Quote:
Originally Posted by sarguy01
Mista Bone, were these transmission swaps done along with engine tuning/modification? If so, that really makes it hard (impossible) to justify the gains the transmission swap gave you.
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Straight transmission swap, no tuning involved. I was just learning how to rebuild these trannys and made a few mistakes as well as trying different ratios. One year (2000 or 2001) I was swapping transmissions about every three weeks. The tune that Blundar (David Blundell - Tuner) used was a best guess first shot, there was more there but 10-12 much was unknown about the limits of the tuning.
Quote:
Originally Posted by some_other_dave
Another point is that you can gain BSFC and still lose overall MPG. Even if the engine uses less fuel per injection, and therefore less per revolution, your need more revolutions of the engine to go one mile with a lower gear than a taller one. So unless the gains from running the engine in its sweet spot are more than the difference between the gear ratios, you get better economy from running in the higher gear.
-soD
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soD: either low rpm like most prefer on here or a higher more normal rpm like I prefer both require the same amount of fuel when cruising at same speed in same car on the highway. The advantage of the higher rpm is if you have to pass someone, like a 18 wheelers doing 55 mph and cars are allowed 65 mph. To make that pass I had to use less throttle input. With longer gears you will have to use more fuel to safely overtake, same thing if on a hill or a stiff headwind.