When we last left Project EVO, we were frustrated because the poor quality of California's 91-octane gas was giving Project EVO fits and making us look like idiots. Despite our best efforts and using some of the best tuning parts available we were unable to see power gains other tuners have achieved with similar parts. Armed with an impressive array of bolt-on performance parts we were only able to eke out an honest 30-hp gain from project EVO, boosting its power from a stock 232 whp to 262 whp after a bit of cam timing on the dyno.
Although the power gains are seen across the board with no loss anywhere in the powerband we are deeply disappointed. Other EVO tuners, using similar bolt-ons, have managed to push output to more than 300 whp on pump gas in other parts of the country where 93- and 94-octane gas is readily available.
The EVO's active engine control computer thwarted our attempts to make power by retarding the timing, lowering the boost pressure and fattening up the air/fuel mixture if even the tiniest hint of detonation presented itself. The ECU's fluctuations made up to 10- to 15-hp variations between runs. This lack of repeatability made it difficult to determine the effectiveness of some of the mods.
The underdrive pulley gains were lost in the data noise and our exhaust system made 7 to 30 hp, depending on which run was chosen. We conservatively chose middle of the road power gains but some of the high output runs we discarded showed the possible potential of the mod if you took out the effects of the poor quality fuel.
What we needed to do is to take charge of Project EVO's engine control system and tune it ourselves. Our goal was to see how much power we could safely make on California's 91-octane pee-like fuel through the catalytic converter. We also wanted reliability for time attack type events on road courses.
Road racing is very demanding. The engine may be at full throttle for a minute or more and will remain at full throttle and under high loads for extended periods of time, lap after lap, for as long as 40 minutes a session. This is way more taxing than a 10-13-second blast down the quarter mile. Road racing, not drag racing, is the ultimate test of tuning and durability. We want a car that can run like this, not a sprinter drag machine or a dyno queen tuned to the limit on the dyno, only to blow up during a long pull around California Speedway's oval.
For assistance, we turned to one of the EVO tuning masters to run on California gas, Shiv Pathak of Vishnu Performance Systems. Shiv has a road racing background and plenty of experience tuning a car so it can live while being pummeled for long periods of time. Shiv's cars have a reputation for being quite reliable among California's EVO-armed hot lappers.
Recently, a Vishnu-built EVO putting out more than 500 whp through a stock bottom end won its class in the grueling Cannonball One Lap of America race. During One Lap, the cars must be driven literally for one lap around America unsupported during the course of the event. There are daily stops for time trials and special stages, like skidpad and drag racing. The Vishnu car was pounded at 25 to 30 psi on road courses and dragstrips while being driven for extremely long distances around the clock at high speeds for thousands of miles. The little EVO won the sedan class and placed fifth overall, beating many exotic, highly modified and expensive cars. As a testament to Vishnu's tuning skill, the EVO still ran perfectly after the event.
When developing a tuning program, Shiv is as conservative as he needs to be. Each programming step must take a full load dyno blast for more than a minute. The car is run at full throttle for 20 seconds at each 1000-rpm increment without registering any significant knock sensor activity. The engine must not register a significant loss of power on subsequent runs, not just during the dyno pass! That tuning pass/fail methodology is a testament to the reliability of Vishnu's tuning.