In the last installment of "Smog Legal Power" (Aug. 2003), we started the process in attaining our 200-whp goal. We started with the Acura producing 161.2 whp as a baseline and ended with the LS/VTEC generating 177.8 whp from three simple bolt-ons. In this segment, we'll push the Integra closer to its 200-whp goal with the addition of a pair of performance camshafts from Crower, fine-tuned with Skunk2 adjustable cam gears.
On our 177.8 dyno run, the Integra was still utilizing a set of factory GS-R camshafts. Upon closer inspection of the dyno graph, the engine was starving for air at the top end, resulting in a power drop-off after 7000 rpm. More precisely, the engine lost 25 hp from 7000 rpm to 8300 rpm. The factory GS-R bumpsticks weren't opening the valves far enough (lift) and long enough (duration) for the engine to completely fill the combustion chamber with enough charge air to make more power.
Originally, we were planning to install a set of JG Engine Dynamics camshafts but they weren't ready, so we decided to go with a different set. Fortunately, we were able to locate Crower 63403 billet camshafts for the engine. We've tested the 63403 camshafts in the past on a stock GS-R engine and they produced 20-plus hp to the wheels.
Installation of performance camshafts should be left to the professionals; the procedures require precise clearances and minute adjustments. One wrong move can result in catastrophic failure.
Our Crower cams featured an advertised duration of 295 degrees on the intake and 293 degrees on the exhaust compared to the stock 274 degrees intake and 276 degrees exhaust.
For lift, the Crower pieces have .472 inches intake and .466 inches exhaust vs. the stock .423 inches intake and .378 inches exhaust (see chart). From reading the cam card, we knew the Crower camshafts were going to make tons more power compared to the stockers. More importantly, Crower cams are made from billet cores-they're not regrinds-ensuring performance and reliability.
We installed the Crower cams with the Skunk2 adjustable cam gears, but left the adjustment at zero for testing purposes. We will later adjust the gears on the dyno for maximum horsepower. After the proper break-in, we were off to the dyno.
On SP Engineering's Dynojet, the Integra came to life with a heart-pounding 190.1 hp to the wheels! This was an improvement of 12.3 hp from the stock cams. The largest gain came at 8000 rpm where the Crower cams made an additional 35 hp more than the stock bumpsticks. The cams made more power throughout the powerband, with the exception of a dip between 5600 and 6500 rpm. With the addition of a VTEC controller, we can solve our power dip situation by turning on the VTEC later in the RPM band. We should be able to completely remove the dip with the installation of the AEM EMS ECU.
Next, we fine-tuned the Skunk2 adjustable cam gears to optimize the Crower cams. By advancing the intake 1 degree and retarding the exhaust 4 degrees, we gained an additional 1.3 hp at peak. We also improved the power curve from the stock-setting run.
An important note to remember is cam gears must be set to each and every engine. Even if the engine is the same and the cams are the same, you still need to either degree in the cams or set them on the dyno to attain maximum horsepower from the cams.
We're close to our 200-whp goal, with only 8.6 ponies to go and several modifications yet to perform. In the next installment, we'll look to further enhance the breathing capabilities of our LS/VTEC monster by adding a JG Edelbrock intake and throttle body. This should help reach our goal of 200-whp-and don't forget, we still have the AEM EMS computer to fine-tune the entire combination. Until next time, keep those revs up!
|Advertised Duration||Duration at .050-inch||Gross lift with 1.55 rocker|
|Int-274 mid Exh-276 mid||Int-230 mid Exh-216 mid||Int-.423 mid Exh-.378 mid|
|Int-295 mid Exh-293 mid||Int-257 mid Exh-246 mid||Int-.472 mid Exh-.466 mid|