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1994 Jeep Wrangler YJ - Big Mini: Part 6

1994 Jeep Wrangler Yj And Exhaust Tubing
Pete Trasborg
| Brand Manager, Jp
Posted October 14, 2013


The goal of this project build was to get this Jeep back on the road and trails. We’ve been tinkering on this Jeep off and on for a whopping five years now. For about three years, it’s been on those 40-inch tires thanks to clearance gained by moving the tops of the rear inner wheelwells up and some early prototype front tube fenders from GenRight Off Road. We put a TJ soft top and factory rollbar on the Jeep and Rhino Lined the interior. Big Mini had the factory dash that was damaged, so we spent some time building a custom dash. We even swapped in an LT1 V-8 and 4L60E automatic transmission before we even started this six-part project buildup.

This last installment is all about dotting the T’s and crossing the I’s, as well as fixing some things we previously rushed through to get it fired up and running. We knew going in to the wrap-up of this project we were going to leave some things to do later because we’ve already done and redone so many little items. This time we wanted to get this Jeep to the point that we could drive it—even if it wasn’t perfect and pretty—and figure out what we really needed to spend time on after driving it for a bit. As with so many projects, this one bit us in the rear at the last second, and something we thought would be a simple fix turned out to be more difficult than expected. So join us as we cruise along to driving this Jeep for the first time in five years. And then don’t.

Step By Step

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  • Last time we played plumber, but we had one more thing to plumb. Big tires like this mean the power steering system is going to get hot so we opted to add a cooler. We only had enough space for a Hayden 401 cooler, which we got from Summit Racing. Since we were in the engine, and the LT1 already had the lines, we added another 401 to cool the engine oil as well. We hung both coolers off of a GenRight Off Road universal YJ cooler mount. It is basically the same kit we used in the last installment, cut for a YJ grille, but it ships raw. We had to weld the tabs on and paint it ourselves.

  • We had the engine ECU under the hood, mounted up high by the battery just to try and get the engine fired up while we were messing with other stuff that had to go through the firewall. But the Painless LT1 harness (PN 60502) comes with a grommet to pass the wiring through the firewall and mount the computer inside the cab. So we remounted it in the factory location behind the glovebox.

  • We didn’t have the stock indicator panel, so we bent this one up out of aluminum to mimic the factory shape. It mounts to the same locations so the factory plastic panel holding the tach and speedo is still removable. We put lights in it for the turn signals and high beams that we got from our local Radio Shack, but the amber light came with our Painless harness. To keep compliant with California smog laws (we hope), we added the check engine light sticker from Max-Bilt.

  • To keep track of our transmission temperature, we mounted mechanical Auto Meter gauge (PN 3351) to our half-finished console with a black mounting cup (PN 2204) we had lying around. The full-sweep mechanical gauge keeps costs down, but still offers more accuracy than a short-sweep gauge. After driving the Jeep and probably changing shifter locations a few more times, we plan on either skinning this console, or building a new one, and flush-mounting the gauge.

  • Rather than reinstall the factory glove box, we mounted a Tuffy Security glove box (PN 036). This is the third Jeep we’ve had this same glove box in and we’ve got no complaints with it. We keep saying we are going to paint it gray to match the other panels, but somehow never quite get around to it.

  • We went with Tuffy’s rear underseat drawer (PN 130) for smaller spare parts and tools that we aren’t planning on needing frequently because it’s behind a 40-inch spare tire and a CJ-style tailgate. In an effort to reduce the number of keys we have to carry, we ordered new locks keyed the same and then rekeyed both of them to match.

  • We were able to scrounge the center stack of factory gauges and the most of the plastic panels from another Jeep but we weren’t able to scrounge the factory speedometer and the four-cylinder tachometer would have been useless to us with our V-8. Again we turned to Auto Meter and installed an 8,000 rpm tach (PN 3991) and speedometer (PN 3982). The speedometer is a GPS speedo so until our satellites fall from the sky we will never have to worry if our speed is accurate. And really, once the satellites fall from the sky the cops will more things to deal with than a speeding Jeep.

  • We opted to mount our Power Tank horizontally so it’s less conspicuous with the top off. We pull it out of the mount and set it vertically before using it. This 10-pound tank might seem a tad small for 40-inch tires, but it can inflate six 40-inch tires from 10 to 30 psi on one tank charge. We could have gone for a bigger tank, but for a Jeep we are going to drive to the trail and then drive home, this should work just fine.

  • Somewhere, somehow the hardware to hold the Y-pipe to the factory manifolds grew feet and walked off. Fortunately, Summit Racing stocks factory-spec parts. We wanted to stick with the factory manifolds for the time being in hopes that we will get through our first smog check easier. However, the factory manifolds have small 2-inch outlets which Summit didn’t have flanges for. We sourced some locally and welded them to 2-inch to 21⁄2-inch Walker reducers from Summit.

