Economy

[cjackson3396]

My 4.7 stroker project has stalled for a bit...So i figured i'd ask everyone a quick question on their experiances with the stroker. Right now the 96 XJ is as i bought it...stock gears stock 4.0 5speed with 114,000 has 35inch tires.....I get about 11mpg if i'm lucky. If i put in 4:10 or 4:56 gears with my 4.7 engine I'm building...will I see better MPG it isn't the biggest concern but I was curious. The 4.7 is a 94-block 99-intake 81-4.2 rods and crank. I'm going to put in a longer duration cam of course. as for the expensive stuff I didn't do as in performance pistons and all the head work..it will have a pretty free flowing exhaust and a k&n air filter if we don't modify it for ram air.

[Biggrnjeep97]

You will see better fuel economy. Will it be good? no. Should you care? no. What you will gain from re-gearing is better driveablity and a happier trans.
-Will

[ilber]

the one^^^^ tells the truth.
I betcha that you drive with flooring the skinny pedal, but with lower gearing you would not need to strain the engine as much. Yes you would have more rev per min at the same speed but you are n a better spot for the TQ. Look at that a 4 hole wrangler does not get better milage than my 6 cylinder, becuase it is being taxed all the time-more fuel...
alternatively... I drive a 6.0L car and get mid 20's in town, because if i floored...well I will be going to prison or will kill someone... so I usually less than 40% load get the job done very well... and in return i get decent milage and can justify driving a nicer car as DD
Regear it! milage would be in low teens anyways, but you would have way more "fun to drive" factor.

ilber

[YJason]

17/14 mpg in my YJ w/33's, 4:10's, AW4 trans, and 4.6 but I have to run 93 octane.

[yuppiexj]

My stock engined 88 XJ got 21/18 with 4.56 gears and 32s. (230K miles too)

it was like driving with the parking brake off when I swapped out the 3.55 for 4.56 axles.
Sure the engine spun a little bit more on the highway at 80+, but the drivability was worth the (potential) trade off in engine life.

Regear

[Jeep4xb4u]

I slapped 4.88's on mine with 33's only a few weeks after lifting because i couldn't stand the sluggish characteristics. Do it and never look back, you may find yourself using your 5th gear more but you wont be disappointed. I went a little over kill with 4.88's but its funner then heck from 0-40 specially with the new engine, but leaves brown stains in me and my passengers underwear on the highway.

As for fuel efficiency, if you select the correct gears you shouldn't loose much if any. As others have said, you wont be pressing that pedal as much to get to point "b".

[Cheromaniac]

My 4.6L stroker with '01 XJ intake delivers better fuel economy on the highway and the same fuel economy in the city as my old 4.0L engine. The reason is that I can drive the stroker on a lighter throttle to go just as fast.

[crustodd]

4:56's with 35"s will put you about equal to stock gearing, but the 35"s are WAY heavier. The stroker's extra torque will compensate for that some, but again it takes more energy to get that mass rolling and will put more wear and tear on the drivetrain and brakes to stop them. FUN costs $$$