K-Series Intake Manifold Shootout - K20A Type-R Engine

Katman Says: Not only did Erick reach 228whp but he managed to reach the 150+ torque range, touching on the RBB's torque output! RRC hype understood.

As you can see with these results, for an internally stock K20A Type-R engine, the tuned RRC wins hands down. It makes the best top end power and even gets into the 150 torque marker. On the other hand, the Endyne ported RBB makes some serious mid range torque gains over all of the manifolds. Comparing both powerbands you can see where the RRC and RBB manifolds shine the most. Skunk2's manifold held its own against the RRC. BluePrint's RBC didn't do too bad either for being on a stock, smaller liter K-engine.

Erick Says: The RRC is good for a stock to mildly-built engine. The powerband peaks 1500rpm earlier than Skunk2 manifold. The Skunk2 is good for a stock to mildly-built engine as well, but because the powerband peaks later, it will prevail on a built engine.

With these final results, on top of having a skilled dyno tuner, cam angle seems plays the biggest role in tuning the K-series engine.

1. STOCK PRC BASELINE 214HP 144TQ

The "PRC" manifold is found on the JDM K20A Type-R engines. The U.S. equivalent or "PRB" is found on the '02-06 RSX Type-S (K20A2/Z1) and '02-05 Civic Si (K20A3), with slight differences in runner design. I've been using this manifold since day one of my K-swap, so about five years now. The baseline run was rather disappointing, as I've been driving on an un-tuned KPRO startup calibration for quite some time. I had VTEC set to 5300rpm and redline at 8800rpm. Power to the wheel as my current engine setup stands (with the 64mm throttle-body) was 193whp/136tq.

Just terrible! Erick went to work, adjusting air/fuel ratio keeping it as close as he could to 14.5, changing cam angle ever so lightly, and adjusting ignition timing. Five dyno runs later, the best he could tune the PRC was a nice 214whp/144tq.
Just terrible! Erick went to work, adjusting air/fuel ratio keeping it as close as he coul
The final tune from 0-5400rpm was leaned out, 5500-8000rpm fuel was richened up, and VTC was retarded about four degrees in the mid-range, and VTEC crossover was lowered to 4000rpm. Dropping the VTEC crossover point helped a lot.
Next, was trying the 70mm Blox throttle-body. The engine had time to cool off during this time, as it was a hot day, close to 94 degrees ambient. Once on, the first couple of runs showed signs of running rich, probably because the engine was semi-cold. Once warmed up there weren't any significant gains and approximately 1-3hp was lost throughout the whole powerband. Erick performed some more tuning with the Blox t/b but was unable to surpass the power made with the 64mm t/b, though, the power made was very close to what the 64mm t/b produced.
The final tune from 0-5400rpm was leaned out, 5500-8000rpm fuel was richened up, and VTC w

2. ENDYNE PORTED RBB -.2HP +11TQ
The "RBB" is a two-piece intake manifold that comes from the '04-08 TSX. This one is owned by a k20a.org member who had it ported by Endyne with a special "K20" specific port job. Endyne cut open the plenum to fully gut this beast out and then welded the plenum back together.

Erick reached the same wheel horsepower as the PRC, yet gained 10lb-ft of torque with this manifold! The torque increase is just amazing when comparing graphs against the PRC. You can thank the RBB's long runner design for the increase in torque.
Erick reached the same wheel horsepower as the PRC, yet gained 10lb-ft of torque with this

3. STOCK RBC +5HP +.6TQ

The "RBC" manifold is currently the most widely-used K-manifold to upgrade to for the K20 and K24 engines. It especially shines on the K24 Frankenstein swaps (K20 head/K24 block). Its design has short runners and a large plenum, great for top-end power. In comparison to the PRC, the RBC drops about 5hp in areas of the low end and mid-range, but has better top-end power after 7200rpm to redline. Final results made 219whp/144.6lb-ft torque.

4. SKUNK2 PRO K-SERIES +10.4HP +2.4TQ

Behold the long awaited Skunk2 Pro K-series intake manifold. Still fairly new on the market, I was able to borrow this manifold from a fellow K20A.org member (pb16b aka Jason at Suja 1 Motoring). Now this manifold was dynoed by a couple other K20A.org members who didn't have pleasing results. This did not discourage me.

If my engine weren't limited to 9000rpm, this manifold would make even more power as the curve keeps climbing. In comparison to the RBC manifold there's a fat gain of mid-range at 4500-5700rpm, then power tapers off matching RBC's power at about 5800-6100rpm, then Skunk2's power gradually takes off all the way up to redline.
If my engine weren't limited to 9000rpm, this manifold would make even more power as the c