Sport Auto 1M Review: Beats M3 at Hockenheim! - "All You Need In A Sports Car"

[swamp2]

Originally Posted by GotM

Swamp, your statement is true here, but in the case of any speed, P is a function of V. So you don't really have one number for the comparison. And, based on the equation max acceleration most likely will not occur at max P/M, since V is in the denominator and this max P/M is at a higher V in any given gear.

Indeed power varies with rpm and thus in any given gear with car speed. However, it does not reduce the insight of the forumula when applied properly. It shows why more power is required for the same acceleration when at a higher speed (drag effects are also not included in this simplified formula). It explains more precisely why if cruising at 70 in 6th or 7th gear why you would down shift to 3rd for a quick rolling freeway race. You downshift so at any given speed (the one you happed to be at) you maximize the engines output power. You do not downshift to maximize torque! You can also view it as maximizing torque at the wheels which includes torque multiplication from gearing. But don't forget that maximum acceleration in any gear still occurs at the rpm when the torque curve peaks. Seems a bit contradictory but it isn't.

Originally Posted by GotM

I have done some of my own modeling of acceleration of the 135 6MT/M3 6MT. The 'rough' calculated instantaneous acceleration for each car is very similar. The 135 has higher acceleration earlier in a gear, but an M3 carries it much longer. In a sprint to 8- 60 mph it is pretty close.

Absolutely correct. High redline, "low" torque engines with larger gear ratios (really gear ratio x fd ratio) contribute to the ability to stay in each gear longer and that is a key component of total acceleration performance across multiple gears. The same exact understanding helps one understand the trade-offs with final drive modifications. You get more torque at the wheels but spend less time in each and every gear.

Getting way OT for sure but all relevant in the total understanding... Cheers.

[swamp2]

By the way running the 1M and M3 in this model for the N'Ring

Car, Predicted, Actual, Deviation, Standard Deviation
1M, 8:17, 8:12, -5, -0.5
M3, 8:09, 8:05, -4, -0.4

The 1M "over peforms" beyond the model only by one half of a standard deviation. And only 1/10 of a standard deviation more than the amount the M3 over performs. I would definitely expect the difference between the two to increase on a tighter and slower track, i.e. the 1M will be more of an over performer than the M3.

[lux.sh]

Swamp2, thanks for the data. If I have time, I plan on verifying the data and adding more vehicles to see how far R2 value travels to 1. Also, I plan on making a Tsukuba track regression analysis, it would be very interesting to see such similar result, but much greater variability(at least for those who can actually analyze regression, instead of just seeing the line and thinking "oh its true").

Originally Posted by ferrari4evr1

Aside from this comment, I think its rather pleasing to see knowledge on this forum. A debate on science, numbers and formulas is a nice change of pace, rather than my car is better than your car (childish) debates...

Hope you know I was joking with that comment, cause I obviously calling myself that at the sametime.

But yes, I definitely enjoy educational debates. I knew swamp knows what he is talking about, so I knew if I argued with him back, we would come out with something useful. Leave the childish debates to kids, this is a BMW forum. People should be generally more educated in this income range. I can also make a regression on this also, just takes too much time.

[FIRSTM]

I was wondering if you chaps use this lap times and figures to base your decision to purchase a vehicle

[swamp2]

@lux: If I recall correctly most of the values for the N'Ring regression were Sportauto times. That eliminates the driver variable. Which will obviously contribute to a better R^2. Larger R^2 variations will obviously result from less consistent data (i.e. many different drivers).

Also

Originally Posted by lux.sh

I can also make a regression on this also, just takes too much time.

If you use the "analysis" add in package with Excel for Windows or whatever it is officially called (not available in Mac versions...) it has full support for very quick "point and click" regression analysis. The results shown in the spreadsheets I posted were generated that way.

Originally Posted by FIRSTM

I was wondering if you chaps use this lap times and figures to base your decision to purchase a vehicle

They do play a small role in my decisions. But basically BMW almost always tops out in its class on track times and I really like M's. That makes the decisions easier. I do think if a certain brand consistently out performed M's at the track I would take those brands more seriously. Of course for everyday driving and even track driving with my skill level, much of the observed and quoted differences are irrelevant. In this way even the science is somewhat bench racing...

Originally Posted by ferrari4evr1

A debate on science, numbers and formulas is a nice change of pace, rather than my car is better than your car (childish) debates...

I think, in the end, If you own an ///M car, you are a very lucky person and part of a enthusiastic community. Whether you own a M3, 1M or other //M car.... Also, I think we might be splitting hairs when it comes down to it (with these cars numbers), but, its nice to see an educated debate.. :drink

Absolutely agree. I enjoy mixing the science with the gear head topics and I certainly enjoy trying to correct some commonly held automotive misperceptions.

[swamp2]

Originally Posted by Wall$treet

I think the easiest way to clarify for the guys that like to think engine torque figures mean anything is to bring up a post by swamp a couple pages back. Paraphrased is " a car has max acceleration at peak torque"

That refers to WHEEL torque and not engine torque. Engine torque * rpm is Horsepower. Horsepower * gearing =effective WHEEL torque.

So engine torque itself is a meaningless value unless you know the RPMS and the gearing of a defined car. (meaning the RPMS which the car is still making power and not endlessly high RPMS)

Its a very simple concept that is probably the most mis-stated or understood on any publication or forum etc.

Another way to view it as simply there are 2 ways to make power. Engine torque and High RPM's (classic example is F1-there torque figures are like 250 foot pounds or something with 700 hp).

Then there is one thing that takes that horsepower and makes a car accelerate which is the gears. That is what is being measured at the tires, a sum of all those componenents.

Simple enough

Correct. Agree all around. It can't ever be simple enough though for those obsessed with torque .

Even though crank hp is much more useful and meaningful than crank torque the statement that "in any given gear maximum acceleration will occur at maximum torque" is still quite true. It does not need to distinguish between maximum wheel torque and maximum engine torque because they are the same (less a pretty minor correction for tire and aero losses)! One just needs to constantly remind themselves that most race engines operate nearly continually in an rpm range way above peak engine torque. Why - to maximize wheel torque which is pretty much equivalent to maximizing power.

On the flip side those who prefer a relaxed or even "lazy" driving style (i.e. I want the acceleration without down shifting) a higher torque, lower power and lower redline motor philosophy will feel like the better car for that preference.

Torque is important for heavy equipment, towing, 0-60 and "lazy" drivers, hp is important for everything else!

P.S. My longish post this morning about these tire and aero corrections I mention above is here.

[Volasko]

I would be interested in the CF mirror caps but your price is pretty high. Marenello BMW has them on sale for around 475 tax. Maybe we can work out a deal if you are willing to let them go for less, if so PM me and we can go from there.
Adam

[MikeVictor]

http://www.caradvice.com.au/116579/b...nd-hockenheim/

quote: "The little 1 M Coupe not only beats the M3′s lap time around the famous Formula One circuit, it also beats the BMW E60 M5 V10 which has previously clocked 1:16.5, and the BMW M6 which has clocked 1:14.4. The only M car it can’t match around the circuit is the BMW E46 M3 CSL, which has posted a lap time of 1:13.5."

[miiipilot]

Damn, shouldve waited to get a 1M...

Just gonna have to get a s1000rr instead.

miiipilot

[ESC OFF]

Swamp2 < Swamp1 game over!

[LateralG'z]

Great article and very impressive for parts bin car. Hopefully my deal goes through and a 1M will be in my drive way in three weeks.