration times for the five speed S500 with the seven speed S500. The car picked up nearly a half second in 0-60 and 1/4 mile times compared to the five speed.

Originally Posted by Improviz

Never said it was; I was simply arguing Gustav's point that mass doesn't matter at higher speeds. Clearly, it does, particularly with two cars whose Cds are relatively close...my point was that the M5 doesn't have an aerodynamic advantage over the E55 which would allow one to dismiss mass, and that in fact the reverse was true.


If your car's gearing is set up to take advantage of the car's horsepower, you mean...but in this case the M5 enjoys its one clear advantage: two more gears.

Read the new Car & Driver for a discussion about how in the new SLK55, which weighs more than the previous one and has only six more rated horsepower, still managed to pull over 1/2 second faster in the 1/4, and was significantly faster in all 0-xxx times. Why? The magazine concluded the extra two gears did it, along with the extra torque.

No mystery here...like all BMWs, the M5 is geared far more agressively than Mercedes products. And having two extra gears allows the engine to be kept in the peak power zone more efficiently, as there is not as big of a drop off in gear ratios in the upper reaches. Once the E55 et al shift to a seven speed, this advantage will be negated.



Yes, but the M5 has way more gearing. If the E55 had the same gear & final drive ratios as the M5, we wouldn't even be having this discussion.



Except that the torque multiplication due to the gearing is less. Look at the following for each car, from fastsaloons.com. It gives the gear ratio, and mph/1000 rpm, for each car, although for some reason, it omits seventh gear for the M:

BMW 5 series M5 (E60 (05-)) 3.99/5.5 mph 2.65/8.3 mph 1.81/12.2 mph 1.39/15.9 mph 1.16/19.1 mph 1.00/22.1 mph

Mercedes E class E55 AMG (211 (02 - )) 3.59/7.9 mph 2.19/13.0 mph 1.41/20.1 mph 1.00/28.4 mph 0.83/34.2 mph

I used 8,000 redline for M5, and 6,500 for E55. Please correct me if I'm wrong, don't have either one in front of me and am going from memory, but they're close.

M5:
mph/1000 5.5 8.3 12.2 15.9 19.1 22.1
max spd 44.0 66.4 97.6 127.2 152.8 176.8

E55:
mph/1000 7.9 13.0 20.1 28.4 34.2
max spd 51.4 84.5 130.7 184.6 222.3


So, look at what happens: first is close, second is a bit further, but third and up is quite dramatic. Ratio-wise (M5/E55, giving a percentage of torque multiplication per gear), we have:

1st: 0.69
2nd: 0.64
3rd: 0.61
4th: 0.56 <-- looky here!
5th: 0.56

So, The discrepency in gearing does grow larger at higher speeds.

Interestingly enough, dividing the M5's max torque of 370 (memory again) by E55's max torque of (memory again) 550 lb-ft gives 67%. So, as long as the gearing is such that the E55's gearing has 67%, acceleration should be pretty equal. Once this drops off, surprise surprise surprise, physics still works, and the M5 will start to enjoy a torque multiplication advantage. This doesn't become pronounced until fourth gear, which does gel with what we see on the video.

But guess what: look at the spacings on the seven speed Benz auto and see how they compare. Advantage = gone. Enjoy it while it lasts.



Sample size = 1. Per your earlier post, it is not scientifically valid to make an absolute claim based upon one data point, particularly when there are other variables (E55 starting in second rather than first if in auto mode, E55 driver not shifting properly if in manual mode, poor gasoline, etc.) which could have affected the outcome.

But yes, based upon its gearing, the M has an advantage in torque multiplication at all speeds, but particularly above 100 where percentage tips to one greater than engine torque discrepancy can cover. But it also has a disadvantage aerodynamically. I do suspect that at triple digit speeds above 130, it will enjoy an advantage, but would be surprised if actual test results show a large gap.

