Ruthless Pursuit of Power: The Sequel

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Induction and Calibration Upgrades

More airflow from the new cam and less back-pressure from the new cats drove some other improvements on the induction side. For MY02, LS6 gets another, new air filter assembly. It’s similar to the ’01 unit, in that it has an additional air intake opening on its cover, but the extra opening is larger.

2001 and 2002 Air Intake Assy.. Click for Larger View
A side-by-side of the ’02 and ’01 air filter assembly shows their differences. Image: Author
[Click Image for Larger View ]
GM did what Idaho Corvette Page regulars have been doing for years with MAFs–remove the air flow straightener or "screen". What took them so long to figure that one out? The LS6 is not GM’s only application of that MAF. Any use of it with an air intake duct that curves just before the MAF (typical of most trucks), needs the straightener for the MAF to sense accurately and GM’s conventional wisdom was to leave it in on Corvettes. In part, the essence of the ruthless pursuit of power is whipping conventional wisdom which was, according to Dr. John, "....you gotta have it in there."

With the Corvette’s relatively straight passage between the air filter box and the MAF, the straightener isn’t needed. Juriga told us it wasn’t until the MY02 development that his people looked at that MAF in a Corvette-specific perspective. "The questions we continually ask are: ‘Do we need it?’, ‘What’s next?’ and ‘What if?’

"The low-hanging fruit is gone," Juriga continued, "as far as changes that make more power so you gotta start going higher–you gotta go to the edge. That’s what the Corvette is all about–pushing everything to the edge."

There were no changes to either the LS6’s intake manifold or its cylinder heads. John Juriga: "The intake manifold was already pretty darn good. We designed it to handle additional flow rates and not require retool the very next year because composite intakes are very expensive to retool and develop. We made sure it would flow more air than we needed in the first year. The same was true with the heads."

A change in engine air flow significant enough to provide 20 more horsepower also demanded a small change in the engine’s fuel and spark curves. This was done with slight changes in the PCM calibration. There was no change in injectors or fuel pressure.
2001-2002 MAF's Click for Larger View
The two MAFs, screened and unscreened. That GM has done this for ’02 ought to prompt the folks who’ve yet to do it to older Gen IIIs to remove their screens. Removing the screen and using the ’02 air filter box together gets about 5hp at airflow levels such as the LS6’s.
 Image: Author [Click Image for Larger View ]

We mentioned the calibration’s antipowerhop algorithm earlier. Confronted with customer complaints and durability concerns about the behavior of manual transmission Corvettes at launch, GM Powertrain has added the feature to eliminate the hop. "The Power Hop algorithm is used on manual transmission Corvettes, only." John Juriga states. "If TCS (traction control system) is turned off, it is possible to get the tires to break loose and have axle hop, or oscillate, during hard launches. To remedy this, the TCS module requests a torque reduction from the ECM, even though TCS has been turned off by the driver. For Power Hop, spark and/or fuel (reductions are) used rather than throttle to improve response time. This request is calibrated so wheel hop can be reduced as much as possible without compromising vehicle performance. The TCS module requests just enough torque reduction for just long enough to get the axle back on the ground during these launch events."



Fixes for Oil Use and Piston Slap