1989 Toyota 4Runner - Tundra Power!
Steroids Under The Hood, Long Legs On The Ground
Most first-generation ('84-to-'89) Toyota 4Runners are easy to catch. Not this one. In place of the 3.0 (AKA 3-point-slow) V-6, you'll find a thoroughly modern 4.7L i-Force V-8 plucked from a donor Tundra.
Will Browne of Redondo Beach, California, has owned this 'Runner for a long time, having purchased it with only 40,000 miles on the clock. Browne is a Baja fan and infused his ride with a Total Chaos Caddy Kit to handle the rough roads and trails south of the border. After several years and multiple trips, some of the 4Runner's stock parts began to call it quits. "I was a few miles into a trail in Baja when I heard a big clunk," recalls Will. "It turned out that the stock torsion bar mount had torn off of the frame on one side. I had to drive out lopsided. I found out that's a common problem on these trucks if they're used hard."
Around the time the torsion bar mount ripped free of the frame, the 3.0 V-6 was showing ominous signs of things to come. "It needed a rebuild," Browne told us. "It was gonna cost around $3,000 for the rebuild, and I found a used Tundra V-8 for the same price. The stock engine was slow and the fuel economy wasn't all that great. The Tundra engine is way faster and gets about 15 mpg."
Swapping an i-Force V-8 in place of a 3.0 isn't for everyone. Browne is a salesman, but has the hands of a professional mechanic and the mind of an engineer-attributes he called on again and again during the engine swap and the rest of the build in general.
What was tricky about the engine swap? First was fitment. The 4.7L is a big pill for the first-generation 'Runner's engine bay to swallow. Custom engine mounts had to be fabricated, and a custom radiator was also required. The firewall was given some love with a sledge. Underneath, the oil pan had to be cut and re-configured to clear the front differential.
Another tricky aspect of the engine swap is that the Tundra motor was originally connected to a computer-controlled automatic, and Will wanted to use his Marlin Crawler-built five-speed manual tranny. To mate the i-Force to the five-speed, Browne cut an inch off of the front of the stock bellhousing. He then contacted a machine shop to have an adapter plate made. The resulting adapter plate is an inch thick and bolts to the back of the V-8. Browne TIG welded the adapter plate to the stock bellhousing. The next task was fitting the stock flywheel to the back of the Tundra crankshaft. This was successfully accomplished by having the Tundra bolt pattern bored into the flywheel. Finally, the engine computer had to be dealt with. Remember, the Tundra ECU is still looking for signals from an electronically-controlled automatic. "There are four solenoids that control the automatic transmission," Will informed us. "My first plan was to get the solenoids by themselves and hook them up to the wiring harness. My dad, who is an electronics engineer, told me that I'd just need to get some resistors of the proper size instead." As soon as the resistors were soldered in place, the Tundra ECU couldn't tell the difference between the resistors and the stock automatic transmission. The engine runs cleanly, and the Check Engine light stays dark. The ultra-picky CARB gave its seal of approval to the engine swap. There's an official California Air Resources Board decal in the passenger's side door jam.
The drivetrain was good to go, but the suspension still needed to be addressed. Instead of living with the shortcomings of the torsion bars, Browne decided to eliminate them in favor of coilover shocks. Up front in place of the original Total Chaos Caddy Kit you'll now find a Total Chaos Gen II Caddy Kit, which uses coilover shocks. The 4Runner's tail section is suspended by a pair of Deaver leaf packs which run under a swapped-in Tacoma axle. To eliminate axle wrap, Browne designed and built a four-link system. Stomp on the skinny pedal as hard as you can. The axle won't wrap one bit.
There's more to tell, but we'll leave that for the photo captions. We'll just say that with Tundra power under the hood and long legs on the ground, this is one 4Runner that's hard to catch.
The Value of Bumpstops
We write all the time about hydraulic bumpstops around here, and I've ridden in several bumpstop-equipped trucks, but this was the first time I experienced a back-to-back apples-to-apples comparison of what a difference hydraulic bumpstops can make.
My personal '04 4Runner is equipped with a Total Chaos long-travel front kit that uses Sway-A-Way coilovers and boasts 13 inches of travel. As mentioned earlier, Will Browne's 4Runner uses a Total Chaos long-travel front kit that also has 13 inches of front travel. Will has Fox coilovers up front, but he also has a pair of Fox hydraulic bumpstops along for the ride.
It's a similar story for the rear suspension. Browne's 4Runner has hydraulic bumpstops and mine doesn't.
We drove on the same terrain on the same day. This was in the Hungry Valley OHV area near Gorman, California. Side note: we went during the week when it was safe to be going fast on these trails. On the weekend it's a bad idea to be going fast in a truck in Hungry Valley because there are lots of dirt bikes and quads running around. Back to the main point. Browne made quick time on me through the rough. When the 'bumps were mellow our speeds were about equal, but when the big stuff came I had to slow down to avoid harsh bottoming and potential truck damage.
Sitting shotgun in Browne's 'Runner, the value of hydraulic bumpstops was glaringly obvious. There was much, much more control during hard landings and big hits. With the hydraulic bumpstops, it was possible to hit the gas in places it wasn't safe to without them. They made that big a difference.
Hydraulic bumpstops are offered by Sway-A-Way, Fox, King, Bilstein, Light Racing, F-O-A, and Fabtech.
Guess what's next on my list?
'89 Toyota 4Runner
Will Browne/Redondo Beach, California
4.7L Toyota Tundra i-Force V-8
Stock EFI, K&N intake tube and filter, custom air filter box
Stock R-150F manual five-speed rebuilt by Marlin Crawler with synchros and shift kit
Stock chain-driven Toyota V-6 type
Total Chaos Gen II Caddy Kit, T.C. idler arm, and T.C. King Kong steering. Fox coilovers and bump stops. T-100 axle shafts. Custom-machined inner CV bells. Travel: 13 inches
Toyota Tacoma V-6 Prerunner with wheels spacers. Deaver spring-under leaf packs, and Browne-built four-link. Doetsch Tech shocks, Fox bump stops, and stock bump stops. Travel: 13 inches
Ring and Pinion:
4.10 to 1
Stock open differential
Stock open differential. Note: open differentials are great for preserving the drivetrain. You won't get as much traction, but you'll also avoid some types of breakage
33x125.0R15 BFG Mud Terrain T/A
American Racing 15x8
Full rollcage, suspension seats, and more trips to Baja. "I'm not going to Baja right now with all the craziness down there. I'll go back when things settle down."