Conclusions

The results also indicate that despite strong seat of the pants feel, headers do little to benefit WOT performance (part throttle may be/is improved) when used without a free flowing exhaust. The results do clearly show, however, that a free flowing exhaust, combined with headers, can add significant benefits, especially in the midrange area. The results also show that the gains from an exhaust taper off after the secondaries on the motor open up. It is the belief of this tester that VTEC motor is designed to run leaner once the secondaries open and therefore is not getting enough fuel to compensate for the additional air flow the modifications provide. This additional air flow leans out the midrange mixture enough to gain significant power, but is too lean for the range above 6000 rpm.

It is also the opinion of this tester that the performance of the latest modifications will be enhanced by a timing boost at least as much as the previous configuration was. This would tend to indicate a slight softening in the torque curve from 3000-4000 rpm while picking up significant low end (sub 3000) and high end (above 5000 power). Predictions for a power peak of 156-157 hp and a torque peak of 125 lb-ft are reasonable. A Dinan chip will be tried to richen up the top end mixture and see if power gains are realized.

Copyright 2002, Temple of VTEC