Whats your RPM at 70?
04-15-2011, 11:22 AM
#31
JK Newbie
Join Date: Apr 2011
Location: Fort Worth, TX
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So for those of us with mostly hwy cruisers, at what RPM is the 3.8 most fuel efficient at maintaining speed. Per the table referenced below, a stock JK with auto and 32" tires, the optimal gear sets are 4.56, 4.88, and 5.13 and the stock 3.73's are barely usable. ("Minimal Allowable Gear set for tire size") So from a fuel efficiency POV, are those gears better than the stock 3.73's or are they better for performance. With all other things being equal, will my JK save more fuel with 3.73's or 4.56?
https://www.jk-forum.com/forums/show...276#post211276
https://www.jk-forum.com/forums/show...276#post211276
04-18-2011, 06:33 PM
#33
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Join Date: Aug 2009
Location: New Jersey
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don't recall 70mph rpm, but at 80mph I'm at 3k.
Rubicon - 6spd - OEM BFG M/T
I plan on going to 35's once these tires wear down, have you guys experienced a drop in RPM range and possible increase in MPG on highway after increasing to 35's? I wish 6th gear was like my 3.21 rear in my previous jeep, I use to get around 21-23mpg easy on the highway @ 80mph.
Currrent:
Highway - 15mpg
Street - 17.5mpg
Rubicon - 6spd - OEM BFG M/T
I plan on going to 35's once these tires wear down, have you guys experienced a drop in RPM range and possible increase in MPG on highway after increasing to 35's? I wish 6th gear was like my 3.21 rear in my previous jeep, I use to get around 21-23mpg easy on the highway @ 80mph.
Currrent:
Highway - 15mpg
Street - 17.5mpg