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      02-07-2012, 10:59 AM   #23
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According to a Ford Engineer the 2013 GT500 has clocked a 0-60 in 3.7 and did the 1/4 mile in 11.7@121mph with traction control on. A good driver ala Evan Smith from Muscle Mustangs and Fast Fords will probably get into the mid 11's with this car @ 124mph, a set of D/Rs and you could be in the high 10s to very low 11 sec. range.

This car is going to be a beast....

Dave
That's not very good. 650HP and 11.7 @ 121 tells me that car get can't get off the line. I'm running 550HP (crank) and ran 11.6 @ 125 on OEM 19's
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      02-07-2012, 11:04 AM   #24
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It's still just a Mustang. I bet someone can find a way to make a civic or a lawnmower go that fast with a big enough engine
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      02-07-2012, 11:14 AM   #25
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Why is it that Ford and Chevy create these beasts of cars with almost more than a 200 HP and almost 300 more lbft than our M3's, yet their 0-60 times of 3.9 are just about on par with the DCT? I remember Road&Track getting a 3.9 once with the DCT and I have been successful hitting 4.0 several times.

Can someone explain this to me? We only generate 414 HP and 295 lbft so how are the times similar to those much more powerful cars?

I claim ignorance in this subject, I'm just looking for some techies to square me away. Thanks.
First, the M3 really is an over achiever in my opinion, and the M division's efforts at minimizing overall rotational inertia effects pay off in this type of comparison.

Second, those 2WD hypercars have fairly long gears (extremely long when compared with the M3), so they're not getting close to max power for a long time (relatively speaking) in this short run. The M3 hits max power in first, and starts getting close in second gear as it hits 60, so average power over that run is closer to max power than what the big guns get. They'll get a fair bit closer to 60 before they hit max power in first, and are barely into second (and way down the power scale in that gear) as they hit 60.

Third (and as has already been mentioned), traction limits have a way of equalizing times over such a short span.

Fourth, the M3 weighs less than either the Mustang or Camaro, so power-to-weight is somewhat closer than what the disparity in actual power suggests.

Last, an 0-60 time is not particularly meaningful out here on the actual planet. Time to speed is essentially unrelated with time to distance, so you have no way of knowing who's actually ahead at 60 based on an 0-60 time.

Bruce
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      02-07-2012, 04:54 PM   #26
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On the track, you can always have more power, but with more power comes more danger, more heat, more brake wear, more problems. It also requires more skill (than I have).
So, so true.

What makes the M3 unique is that its performance envelope is very accessible. You don't have to be a superhero to make it go fast on a racetrack but at the same time it still rewards good driving habits, so you have room to grow with it.

It keeps things interesting and exciting, without scaring the $hit out of you.


I'm hitting nearly 150mph on my local track in the basically stock M3 - I mean, how much faster do I want to go?
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      02-10-2012, 01:13 AM   #27
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Thanks for all of the information, Can somone explain "power band" to me?
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      02-10-2012, 01:58 AM   #28
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That's not very good. 650HP and 11.7 @ 121 tells me that car get can't get off the line. I'm running 550HP (crank) and ran 11.6 @ 125 on OEM 19's
I think the car will run better times than this. These were times that were run by a Ford engineer and a good driver can probably eek out low 11s. I do feel that we are getting to a point now that street cars with this kind of power are really going to have issues in getting the car to hook up with whats available with tire technology today. Also, the 2013 GT500 had to reduce the amount of torque multiplication through the gear box and final drive as there was no way a car that was having issues with traction with only 550hp would have hooked up with 650 hp.

I will say this though..these cars are going to tear from a roll though.

Congrats on your good times..
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      02-10-2012, 01:59 AM   #29
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So, so true.

What makes the M3 unique is that its performance envelope is very accessible. You don't have to be a superhero to make it go fast on a racetrack but at the same time it still rewards good driving habits, so you have room to grow with it.

It keeps things interesting and exciting, without scaring the $hit out of you.


