In addition to differing in flow rate, the injectors used in various LS engines also differ in overall length and connector style. Depending on the engine and year of manufacture, LS injectors can be the "long-style" with EV1 connectors, "short-style" with EV6 connectors, "short-style" with Delphi connectors or "extra-short-style" with EV6 connectors. Most 4.8- and 5.3L truck engines are equipped with "short-style" injectors that accept either Delphi or EV6 connectors. That being the case, injectors from an LS2 Corvette engine can be installed with no modifications-except for the connectors on trucks originally equipped with Delphi connectors. The LS2 injectors are a good choice because take-out sets are available at relatively low cost from companies like Cody Motorsports.

Now for the results of the second dyno test session-which didn't provide the data we anticipated. In retrospect, we really should have expected relatively little increase in midrange torque, considering that with the stock cam, (which has a paltry 190 degrees of duration at 0.050 inch lift) the engine's torque peak of 308 lb-ft was at 4,000 rpm (which is both the factory specification as well as the actual test results logged at Atlanta Chassis Dyno). That being the case, even with 112 degrees of lobe separation, a duration of less than 200 degrees will probably be required to substantially increase torque between 3,000 and 4,000 rpm.

On the horsepower side of the ledger, improvements were much more dramatic. The power curve jumped by 34, hitting a peak of 302 at 5,300 rpm. And although the engine's torque peak moved to 4,600 rpm, the reading at 4,000 rpm was identical to that recorded by the stock engine.

In spite of the torque readings recorded on the dyno, at part throttle, the truck seems noticeably more powerful, both in normal driving, and when towing. As might be expected, once rpm pushes past 4,000, the difference in performance is dramatic.

We have a few more modifications in mind to pump up midrange torque. Depending on how they work out, you may see "Tow Story 3" in a future issue.

SOURCE
Atlanta Chassis Dyno
1855 Buford Hwy.
Duluth
GA  30097
770-623-9789
www.atlantachassisdyno.com/
VMax Motorsports
813-469-4665
www.vmaxmotorsports.com
Cody Motorsports
Lawrenceville
GA
COMP Cams
EFILive