gavriil

You know, up to now, I thought that torque is the best way to measure how fast a car will really feel. Cos with HP you just cant tell, simply because the driver and passengers feel only the torque. That's why a Z06 feels way faster than a Modena for example. I remember when I first test drove my CLS coming from owning a 1996 Eagle Talon AWD TSi (basically a detuned Evo V engine), I thought to myself "holy moly, this Acura has no grunt at all at mid rpm".

But even with torque, you have to keep in mind things like rpm. And even more acurately rpm range. From where to where is thsi car pulling by that much torque? Now I think I found a better way of mesuring exactly how fast a car will feel.

I was reading the latest Autmobile mag edition in DC and I saw their $30K Mega Test article.



I was reading the specs and although this is a unit of measure that Automobile mag has been using for a few months now, I saw how much of a difference it makes with under-$30K cars which we pretty much all know and many of us have driven.

I am talking about the unit of measure of PEAK ACCELERATION which is measured in "g" which is the acceleration of gravity. If I remember correctly from school, "g" = 9.8 meters per second to the 2nd power. Which means that a free-falling object is an object which is falling under the sole influence of gravity; such an object has an acceleration of 9.8 m/s/s, downward (on Earth).



Automobile mag (very appropriately) measures every car now, "that way", as part of their standard test. This unit of measure folks, I believe TOTALLY describes how fast a car feels. Or how hard it pulls, you fill in the blanks.

Actually the mag goes a step further and tests decceleration that way as well. So now you know how good those brakes really "feel" (plus how soon they stop your car). That way you get a more complete picture of the performance in the car.

The cars in the $30K Mega Test were (this is by order of best to worst in the end):

1. Acura TSX
2. BMW 325i
3. Inifiti G35
4. Mitsubishi Evolution
5. Mazda 6s
6. WRX
7. IS300
8. Audi A4 1.8T Quattro
9. Saab 9-3 Linear
10. Mercedes C230K Sport
11. Pontiac GTP
12. Nissan Maxima SE

The results for example for the Mazda 6 were:

0-60mph 7.1 sec
0-100 18.7 sec
0-110 29.8 sec
1/4 mile 15.6 at 93.mph
30-70mph 9.8 sec
Peak accel 0.44g
Cornering L 0.84g
Cornering R 0.84g
70-0 171ft
Peak braking 1.00g

Some results for the Evo were:

Evo did 0-60 in 5.6, 0-100 in 14.7 and the quarter in 14.1 @ 98 mph. Cannot find or remember more of the specs....but

One thing I do remember which is my point. The Evo and WRX were BY FAR the winners when it came to the measurement of the PEAK ACCELRATION in Gs and the TSX was BY FAR last on the list for that measurement. And it totaly makes sense. The TSX makes pathetic torque numbers for its weight. On the other hand, the winner/EVO makes great torque.

But I think there are 3 more factors here.

1. How fast that torque KICKS IN.

We all know about the issues of small displacement turbo engines that make high specific power. I remember my Talon. At 2800 rpm that thing made moderate or below-moderate torque and then at 3000rpm...BANG! All the torque comes at once. I know that Mitsu claimed 214 lb-ft of torque at 3000 rpm for the 4G63 of the 2G DSMs, so just to put it into perspective, if 214 pounds were present at 3K rpm, there was probably 110 pounds available at 2800 rpm.

2. The second factor is how well can the car put that torque on the ground. Because the EVO (and the Talons/Eclipses) is AWD and there is no slipage, all that power goes to the ground and you feel the...total effect of that application of torque.

3. Finally, gearing. And maybe I should have put that as the second factor. Because of the "no spin" issues of the STi and the EVO, these auto makers can be really aggressive with gearing. Short gearing that is. That amplifies the effect of PEAK ACCELERATION and how fast a car feels. Of course, it also helps with acceleration times which makes sense.

So, high torque numebr, explosive torque output, AWD and short gearing, make for a VERY FAST CAR in terms of how fast it feels (and of course is).

There you have it. My new favorite unit of measurement. PEAK ACCELERATION. Might make it enough of a reason for me to subscribe to Automobile mag.

If someone has the mag, please post results here or scan and I will host. It is very interesting to try and judge how fast cars are when compared on that unit of measurement.

Red Nj-s

cool stuff, the acura in no way feels even CLOSE to the feeling i get in the z-28. You can tell it is quick, but there is just no ooomph there that can be had from 5.7 liters of displacement.

Python2121

so this is like a more encompassing torque rating that leaves out hp?

very interesting number ill look for it, thanks for the heads up and the summary of what it means

gavriil

Nice way of putting it. It is that in many respects.

Thanks for the nice word.