ah, no.
Your first part is correct.
Lets assume 2 dakotas, same tranny, and vehicle weight. Using 2 5.2L engines
with EFI.
If we compare 150 hp vs 100 hp at the same rpm (say 2500rpm), the amount of work
produced to maintain a constant velocity is the same for both engines. But what it
takes to make the 100 hp engine to maintain the trucks constant velocity is more
expended energy (fuel) inorder to overcome resistance.
To get complicated and yet explain...both engines are Identical to the Volume of
fuel delivery per time unit. However the 150 hp engine has cold ramair induction,
Ported Throttle body, Headers and low resistance dual cat and exhaust. This will
reduce the resistance on the engine makeing it more efficient (as you pointed
out). The 150hp engine in this case will use less gas.
BUT, if we take 2 engines with 2 different Carbs (2 bbl vs 4 bbl), and leave the
resistance the same, yes, now we are pouring more fuel per time unit in to the
engine to gain the performance increase. (overcoming the resistance with more
energy to increase work.).
The 150 hp engine here will suck your tank dry.
4x4 will have more resistance than a 4x2,
RT witha 5.9L engine is using a greater volume of fuel per time unit than a 5.2
at the same RPM. this doesnt scale exactly because the 5.9 has More hp to do
work, but by brute size, is using a little more fuel to get the job done.
whew.....that was a mout full.
Jetmugg@aol.com wrote:
> While it's true that a more powerful engine can be more efficient, what
> determines the speed that your Dak is travelling is the rpm of the engine, not
> the HP. For example, if your truck is going 70 mph, we'll assume that the
> engine rpm's are 2000, and assume that the engine HP is 100. If the engine in
> the truck makes 150 hp at 2000 rpm, you will still only be travelling at 70
> mph at 2000 rpm, assuming no change in gears, etc. However, now you are
> supplying gasoline and air to an engine which is making 150 HP instead of 100
> HP. I think we can all agree that the 150 HP engine will use more gas.
>
> The numbers above are completely fictitious, so please don't jump on me for
> false numbers, but the concept is valid.
>
> Steve M.
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