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Thread: possible horsepower theory

09242010, 12:42 AM #1Member
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possible horsepower theory
I have an idea, that may have already been thought of, but I dont know of any of that so, just take it for what its worth and corrections or negating arguments are welcome!
wouldnt it make more sense to rate a vehicles horsepower based on the average horsepower it produces between its rpm band in a certain gear? same with torque.
It seems to me that two cars with, for example, 350whp and identical weight, will perform extremely differently based on torque and the looks of the powerband. lets say we have these two cars:
1. peak whp: 410 avg whp from 1006950rpms :360whp
2. peak whp: 370 avg whp from 1006950rpms :360whp
would it be safe to assume that they would end up with a similar 1/4 mile ET and trap? or does this theory hold no water?
(No, i am not trying to race anyone, and figuring out the math, i just would like to know if this makes sense to anyone; why or why not? thanks!)
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09242010, 01:07 AM #2Guest Vendor
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I get what you're saying, but there are simply too many other variables to account for including traction, suspension & chassis tuning, trans and diff gearing, even aero in a 1/4 mile for this to be a realistic measuring stick. You can compensate for lack of torque at the flywheel with numerically higher diff gearinggiving you more lb/ft at the tires.
Manufacturers rate with peak numbers because A) that's how it's always been done, and B) bigger is better.
To answer the question accurately you'd have to overlay dyno graphs and correlate with shift points assuming all else equal.

09242010, 01:12 AM #3Member
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true, it is complicated. but considering only the hp of a car, would it make sense to compare like suggested? especially since in the end it gives you a more accurate way to compare to another car, AND hp means nothing without torque. i mean low eand torque means you are making more hp earlier in the powerband.
but, i get what you're saying!
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09242010, 01:27 AM #4Guest Vendor
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HP is a mathematical function of TQ, keeping that in mind if all you're asking is if rating cars in avg hp/tq throughout it's WOT powerband is a more accurate guage of performance, yes it makes sense, but won't happen due to the above reasons. Diff gearing can overcome whatever lack of torque you may have, although you pay the price with higher revs when cruising on the highway, constantly shifting, etc.
As far as only considering the HP of a car, you would have to take torque into account as well, and again that's only at the flywheel not the tiresa lot of tq multiplication can happen along the way via a torque converter (conv auto), trans gearing and diff gearing. So how accurate would it be even if we had identical cars with identical powerbands, weight, aero, etc with the only difference being one has 3.73s the other 4.10s? Depending on the length of powerband you very well may have to shift 3x with 4.10s in the 1/4 vs 3x with 3.73s. Some of the extra torque multiplication the 4.10s provide is mitigated by the extra shift.
So I guess what I'm saying is if you rated avg hp/tq at the wheels in each gear then factored in weight, aero and whatever other tangible data you could it would be the way to go for a performance enthusiast.

09242010, 10:10 AM #5Member
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09242010, 02:14 PM #6Guest Vendor
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