There is the combination of torque and RPMs that must occur in order to produce horsepower.
It's best to keep the explanations simple. There is no doubt that torque is the amount of force in the engine. HP is the amount of work (force/ torque etc) done over time. Increasing the RPMs allows the small amount of force in the S2000 to be done more rapidly thus increasing the amount of work done over time.
The only difference is you (the operator) have to work a little harder to use that power.

 

muscarel: Let's move away from the theoretical to the practical, since we can go round and round on a theoretical discussion. I would suggest that you test drive any high performance car, especially one that produces lots of torque like a C6. What your backside dyno will tell you is that the maximum acceleration, i.e., being pushed against the back of the seat, occurs at a relatively low RPM. In a Vette I would guess that it occurs at around 4K RPM.

In any car the maximum acceleration occurs when the engine reaches its maximum torque output. The HP at that point in time may be relatively low since the RPMs are relatively low: HP = Torque X RPM/5252. So as the RPMs increase and torque begins to decrease, HP will actually be increasing because of the RPM factor, provided that the torque doesn't decrease precipitiously.

So why is HP important? It's a quick way of telling a driver how much torque I have at very high RPM, and if I'm racing that is critical info. When racing, a car is going to typically be near redline because of the high speed involved. Hence, if I'm driving a car that produces 450 HP at 7500 RPM and you are driving one that produces 500 HP at the same RPM and our cars are geared identically and weigh the same, you'll be able to easily pass me because of the extra HP. Or another way of looking at it is that your car produces more torque at 7500 RPM than mine does, even though it will be far less than what it produced at 6K RPM.

But again the best way of testing what I post is by a simple test drive.

 

Fast1, it is you that are not understanding the point - Torque is ONLY important when an RPM is known (because you then know horsepower).

Obviosuly if 2 cars have everything else alike except one has more torque, then yes, the car will accelerate greater because the car has more horsepower at that point.

Forget about your "butt dyno" and try to understand what is actually happening. Look at a vehicles torque and horsepower curve to try and get a better picture of what is happening. The most simple way of explaining it is to look at that motorcyle dyno I posted. The torque curve is FLAT. A flat torque curve to you, would mean that the car would accelerate the same at 3,000 rpm as it would at 10,000 rpm. That is FALSE. Why? Because at that same torque value, the bike is producing 3x the horsepower at 10,000 rpm as it is at 3,000 rpm.

A vette has alot of torque down low, which in turn means alot of horsepower down low (they are a function of each other). So, if you smash the gas pedal on a vette at 2,000 rpm, and are trying to compare it to a s2000 at 2,000 rpm, the vette will have better acceleration (more horsepower). That point, although true unto itself, doesn't prove your point true. It's the power that made that vette accelerate faster at that point. The vette has 3x the torque at 2,000 rpm, so it makes 3x the horsepower.

The whole point of this is that when speaking of peak acceleration, you cannot just look at peak torque, you need to look at peak horsepower (which may occur at a high rpm on some cars depending on the torque curve).

 

The whole point of this is that when speaking of peak acceleration, you cannot just look at peak torque, you need to look at peak horsepower

I'm very happy that you put it that way because that statement is 100% inaccurate. If a car makes its peak Torque at 3500 RPM, that will be its maximum acceleration point, even if it maintains that peak output to 5500 RPM. As a matter of fact the car's acceleration will actually be decreasing a tiny amount beyond 3500 RPM due to the effect of air resistance.

A Cayman S for example makes its maximum Torque of 270 lb/ft at 3500 RPM , and as I stated above, that its maximum acceleration point. The HP for a CS at 3500 RPM is 270 X 3500 / 5252 = 179. The maximum HP for a CS is a conservative 295. So the Cayman S is producing its peak acceleration at 3500 RPM when its HP is only about 60% of its maximum. Using the same formula at 5500 RPM, the CS puts out 282 HP at 5500 RPM since it maintains its peak Torque up to that point, and yet it's not accelerating even a tiny bit faster even though its HP has increased by almost 60%.

Anyway this is getting boring , since it's so elementary. Since you don't want to use the butt dyno method that I suggested, why not go to any Speed Shop and drop your statement on them and get their reaction. BYE, bye.

