To recap from the first two installments of project Sami Supreme, our '86 Suzuki Samurai underwent a few major transformations including a Toyota dual t-case drivetrain swap, a completely new three-link suspension, and some serious tube work from top to bottom. one of the main goals for the project was to increase the tire size from the previous 35-inch Baja Claws to a slightly taller 37-inch tire. With the sami riding on the taller 37-inch Goodyear MT/RS, it was obvious on our first test run that the anemic 1.3-liter stock Samurai engine simply didn't have enough guts to leverage the larger tires on serious obstacles.
The preferred solution to any weak engine is to replace it with something larger, perhaps with a few more cylinders. after all, there is even a popular phrase for just such a dilemma that states, "there's no replacement for displacement." While swapping engines may look like the obvious fix, there are a few parameters that must be met, namely the budget. Another limiting factor is weight. the stock Samurai engine may be lacking in a true test of power. If you can throw a rooster tail uphill in the sand with 37-inch tires, you're doing oK. the new Wild Bore carburetor setup is phenomenal, providing a noticeable power increase. the horsepower department, but it also lacks in the weight department, weighing a mere 200 pounds complete. one of the initial goals for the project was to keep the rig as light as possible, so swapping in a heavy iron block V8, V6, or an even larger four-cylinder like a Toyota 22RE would not exactly be ideal.
A popular engine swap for Samurai owners has long been the 1.6L, 16-valve Suzuki engine found in Geo Trackers and Suzuki Sidekicks. this engine is essentially the same as the Samurai 1.3L, eight-valve engine but with slightly more displacement and twice as many valves, giving it about 20 more horsepower with no noticeable weight increase. the 16-valve Suzuki engine has also become a popular choice for its fuel injection, allowing it to perform flawlessly on extreme angles unlike the carbureted Samurai setup.
The sos/rock 4X Fabrication Toyota drivetrain adapters used in the first part of our project utilized a sidekick bellhousing, so swapping in a matching 16-valve Suzuki engine would be a no-brainer. Looking over everything involved, the 16-valve engine would be the perfect candidate for Sami Supreme with only one exception. The progress on the rig to this point has been pretty rough on the budget, so unfortunately the engine swap would have to wait for now.
After looking at some other less expensive upgrade options to squeeze more power from the "little engine that could," a few alternative fuel delivery systems were discovered. The stock Samurai carburetor is the notorious culprit behind most brokendown, left-for-dead Samis and is by far the single most complex, problematic component on the entire vehicle. replacing this menace with something that provides more power, better fuel mileage, and the ability to operate on extreme angles would be a blessing.
There are actually quite a few options available to replace the stock carburetor. The list includes: retrofitted, stock electronic fuel injection, Weber carburetors, Bosch mechanical fuel injection, Harley-Davidson carburetors, and the one that caught our eye, the Wild Bore sidedraft setup from Samuraiguy.com. the Wild Bore setup utilizes four synchronized Mikuni sidedraft carburetors attached directly to the engine head with a custom aluminum intake manifold. the four large-bore Mikuni carburetors used in the kit are from '88-'02 Suzuki GSX-R motorcycles and are readily available at local salvage yards and online auctions for only a couple hundred dollars. Samuraiguy.com also offers a complete kit with tuned, rejetted carburetors included for easy bolt-on power.
Designed to work on race bikes that are "laid down" the majority of the time, these Mikuni sidedraft carburetors will even run upside down, so extreme off-road angles are not an issue. Most carburetor applications have been replaced with fuel injection in this day and age, and these sophisticated yet simplistic carburetors were some of the last attempts at carbureted fuel delivery. Featuring a vacuum-slide action, these carburetors are very responsive, reliable, and tunable as you can imagine, considering their race-bike background.
Unlike all of the other fuel-delivery options available, the patented design of the Wild Bore kit completely replaces the restrictive stock intake manifold with a custom aluminum intake that feeds a healthy fuel/air mixture directly into the Sami's head. Samurais are well known for overheating issues, specifically due to factory intake manifold cooling restriction. the Wild Bore kit reroutes the factory cooling system with an included inline thermostat, entirely replacing the poorly designed factory cooling system with a setup that keeps it running cool, even on the hottest days idling on the trail.
Although the Wild Bore setup is not street or smog legal, Jeremy Walker, inventor of the Wild Bore kit, claims that it actually improves fuel mileage and even runs cleaner than the stock setup while making almost 50 percent more power. Best of all, the complete Wild Bore kit retails for only about $600, making it an affordable upgrade with our current budget. Another benefit is that these same Mikuni carburetors will also work on Sami Supreme's future 1.6L, 16-valve Suzuki engine. that's right. Samuraiguy.com also offers the Wild Bore kit for the big-block Suzuki motor, so we'll only have to upgrade to the 1.6 Wild Bore manifold when the future engine swap occurs. Replacing the electronic fuel injection of the 1.6L, 16-valve eliminates the horrific hassle of modifying the 16-valve EFI wiring harness to function in the Samurai. to top it all off, the sidedraft carburetors will ultimately make more power than the stock fuel injection.
In addition to the Wild Bore carburetor upgrade, this segment also features some new additions to the rig and finally some real Sami Supreme action from the trail. this project has been anything but easy, but it is clear just after the first few test runs that all of the hard work and invested time was well worth every penny and evening spent in the garage. Sami Supreme is almost complete, but as with any project of this caliber, "it's never done." stay tuned, as there just may be more to come on Project Sami Supreme!