Quote:
Originally Posted by redpoint5
I would be very interested in your results after the pulley mod.
I am under-driving my Acura with aluminum pulleys that saved a bunch of weight, but I only had the car a couple of months before I did the mod, so my driving style was still evolving. I don't know how much of a FE difference it made. I figure turning the power steering pump, water pump, alternator, and AC at a slower rate should save some power. It will probably take 20yrs to recover the cost of parts alone, assuming a 1% fuel savings.
I still say all of this is lunacy when you can just go MT and outperform the most outrageously modded auto. It may be fun lunacy though.
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Sorry, missed your post yesterday!
The pulley is more critical with AWD and an automatic. The Subaru, well mine at least, actually maintains into the 33-38 while at highway speeds, and it its pretty good for around 30-33 range for 40-55. The problem is parasitic loss from the acceleration of all the rotational mass.
I can't pull out reasonable without dipping down to 8-10mpg and staying in an low rpm range. Even then it takes 1/4 of a mile to get up to speed, so for that quarter of a mile i'm using a 1/40th of a gallon for every stop sign, for every slow bum that near stops to make a turn. So I'm probably wasting half a gallon a gas a day just stopping and going. When you're only using 3-3.5 gallons a day, you're talking ~15% loss in FE as waste, this would bump my trips with the Subaru into the 30.x marker.
This is terribly true for any hills as well, the climb rate at 25-30% load to maintain even 35-40mph dips me down to 16-20mpg. All I really need to do is reduce the load the engine is under in these conditions and I would gain full mileage...at this point, look at hybrids. These are exactly how they get a ton a mileage.
Thus the only solution to reduce load is to reduce rotational mass or static mass of the vehicle. Since I kind of like doors and trunks and seats, it is hard to reduce static mass. Rotational mass can be done through pulleys, driveshafts, rotors, tires etc.