Next Jeep project decision

[FINOCJ]

Thinking a bit about my next big jeep project...trying to decide whether to go with a 4 speed swap or installing a selectable locker in the rear. The goal here is to improve off road capability with the most bang for the buck - say in preparation for a Rubicon trip next summer. I am leaning toward the locker...but a bit intimidated by differential work. I think it would give a huge traction improvement for less money than the 4speed swap. But the new BDS springs have really helped with traction and I air way down with MTs. The 4speed would probably cost more and take more time with fabrication for all the aspects (floor tunnel mods, crossmember etc), but I am pretty comfortable with what I think needs to be done. As I have 4.88s with 3.15 tera low gears, my CR is already at 47, which just gets the job done...not good but hard to justify a swap to a 4speed (which would provide CR of over 90) IMO.

As a total dream...a 3rd option would be TBI...most expensive, extensive and complicated in all aspects...whaddaya you all think?

[open_circuit]

I lack the expertise to offer any advice here, but I will ask what "TBI" is, since the acronym isn't jumping to mind.

[newracer]

TBI = throttle body injection

I vote for locker.

[Spieg]

Hard to say without more info. What transmission (t-86, t-90?) and gear ratios have you got now and what would you be going to (t-98, ?)? I would think the EFI would not be that expensive to do (at least you don't have to worry about emissions compliance which makes a junkyard TBI swap an option assuming you don't need something special to make compatible with your odd-fire engine).

[Java]

I vote locker, even with the other two you'll still want that, but with it you may not want the 4speed. I've changed carriers a few times, it's surprisingly easy. In my current Jeep I've gone from open to a truetrac in the d30, and in te rear 44 from tracloc to spartan in an open carrier to an old style truetrac to a new style truetrac, so 4 times total with no problems. When you have the OEM carrier out put it on a known flat bench next to the new one. Put a flat edge on the mounting surface for the ring gear and across the top of both carriers; if those line up, you should be gtg if everything else remains the same.

[Brian]

Locker for sure.

[FINOCJ]

Hard to say without more info. What transmission (t-86, t-90?) and gear ratios have you got now and what would you be going to (t-98, ?)? I would think the EFI would not be that expensive to do (at least you don't have to worry about emissions compliance which makes a junkyard TBI swap an option assuming you don't need something special to make compatible with your odd-fire engine).

I would be swapping my OEM t14 3 speed with 3.1 1st to either a t18 (6.3 1st) or sm420 (7.0 1st). Biggest hassle with tbi is the odd fire coil doesn't provide a consistent signal for tach input...can be overcome with a crank tach signal. Pertronix should work for spark but some seem to need HEI. Additionally I need to figure out fuel delivery with my dual tanks and switch set up. Finally I would need either a 4 barrel to 2 barrel manifold adapter or new 4 barrel intake. Its gonna happen but not sure I am ready for a $2500 bill just yet.

[Jim]

My order...

1) Selectable locker for the rear (so long as you're set with axle housing / gear ratio). If gear lash/setup is a concern - just pay to have it tended??

2) TBI.

Crank sensor might be easy. My TBI setup has the crank sensor bolted on to the block to the already crank sensor capable crankshaft pulley or damper. I should think you could "roll your own" sensor setup with glue-on magnet onto your crank pulley with a capable sensor pointing at it. I recall Dad doing this with aftermarket cruise control kits that needed vehicle speed inputs (late 60's to late 70's) with a small rare earth magnet (or set of magnets) to the axle shaft. One magnet / sensor pulse per revolution of the crank for your needs. If you need more pulses per rev, equally spaced, magnets then equally spaced.

Your fuel tank setup, I'd think would not change - is one tank your master tank which is always pulled from? Dual tank might be a benefit for the "failed fuel pump" issue - one in-tank pump for each tank.

3) Trans

[The StRanger]

I vote locker. Crawling in a stick is a pain.
If you have a real low crawl gears it might be different but. I'd still do lockers nd skid plates...

[JGRubicon]

@73:1 you really do not even need the clutch. But I would put a manual in if it wasn't offered, I'm a masochist, I enjoy it.

My list is the same as Jims.

Locker - When you finally need it, it's so sweet
EFI - I remember running with you and you saying something to the effect of, it's running like a dog up here, but I don't want to re-jet it. I can't imagine a world in which this won't be an amazing mod.
Trans - Yeah, I like rowing, but it's still last of the three.

[Java]

Maybe this could work with a little tweaking? the GMtbi for the v6 and v8 are the same except for the injectors which are cheap https://denver.craigslist.org/pts/d/tbi-fuel-injection-conversion/6662325478.html

[Jim]

the GMtbi for the v6 and v8 are the same except for the injectors

How does one convert between 8 and 6? The dist cap is 8 - put on a 6? Does the computer have a jumper for 6 / 8?

[Java]

His distributor is another monkey wrench, short version is that one in the ad would not work but the rest of it would with only (I believe) two new injectors and a PROM chip. I did this conversion via Howell for my 4.2 YJ years ago, it was a great upgrade. I also did a swap from the BA-10/5 to a Ford T18a on the same rig, if I had it over I would have done an AX15 or NV3500 instead.

[Spieg]

not sure I am ready for a $2500 bill just yet.

OUCH!! For that kind of money you could almost swap the entire engine. GM Vortec 4.3 are plentiful and cheap.

[FINOCJ]

OUCH!! For that kind of money you could almost swap the entire engine. GM Vortec 4.3 are plentiful and cheap.

yup - that is why TBI is not a common upgrade. I want to keep the oem oddfire 225 so that limits my options. I think it could possibly be done for $1500 (all new parts) by someone who has done it before and knows exactly what is needed and not needed (checking with a friend in the springs who has done 2 of them). But he already has some of the upgrades like HEI, 4 barrel intake, useable tank and fuel lines for the fuel pump etc. The actual TBI units (from EZEFI, FiTech, Howell, Holley Projection etc) are all GM knock-offs and alone are kind of reasonable. But none will provide support for an odd-fire application, so then its a bit of a go it alone with getting the right additional pieces, harness, sensors, pumps etc that will work. I'd be happy to buy a complete kit (even without warranty and support) and come out at 1500-2k even with some wasted expense, but there is always some unexpected expense and screw ups along the way.