Does more horsepower equate to more speed?

Question

I was just wondering, because as far as I can tell by supercharging and reworking an engine to get more horsepower, you end up sacrificing so much fuel efficiency that you can basically start the car, drive it to the end of the block, and then have fun pushing it home.

Nobody has ever really explained to me what horsepower is/means.

Answer 1

No one has been completely accurate yet. I will have to do some checking in some books I have to answer all your questions. (Horsepower of your car) Your top speed and to an extent your acceleration depends greatly on horsepower. I have a car that if there were no wind resistance would top out at over 340 miles per hour. It has done a 13 1/2 second quarter mile at around 108 mph on a drag strip. I have had it near 140 and it had seemingly much more left in it. But wind resistance has a great deal to do with speed and it takes progressively more horsepower to go faster and faster.

Keep this open and as soon as I can I will finish it for you in an edit. It is late and I must get some sleep.

Edit:

One horsepower is equal to 33,000 lb/ft per minute. That means if you move one pound 33,000 feet in one minute, you have done one horsepower of work. Or if you move 33,000 pounds one foot in one minute, or any combination in between, just as long as the figures come out the same. As an example, 11,000 pounds moved three feet in one minute is also one horsepower. I mentioned my car. If I put a different third member (rear end on a rear wheel drive) in it with acceleration in mind and had the proper tires, probably 10 inch slicks, it likely would do under an 11 second quarter mile. When I put it on the strip, I was just interested in a ballpark idea of how it performed. I took off from idle, used street tires and since the shifter is not right yet, did no power shifting. It is a five speed stick. At the end of the quarter, I was still in third gear and it was pulling fairly hard. Changing the rear end ratio would greatly affect my gas mileage. I get about ten per gallon right now. It runs well enough to be fun. I think I will keep it as is.

Now, as far as horsepower and speed, if you are carrying a four foot by eight foot sheet of plywood and no wind, you should do OK. You might even be able to run with it. But imagine a five mile per hour wind blowing. It takes more force to move. If you have only a certain amount available, an increase in wind speed will slow you down more and more. Imagine a ten, twenty and fifty mile per hour wind. As your speed increases, the horsepower it takes to go faster goes up dramatically, along with the fuel burned to get the work done. That is why dropping your speed from 70 mph to 55 saves so much fuel.

It has been a while since I have built a Chevy small block, but I have been kicking around getting a 400 mouse engine and putting in a crank from a Z28 if I can find one. They are billeted steel and have a 3 in. stroke. TRW at one time made special bearings so you could use different crankshafts in the 400. The bore for the main bearings is larger in the 400 than the other mouse engines. If you did not know, small block and big block Chevy engines are known as mouse and rat motors respectively. Good luck and have fun, but be safe.

Answer 2

Horsepower is work and work takes energy.  The reason to improve air flow, or blow more air into an engine with turbo or supercharger, or larger engine is to have more air to burn more fuel to produce more power.  A small engine with a turbo or supercharger can cruise more efficiently than a larger engine always pumping more air with more mass moving around.  Although, a large engine can improve efficiency by cruising at a lower rpm, or by cutting out some of the cylinders (like Active Fuel Management).

Answer 3

If you're looking to save gas, don't look into horsepower.

Answer 4

depends on what your doing drag racing yes highway driving no