Quote:
Originally Posted by jamesqf
But most of us - ok, some of us - don't live lives that involve doing only one particular thing. On a hot day, I can get close to 100 mpg on the flat road into town, but I can also drive up the mountain on a snowy winter day to go skiing, or ford streams on dirt roads out in the desert.
I worked it out as about 17 HP, from the fact that it'll hold about 65 mph on a 6% downgrade.
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17HP
may be able to maintain the desired speed. The issue is getting there while on an up-hill on-ramp to safely merge into traffic that is going 65+ mph. Based on cD and weight, my car (05 Mitsu Lancer) requires 21.75 HP to maintain interstate speeds (70 mph speed limit here in Indiana). It started with a 0.30 cD, weighs 2701 lbs and has a frontal area of 25.1 sq ft. I am sure there is a formula for calculating exactly how much horsepower is needed to excellerate from 0-70 mph in the distance of an on-ramp with a slope. The design parameters of typical on-ramps would probably need to be known.
Horsepower Design Equation Formula Calculator - Engine Horsepower Trap Speed Method calculated my car needing ~73 HP to accelerate to 70 mph. Although, it seems to be very basic and not adding in cD which will have an affect.