The crate engine has become a player in short-track racing. In mostcases, the track or series limits the engine selection to that of onemanufacturer, but there are a few cases where attempts are being made tobring in multiple crate engines.
One attempt is being made in the FASTRUCK Series. Promoter Bobby Diehlbrought in the General Motors' ZZ4 crate engine and decided to see whathe could do to get the other manufacturers involved. With the help ofsome willing competitors, Diehl has taken steps to find out.
Earlier this year, an engine was borrowed from teams running eachtype--Chevrolet, Ford, and Dodge. They were taken to the engine dyno ofRichards Racing Engines in Haines City, Florida. The Chevrolet went intothe cell first, followed a few weeks later by the Ford. The Dodge, whichrequired a set of headers that took some time to acquire, was last tovisit.
The idea was to get the lay of the land on the important numbers. Eachmanufacturer provides this basic information to its customers, but thosenumbers generally pertain to the four-barrel carburetor. This seriesmandates a two-barrel carburetor, so there would be some difference inthe performance numbers. The intent was to find out what needed to bedone to get the engines to perform within a few horsepower or a coupleof pounds of torque.
Scotty McLendon of McLendon Carburetors was an active participant in thetesting. His carburetion knowledge gave insight into the changes neededto get the figures in the ballpark.
The majority of the testing used the BG Fuel Systems Demon two-barrelthat was unveiled late last year. For ease of comparison, the removablesleeve (RS) model was selected. The carburetor's role in the engine'sperformance could be changed in minutes by simply pulling out a sleeveof one size and inserting a sleeve of a different size.
The ZZ4 crate engine (PN 24502609) is among the most popular enginesavailable for racing. Most of the sanctions that mandate the crateengine chose the ZZ4 for a number of reasons. With the steel rollertappet camshaft (0.474-inch intake/0.510-inch exhaust valve lift), theengine made 355 hp at 5,250 rpm and torque figures in excess of 300across the range. However, that was utilizing the four-barrelcarburetor, so the figures were tossed out.
In the first test, the 500-cfm Demon two-barrel was fitted with silver(1.373) sleeves. Using 79 jets and 34-degree timing, the first test wasconducted with peak horsepower at 5,900 rpm (see Figure 1).
After the first test, the carburetor was removed to change the sleeves.The jet size was changed to a 77 jet, and the green sleeves (1.28) wereinserted. This test drew the numbers down with the engine recording itspeak horsepower of 307 at 5,700 rpm (see Figure 2).
Crate engines from General Motors, Ford, and Chrysler took their turnsin the dyno room for
Richards Race Engines head Bobby Richards explains some of the readingsand processes that
The primary carburetor is the BG two-barrel Demon, which featuresremovable sleeves. Changi
Removing the sleeves was a simple task that kept the dyno from anabundance of down time.
FASTRUCK Tech Director Carl Green makes an adjustment on the Chevy ZZ4.
Scotty McLendon (right) provided his expertise and time to the project.