Power Pages: Acura Integra

The Engine
So far, the tried-and-true B18C engine has been able to live up to the norms of an aftermarket intake, exhaust and header set-up, and now it's time for a little bit of Valvetrain 101. Tuning the sophisticated valvetrain found in Hondas has always been an ongoing learning curve, with plenty of room for improvement. Whether it's camshafts or cam timing, horsepower is always found in the valvetrain.

With this session of Power Pages, we'll see how much camshaft technology has changed and how much improvement cam grinders have achieved over the years.

Performance Components
We started out with Skunk2's newest line of Stage II camshafts. When we last checked, we were able to gain 12 hp with the Stage I kit on a 1.6-liter dohc B-series engine. The new Stage II units are rumored to make more power with sprocket tuning. For this round, we were going to do a with-sprocket and without-sprocket test. Due to the extreme lift of the cams, Skunk2 recommends using its valve springs to ensure no coil bind or valve float occurs.

The cam sprockets we'll use are also Skunk2 items that are extremely lightweight and made out of aluminum with stainless-steel hex bolts. These sprockets allow for tuning up to plus or minus 5 degrees and come in a variety of cool colors.

Fuel supply is also a critical part of making horsepower, so we relied on a Field SFC fuel computer to keep our GS-R running a safe air/fuel ratio. The unit is able to control up to eight rpm points with plus or minus 30 percent of the fuel supply. This percentage is not exactly measured as a 30-percent increase, but represents more of a raw number, relating to how much change to the voltage signal on the map sensor there is. What this means is some of the newer vehicles cannot measure up to the 30 percent before the check engine light turns on.

Dyno Testing
Last time, our final results ended at 161.1 hp and 124.0 lb-ft of torque. This was achieved by installing a Comptech air intake, DC Sports header and a Skunk2 exhaust.

This time out, our first install was the set of Skunk2 Stage II camshafts. To test the true potential we added a pair of cam sprockets during the second half of our session. However, for our initial run we ran the cams at 0 degrees. At this setting the cams were able to put out great numbers and, considering we hadn't touched the sprockets yet, we knew we would be able to put out even more power. Peak power jumped up to 166.7 hp, making most of the gain in the peak area. However, a severe loss was evident from 4800 to 5500 rpm.

We figured this should be easily cured using the SFC fuel computer. The factory rev-limiter also hurt us since it was obvious the graph didn't want to stop. We predicted that with an additional 1000 rpm we could have been easily hit the mid 170-hp range.

Tweaking the sprockets we found that with the intake at 3 degrees advanced and the exhaust at 2 degrees advanced we were able to extract 3.3 more horsepower and 5 to 10 more ponies in the mid to top end. Torque was also brought up from 117.1 lb-ft of torque to 119.3. Ignition timing was set at 19 degrees advanced.

We began to feel that a timing belt change was in order, which is probably why we ended up advancing both camshafts. The final test showed the Skunk2 cam and sprocket combination putting down an additional 8.9 hp over our previous run.

Fuel tuning was going to be a key element to making power reliably, but first we had to fix the stumble caused by the VTEC crossover point. By moving that point to 5300 rpm we cancelled out the stumble and added a smoother transition to the graph. Fuel tuning aided in the mid to high rpm, but we were only able to gain a total of 169.6 peak hp.

Conclusion
Since the cams and fuel tuning bumped the power up to 169.6 hp and 120.3 lb-ft of torque, we will now prepare for our next round of tests, which will incorporate various components found in Venom Performance's impressively lethal arsenal.