| K-series Internal Upgrades - Inside The K
If you hadn't yet picked up on it, we're gonna make it clear: Honda's K-series engine is where it all goes from here. Every four-cylinder Honda/Acura in the United States, except the Civic coupe/sedan, has a K underhood. The tuning heads at labs like HyTech Exhaust, Hasport, Skunk2 and Hondata confirm that this engine has more room to explore-more power to yield-than its B-series predecessor. Skunk2 has pushed the K to its all-motor limits, posting a 9.86-second quarter-mile in its Project Delta.
Since the K is here to stay, what are you gonna do if you're serious about making power beyond adding the typical gaggle of bolt-ons? You're gonna pop the head and drop the crank, that's what. And once it's open, you're gonna use this guide to plan your strategy for bigger power accordingly, everything from inside the oil pan to under the valve cover.
Though the aftermarket has leisurely accepted the K, more and more companies are getting with it month by month. So start hunting for wrecked DC5s and Accords and keep this issue handy!
VALVETRAIN
Crower619/661-6477 * www.crower.comThe hard-core guys at Crower went all out with their complete line of K-series internals. They say Crower is the only company using Ti-17 titanium for retainers, a grade of titanium eight to 10 points harder on the Rockwell C scale than the 6AL4V titanium used by other manufacturers. The result: added longevity and durability. Crower's K20A2 retainers weigh half as much as the stock units (seven grams vs. 14), placing less weight on the valve and freeing up an additional 250 rpm. Wound from chrome silicone alloy, Crower's valve springs are chamfered to reduce imperfections and stress risers that can cause breakage, and are good for 10,000 rpm and over 13.5 gross valve lift. Finally, the company's stainless-steel valves feature the Pro Flo head design, with a tip area hardened to RC50 (including past the critical keeper groove area for added strength. Standard, 0.5mm and 1mm oversize on certain engines or titanium are available on a custom-order basis. Expect to pay $176 for retainers; $333 for springs (a full kit runs $473) and $284 for the valves.
Endyn817/924-9334 * www.theoldone.comEndyn is a quiet one in the aftermarket. It holds a strong racing history of more than 30 years and now specializes in creating Honda race engines. Endyn's valves are all stainless with a unique heat treatment coating, and are available in stock and +.5 and 1mm sizes for $18 each. Keep them in control with custom valve springs and lightweight titanium retainers. Made from Japanese steel, they feature inner and outer springs from better-than-stock to full race versions for use with huge cams and 10,000 rpm. $285-$385 for springs, $287 for valves, $149 for retainers.
HyTech Exhaust949/581-2181 * www.hytechexhaust.comHyTech is all about the K series. We've already featured its 260-plus-whp all-motor RSX-S and the techs there say they're working on a 300-whp upgrade to further blow our minds. This valvetrain has proven itself to be 10,000 rpm-ready in Indy Car racing (springs), and with custom titanium retainers and hardened spring bases, nothing should go ballistic. Street applications run $275 (without retainers) and $850 for the full Indy Car deal with retainers. For flow, consider swirl-polished standard sized stainless valves with dish or flat bottoms. $275 for all 16.
Skunk2951/808-9888 * www.skunk2.comCurrently home to the fastest all-motor Honda in the country, Skunk2 recently introduced its line of K-series performance parts. Their valves are lightweight, durable and offer excellent heat and corrosion resistance and flat bottoms. The valve springs are made from top-quality chrome silicone wire out of Japan, and are designed from Skunk2's and their suppliers' experience in touring car and drag racing. Valves $435; springs $400; titanium retainers $170.
TODA714/327-0181 * www.todaracing.comTODA has a set of valve springs matched for the factory retainers and custom-designed to work with their camshafts, even the full-race VTEC killer version. TODA maintains that its single-spring design is superior to inner/outer versions by preventing valve float at higher rpm and lift and also by reducing stress on the cam and cam chain. Race-tested on TODA cars in Japan on their N+ race engines, TODA says these are the only springs able to withstand up to 13mm of cam lift. $400.
