HP at 4000 rpm?
08-30-2002, 04:57 AM
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HP at 4000 rpm?
I've been a good dube and not exceded 4000 rpm, though I love the car, the acceleration is fair. realizing the I haven't hit the peak power band yet I was just wondering what was instore for me. does any one know what the HP is at 4000 rpm or what percentage of full HP I'm using?
08-30-2002, 07:34 AM
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macabre, the difference in charts is crank vs. wheel...the first chart is the actual output of the engine before drivetrain loss. It is real. This is the number that basically every manufacturer quotes.
08-30-2002, 08:08 AM
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No, that's not what I'm talking about. Remember, torque is measured and HP is calculated by the formula: HP = torque * RPM / 5252. If you remember your algebra you'll see that this requires HP and torque to always be equal when RPM is 5252. In the first graph, this is not the case. You'll also notice that the HP curve is not accurate at all if you calculate a few points from the torque curve. Somemone made it as a marketing tool, thats all. It should not be used as a performance indicator.
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08-30-2002, 08:12 AM
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The process of smoothing it over moved the torque curve forward 400rpm and increased the HP curve significantly all the way through? I don't think so. It's not even close. There probably wasn't a real dyno graph available to the marketing dept. when this graph had to be made, so they guestimated. Not uncommon.. tuners do it all the time.
08-30-2002, 08:23 AM
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although the difference is brobably crank vs wheels, it is iteresting that the percentage power of max is the same on both curves:
200/287 = 70 %
175/250 = 70%
so people who are driving under 4000 rpm will still have 30 % more power to play with.
200/287 = 70 %
175/250 = 70%
so people who are driving under 4000 rpm will still have 30 % more power to play with.
08-30-2002, 10:44 AM
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Originally posted by Macabre
No, that's not what I'm talking about. Remember, torque is measured and HP is calculated by the formula: HP = torque * RPM / 5252. If you remember your algebra you'll see that this requires HP and torque to always be equal when RPM is 5252. In the first graph, this is not the case. You'll also notice that the HP curve is not accurate at all if you calculate a few points from the torque curve. Somemone made it as a marketing tool, thats all. It should not be used as a performance indicator.
No, that's not what I'm talking about. Remember, torque is measured and HP is calculated by the formula: HP = torque * RPM / 5252. If you remember your algebra you'll see that this requires HP and torque to always be equal when RPM is 5252. In the first graph, this is not the case. You'll also notice that the HP curve is not accurate at all if you calculate a few points from the torque curve. Somemone made it as a marketing tool, thats all. It should not be used as a performance indicator.
they only cross at 5200 on a graph if the same scale is used for torque and hp...in the first graph shown different scales are used. It IS a valid plot, and taking into account that the scales are different you will see that calculating a few points from the plot ARE accurate.
Last edited by The Unabageler; 08-30-2002 at 10:47 AM.
08-30-2002, 11:33 AM
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My question is what kind of speed are you looking at for 4000rpm? I'm sure you can easily top 100 in 5th and 6th, but I know that the break-in period is really not the time to be stretching it out like that.
08-30-2002, 12:33 PM
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Originally posted by Macabre
No, that's not what I'm talking about. Remember, torque is measured and HP is calculated by the formula: HP = torque * RPM / 5252. If you remember your algebra you'll see that this requires HP and torque to always be equal when RPM is 5252. In the first graph, this is not the case. You'll also notice that the HP curve is not accurate at all if you calculate a few points from the torque curve. Somemone made it as a marketing tool, thats all. It should not be used as a performance indicator.
No, that's not what I'm talking about. Remember, torque is measured and HP is calculated by the formula: HP = torque * RPM / 5252. If you remember your algebra you'll see that this requires HP and torque to always be equal when RPM is 5252. In the first graph, this is not the case. You'll also notice that the HP curve is not accurate at all if you calculate a few points from the torque curve. Somemone made it as a marketing tool, thats all. It should not be used as a performance indicator.
Look at the graph again. The torque scale and the horsepower scale are different. Therefore they won't cross at 5252rpm.
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