I'm hitting nearly 150mph on my local track in the basically stock M3 - I mean, how much faster do I want to go?
200mph..
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      02-10-2012, 01:25 PM   #30
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First, the M3 really is an over achiever in my opinion, and the M division's efforts at minimizing overall rotational inertia effects pay off in this type of comparison.
Bruce
Mind giving more detail about what you mean by this? I assume you mean something about how the engine spins up quicker perhaps? Just curious about the explanation, and what has been engineered into the car for this.
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      02-11-2012, 12:34 PM   #31
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Mind giving more detail about what you mean by this? I assume you mean something about how the engine spins up quicker perhaps? Just curious about the explanation, and what has been engineered into the car for this.
There are at least two reasons why the four-liter V8 spins up so quickly. One is the multiple throttle bodies (often given all the credit for "throttle response"), and the other is low rotational inertia. In my opinion, part of the excellent "throttle response" is really a low overall rotational inertia issue, assisted by lightweight engine components, lightweight (or disconnected) accessory drives, reduced (by German standards) engine flywheel weight, and, since the transmission also has a bunch of rotational inertia in the lower gears, reduced weight of internal gear clusters, etc.

One reason the transmission can be engineered for lower rotational inertia is that the engine makes relatively low torque per cylinder (much lower than the 335is, for instance), and torque per cylinder is all the transmission needs to be designed to withstand. Overall torque is not an issue, since only one cylinder is firing at a time.

All this doesn't matter a bunch when you're running for red line in, say, fifth gear (because you're not picking up a lot of rpm per unit of time), but it matters a bunch in first and second - hence a positive effect on 0-60 times.

If you'd like to do a basic rotational inertia test your self, get an automotive G-meter (available from several vendors, sold to measure acceleration/deceleration figures such as 0-60, quarter-mile, etc.). Then on a nice warm day on a sun-warmed, high-traction surface, measure max acceleration (expressed as max G) in both first and second gear. You'll notice that the peak G number falls well short of what you'd expect in first gear, based on observed second-gear peak G numbers.

The best numbers I've ever gotten were on a stock (light flywheel) '85 Vette. That car had a first and second gear relationship of three to two, numerically speaking, so with a baseline max G of .5 (point five) in second gear, one would have an expectation of .75 (point seventy-five) in first, given good traction. Instead, what I got was .66 G max, or 88% of what I had expected.

That 12% shortfall was due almost entirely to rotational inertia. The engine, flywheel, clutch plate and disc, engine accessories and transmission input shaft, etc. all had to accelerate 50% more for each mph gained in first gear compared to second gear, and per Mr. Newton, they just don't like to do that.

I've tested at least a couple of dozen cars since then, and 12% was the smallest shortfall I've gotten. Most were in the lower 80s, percent/wise. My '95 M3 had a shortfall of 17.5%, as an example.

The big guns from Ford and Chevy will have a lot more rotational inertia than the M3, including a big chunk from the transmission, which has to be designed to absorb a bunch more torque per cylinder. Of course, first and second gears in those cars are a lot lower (numerically speaking) than the M3, so they will be able to absorb more torque per cylinder, everything else equal. Still, they have to be more massive than the bimmer box, which costs in terms of rotational inertia, along with massive pistons and rods, a more massive crankshaft, etc.

If you're interested in more detail on the topic, get a copy of Gillespie's book, "Fundamentals of Vehicle Dynamics". It's a worthwhile read, authored by an internationally famous engineering teacher, covering virtually all aspects of automotive performance dynamics.

Bruce

PS - If you do an M3 test, you're still likely to get a significant first-gear shortfall, because there is a large gap (around 40%) in gearing between first and second gears. Quite a bit bigger than the gaps in the Ford and Chevy. However, the test is only measuring the difference in rotational inertia between gears. Not the inertia values themselves.

PPS - Understand that I have no specific knowledge of the weight of various parts of the M3 engine and drive train. I just know that the M Group has worked very hard on reducing rotational inertia in this car, since even with its overall very aggressive gearing (thereby increasing rotational inertia) it still spins up like a maniac freezing ice cream.

Last edited by bruce.augenstein@comcast.; 02-11-2012 at 12:51 PM.
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      02-12-2012, 02:53 AM   #32
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There are at least two reasons why the four-liter V8 spins up so quickly...
Thanks for your insight! Can you describe the power band I hear mention of?
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      02-12-2012, 03:27 AM   #33
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They can't put the power down duhh. The M3 could crack a 3.9 or faster with drag radials, or on a prepped surface, new tires with a great launch...