Finally, the tested 0-125 times for these cars are only 0.8 apart. Per my earlier posts, I have not seen one instance, even in comparisons of cars faster than these, wherein a car with an 0.8 advantage in 0-125 was more than 0.1 or 0.2 faster in the 1/4 mile, and in many cases not even that. But again, we will see when tests come out....which hopefully won't be long, but BMW seems in no hurry to release the M stateside.

The reason the thread will not die is because certain people insist in seeing this test not as an unscientific test run with unknown conditions inside the E55 (and M5), but as The Absolute Final Last Word on the subject. It is not, and I and many others will be awaiting instrumented test results on time to distance testing, as the time to speed testing posted so far simply does not point to a huge time-distance advantage for the M.

We shall see. Like you, I am an Engineer, and I prefer objective instrumented data generated under controlled conditions. If the M comes out faster under such conditions, fine, but for the aforementioned reasons I am unwilling to make a sweeping general statement for all data points based upon a sample size of one.

Obviously, the M's time-speed data are irrefutable at high speeds, but I'm doubting that the time-distance will be significant, and am betting that 1/4 mile speeds will be a tenth or two apart max, if that.

We shall see...

Originally Posted by Improviz

Wrong as usual. The Mercedes 5.5L kompressor motor has peak horsepower at 6100 rpm, 400 short of redline. The M5 makes peak horsepower at 7750 rpm, 450 rpm short of redline.

Originally Posted by Car & Driver

Let us introduce a previously unused AMG performance trick: Mercedes' seven-speed automatic. The German automaker introduced that transmission for 2004, but until now the most powerful engine it was bolted to was the company's 302-hp, 5.0-liter V-8, so all AMG models had to rely on the five-speed automatic. So what are a couple more gear ratios going to do? Let us explain.

The previous-generation car, the SLK32 AMG, had a supercharged and intercooled 3.2-liter V-6 putting down 349 horsepower and 322 pound-feet of torque. The last one we tested weighed 3265 pounds, scampered to 60 mph in 4.5 seconds, and crossed the quarter-mile in 13.0 seconds at 110 mph. Now, the SLK55's 24-valve, 5.4-liter naturally aspirated V-8 cranks out just six more horsepower--but an additional 54 pound-feet of torque. Still, the new car's weight is up 190 pounds to 3455, so the power-to-weight ratio has worsened slightly.

Despite this fact, the SLK55 outaccelerates its predecessor, ripping to 60 mph in 4.3 seconds and clearing the quarter in the 12s--precisely, 12.7 seconds at 111 mph--largely because of improved gearing, not just power. Still not impressed? How about this: the 400-hp Corvette in a recent comparo outguns this SLK55 by 45 horsepower and 24 pound-feet of torque, and weighs 155 fewer pounds. Yet the Vette ties the SLK at 4.3 seconds to 60 mph and loses the quarter-mile race by a 10th, 12.8 versus 12.7 seconds. And that was a six speed manual Corvette. Or consider this: the SLK55 matches its big brother E55 to 60 mph--despite the E55's 469 supercharged horsepower propelling fewer pounds per pony--and is just 0.2 slower through the quarter mile....

...With the closely spaced cogs, the engine is always kept in a sweet spot between 5000 rpm and the 6700-rpm redline; thus, acceleration is never peaky, just strong and nearly constant, with upshifts executed nearly manual-tranny quick.

Originally Posted by Car & Driver

At 4048 pounds, our CLS500 was burdened with 79 extra pounds compared with the E500 we tested in '02. Yet armed with Mercedes' new-for-2004 seven-speed automatic, it proved to be substantially quicker, ripping from 0 to 60 in 5.5 seconds, 0.3 sooner than the five-speed E. (But a current E-class with the seven-speed would most likely match the CLS's numbers.) THe CLS500's quarter-mile time comes in at 14 seconds flat at 100 mph, putting it ahead of the E500 (14.3 at 99), and just behind the 325-hp 645Ci (13.9 at 102).

Originally Posted by Improviz

But hey, what do those professionals know compared to a paid BMW brand spokesman like Monkey&Moron?


Unfortunately, it won't work. Gear numbers tell the tale.

Originally Posted by MikeHK

And are you the paid MB brand spokesman. Hmmm.....