  • To piece together the rest of the exhaust we used an assortment of 6-inch mandrel bend 3-inch tubing (PN SUM-622005-SS) and 3-inch straight pipe (PN SUM-640130-1). We got a tailpipe expander from Summit as well, but it was too small for the 3-inch pipe. So we slit the tube (note the horizontal weld) to get them to slide inside each other. We prefer this method to butt-welding, since it’s less likely to break apart under the kind of use we’ll put the Jeep through.

  • We used mandrel-bent 21⁄2-inch tubing we had laying around to build a Y-pipe. We thought about running a true dual exhaust, but there is no space for anything under this Jeep to begin with. Most headers for the LT1 have a 21⁄2-inch outlet so while we’ll have to go back later and swap that adapter out. Building exhaust at home with a chop saw and welder takes forever. Right now it’s just tacked together; we weld as much as we can in the Jeep and then we will remove it and burn it home with our trusty Lincoln Weld Pak 255 once all the tubes are ready to go.

  • Notice the way we attached the 3⁄8-inch solid rod hangers to two spots on the tailpipe rather one. That makes things much more durable than just welding it to the side of the pipe. We learned that little trick from Chappelle’s Exhaust and Kustom Shop which is where we should have taken this Jeep to get its exhaust done. It would have cost about the same and taken us way less time. However, towing it wasn’t going to happen, nor was driving it with no exhaust 200 miles.

  • From the Y-pipe we went into a 3-inch pipe and a California-legal catalytic converter. California banned sale of catalytic converters to private parties a few years ago because of the albino grub worm or some such thing. The Walker CalCat line cured that and we got our catalytic converter (PN 81919) and 50-series Flowmaster Stainless Steel muffler (PN 853057) from Summit racing as well. The 50-series is just a bit quieter than the 40-series. We picked up weld-in O2 bungs from our local shop because we simply forgot to order them from Summit.

  • We were able to route the shifter cables through the floor to our Winters Sidewinder shifter. There is no button to push or brake lockout in this Jeep, so the gates are all that keeps us from accidentally bumping the shifter from one gear to the other on the freeway (like from Drive to Reverse). Some guys will cut the detents (arrows), but we will leave ours alone for now. There are also “Rock Crawler” shifters that feature a straight pass from Reverse to Low, but they require a reverse valve body and we don’t want to dig into our transmission right now.

  • Up front, we gave the Jeep a nose job in the form of a Mile Marker SEC95ES winch that’s completely sealed against water and mud. While we are planning on rockcrawling this Jeep, we won’t be able to stay out of the mud. In addition to the motor being completely sealed, the 500-amp solenoid is sealed. The winch features a 9,500 pound rating and has a 4.8hp motor running through a 212:1 planetary gear.

  • We ordered the winch with winch rope, but when it showed up it had steel cable because Mile Marker has discontinued the rope. So, we turned to Viking Offroad for 100 feet of replacement 3⁄8-inch rope. Made from Dyneema SK-75 in the USA, it is lighter, easier to handle, and this new line boasts a 30-percent strength increase over steel. It will also float on water and is UV stabilized, unlike some other winch ropes. We opted for a thimble over a hook because we like D-rings, and the aluminum hawse fairlead saves us 24 pounds over steel cable and roller fairlead.

  • We strapped on a set of new DOT-legal 40x13.50R17 Nitto Trail Grappler MTs to our TrailReady wheels. They are actually closer to a true 40-inch tire than our old Goodyears. This made us happy we didn’t go through all the trouble of setting bumpstops, since they would’ve been too short. The 3-ply sidewalls will help keep us from sticking things through the tire. They are also a Load Range C tire, unlike most of the rest of the Trail Grappler lineup.

  • To use the Hi Fenders, we needed to chop 4 inches from the hood, which moved the hood latches. After trying different stock YJ and TJ latches without success, we ultimately got the hood to cinch down securely with these Rugged Ridge adjustable billet latches.

  • Of course, there’s a fly in the ointment. The bolt holes in our custom high-performance torque converter didn’t line up with our flexplate. We thought it would be a “simple” matter of getting a factory replacement torque converter, but after trying a few parts warehouses we came up dry. Most places rebuild your old converter, but that didn’t help us. We have a solution in the works, so stay tuned for the fix in an upcoming issue.


Auto Meter
Sycamore, IL 60178
Nitto Tire
Cypress, CA 90630
Summit Racing
Akron, OH
Lincoln Electric
Cleveland, OH 44117
GenRight Off-Road
Simi Valley, CA 93063
Rugged Ridge
Suwanee, GA 30024
Painless Performance Products
Ft. Worth, TX 76105
Chappelle's Exhaust And Kustom
Viking Offroad
Mile Marker
Pompano Beach, FL
Mile Marker
Eau Claire, WA 54703
Tuffy Security Products