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Lowest gear ratio possible?

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Old Sep 16, 2008 | 12:29 AM
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Default Lowest gear ratio possible?

Well, I'm kind of a newbie when it comes to rear ends but my buddy has a stock 10 bolt in is TA and just came across a 12 bolt for super cheap. He wants to find out what the lowest gear possible to put in either of those rear ends for highway mileage purposes. I told him that it's probably a stupid idea but was curious nonetheless. The lowest I've read up on is the stock GU2 code A4 cars with 2.73 gears...can they go any lower to obtain better gas mileage?

thanks!
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Old Sep 16, 2008 | 01:22 AM
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1.73's














jk...i have no clue, good question id like to know this too...just out of curiosity lol
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Old Sep 16, 2008 | 08:06 AM
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I have a set of 2.41s' hanging on the garage wall as an item of curiousity.2.73s'(GU2) are rated at about 30 mpg and 3.23s'(GU5) are rated at about 25-26 mpg.Between those two is where the biggest change occurs.A lower gear(higher numerically) above 3.23s' will reduce mpg but not to the point of theoretical change based on mechanical change because as it becomes easier for the engine to move the vehicle(gears provide a mechanical advantage).4.56s' give me 21.5 mpg.A higher gear(lower numerically) past 2.73s' will improve mpg but not by much as the engine is now being loaded at a higher level and fuel mapping will richen up to negate some gain caused by the ratio change.
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Old Sep 16, 2008 | 09:21 AM
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I have a 2.29 used gear set out of an 1980 G-body, the pinion is almost the same size as the ring gear.
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