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Old 12-20-2019, 12:45 PM   #10 (permalink)
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Originally Posted by Big Dave View Post
What's your final gear ratio?

That Cummins can live with a staggeringly low (numerically) ratio.

My 7.3 Powerstroke thrives of (3.08 x 0.8 =) 2.45:1 plus the ZF6-550's overdrive gear.

Low gear ratios are very potent for diesels.
Not sure what the final GR is, gearing is 3.73's with the late G56 which has the preferred gearing. Last time I chatted with Skyking he had the same trans but 3.42's with 2 sets of tires. He mentioned recently he was able to get 25's but did not answer my question about the tires. (34's or 31's) I drove his truck back then, not bad but on a stock tune, it did not sit well with me. Seemed like a lot of throttle to get going and I would expect the hills would kill his mpg.

The way the truck is now with the light weight parts and the huge overall bump in throttle response, it would be way better. Still are faced with the grades everyday on the way to work. As of now, fueling is dialed back significantly to tone down that throttle response change and it still has room to be dialed back. Dialing back = dropping rail pressure & adusting timing, then trimming duration to cut smoke output.
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