|
|
|
|
|
|
BMW Garage | BMW Meets | Register | Today's Posts | Search |
|
BMW 3-Series (E90 E92) Forum
>
Why BMW needs turbo for E54 engine to acheive 306hp?
|
|
03-01-2006, 09:25 AM | #133 |
New Member
0
Rep 21
Posts |
One final reply from me.
Too many people say that: "Torque = acceleration and Power = top speed". That's such a gross over simplification that it becomes a stupid statement. What do people mean when they say 'acceleration'. Do they mean the *instantaneous* acceleration (which varies with RPM), or do they mean *average* acceleration (which is constant)? The "push you feel in the back" when you mash the pedal is *instantaneous acceleration* - and this is what Garrett refers to. The *instantaneous* acceleration correlates to the torque curve of the engine. So if the torque curve rises from 100Nm at 2000rpm to 200Nm at 4000 rpm, you will feel twice the 'push' (ie the force) and hence twice the (instantaneous) acceleration at 4000 rpm than you do at 2000 rpm. But when people talk about 0-60 times, this is a measure of the *average* acceleration. The *average* acceleration of a car is constant. But ppl don't make this distinction when they say stupid phrases like "Torque = acceleration, Power = top speed". A more accurate statement would be "Torque = *instantaneous acceleration*, Peak Torque = *max instantaneous acceleration* and Power = *average acceleration*". Taking this perspective into account, *both* torque and power relate to acceleration, it just depends on whether you are speaking of *instantaneous* acceleration or *average* acceleration. That being said, *average* acceleration is the key to an engine's performance. So if you want a car to be accelerate quickly to high speeds, look at power, not torque. |
Appreciate
0
|
03-01-2006, 03:59 PM | #134 | ||||||
Banned
23
Rep 1,356
Posts |
Quote:
Yes..YES and YES. But NO !!! I KNOW it's irrelevant. If I tell you that my car has 4 tires, that is also irrelevant, but is also TRUE. Torque=Acceleration Your trying to put words in my mouth and teach me something I am fully aware of. Also, your "intantanious acceleration" is not my words or my analogy. I'm talking about the RATE of acceleration. As infatesmol or irrelevant as it is in dealing with the overall acceleration of a car. Never-the-less, the rate of acceleration is fastest at the highest torque point within the engine. Albiet, minus anomolies such as torque converter, clutch and limited slip...etc. Now there are many small discrepancies in CARS that will alter that formula somehwhat.... but those are irrelevant to the overall debate at hand. In which your in agreeance with me on. "Average acceleration" was in quotes... because it was something you (or another said) Not my words. Meaning, but you can have an engine with a torque curve like a bell (Peaky) or one thats more smoother and more of a perfect curve like the top of a basketball. If the bell curve has 400 ft-lbs and the Ball curve has 350 ft-lbs i would chose the Ball curve. Because overlaying the two, the ball curve has more torque when compairng their delta's. *BUT THAT IS NOT THE TOPIC OF THIS DISCUSSION* Just because I didn't discuss it earlier or add any other benifits from torque doesnt mean I'm unknowladgeable, I'm just trying to keep this debate on track... and if you havn't read this whole thread let me remind you what we were dealing with. Quote:
Quote:
Quote:
Quote:
Quote:
So, after all that it's obvious he doesnt understand torque. I know what torque is and does... but I am trying to show him ONE simple thing that almost un-debatable. Once he understand or ackowldge it, then we can go on to educate him the other aspects of it. -Garrett Last edited by Garrett; 03-01-2006 at 04:15 PM.. |
||||||
Appreciate
0
|
03-01-2006, 04:30 PM | #135 | |||
Banned
87
Rep 2,446
Posts |
Quote:
Garrett, you are such an imbecile with your smart-ass attitude. Get your head out of your ass! You can't even find the standard specs for a 2006 9-5 (it took me 5seconds) on saabusa.com 2.3-LITER 4-CYLINDER HIGH-OUTPUT TURBOCHARGED 260-HP ENGINE Engine specifications–2.3T Type–4-cylinder turbo Displacement–140 cu. in. (2,290 cc) SAE horsepower rating: 260 hp @ 5300 rpm SAE peak torque: 258 lb. ft. @ 1900-4500 rpm (Standard) Quote:
Quote:
|
|||
Appreciate
0
|
03-01-2006, 06:47 PM | #137 | ||
Banned
23
Rep 1,356
Posts |
Quote:
Saintor, I am not at all concerned about the SPECs. Spec are a snapshot. Peak torque tells you only 1 thing. A torque curve tells you EVERYTHING. Thus, thats why I have asked for the engine so that we can start discussing why your SAAB doesn't do much at 1,900rpm's. If you don't understand a what "peak" is or a "revband" which are extremely simply concepts, then it's no wonder why you cannot grasp TORQUE. Torque = Acceleration Horsepower does not.. as your so inclined to keep telling people. Now there are benifits to makng torque higher in the rev range, but that takes nothing away from my statment. Unlike this: Quote:
. Your SAAB's peak torque is 4,500rpm'ish. but that engine has a very flat torque curve and would pull strong all the way threw the revband. However @ approx 4,500 is when the car would be pulling it hardest. IE Fastest acceleration. -Garrett Last edited by Garrett; 03-02-2006 at 07:00 AM.. |
||
Appreciate
0
|
Bookmarks |
|
|