The Temple of VTEC - Honda and Acura Enthusiasts Online - Articles - Dyno Test of Timing Changes: Page 1

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Author

notyper

Categories

All Honda/Acura, Integra Engine/Power

Create Date

January 16, 2002 01:25

Last Update

June 06, 2002 12:27

Page 1 - Test Conditions & Modifications

Last Updated: 07/29/96
by Shawn Church

Thanks to Chris, Jeff and Tony of Pro-Dyno for their assistance.

Test Conditions

The first two dyno sessions were performed in the winter months with dry cool air. Testing conditions were in the high 70s, low 80s. The latest test session was performed with air nearing 90 ambient in a swamp cooled warehouse structure (meaning high humidity). Engine operating temp was probably higher as well and fans may have been in operation more often on the latest test. Winter tests were also performed on reformulated gasoline which may have impacted results. Conventional wisdom says that reformulated gas contains less energy, but may burn more efficiently. Despite SAE correction factors, it is difficult to compare runs separated by such a large time period and divergent weather conditions (this assertion is supported by both Pro-Dyno and the documentation from Dynojet).

Condition of Car

The first test was performed with the car in need of a valve adjustment. The second session was performed almost immediately after a valve adjustment. This could certainly account for some differential in power. Regardless, the tests show that headers probably do not provide a significant boost without a freer flowing exhaust system. The third session was performed after an air conditioning compressor replacement, 6000 miles since the last valve adjustment, with a malfunctioning O2 sensor. The O2 sensor should not affect WOT readings, but the car will be retested to verify.

Modifications

The first test was performed with the DC ceramic headers and an open element conical K&N on a DC bracket and pipe (connected to stock intake tubing). The second test was performed with the stock headers after the DC unit developed a crack. The air filter remained in place, but the timing was bumped significantly over the 15 BTDC run on the first test (this combined with the valve adjustment allowed the stock header test to produce more power than the test with headers). The third test used the rewelded/recoated DC headers, a Dynomax custom cat back with 2.5" piping and a resonator, and a K&N filter supported by the bottom half of the stock airbox after the mounting point for the DC bracket broke. This change in the air filter configuration (in addition to being somewhat dirtier after a previous ram air experiment) is predicted to have affected intake efficiency somewhat. Timing was also reset to just under 18 BTDC to compensate for the hot summer weather here in Arizona (avgerage daytime temp in the 110F range).

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