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Honda K20A2 I–VTEC - Power Pages

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Engine Dynamometer Model: DTS Powermark
Testing: Charles “Dr. Charles” Madrid

Baseline

Pros
In 2001, Honda introduced the K-series 2.0L and 2.4L naturally aspirated engines (a 2.3L turbocharged model appeared in 2007), all of which replaced the B- and H-series engines. The motor was a godsend for tuners across the world, making it possible to reach power levels of over 250 hp with aftermarket bolt-on parts and tuning. We recently had an opportunity to test a K20A2 found in the Acura RSX Type-S on Skunk2’s DTS engine dynamometer for this month’s Power Pages at Skunk2’s headquarters in Norco, CA. The Skunk2 engine dyno has become an integral part of their R&D program, allowing them to test multiple race engines in various stages, as well as prototype parts before introducing them to the market.

Cons
Chassis dynos are fairly common among tuning shops, but locating an engine dyno can be more elusive. If you’re in need of engine dyno services to break in a new engine or to test a few bolt-on parts to see which products will net maximum power gains before attempting to drop that engine under your hood, browse the Internet to help find the nearest shop.

Notes
Prior to recording a baseline run, we should mention that our 2.0L engine was equipped with a Skunk2 4-2-1 long-tube cat-delete race header, custom intake plenum, and K&N filter (used on the engine dyno), and was tuned using a Hondata K-Pro programmable ECU. With modifications thus far, the K20A2 engine netted baseline power figures of 229.6 hp and 163.0 lb-ft of torque.

Skunk2 Pro Series 74mm Throttle Body

Parts
Manifold, mounting hardware, thermal gasket, stickers, instructions

Tools
12mm socket and wrench, Allen wrench, extension, screwdriver, pliers

Installation time
50 minutes

Pros
Skunk2’s 74mm Pro Series throttle body is the biggest K-series throttle body currently on the market. The throttle body is CNC-machined from forged billet 6061-T6 aluminum and anodized in a black finish. Skunk2’s unique K-series throttle pulley design allows for smooth pedal modulation and is designed to be used with the OEM manifold or the Skunk2 Pro Series intake manifold.

Cons
With the OEM throttle body measuring 62mm in diameter, Skunk2 recommends port-matching the OEM intake manifold when using their 74mm throttle body.

Notes
The Skunk2 74mm throttle body delivered a gain of 3 hp and 2 lb-ft of torque through the low- and mid-range. The dyno also recorded top-end gains of 3 hp and 3 lb-ft of torque at 7,500 rpm. You might consider the Skunk2 throttle body excessive in size, but consider that once you start diving into internal engine work, such as larger cams and higher-compression pistons, the air demands increase greatly, thus benefiting power even more.

Skunk2 Pro Series Intake Manifold

Parts
Intake manifold, throttle body gasket, mounting hardware, stickers, instructions

Tools
10-, 12-, and 14mm sockets, 10-, 12-, and 14mm open-end wrenches, ratchet, extension, crescent wrench, pliers

Installation time
80 minutes

Pros
Skunk2’s Pro Series intake manifold is a direct-fit replacement for all K20/K24 engines, and the design was inspired by the popular ’06-10 Civic Si’s RBC intake manifold. The Pro Series manifold features shorter length runners and a larger intake plenum in comparison to the RBC manifold. The Skunk2 manifold is cast with thicker walls to allow porting as horsepower demands increase with additional bolt-ons. The manifold is compatible with TBs up to 76mm while its unique runner design allows ample hood and core support clearance on ’88-’05 Civics and ’90-’01 Integras with K-series swaps.

Cons
Installing the new manifold requires transferring a slew of components, including the fuel injectors, the fuel rail, and TPS sensor to name a few, which can leak or become damaged if not removed/installed carefully.

Notes
A series of dyno pulls after installing the intake manifold and 74mm TB combo revealed that our 2.0L engine had lost a maximum 4 hp and 4 lb-ft of torque from 4,500 to 8,000 rpm. Why the horsepower loss you ask? Plain and simple, this manifold really likes aftermarket cams, higher-compression pistons, etc., which we lacked in our engine. “K-series engines are pretty sophisticated (compared to B- or D-series engines), and the days of slapping on a bigger manifold and making instant power are long gone,” states Skunk2 Communications Director Aaron Bonk. “It’s all about using the right combination of parts, including a set of larger-profile camshafts and tuning to make power with the K-series engines.” The RBC manifold has been known to develop good horsepower gains as a single bolt-on, but run out of steam as other mods are added, unlike the Skunk2 manifold which can be beneficial to gaining power with future engine modifications. The Skunk2 manifold gained power in the high-rpm range due to the better flow characteristics of the manifold compared to the stock RBC manifold. Even though power did drop off at the early stages of the pull, the Skunk2 manifold made up for the loss by gaining 10 hp and 5 lb-ft of torque over our factory manifold up top.

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