2011 GT500 1/4 mile record. 11.16@124

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      02-12-2012, 07:01 AM   #34
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and your M is still just a 3 series

And that is a bad thing? The 3 series is probably the best all around sports sedan in the world.
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      02-12-2012, 11:18 AM   #35
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Thanks for your insight! Can you describe the power band I hear mention of?
There is no way to pinpoint what the "power band" actually is for all engines, but on any engine at all, one could say that the power band exists between peak torque and peak power. In that region, any engine seems most willing, eager, or even joyous.

It gets a little more complicated, however. On those engines with broad torque curves, the perceived power band will begin well before peak torque, and extend past peak power. The M3, for instance, starts to feel very happy at anything past 3000 rpm, and trust me, if you could rev it to 9000 rpm (in dead-stock form), it would rev very happily to that number. Of course, it would blow up fairly quickly.

The other bit of complication is with engines that make a lot of torque. The current Corvette Z06 powerplant makes max torque at 4800 rpm and max power at 6300, which seems to be a pretty narrow band. However, smacking the gas at 2000 rpm in this car will shorten your eyeballs up by a diopter or two, because the engine is already making a bunch of torque. It's also screaming for more at 7000 rpm.

Perhaps the best definition of the power band is "everywhere the engine makes the driver smile". Yeah, I know it ain't science, but it works.

Bruce

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      02-12-2012, 04:51 PM   #36
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3.9 is not gonna happen for an m3, more like 4.3....
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      02-12-2012, 05:34 PM   #37
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law of diminishing returns...maybe?? I dont know.......am not a techie, but, seems like you would need an exponential power increase (in a geometric progression of sorts) to shorten acceleration times and increase top speed as you keep going up on the power scale........what I mean to say is, i guess, the difference perceived from the increase in power depends on where your baseline is -- the power difference noticeable between 100hp to 180hp will be a lot more than what is noticeable between say 400hp to 480hp, although the delta is the same (80hp).........

thats the best way I can make myself understand...... the tech gurus on here will probably be able to explain it better......
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      02-12-2012, 05:39 PM   #38
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According to a Ford Engineer the 2013 GT500 has clocked a 0-60 in 3.7 and did the 1/4 mile in 11.7@121mph with traction control on. A good driver ala Evan Smith from Muscle Mustangs and Fast Fords will probably get into the mid 11's with this car @ 124mph, a set of D/Rs and you could be in the high 10s to very low 11 sec. range.

This car is going to be a beast....

Dave
dont know much about times, but i agree with your last comment, the mustang is just such a quintessential muscle car.....to me, even more so than the camaro and the challenger, although i like all three. plus, with around 630hp (albeit at the crank) from a blown V8 on the 2013 with a live rear axle just makes it sooooo........romantic.........
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      02-13-2012, 11:04 AM   #39
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law of diminishing returns...maybe?? I dont know.......am not a techie, but, seems like you would need an exponential power increase (in a geometric progression of sorts) to shorten acceleration times and increase top speed as you keep going up on the power scale........what I mean to say is, i guess, the difference perceived from the increase in power depends on where your baseline is -- the power difference noticeable between 100hp to 180hp will be a lot more than what is noticeable between say 400hp to 480hp, although the delta is the same (80hp).........

thats the best way I can make myself understand...... the tech gurus on here will probably be able to explain it better......
Acceleration varies as per the cube root of the power to weight delta.

In English, that means you need to add a lot of power to get a relatively small result. As an example, adding 30% more power nets a 9.2% improvement in acceleration. (1.092 X 1.092 X 1.092 = 1.30).

In other words, if your car was finishing a quarter mile in 14 seconds flat at 100 mph, adding 30% more power would theoretically net you a 12.82 @ 109.2 mph - reached by dividing the ET by 1.092 and multiplying the trap speed by 1.092.

Of course, in real life, adding 30% more power might very well have you going up in smoke, traction-wise, so the 12.82 is suspect. The trap speed prediction will probably be pretty close, though.

