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Old 04-15-2010, 01:49 PM   #19 (permalink)
comptiger5000
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Join Date: Feb 2010
Location: CT, USA
Posts: 544

RaceJeep - '98 Jeep Grand Cherokee (ZJ) 5.9 Limited
90 day: 13.62 mpg (US)
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I would LOVE to put a stick in this thing.

However, it is expensive, and requires a lot of custom fab work, although it's been done a couple times before. If it was a 6 cylinder, it would be much easier, as the first 2 years (93-94) were available with a 5 speed. However, the V8 version of this thing never came with a stick. It requires fitting a transmission that was never meant for this vehicle, custom tranny mounts and crossmember, custom shifter, ECU swap from a dodge pickup, etc. Total cost is about 1500+.

And, if I really wanted to do a good stick setup, I could adapt a Viper 6 speed to the engine, although that would have even more cost (2500+), as I'd need to re-gear the axles from 3.73 to 4.56, as the Viper tranny has such tall gearing through the whole range. Without a gear change, I'd be lugging 1320 rpm at 60, making 6th gear unusable except on dead flat ground. Also, the lower gears are pretty tall, so I'd have no power off the line in 1st. Currently, I turn a little over 1800 rpm at 60.

With the viper tranny and 4.56 axle gearing, I'd turn just over 1600 at 60. I could even go as far as the axles will support, to 4.88, giving me a bit over 1700 at 60. That would probably be my best option, as I would drop my crusing RPMs a bit, but not enough to worry about lugging, or having to downshift a lot on the highway (it never does with the current auto). And, I'd have plenty of power in the lower gears.

Basically, for this vehicle, I can put A LOT of gas in it for the cost of a stick conversion. When I go away to college in the fall, my goal is to hit 22mpg on the trips between there and home. After college, I fully intend to buy another vehicle and retire this one from DD duty.

And just think: If I drove like a normal, inefficient driver (hadn't found this site, and learned about DWB, etc), I'd probably be getting 9 - 10 mpg in my current cycle. On this tank, the computer is saying 13.3 so far, as it's vacation week from school. More or less the same driving, including the short trips. However, it excludes the really inefficient drive to and from school (lots of short roads, up/down hills, only 2.5 miles, etc). But, regardless of the gas mileage, I love my Jeep . Plus, my auto is in pretty good shape and shifts great with 102k miles on it. Rest of the Jeep runs well too.
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Call me crazy, but I actually try for mpg with this Jeep:



Typical driving: Back in Rochester for school, driving is 60 - 70% city
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