wolverine

Engine torque alone does not tell you anything about acceleration. High engine torque at low rpm doesn't result in quick acceleration. Diesel engines make boatloads of torque, but they're not very quick.

Engine horsepower determines acceleration. That's because HP is torque multiplied by engine rpm. At high engine rpm, the gearing can more effectively be used to multiply the engine torque to the wheels. Torque to the wheels over the range of engine rpm is what ultimately determines acceleration. Torque to the wheels is a function of the engine torque, the engine rpm, and the gearing.

I suspect the E63 will be very close to the M5, depending on the weight and the gearing. If it's about the same weight, and has about the same gearing, it will be a match in straight line performance.

clkcadet

whoa 5200rpm to reach the torque peak...i dont know if thats a wise move since most benz engines offer peak torque at about 2700 rpm etc

BoBcanada

Another thing is , i bet for CLK SLK this engine is gonna be very detuned.... what you think?

Evolution Marine

Sorry for the long post but I am addicted to thechnology and can't help myself.

wolverine - Your example using Diesel Engines is correct, but for another reason. Diesel motors are used in commercial purposes and are about 70% heavier than gas motors, so it would be very unusual to have a diesel motor being used in a lightweight, sporty platform to maximize the Diesel's acceleration thus the resultant popular conception that Diesels are not quick.

As for Torque not being the major ingredient of the energy contributing to acceleration, this is just not correct. Torque is the energy that produces the RPMs that, together, are used to calculate the HP. Torque by definition is the measurement of the twisting energy, at the crankshaft, of the motor and HP is a calculation and basically defines the ability of a motor to maintain its energy output. True, Torque can never exist alone, however it is what HP is calculated from along with the RPM and I think IT GOES WITHOUT SAYING, where there is Torque there is always RPM and the resultant calculated HP. So if "Engine HP determines Acceleration" and Engine HP is calculated from Torque you tell me what is the base energy is that's producing the acceleration. It all starts with Torque then RPMs and then we calculate HP.

I think we are in basic agreement about the relationship between Torque, RPM and the calculated HP. A good example of Torque Multiplication would be the M5 motor at a low 385 lb. ft. of torque and an high 8,300 RPM Rev. Limit. BMW has multiplied the torque with a seven-speed trans. (more Lower Gears) and is able to take advantage of this because of the high RPM design of their V10 motor. Multiplying the torque, with lower gearing, BMW has over come the low torque of their motor and produced acceptable acceleration. With out this Torque multiplication the BMW V10 motor would not be the acceleration performer that is today.

I am sure you are aware of how many times you and I have had to mention Torque when we attempt to describe what produces acceleration, so please do not miss-interpret what I have said about Torque and it's importance in producing acceleration.

On to weight and Gearing. The new M5 weight is about 3,900 lbs. and the new 6.3 motor will be lighter than the current FI 55 motor, by how much, I do not know. However, lets say the new E, with the 6.3 motor in it, weighs 4050 lbs.. The 150 lb. weight advantage that the M5 has over the E63 will melt away with the 20% torque advantage the E63 has. As far as gearing goes AMG will have plenty of opportunity, with 7 gears, to optimize the gearing. So having said all this I still say watch out BMW the E63 is coming. Got to love it when the automotive giants get into a performance dual and don,t forget the old saying "There is no replacement for displacement". - Bob

wolverine

I agree it's a great time to be an automotive enthusiast. I really can't remember when we've had it so good!

As for the torque creating the horsepower, you are basically correct: it's the twisting force that the engine produces at the crankshaft, multiplied by the speed at which the crankshaft rotates that determines horsepower. So, without torque, there is no horsepower. But there can be torque without any horsepower (there is a twisting force, but no rotation).

Without getting into the details too much, horsepower generated at the crankshaft can only decrease by the time it gets to the rear wheels. A typical automatic transmission car loses about 20% of the engine horsepower on the way to the wheels. Quattro systems can lose 25% or more. A good manual system will limit the losses to about 15%.

Torque at the crankshaft is actually increased on it's way to the rear wheels. The amount the torque is increased depends on the final drive ratio of the particular gear the car is in. For the lower gears, the torque is multiplied by a higher number than in the higher gears. This is one of the reasons that cars accelerate more quickly at lower speeds.

So, a 20% advantage in torque at the engine crankshaft may not be a 20% advantage at the rear wheels. A car's acceleration depends on the torque it puts to the drive wheels, not the torque it makes at the crankshaft.

M&M

I wouldn't want to post scannes articles that have been posted many times , but if you do a search you will find it. The M5 is significantly faster than the E55 on the rolling runs in gear. In fact, the M5 one gear highly is still faster than the E55 in the rolling runs SPort Auto did (80-200 km/h).

I know its not fair to compare a 5 speed to a 7 speed, but it's also not fair to compare a 5.5 L supercharged engine to a 5.0 NA one. But such is life.

Point is torque to the wheels is all important & horsepower is THE RATE AT WHICH THE TORQUE IS APPLIED. Torque doesn't do anything if it isn't applied on an object over a certain period of time. That, my dear friends, is horsepower.

vraa

Actually it is fair to compare the engines because the NA one did come out later.

Evolution Marine

M&M - could not have said it better than that myself.

wolverine - To date AMG has not disappointed us, and I would be shocked if they were not able to get at least 15% of that 20% increase in Torque back to the rear wheels, which I feel is still enough to push the E63 past the M5. If you play with some numbers it comes out that the net increase in torque at the rear wheels will be about 48 to 50 lb. ft. for the E63 over the M5, and that is using 20% loss for the E63 and 16% loss for the M5. Personally I think 20% is to high, but the difference in torque is still substantial enough to give the E63 the performance advantage over the M5. - - Bob

Bilal

I much prefer my own definition that horsepower is an indication of the engine's ability to sustain/produce torque at higher engine speeds.

