Here is a list of things I did:
1) Electric Fan, go with high CFM! The engine will overheat in the summer with AC on.
2) Remove front driveshaft. Simply get a crecent wrench and undo the bolts holding the front shaft in place. You will notice a reduction in the amount of pedal you need @ 75Mph+. I can post pictures if you do not believe me... this mod really works!
3) Disconnect alternator cables and run in Hybrid mode. The Jeep TJ can travel 30 miles with four restarts in this mode on the stock battery. I bought a 12 amp battery charger at the local hardware store and recharge with a quick disconnect cable everynight.
Here are some pics:
Here is a 90% efficient power supply that I rebuilt/upgraded for this use.
I now get 22 MPG on a lifted 33" tire TJ.
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