1991 Acura Integra LS - Power Pages

It is time to take it back to the old school. It's scary that I'm actually stating that a 1991 Acura Integra is old school, but the car is nearly 10 years old and two newer generations of Integras will already have made it to the production floor by the time this issue is printed.

The blue Integra, which graces these pages might look familiar because we already performed a "Power Page" upgrade in our March 2000 issue and now we are back for more. To refresh your memory, the tired 1.8-liter non-VTEC engine that previously occupied the Integra's engine bay was yanked out in favor of a 1.6-liter DOHC B16A1 VTEC engine from Japan. Even with a 0.2-liter displacement disadvantage, the five-speed model engine produced 20 more hp (140 vs. 160) than the B18A engine.

However, we later found out that the engine we tested was an automatic model, which incorporated a smaller camshaft, thereby lowering overall horsepower output. Final power output with the trio of products installed only registered 133.2 hp and 102.1 lbs-ft of torque. In this episode of "Power Pages," we'll try to fix our ailing B16A and make it really sing.

The EngineWhat more can you say about the B16A engine, other than being one of the better-engineered small displacement engines made on the planet. From a mere 1.6-liters of displacement, the engine pumped out 160 hp to the flywheel. The B16A engine is probably one of the most sought after transplant engines because of its relative low costs and high rewards.

A complete transplant can run around $1,800. Developed more than 10 years ago, the engine can still be found in the 2000 Civic Si. With such a long production run, finding stock and aftermarket components is rather easy. With the wealth of aftermarket support, the B16A is a versatile engine for street enthusiasts and racers alike. One of the more renowned racers who utilizes the powerplant is Lisa Kubo and the Kubo Racing Team.

The totally reworked powerplant residing in the Kubo Racer pumps out an amazing 600-plus hp. With that kind of potential, you can see why the engine is so heavily used. As stated earlier, the automatic and five-speed models are rated at different horsepower levels because of the cam profile of each engine.

If you have a choice, locate a five-speed model or swap out the cam in the automatic with a unit with higher lift and duration. To remedy our horsepower ailment for the meantime, we found a pair of 2000 Civic Si cams and decided to try them out.

The swap was beneficial, as the power rating was pushed to 138.9 hp, an improvement of 5.7 hp more than the previous automatic camshafts.

Performance ComponentsIn part one of the "Power Pages" build-up of the Integra, we equipped the B16A engine with an AEM cold-air intake, Tanabe exhaust and DC Sports header. The trio of products bumped power ratings from 125.3 hp and 98.9 lbs-ft of torque to 133.2 hp and 102.1 lbs-ft we extracted an additional 7.9 hp and 3.2 lbs-ft of torque from three simple bolt-ons.

After discovering our low horsepower output because of the camshafts, we installed a pair of 2000 Civic Si units and further pushed the power envelope to 138.9 hp and 102.2 lbs-ft of torque.

In this installment, we decided to get a little more technical than the ordinary simple bolt-ons. The first item we installed was a larger bore throttle body from SPW Industries. SPW carries a complete line of JDM products available for your consumption. We elected to go with a brand new Civic Type R throttle body, which utilizes a 3mm larger bore than the factory B16A unit. The larger bore allows for more air to flow into the intake with less restriction and increases performance throughout the powerband.

Second on the list was the Integra Type R intake and exhaust cams from SPW. Although we already installed a pair of 2000 Civic Si units in the B16A, we knew that the higher lift and duration from the Type R cam would still create more power. Unlike regrinds, SPW sells the real McCoy direct from Japan and no exchange is necessary. The cams are sold brand new in the box and have never been used.

The key to performance camshafts are adjustable cam sprockets. Without the use of cam gears, the gains from the cams might not be fully realized. The cam gears allow the tuner to fine-tune the powerband to its fullest potential. We went with Hayame Racing units, which are constructed from CNC billet aluminum, making them very lightweight and strong. Adjustments are made from loosening the six hex bolts, that provide a tight non-slip gear when clamped down.

Dyno TestingLet the fun begin! Unlike other magazines, who have nonstaffers doing the grunt work, we elect to perform it ourselves. Can you say true enthusiasts at work? Well, as we noted earlier, we re-baselined the Integra to the tune of 138.9 hp and 102.2 lbs-ft of torque.

First up to the plate was the Civic Type R big-bore throttle body. Unfortunately, the throttle body is not a plug and go proposition, as the intake has to be bored out, in order to realize the full horsepower benefits of the new unit.

We highly recommend leaving it to the professionals to install it. With our safety goggles on, it was time to grind away. With the proper size enlarged, it was time to mount the unit. As predicted, the throttle body showed improvements throughout the entire powerband peaking out at 140.3 hp and 102.7 lbs-ft of torque.

After a lengthy cool down period (lunch break), it was back to the elbow grease. Installing VTEC camshafts requires patience and the right tools. Bolting on the camshafts is the easy part of the job, adjusting the valve clearances is the hard part.

Making sure all the valves are adjusted to the same specs require a mechanic's touch. Also, without the right tools, performing the job is nearly impossible.

Fortunately, we were able to install the cams and adjustable gears without a problem. Back on the dyno, the B16A sang a tune of 143.3 hp. Not bad, but we lost a lot of midrange power. As we mentioned earlier, the cam gears are the key to performance camshafts. By fine-tuning the pair of Hayame cam gears we were able to make up the horsepower lost in the midrange and then some. We were also able to push peak power to 148.4 hp improving peak power by 5.1 horses!

The ConclusionTalk about hidden horsepower. From the pathetic 125.3 hp baseline of part one to the amazing 148.3 hp conclusion of part two, a skyrocket of 23.0 hp! The B16A now sings with desire whenever the pedal is smashed. Stay tuned, as we plan to test out the A'PEXi VTEC AFC and some other performance products on the B16A. Until next time lets roll, the dyno that is.

The FactsEngine Tested: B16A1Applications: 1991 Acura Integra LSCommon Swaps: 1988-2000 Honda Civic/CRX/del SolReplacements: B18A/B/C, H22A and H23