Sometimes you have to fill your day by watching dumb car videos on YouTube, and luckily for you, the world has a great new example of such a production. The Russian car-experimenters at the Youtube Channel Garage 54 hooked three engines together via belts to see how much power those motors could make in unison. Here’s what the team learned when it took the tri-motor machine out on a track.
You may recall Garage 54's most epic pointless project: Bolting three four-cylinder engines together in series. Now the team has conducted a similar experiment, this time hooking three motors in parallel via belts spanning between crankshaff pulleys:
Technically, all three aren’t “connected.” It’s just the two inline-fours up top that have their crankshaft pulleys spinning belts that reach down to the engine hooked to the Russian GAZ’s manual transmission. In some ways, you can think of each of the top engines as fulfilling the “boost” function found in cars with electric Belt-Starter Generators (those have an electric motor as part of the accessory drive in place of the alternator; that motor can feed power through the belt to assist the crankshaft).
Getting all three engines to function together was no small feat for these Russian geniuses. The wrenchers had to precisely align the belt pulleys, tension the V-belts, and source belts that could transmit quite a bit of power without slipping.
All three carburetors had to be synchronized, with the team having to figure out how to get a gas pedal linkage to hook up to the three throttle plates. The starter motor situation was apparently not too difficult, as the battery and lower engine’s starter was strong enough to crank all three engines simultaneously; this was impressive.
The YouTubers hard-mounted the top two engines to one another, to the engine below (even welding to the thin valve cover), to the fenders, and to the front radiator crossmember.
The cooling system is quite interesting. It appears as though the large radiator that the team mounted rather inelegantly to the front of the car feeds coolant from the bottom of its passenger’s side tank to the lower engine’s water pump inlet. That engine then sends coolant up from its thermostat outlet into the two top engines’ water pump inlet ports. A hose goes from each of the top engine’s thermostat outlet ports into a tee-junction, where the coolant from the two engines merges into a single hose going to the top of the radiator’s driver’s side tank.
The whole thing is just ridiculous. The GAZ’s front suspensions had to bear three engines worth of weight, there’s basically no forward visibility from the driver’s seat, and frankly, I’m not convinced that those belts really allowed for a whole lot of power transmission.
But maybe they did? I’d need to learn more about the belts used, because the reality is that rubber belts can actually transmit quite a bit of power, as we’ve seen with motorcycle drive belts. Of course, the V-belts on Garage 54's GAZ are quite a bit different than those found on a bike, but a bit of research shows that even the classic V-shaped belts that these Russians are using could transmit quite a bit of power.
You can check out prominent drive-belt manufacturer Gates’ brochure here. It describes how to size a belt for a given power transmission requirement given a certain shaft speed. In the image above, the alphanumerics represent a certain belt cross section type. So, if for example, you had to transmit 250 horsepower at 2,500 RPM, you’d want a 5VX or 5V style belt.
Gates provides a guide for belt sizing below. It’s a bit more complex than simply reading off a horsepower versus faster shaft-speed graph like the one above. The diameter of the sheave (often called the pulley) is important, as is the center distance between the pulleys, and the ratio of angular velocities between the pulleys (which is related to the pulley diameters), and there are a number of other factors in play.
The point is that belts can actually transmit quite a lot of power, so as silly as this Garage 54 experiment may seem, it could actually be brilliant.
Okay, probably not “brilliant,” but you know what I mean. Not completely idiotic.