Bruce
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      02-14-2012, 10:46 PM   #40
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Acceleration varies as per the cube root of the power to weight delta.

In English, that means you need to add a lot of power to get a relatively small result. As an example, adding 30% more power nets a 9.2% improvement in acceleration. (1.092 X 1.092 X 1.092 = 1.30).

In other words, if your car was finishing a quarter mile in 14 seconds flat at 100 mph, adding 30% more power would theoretically net you a 12.82 @ 109.2 mph - reached by dividing the ET by 1.092 and multiplying the trap speed by 1.092.

Of course, in real life, adding 30% more power might very well have you going up in smoke, traction-wise, so the 12.82 is suspect. The trap speed prediction will probably be pretty close, though.

Bruce
cooll....thanks....thats a much better explanation.......and just for fun....considering that they actually give the 2013 GT the tires that have the traction to match the output, whats your guesstimate of the car's performance. I am just asking, I like it just the way it is now,,,,so even if its just going to be more wheelspin, I know that I am still going to like it even more. Dont really consider myself a number's guy.....but....... and a big but at that........upwards of affordable 600hp that you can get off the shelf from a dealer in a mass produced vehicle with warranty n all is just a milestone in automotive history if you ask me........
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      02-15-2012, 12:11 PM   #41
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cooll....thanks....thats a much better explanation.......and just for fun....considering that they actually give the 2013 GT the tires that have the traction to match the output, whats your guesstimate of the car's performance. I am just asking, I like it just the way it is now,,,,so even if its just going to be more wheelspin, I know that I am still going to like it even more. Dont really consider myself a number's guy.....but....... and a big but at that........upwards of affordable 600hp that you can get off the shelf from a dealer in a mass produced vehicle with warranty n all is just a milestone in automotive history if you ask me........
At a guess, the new GT500 will likely be turning trap speeds in the 125-126 mph range, given decent traction, but with traction control off. This estimate is based on an ancient (but tried and true) formula for estimating horsepower based on quarter mile trap speeds.

Take the trap speed, divide it by the constant 234, cube the result, and multiply that figure by car weight with driver. The result is a reasonable horsepower estimate. As an example, Car & Driver ran a ZL-1 Camaro to a trap speed of 119 mph, so assuming a 4300 pound curb weight with driver (4120 empty), we get:

119/234 = .508547, times .508547, times .508547 = .1315, times 4300 = 565 HP. Close enough to the rated 580.

Doing the same thing with the Mustang at 4100 pounds, trapping at 126 mph, one gets a result of 625 HP. Again, close enough.

ET? A goal for front-engine, rear-wheel-drive street cars on stock rubber is that ET times mph should equal about 1400 or so, or as close as you can get. This is easy with low-powered cars, but gets tougher as power goes up. Using this as a guideline, the new Mustang could likely be in the very low 11s in the quarter mile.

Doubt it, though. Consider the ZL-1 at 12.3 @ 119 mph. That product is about 1464, so assuming the Mustang could hook up as well as the Camaro, 126 mph gets you in the mid 11s.

With well-warmed slicks? High 10s, I think.

Bruce

PS - Its not as if the goal of ET times mph equaling 1400 is unobtainable in higher powered street cars, though. I have watched a stock ZR-1 Vette go 10.75 at 130 mph at a carefully sprayed drag strip on a perfect day, so it's possible. Of course, the Vette has better weight distribution, and extremely aggressive street meats on it right from the factory.
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      02-17-2012, 01:22 AM   #42
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There are at least two reasons why the four-liter V8 spins up so quickly. One is the multiple throttle bodies (often given all the credit for "throttle response"), and the other is low rotational inertia. In my opinion, part of the excellent "throttle response" is really a low overall rotational inertia issue, assisted by lightweight engine components, lightweight (or disconnected) accessory drives, reduced (by German standards) engine flywheel weight, and, since the transmission also has a bunch of rotational inertia in the lower gears, reduced weight of internal gear clusters, etc.

