Old school Japanese cars have never been more popular. This fine publication often covers the Japanese Classic Car Show (now in its sixth year), and the quality of the cars on display and the sheer number of them continues to impress. Have a peek at websites like Speedhunters.com and you'll also notice more and more coverage of classic Japanese vehicles, with comment sections full of enthusiastic declarations of love and desire.
Simply put, Japanese classics like the S30 Datsun Z, Mazda RX-2/3/4, Hakosuka and Kenmeri Skyline GT-R, and the "Japanese Mustang" Toyota Celica GT are fantastic to look at. There's also something undeniably appealing about their simplicity and purity of design, especially when compared to their bloated and electronically neutered modern-day counterparts. Sure, a Hakosuka GT-R is no match for a R35 in terms of brute force or outright speed, but there's something special, something visceral and even empowering about driving a car with no stability control, no traction control and no ECU at all, for that matter.
Want to own a classic Japanese sports car like the Hakosuka Skyline? Better learn how to t
As someone experienced in the ways of fuel injection and electronic engine management, the thought of fiddling with carburetors is a bit intimidating. By the early '70s, most cars had electronic ignition systems, but carbs were still the norm and represent an area of automotive technology that to anyone born in the '80s (or later) tends to be as mystical and foreign as high-waist, plaid bell bottoms and acoustic folk music. I mean, come on, a "float bowl" sounds like it has more to do with toilet plumbing than fuel injection, and "jetting the carbs" could easily be some sort of high-flying diet plan.
Thankfully, there's still a wealth of knowledge out there on the subject of carburetion, which makes understanding how the maze of fuel and air passages that constitutes a carb a fair bit easier. And the truth is, a carburetor is a pretty complex piece of engineering, given that it has to be able to mechanically meet the changing fuel needs of an engine, from idle to wide-open throttle at high rpm.
Despite the complexity of the device itself, the concept of carburetion is really quite simple. In liquid form, gasoline doesn't burn and therefore needs to be vaporized. Through an elaborate network of internal air and fuel passages, the fuel is atomized and introduced into the air stream before the throttle plate(s) and intake manifold plenum. As the atomized fuel mixes further within the intake plenum, it vaporizes into a gaseous state as it travels down the intake runners on its way to the intake valves, at which point it's ready to enter the combustion chamber and start that wondrous process of internal combustion.
At its core, a carburetor is basically just a tube - like a modern throttle body - including a throttle plate to control how much air is being allowed into the mix. Where a carb differs from a throttle body is the way in which it introduces fuel into the airstream, using a narrowing of its air inlet to create a pressure differential. The hourglass shape of the carb's inlet uses the venturi effect to create a low-pressure area that serves to draw fuel from the carb's bowl and up through a hole called the main jet and into the airstream.
It's a common misconception that vacuum within the intake manifold pulls fuel from the carb's bowl, but since manifold vacuum drops to zero at wide-open throttle, it's the venturi effect that actually moves the fuel into the airstream. A carb's fuel bowl has air vents, which allows the bowl area to be pressurized to 14.7 psi (normal atmospheric pressure). The venturi effect reduces pressure to about 13.5 psi at the manifold, so it's this 1 psi of pressure differential that draws full up from the bowl and through the jet into the airstream.