[QUOTE=1speedbike;13193977]You can TUNE the engine to have a slightly different torque curve, but no matter what the application, the conversion between horsepower and torque remains the same at any given RPM:
So, let's look at three examples...
Quote:
How much TORQUE is required to produce 300 HP at 2700 RPM?
Answer: TORQUE = 300 x 5252 ÷ 2700 = 584 lb-ft.
Example 2: How much TORQUE is required to produce 300 HP at 4600 RPM?
Answer: TORQUE = 300 x 5252 ÷ 4600 = 343 lb-ft.
Example 3: How much TORQUE is required to produce 300 HP at 8000 RPM?
Answer: TORQUE = 300 x 5252 ÷ 8000 = 197 lb-ft. [/quote]
Horsepower is a function of torque over time. So you can see that the amount of torque needed to produce the same amount of horsepower at different rpms decreases as the engine spins faster, because horsepower is basically defined as the amount of torque being produced per second. If the engine spins more times per second, the horsepower increases for the same amount of torque because that force is applied more per second.
It doesn't matter how the engine tries to modulate the boost. (At least, I don't think it does. If you think I'm wrong, go ahead and tell me how. I'm not trying to argue, and I will concede if you are truly correct and I am not).
The numbers of horsepower and torque are inherently linked at any given RPM. The engine can try to keep the rpms higher, so more horsepower is produced for the same amount of torque, and this is basically what happens during the long flat part of the torque curve. The engine is creating the force, not the power. The engine creates the same amount of force from 2500 all the way to 5500 or so RPMs, but the horses steadily increase because the same force is being applied more often per second as RPMs increase.
As you go higher in the RPM range, the engine becomes less efficient and creates less force. However, the RPMs are still increasing, so the HP doesn't necessarily taper off yet until the negative effect of the torque decrease outweighs the positive effect of the engine spinning faster. When you see a dyno sheet, the only thing the engine "creates" on that sheet is the torque curve. The engine can produce different amounts of force at different RPMs, but given a torque curve, the horsepower curve should more or less be the correspond directly to it, because it's a mathematical relationship. The engine isn't producing both power and force, it's producing force, the the power is "makes" is related to the force produced at a given RPM.
What you were saying is correct in that you can limit the torque and boost and still achieve the same PEAK horsepower through modulating the engine, and have similar horsepower numbers in the upper RPM ranges where less torque is required to achieve those numbers, but down low you would suffer in terms of horses because to achieve the same horses at a lower RPM you would need that extra, tranny-crushing force.
But for trying to save the tranny, I don't think that keeping the same peak horses while limiting torque is what he is trying to achieve. At least that's my take on it. There's no real way around it. Again, I don't appreciate being called "absolutely ridiculous" and I am not trying to have a flame war or an argument here. I'm just explaining what I know. If I'm wrong, I will gladly concede and agree you're right, but in this case I do not believe I am. Also, I figured it's probably helpful for anyone reading (including OP) to know the relationship, so forgive me if I rehashed things you already know since I'm just trying to create a good basic explanation for readers (because honestly, Freon, I consider you one of my most knowledgeable people on this forum.. i just think this time you're wrong  )
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thanx for the explanation, but i don't think it's a basic rule for all type of engines, for example the E90 M3 with ESS SC VT625 it puts down about 550 rwhp, about 380 torque or lower
if w apply this rule TORQUE = 500(hp) x 5252 ÷ 5500 = 477 impossible!!