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Old 07-19-2008, 08:07 PM   #10 (permalink)
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ALS and garys_1k -

Originally Posted by ALS View Post
2.73's are too high for that set up. The best bet is to go to 3.08's from the 3.27's. The computer and transmission are already set up for the 3.27's.
You go to 2.73's you will take your car way out of it's power band and confuse the transmission of where it should be shifting. Don't you love computerized cars we have today. In most cases, you noticed the word MOST the automobile manufactures drop the optimum gearing by a set to improve the acceleration. It is the happy medium between fuel mileage and drive ability that is built into the cars today. It's like tire pressure.
They recommend 34 psi for the ride although 40 psi would be much better for fuel economy. There is always a compromise.
Around town there will be a minimum improvement in fuel mileage but expect between 1 and 2 mpg better on the highway. The trick is to incorporate multiple improvements to maximise the fuel mileage gains.
Without knowing the nuts and bolts of it, that's what I was afraid of. Unless you can also override the ECU/PCM with some kind of "manu-matic" paddle-shifter arrangement, I would think you'd have lots of shifting problems.

garys_1k writes :

Of course, if you could recalibrate the shifts to work at the same vehicle speeds, then you'd be more likely to gain in city driving, too. I'm not sure how it's now calibrated -- to work off real vehicle speed or transmission output shaft (driveshaft) speed. If it's the latter than you'd definitely just delay upshifts with a lower numerical final drive.

Can this be done? At least for a Mustang, I would think there is more aftermarket options for something like this.


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