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Old 08-20-2012, 11:34 PM   #56 (permalink)
Join Date: Jul 2012
Location: goode, va
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no worries - '91 Subaru legacy L
90 day: 31.45 mpg (US)

weevee - '08 suzuki vstrom dl650
90 day: 61.22 mpg (US)

wrx - '09 Subaru wrx sedan
90 day: 29.8 mpg (US)

Big Bright Green Pleasure Machine - '09 kawasaki ninja 250 se

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Originally Posted by aerohead View Post
All the show cars and concept cars that get great mpg have special,low-rolling-resistance(LLR) tires.These particular tires are not in production and are not for sale,however,for the tires that are available to the general public,there is a "range" of coefficient of friction(Fr) for the tires available.------------------------------------------A 10% reduction in rolling resistance will net about 3.8% improvement in mpg,for comboned city/hwy driving.------------------------------------ Neglecting your tires,and letting the cold inflation pressure drop 25%,will cost you 1 mpg.-------------------------------- overinflating your tires 25% will net you a 1% improvement,but could destoy the tire,throw you out of control,and kill you,your passengers,and anyone else around you.------------------------------------ Tire manufacturers recommend that you never exceed the maximum pressure embossed on the tire sidewall.--------------------------.Also,it takes about 5-miles (8 km ) of continuous driving to get your tires up to their equilibrium temperature and highest economy.If your car is OBD-2,and should choose to monitor your mods with a Scan-Gauge,bear in mind,that any testing done without a 22-mile (35 km ) warm-up drive,will yield erroneous data,compared to a fully-warmed-up vehicle.In addition to the 5-miles necessary for the tires,all your lubricants will be below their equilibrium temps(and best performance) without at least 22-miles(35 km ) of warm-up.
My experience with the 98 corvette i had would tend to support your assertion. It takes an incredibly long time for transmission and engine oil to get up to temperature, even in warm weather. I used to monitor oil and tranny temps asmuch out of curiosity as anything else and was truly astounded. I would think circulating engine coolant thru heat exchangers in both manual transmissions and rearends would make measreable improvements in economy by using excess engine heat to warm the drivetrain lubricants. Any thoughts on that anyone?
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