The all important factor now is, the gearing and final ratios of the transmission that will handle this engine. Nevertheless, there are a multitude of factors which contribute/affect straight line performance.



EDIT: What does this mean....(AMS article translation using babelfish)

"At present the new engine in a reequipped test platform on basis of the CLK DTM receives its final touch. There it carries even 580 HP out because of another exhaust system."

http://babelfish.altavista.com/babel...de%2fd%2f86810

wolverine

Here is another way to think about torque and gearing.

Suppose we have two cars running at 100 mph. Suppose one car's engine is running at 3500 rpm, and another is running at 7,000 rpm. If both engines are putting out the same amount of torque at the crankshaft, the car whose engine is running at 7,000 rpm is capable of putting out TWICE the torque to the rear wheels at that speed. Therefore in a race, the 7,000 rpm car will win easily.

This is because if both cars are moving at the same speed, the gearing on the car running at 7,000 rpm must be double the one running at 3,500 rpm. That then means that the torque multiplication to the rear wheels doubles as well. Another way to think of it is the 3,500 rpm car would need to be producing TWICE the engine torque at that rpm just to stay even in acceleration. This is why you can lose a race to a 'slower' car if you don't downshift.

One of the reasons the F1 cars can accelerate so quickly with relatively low torque is that they rev to over 18,000 rpm, so they have a high multiplier for torque to the rear wheels.

mrankovic

Well that and the fact they only way about 1,300lb with the driver in them!

vraa

I'm a little confused on this part, wouldn't the car whose engine is at 3500rpm win though because it's still got the rest of it's rpm band to rev too?
If it creates the same amount of torque at 3500rpm that the CarB makes at 7000rpm..?

I do understand this in reality though, just as later on in your post it talked about downshifting.

Evolution Marine

wolverine - Nice example of Torque multiplication. I am sure AMG will have no problem optimizing the gearing in the E63 trans. and rear diff., and then it will be up to us to choose the best gear when the new M5 pulls up along side of us and looses the eventual contest that will take place.

Also read some where that AMG did a lot of the development work on this 6.3 L motor in a DTM chassis and the only difference from the road going version, was a better exhaust system, and the 6.3 motor was putting out 580 HP with this exhaust system, which is about 92 HP per Litre. 92 HP per litre is up there, but not as strung out as the BMW M5 motor at 100 HP per Litre. - Bob

Beowulf

from http://www.jesmb.de/indexie.htm: (translated)

"Mercedes AMG will present the new ML 63 AMG at the 61st annual International Motor Show (IAA) in September. It is the first model to be offered with the completely all-new AMG-V8-Sauger engine. This engine is designated M156 E 63 and has 6208cm³. It carries a rating of 510 HP and 630 Nm. The maximum number of revolutions is 7200 U/min. The bank angle is 90°. The 63er AMG engine will be offered in the ML as well the S-class, CL, R-class, SL, CLS, E-class, CLK and SLK. The M156 has 4 valves per cylinder. Its more powerful brother M157 has 6.0 litres and has a Bi-turbo as well as a 80° bank angle, so that the turbos can be well accommodated. It develops over 600 HP and approx. 800 Nm. It will debut in 2007.

Meanwhile the SLR (C199) will be offered in two new colors, metallic green and blue."

I'd be quite surprised if the 510 HP version of the 6.3 were offered in virtually every platform variant - an SLK63 vs. a SL63?????

Note that according to this source, the twin-turbo supposedly carries a different engine designation (M157 vs. M156), has less displacement (6.0 vs 6.2 liters) and has a 80° bank angle. It sounds like a completely different engine, not based on the 6.3 at all. That makes a lot of sense, since these engines go about making power in very different ways.

Interesting, but still there's still a lot of speculation at this point.

Jon200

if it is not fair, why mention it? I think you have forgotten to say that 5L NA is no ordinary NA, it is a F1-style NA

And you are still saying torque means nothing, geez, would you have said the same if the M5 had more torque than the E55? Get a grip my friend

M&M

Errr, no. 'Cos I studied Physics at college & preference for a certain brand will not change the fact that horsepower has a unit of time in it & torque doesn't.

ANd this Fq1 style engine, WTF. A 5.5l engine supercharged is effectively an 11 litre engine (assuming 1 bar boost).

Bilal

vraa

Right you are, but it's not like BMW didn't have a look at their competition when designing the M5 (and it's fantastic V10 engine).

However, you're entire argument is futile. No one here is comparing M5 versus anything. Much less anything versus anything, it's just speculation and education on basics of an engine.

Next time when you post in this forum on a thread like this...

Leave the first two paragraphs out, makes you look like a troll.

Jon200

Are crying about the AMG engine having a S/C and you ignore the fact that the M5's engine has a very similar setting to the F1 engine?

Jon200

He is

Jon200

630Nm of Torque

medici78

That looks very promising. However, I will probably just mod mine in the coming months once I adjust to life with my newborn child and keep it a couple of years. Then i'll just trade it in when the biturbo model comes out.

M&M

Yeah man, except F1 engines have 300hp/litre & rev to 19000rpm. What do you mean the setup is similar to F1. The only similarity is that the are both V10's. So I guess the Viper engine is also an F1 "style" engine?

Ricky, you are correct. However, those 1st 2 sentences were only to illustrate that out on the road the car with more torque might not necesarily be quicker on the rolling runs.

reggid

you better post that scan of the e55 vs m5 i haven't seen a proper one yet

Jon200

Yup and I did say the M5 and an F1 car has simialr outputs didn't I? Do you agree or not that there is no F1 technology technology in the M5 engine?

The above paragraph was taken from www.bmw.com.au

back to the corner now?