Leno's Tank Car Gets an Upgrade: Jay Leno's Garage
The Tonight Show host resorts to modern engine technology to squeeze more power — and gas mileage — out of his M-47 Patton tank-engine car.
By Jay Leno
Some days, a man has to make a statement by driving a car with a 15.8-ft. wheelbase and an engine with a 16-gal. crankcase.
Jay Leno, host of The Tonight Show and PM Contributing Editor (Photo: Matthew Welch/Icon)
A few years ago, I bought an M-47 Patton tank-engine car. Any way you look at it, this thing is a monster. Its wheelbase is more than 15 ft. The engine is a 30-liter V12 -- each of those 12 cylinders is bigger than a four-cylinder Toyota engine -- and it had between 800 and 900 hp. But given that the car weighs 10,000 pounds and that I live in a hilly area, the Patton's engine performance was, to quote the old Rolls-Royce ads, "adequate."
The car needed more oomph to get up those hills. Besides, gas mileage wasn't too good, either. The engine was fed by two huge Stromberg carburetors with needle jets that looked like arrowheads. And the carbs weren't efficient. If I didn't shut down the car when I was at a filling station, the idling engine sucked gas out of the tank faster than I could pump it in.
I decided to up the performance and the fuel economy. So I turned to my friend, high-performance tuner Gale Banks. "Why don't you turbocharge this thing," he asked, "and put fuel injection on it?" I gave him the engine, and turned him and his crew loose.
Unlike, say, a small-block Chevy, there's not a lot of bolt-on speed equipment out there for a tank engine. In fact, there's none. So Banks had to engineer a system and modify components to fit it. He also had to fabricate what didn't exist. His shop spent over 1500 hours on this project.
First, his crew tackled the fuel delivery problem. With a big Stromberg carb centered on each cylinder bank, the inner cylinders were getting more gas than the outer ones. So Banks tossed the carbs and installed a Bosch electronic fuel-injection control unit based on the company's MS 2.9 system for Formula One race cars. The custom-built rig was the only one that could deliver enough fuel.
Then, Mr. Turbo, as Banks is affectionately known, turned to the air. He used two serious 91mm magnesium Garrett turbochargers -- the same ones found on 2002 Toyota Champ car racers. Banks then made up a beautiful new intake manifold with special runners that look like the ones on an old 2.9 Alfa. He fabricated metal caps that take any sort of modern look out of the engine. Everything is under metal fittings.
We left the rest of the engine essentially unchanged. Camshafts and valve timing stayed the same, and we kept the four giant magnetos.
Six more cylinders and another giant turbocharger sit on the other side of that hood. Altogether, it's 30 liters' worth of engine and more than 1500 hp.
All the work paid off: Fuel economy doubled -- from 3 mpg to nearly 6. Hey, don't laugh. How many people can say that they've cut their fuel consumption in half? And if I ride with a friend, I can drive the vehicle in the car pool lane and really save gas!
I'm not just saving gas, I'm having fun doing it. I can break the rear tires loose in the first three gears. The transmission is an Allison six-speed with a double overdrive, and each rotation of one of those rear tires is 11 ft. There was no way I could break them loose before. I have no idea what the top speed is for this thing. We ran it at the General Motors proving grounds and hit 145 mph. But at that speed, the car starts to walk around a little bit. So I'm happy to leave it at that.
As it is, it's hard to describe what the power output is like. The best I can do is compare it to an elephant we once had in the studio when we were taping The Tonight Show. I pushed against the elephant's trunk, just playing with him. Then he moved and, with the tiniest effort, knocked me down as if I were a fly. That's kind of what this car feels like. I never notice it strain. The torque has to be over 2000 lb.-ft. And the engine responds to the gas pedal sooo quickly.
When I'm out driving the tank car, the reactions are incredible. If I'm sitting at a traffic light, and people in the car next to me look over, I ask, "You think I have sexual problems?"
Driving the tank car is like when I was a kid and my dad let me sit behind the wheel of our '57 Plymouth. I feel like I'm little again and in some giant vehicle. Boys between the ages of 7 and 13 just go nuts when they see me in this thing. It's funny to watch them jump up and down. So I let them sit in the driver's seat and move the steering wheel. I love to get the next gen­eration of car enthusiasts excited.
Even though I like to take it to The Tonight Show when Governor Schwarzenegger is a guest -- he says "dat iz der Terminator's cahhr" -- it's not something I can drive every day. In fact, it's a lot easier to drive it around the world than it is to make a U-turn. So I just keep on going until I wind up in the same place I started. Forget trying to parallel park it. Can you imagine a valet's expression if I pulled up to a restaurant and handed him the tank car's keys? When I fall in behind a Mini on the road, you should see the fear in the driver's eyes: "My God! What is that?"
As a kid, I watched the TV program Mannix. Mike Connors was Joe Mannix, a private eye who drove a custom Olds Toronado -- no roof, big headrests and a flamboyant paint job with bold stripes. When Mannix tailed someone, he'd get down behind the steering wheel so no one could see him. Yeah, right: They couldn't miss him.
You can't miss this thing, either.
With its giant air horns, the Patton sounds like a diesel train. Actually, everybody thinks it is a diesel. One hot-rod magazine ran a photo of the car with a caption that read, "Diesel!" Believe me, it has a gasoline engine. Before we modified it, the car ran just fine on regular. Now, I fill it with premium, even though we're limiting the turbos to only 6 psi of boost. We're kicking around the idea of cranking up that boost to see if we can get another couple of hundred horsepower out of it.
Meanwhile, people ask if having almost 1600 hp is changing my driving habits. I don't think about all that power. I just know that now I've got enough oomph to get over those hills -- and I'm saving gas while I'm doing it.
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