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I'm curious about all these fantastic performance claims Toecutter likes to go on about, as if the entire engineering community is unaware of them. So putting a canopy and skirts on a pickup will extend range from say 100 miles to 140? If it's that simple I can't understand why he hasn't put skirts on that Sidekick or whatever it was and begin to reap the benefits of doubled FE and quadrupled top speed right away??? Come on man, start a gaslog here, throw them skirts on, and DO IT.

I very badly want to modify the Sidekick, but it is my step mom's vehicle and she said no. Otherwise I would have done so last year.
I most badly want to see how aeromods would affect top speed. Before the tuneup, it was an absolute dog topping out at like 71. While the speedo only goes up to 90 and with a recent tuneup it can now actually hit 90(drag limited), I'd be able to see how much faster it was going by eyeing the RPM gauge. With the vehicle's tires and gear ratios, in 5th gear, each 1000 rpm is 20 mph. At 90 mph, it is exactly at 4,500 rpm, 60 mph exactly 3,000 rpm. It governs out at like 6,000 rpm, but will never reach it in 6th gear from the drag. It would not surprise me if rear wheel skirts, bellypan, grill block, rear diffuser, removed roof racks, front and rear wheel spoilers, side skirts, wheel covers, removed passenger mirror, and partial boattail improved top speed to about 100105 mph and has a positive effect on highway mpg by 1520%. But sadly, I just won't get the chance to test such mods, unless say, my step mom were to give me that piece of crap and tell me to do whatever I want with it. She has been considering a new car, but I think it is stupid since the vehicle she has is still usable. But there isn't much convincing her...
I do have two cars under my name, both of which aren't yet road legal. I have the 1996 Ford Contour that needs engine repairs and needs to have its emissions system replaced to pass inspection(I used to drive it as a teenager until it developed engine problems and was taken in to get inspected and it didn't pass emissions), and I have the 1969 Triumph GT6 MkII that is undergoing a restoration and conversion to an electric vehicle. Once I get the Triumph going, I certainly will experiment with that and certainly will report the results here. As for the Ford, it would probably be cheaper to convert the Triumph to a simple 6070 mph capable electric car with contactor controller, bridge rectifier charger, Prestolite motor, and 144V pack of Universal Battery UB121100 AGMs. That's doable for about $2,000 more. Therefore, the Triumph is what is getting my money.
I would keep a gas log of the Sidekick if I had an accurate way to keep track of the fuel used and miles driven. The problem is that it is not an OBDII(therefore not scan gauge compatible), and even if it was, that $250 for a scan gauge would be better spent on the Triumph. Further, my dad and step mom both use the vehicle too, and sometimes they put gas in it just as I do. I'd have to pester them for the numbers each time they put gas in it, and if they don't have them, it ruins any validity for the experiments. The only time I've been able to get any reasonable fuel economy estimates is when I've started a set of trips with a full tank and refilled it myself, and I imagine the error is about 10% or so given that all I have to rely on is the fuel gauge needle, the odometer, a gas pump, and the fact that it's a 12 gallon tank.
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I'm curious about the equations you use to arrive at this data. Run these numbers and tell me how fast this thing accelerates and tops out at:
2800 lbs
100 hp
22 sq ft frontal area
Cd .37

Let me guess? Your Tempo?
I won't be able to calculate top speed unless I have a map of the engine.
Acceleration needs an engine torque vs rpm map at full throttle to be calculated accurately. But it can be reasonably estimated +/ 10% with power to weight ratio.
(Mass in kg)/(.9 * horsepower) = 060 mph acceleration time in seconds is a commonly cited rule of thumb for a gasoline powered car.
So, using this estimation, 060 mph of this 100 hp, 2,800 pound car is 14.1 seconds. My friend timed his Ford Tempo GL from 060 mph and got like 15 seconds. He has the 98 HP 2.3L HSC L4 engine.
I can fairly accurately estimate fuel consumption though, but it may be a little off without a specific map of the engine and instead using the graph below to estimate how the engine will behave in regard to efficiency:
Mass(W): 1,270 kilograms
Drag Coefficient(Cd): .37
Frontal Area(A): 2.05 m^2
Rolling Resistance Coefficient(Cr): .010
Transmission Efficiency(TE): .8 (Includes stray losses like wheel bearing friction, accessory loads, ect.)
Velocity(V): expressed in meters per second, in this case 30 mph or 13.4 m/s
Force Drag(FD): expressed in newtons
Force Rolling(FR): expressed in newtons
Force Sliding(FS): 30 newtons
Wheel Power(WP): expressed in watts
Motor Power(MP): expressed in watts
Engine Efficiency(EE): thermal efficiency of engine at given load expressed as decimal
Fuel Power Required(P): expressed in watts, the rate at which gasoline is being used(33,800 Watt hours in a gallon of gasoline)
Air Density(Rho): 1.25 kg/m^3
Gravitational Constant(G): 9.8 N/kg
Equations used:
FD = .5 * Rho * Cd * A * V^2
FR = Cr * W * G
WP = (FD + FR + FS) * V
MP = WP / TE
P = MP / EE
Results:
At 26.8 m/s(60 mph):
FD = 340.5
FR = 124.5
FS = 30
WP = 13266
MP = 16583
The motor itself is 67 kW peak power. You are using at 60 mph 16.583 kW of motor power to maintain speed. This is 25% engine load. Looking at the graph above, you get roughly 24.5% engine thermal efficiency.
So:
P = 67686
At 60 mph, you are using 67.686 kW worth of fuel while the engine is outputting 16.583 kW.
(33800 Wh / gallon) / (67686 W) * (60 miles / hour ) = 29.96 mpg
Your Tempo would thus get an estimated 30 mpg at a steady 60 mph from the above. How accurate is this? The EPA rates it at 28 mpg highway, for comparison.
The above graph is very flawed, because it doesn't factor in RPM, and a real BMEP vs RPM map has circular shapes representing a certain amount of kWh per gram of fuel delivered for given areas on the RPM versus BMEP graph. It's often graphed in two dimensions sort of like an elevation map.
Using the above methodology, if you were to cut your drag coefficeint to .20, you'd need 11,341 kW produced by the motor at 60 mph, giving you 17% engine load, giving you 22.7% thermal engine efficiency, and you'd get an estimated 40.6 mpg.
This would be an estimated 35% improvement in FE if you got your drag coefficient down to .20 and no other changes whatsoever.
LRR tires(Cr .006), synthetic tranny oil and zeroed alignment(now .85 efficiency for transmission, 20N sliding friction), reducing weight by 150 kg, along with lowering drag coefficient to .20 would get you an estimated 50 mpg at 60 mph.
All of these cases are with no engine modifications at all.
Sadly, I do neglect cross winds and other factors like such, and again, that graph is general and doesn't account for engine RPM.
Find me a specific map of your engine, for both torque vs rpm, and BMEP vs RPM vs kWh/g fuel efficiency, and I will do my best to model how all of this will affect the performance of your ride.
***note***
I typed 67 kW when the engine actually is 73 kW. Misconversion from HP to kW on my part. Oh well. Shouldn't affect the results much, as the only thing this number was used for was finding percentage engine load. Probably remove about 0.5 mpg from it or so.