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      02-26-2013, 04:09 AM   #225
swamp2
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Drives: E92 M3
Join Date: Sep 2006
Location: San Diego, CA USA

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Quote:
Originally Posted by Pete_vB View Post
I disagree with Swamp and others here that torque doesn't matter.
Wow where to begin... here we go again...

Let me start with this correction by rearranging your words a bit...

If a lazy driver who won't properly put the car in the gear which maximizes acceleration and at the same time "requests" maximum acceleration cares (continue reading on with the quote...)
Quote:
Originally Posted by Pete_vB View Post
about acceleration, they should be very happy the new car is getting 100+ lbs lbs more torque."
Anyway no, no, no on the torque. Weight reduction, if present in the new car, will be more important than a power increase (since it improves handling) but what is far more sensible than a torque increase is a power increase. And although we are very likely to get one, again partly in the form of under-rating, BMW now has some believing the exact opposite of what they've been saying (and doing) for decades. Nothing is particularly wrong with torque nor with a broad torque curve, but FOR THE SIMPLICITY of a single number peak power (to weight) rules, period.

Now that we have that straight let's continue.
  • If you know the entire torque curve that's fine, you then also know the entire power curve. The torque results are still meaningless without knowing gearing. Look at your own forumula! Thus torque isn't meaningless, just massively less important than just knowing peak power (certainly over peak torque or any other such under the curve BS - do you think most enthusiasts can do an bloddy integral...). And again assuming on a per weight basis, of course.

  • Do you note the importance of the final drive in your formulae? 3.85 vs. 3.15. If you look more closely you will realize this ratio is basically a short cut to using power instead of torque. Not conincidentally, (3.85/3.15) x 350 = 423. More on the 350 number below. Do you still not see it?

  • Numbers can be chosen at any given single speed to show a result not in line with general results. What matters in the real world is results across a broad speed range and typically across multiple gears. You need a very fancy spreadsheet (I've actually built one) or something like the CarTest physics based simulation software to show this.

  • The 1M is pretty clearly under-rated and that's why it does a better job of keeping up with an M3 that its factory QUOTED peak power would indicate. 350 hp at the crank provides performance numbers much more in line with typical results from journalists.

  • Let me give you a formula anyone can walk through.

    a = P/mV

    Thus at any given speed the vehicle that can make the higher power to weight ratio WILL out accelerate the other. Period, no if and's or but's. Basic physics, no torque, no gear ratios, no nothing.

  • You've got your 1M weight way off. Using the correct US unladen weights of each vehicle, 4145 lb and 3362 lb and a realistic power figure, which by all accounts is again about 350 hp for the 1M, you will find that the 1M has a better power to weight ratio and in a full physics based simulation slightly outperforms the M3 particularly in time to distance (which means who is ahead in a drag race). Of course at higher speeds, say a 60-130 or similar, power to drag dominates the performance and the M3 would best the 1M. See attached simulation results, across gears, not at once speed nor in one gear... These particular cars are close enough it is pretty well a drivers race, but technically the M3 even has a slight advantage in the 1/4.
Attached Images
  
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