Is that Dwayne "The Rock" Johnson doing the eyebrow thing from the movie Be Cool? No, that
Who isn't a fan of the original 23-degree small-block Chevy? After all, it revolutionized the automotive aftermarket and has truly earned its legendary status. For those new to the Chevy scene, ask any small-block owner and chances are they have at least one cool story involving their beloved mouse motor. Never mind all the past racing success in nearly every form of professional and amateur motorsports, the original small-block continues to be a mainstay of the performance aftermarket industry, despite being phased out in favor of the modern LS family.
The LS engine series offers everything we knew and loved about the original and made it not only more powerful, but lighter and more environmentally friendly to boot. As much as we loved the Gen 1, the LS is certainly a worthy successor.
The LS looks bound and determined to make its own mark in history. Despite an impressive combination of power, mileage and low emissions, there are many Chevy enthusiasts who refuse to embrace the LS family for one simple reason: They were brought up on carburetors and electronic fuel injection is simply too complicated.
5.3L LS-Carb vs. EFI
In looking at the two graphs, it is easy to dismiss the carbureted
Having run untold numbers of both small-blocks and LS motors on both engine and chassis dynos, we can vouch for the fact that setting up any EFI motor is considerably more complex that its carbureted counterpart. From a sheer simplicity standpoint, it is tough to beat a carbureted engine. That ease of installation has carried over to the new LS engines, thanks in part to companies like Edelbrock, who have seen fit to produce carb conversions to replace the factory fuel injection. More than just bolting on a carbureted intake and calling it good, the Edelbrock conversion includes a plug-and-play ignition system that connects directly to the factory coil packs, cam, and crank sensors.
It is certainly true that simplicity is on the side of the carbureted combo, but does the modern EFI system have anything to add? In truth, a factory or even aftermarket EFI system has a lot going for it. That the OEMs have abandoned the carburetor in favor of electronic fuel injection should tell you something about its potential. The great thing about a sophisticated system is the ability to properly dial in the air/fuel ratio and timing curves for any combination of load and engine speed. The carburetor is very effective at metering fuel under most conditions, but it can never match fuel injection for precise metering under all conditions.
5.3L LS-Base vs Racing Tricks
After the FAST LSX induction system increased the power ou
The one benefit carburetors often have over their fuel-injected counterparts is power production at wide-open throttle-assuming the same type of intake manifold is used. This advantage comes not from fuel metering as much as the position of the fuel supply. A carburetor supplies fuel to the top of the intake manifold, where it provides a significant drop in the inlet air temperature. Typical fuel injection systems (other than TBI) inject the fuel directly into the intake or head port (usually aimed at the back of the valve). This greatly minimizes the cooling effect offered by the carburetor.
Our 5.3L was hardly a race piece, consisting of a stock iron short-block machined by L&R
Comp Cams supplied a healthy hydraulic roller cam for our testing. The still street friend
The wimpy stock 5.3L cam is probably the mildest cam in the LS family, so swapping it out
We replaced the stock heads on the 5.3L with a set of Gen X 205 heads from Trick Flow Spec
Designed for the small-bore 4.8L and 5.3L motors, the Gen X 205 heads from Trick Flow feat
Edelbrock supplied its Performer RPM LS1 package, which includes a dual-plane carbureter i
Part of the Edelbrock Performer RPM LS1 kit was this timing-control module that plugged di
The Edelbrock Performer RPM intake was run with a Holley 750 HP carburetor. Note the use o
All testing was run with a set of 1 3/4-inch long-tube headers feeding a set of 18-inch co