4banger tires and gears

After almost 5 months of mostly being in the garage "Norbert" is road worthy again, the new hub bearings being the last major issue. I'd like to thank you for the great ideas we incorporated into the rebuild with more yet to come. My question is for Ghost or anyone else running an old 4 banger. How is your power with the larger tires? I'd like to put on some 33s but don't know quite where to go with the differential gearing. The front and rear are stock Dana35 and 30. As near as I can tell I need to go 4:65. Keep in mind that I'll have to take it over Vail Pass to get to Moab.

P.S. Just like to commend everyone on this forum for passing along the great info and not just flamin' poor dumb souls like me who are somewhat new to build-ups.

Definately 4.56 with 33s, 4.88 are worth considering too. I did a 4.10 to 4.56 on my 4 banger and the difference was there but hardly back to stock.

No personal experience, but there is a guy im my school's 4x4 club who has a YJ with the 2.5 and 4.56s. Hes running 38s (now 35s I think) and wheels the piss outta it.
Its not the most ideal combo, but over a big group ride at Windrock in TN, he put a couple of bigger rigs with 360s to shame crawling on the rocks.

Well......

I'm running 31's right now and 4th gear is useless except going down hill. I am running 3.73's right now. I will be going to either 4.56's or 4.88's in the very near future. 33's should be here this week. I'm leaning towards 4.88 bc I would rather have the lower gear and high RPM's on the highway then not haveing the ability to pull my self out of the way! LOL! ALso in my experienc that little 4 banger can really handle the rev's. I used low range mostely when off road right now just bc it is easier to turn the tires over and clean them out! How did you do the TBI swap? I am leaning towards a Weber right now but that would more appeal to me bc of the steep incline I plan on being on!

TBI swap

If your engine is out then it's not too bad. Get the tbi and manifold and anything else connected to the wiring harness. You have to swap flywheels and bell housings because of the crank sensor but I needed a new clutch anyway. There is a plate that blanks out the mechanical fuel pump. The electric fuel pump will fit in the same hole as your tank level sensor and that (for the fuel pump) is the only extra wire you have to run through the firewall. I took the fuel pressure line (with the mount for the fuel filter) and return line out of the donor because they screw right into the throttle body. From there I just took the wiring harnesses, cut the old firewall plug and spliced it to the new one. The only mistake I had was mixing up the washer motor pump and washer level sensor wires which look exactly the same. I had a few extra wires from the firewall because of no a/c on the new. The hardest part is getting the ignition and fuel injector before they disappear from the junkyard. There are a few other items including the airbox, coolant overflow and windshield washer tank that you need to swap also. There is alot of crap that comes off the carburated and frees up space. All in all I'd do it again and might even tackle efi for the 2.8.

I've been wondering if the 2.5L TBI might not work on the 2.8L. There really isn't much difference in displacement, so if you keep the revs below redline I don't see why it wouldn't work.

'Course, you could also grab the injection and computer for a Chevy 3.4 from a junk yard and go at it that way.

So the 86 TBI uses a CPS also? Or is this off a 91 and up? I thought the CPS did not come into play until the 91 MPI? Hmmm I may try this out.

CPS

Yeah , the cps came off the '86. I think they moved it to the front of the engine later on.