 

+1 LOL

Fast, given your theory, you would always shift a G35 (HR) around 4,800 rpm because that's it's torque peak (yes, I'm aware that based on your "track driving training", you'll say you have to shift a bit higher so you're close to the torque peak in the next gear).

In an HR, even if you do shift later around 5,500, you're missing the HP peak at 6,800. And surprise!! Your acceleration times will suck (well, comparatively ). An experiment with a Cayman will deliver the exact same thing.

The 335 is faster because it not only has a high HP peak, it also has high torque down low due to the turbos. So it's making great power all the way through the rpm range.

Muscarel, thanks for the useful explanation !

 

I'm amazed that after all of this back and forth, you have not tried to check some reputable resources on this topic. Just the fact that you keep saying my statements are inaccurate and then go on to write multiple false statements is amazing to me.

5 minutes of research would net you quite a bit of information that would help you see that your understanding of this topic is poor. I can't believe that any reputable track professional would give out bad, incorrect information (if that is where your knowledge on the topic is from). More likely, you have misunderstood what was being taught. For instance, they may have said having more torque around a specific turn is beneficial to coming out fast from the turn. True statement. But extrapolating that statement into all the statements you have made is wrong.

I tried giving you very obvious examples (the F1 car, the motorcylce) that clearly show you how you are misunderstanding acceleration. Please ask yourself this simple question (once again) - why does a bike with a FLAT (not changing) torque curve feel obviously faster at 10,000 rpm than at 3,000 rpm? C'mon, you can't tell me it hasn't hit you yet. Please do not take my comments as hostile, I am just trying to explain the engineering and science behind this topic.

G35 Now, shifting early is almost always a bad idea because not only haven't you taken advantage of addiitonal horsepower in the gear you are in, but once you shift, your transmission (due to gearing), chops off a substantial amount of power (less torque multiplication). I remember awhile back seeing people post how it made more sense to short shift the G35 because of its low torque peak. I ignored posting of bad information back then, although for some reason I am being persistent this time around.

 

Lol, I remember this huge debate going on my350z

Same assertions....

Shifting at the peak torque will never yield a better time, then pushing it through at or near redline. Shift at peak torque, and you will most likely be out of the powerband in the next gear.

 

Yes... Often people don't understand that you can actually have a lot of torque with NO work or horsepower being produced. I can exert 500 lbs ft of torque onto a brick wall and prduce 0 horsepower. It is only when you add in RPMs that any work or horsepower is produced. Horsepower is th amount of work being done within a finite period of time. At higher RPMs or peak HP most engines are accomplishing more work than at it's peak torque range- thus more acceleration.
Under certain conditions however, the rate of acceleration could be adversely affected depending on the torque drop even with an increase in HP (i.e. wind resistance, hills etc)

 

You guys are missing the obvious one...

There are SLOWWWWww trucks that make FAR more torque: weight that feel slow as slugs. Ever been in a torquey truck? They aren't fast even though they have more torque per pound then a lot of faster cars.

FAST1 I've told you before, check out howstuffworks.com on this subject, you are woefully inept and undereducated when it comes to this subject.

 

Well I'd say just take the factory figures which were like 5.1 last I checked, and add another second or two to make up for those 22's your planning on throwing on there.

 

offical specs confirm
2008 Infiniti G37 Coupe
Base Price $35,000 (est)
Vehicle Layout Front engine, RWD, 4-pass, 2-door
Engine 3.7L/330-hp/270-lb-ft DOHC 24-valve V-6
Transmission 6-speed manual, 5-speed automatic
Curb Weight 3600 lb (MT est)
Wheelbase 108.3 in
Length x Width x Height 182.1 x 73.0 x 54.0 in
0-60 MPH 5.2 sec (MT est)
EPA City/HWY Econ 20/27 mpg (MT est)
On Sale In U.S. August 2007

 

Where did you get the "official" specs from? I checked infiniti's web site and it hasn't changed.

 

1 second! Fastest car on earth!

-Sean

 

I saw those specs in the May issue of MotorTrend. I am not sure how accurate they are, as Nissan/Infiniti has not released the final production specs.

 

My guess is:

0-60 - 5.1 seconds
0-120 - 18.1 seconds
1/4 mile - 13.7 at 103