One reason the transmission can be engineered for lower rotational inertia is that the engine makes relatively low torque per cylinder (much lower than the 335is, for instance), and torque per cylinder is all the transmission needs to be designed to withstand. Overall torque is not an issue, since only one cylinder is firing at a time.
Overall I agree with you. I've read about the extreme efforts BMW M engineers went through to reduce both weight and rotational intertia through out the M3. However...

The Getrag designed M-DCT is rated for 443 ft lb and 9000 rpm. It was not specifically designed for the M3 but did have it's debut in that. Thus is was not specifically designed for the relatively low 295 ft lb torque in the M3 and certainly has a much greater capacity than the S65 generates.

Also I've never seen a transmission speced based on torque per cylinder. It is always dynamic torque or torque which is not measured per firing or per cylinder. It would be the same way an electric motors torque would be measured.

Also from way back you said:

Quote:
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we well know that German cars use flywheels that may as well have been liberated from old Panzer tanks, or U-boats.
Which is it in the M3, super light flywheel or tank like heavy? You can't have it both ways.

One key reason the M3 is an overachiever is because of its fairly low total drive train parasitic loss. The most accurate measurement of this is done by Rototest Research Institute (rri.se). They found only an 11% loss (less tire losses). This is not comparable to other loss specs that do often include tire losses.
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      02-17-2012, 01:41 AM   #43
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For all those saying the M3 cannot do a 3.9 s 0-60 please get your facts straight. Yes, this number is the best magazine number achieved and yes it is an outlier of sorts in that regard. However, it has indeed delivered the magic sub 4.0 s run, 3.9 s to be precise.

Evidence here from C&D.

Other reasons the car is sort of an overachiever based on it's power and weight.

1. Good traction which requires both good tires and good rear suspension design
2. Broad torque curve so acceleration can be near peak in gear levels at the rpm right after launch.
3. DCT transmission (obviously DCT model only). Some recent simulation work regarding the "power equivalence" of the DCT transmission puts the number close to 50 hp (mostly from a 1/4 mi perspective). In other words a MT M3 would need 50 extra hp to have about the same 1/4 mi performance as a stock DCT car. Prior efforts of mine put that figure at about 20 hp but I was probably using unrealistically short human/manual shift times which does lower this advantage. Also this "power equivalence" argument does depend of which performance contest you are looking at 0-60 vs. 0-100 vs. 60-130 vs. 1/4 mi, etc. Since the 0-60 contest does include 1 shift in a DCT car you will see this advantage equal to roughly the time for 1 human executed shift, perhaps 0.3-0.6 seconds. Link with the evidence for this as part of another lengthy loosely related debate here. Any way you look at it DCT makes the car substantially faster.
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      02-17-2012, 03:21 PM   #44
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Originally Posted by swamp2 View Post
For all those saying the M3 cannot do a 3.9 s 0-60 please get your facts straight. Yes, this number is the best magazine number achieved and yes it is an outlier of sorts in that regard. However, it has indeed delivered the magic sub 4.0 s run, 3.9 s to be precise.

Evidence here from C&D.

Other reasons the car is sort of an overachiever based on it's power and weight.

1. Good traction which requires both good tires and good rear suspension design
2. Broad torque curve so acceleration can be near peak in gear levels at the rpm right after launch.
3. DCT transmission (obviously DCT model only). Some recent simulation work regarding the "power equivalence" of the DCT transmission puts the number close to 50 hp (mostly from a 1/4 mi perspective). In other words a MT M3 would need 50 extra hp to have about the same 1/4 mi performance as a stock DCT car. Prior efforts of mine put that figure at about 20 hp but I was probably using unrealistically short human/manual shift times which does lower this advantage. Also this "power equivalence" argument does depend of which performance contest you are looking at 0-60 vs. 0-100 vs. 60-130 vs. 1/4 mi, etc. Since the 0-60 contest does include 1 shift in a DCT car you will see this advantage equal to roughly the time for 1 human executed shift, perhaps 0.3-0.6 seconds. Link with the evidence for this as part of another lengthy loosely related debate here. Any way you look at it DCT makes the car substantially faster.
Couldn't agree more about the shift times. The DCT shifts ridiculously fast, especially when you have it floored. I don't think there is a human alive who can shift as fast as that car can when it's being pushed hard.
jamze132 is offline   Germany
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