CAMSHAFTS
Crower619/661-6477 * www.crower.comCrower makes their cams with premium induction hardened cores, made from the highest quality steel. They've also spent considerable time engineering all new lobe profiles to work with the unique flow characteristics of the K series head. A wide variety of profiles are available, including a forced induction grind that "delivers impressive HP numbers." $843.
HyTech Exhaust949/581-2181 * www.hytechexhaust.comHyTech has gone all out with camshaft design, offering four grinds ranging from "nice improvement over stock" to full-on road rage. HyTech makes their cams with new blanks in a process that cools the cam evenly to prevent the high RPM cracking that kills inferior cams. Each stage of grind is designed with the other systems and parameters in mind (i.e. intake, exhaust, compression, header, even different intake manifold). HyTech recommends a brief chat before purchasing to match your whip to the right grind. VTEC-less grinds for racing are also available. Standard grinds start at $900. A custom grind will set ya back $1200.
Intrinsic Performance310/697-3045 * www.intrinsicperformance.comIntrinsic is a newbie to the Honda fold, offering a single-model cam for the K. Intrinsic cams feature extensive valve motion and harmonics analysis, and allow you to keep the OEM valve springs while still enjoying a good bump in performance. Check out their website for some hardcore info and dyno charts. Sold as a set for $1,200, and also available packaged with a Hondata setup.
Skunk2951/808-9888 * www.skunk2.comSkunk2 has quite possibly sold more B-series cams than anyone and now they're ready with a K cam. The Pro 1+ cam was 100 percent designed, engineered and tested at the Skunk labs in Southern California. They've improved on previous cam designs with revised blanks that have increased torsional strength, improved durability and reduced friction. Promising to be "the best all-around street cam that dramatically improves horsepower, torque, engine response and valvetrain stability," we can only wonder what Skunk's got in mind for a 2+ cam. For core racers, Skunk also offers cam gears. With a total of six fasteners they won't slip, but they will remove the "i" in your i-VTEC. Cams $950; gears $450.
TODA714/327-0181 * www.todaracing.comOne of the first companies to get on the K performance wagon was TODA, and their cams are designed, tested and manufactured using the same IBM CATIA CAD/CAM/CAE system that Honda, Ferrari, even Boeing, use. Four versions are available, including the popular Spec 2. Combined in a kit with springs and ECU reflash, the kit pumps out big power. Check the dyno charts on their Web site. Race-only VTEC cams, like those pictured here, require the rocker arms and cam gears. Pricing ranges from $1,100 to 1,200.
PISTONS
Mahle888/255-1942 * www.mahlemotorsports.comMahle lays claim to manufacturing the world's first aluminum piston and quickly earned the favor of Porsche executives. If that don't impress you, consider that they're also the largest piston supplier to Formula 1 teams. If that don't impress you, buy a Toyota. A piston that can hold up to 19,000-rpm strikes us as a pretty well-engineered piece and luckily for us the German company now offers a complete line of Honda pistons. Forged from low expansion alloy with correct radius valve pockets, Mahle pistons feature a unique outer coating to prevent heat , as well as a side skirt coating to prevent wear from excessive side loads. Mahle is also the only maker we know of that includes performance rings and wrist pins with all of its pistons. $499 for turbo pistons; $449 for flat-top 10.5:1 pistons.
Endyn817/924-9334 * www.theoldone.comEndyn was one of the first to use a swirl meter to peek inside a combustion chamber to see how airflow affects combustion. That knowledge has enabled them to produce their Roller Wave series of pistons. Designed specifically to match the Honda cylinder head, they feature matching quench areas for faster burn (less detonation and timing), extended skirt contact area to prevent excessive piston "rocking," minimizing cylinder wall and ring wear under high-stress conditions. The oil return holes are also placed to maximize oil return to the crankcase, with more area placed beneath the lower ring rail and a total of four ring-pressurized piston pin-oiling ports, two per side for improved pin lubrication. Every one of the Roller Wave pistons are hand-made to the applications requested. Endyn covers nearly every application possible. $485/set.
CP949/576-9000 * www.cppistons.comThe guys at CP Pistons are relatively new, opening doors in '98, but their reputation in Honda circles would be the envy of any small tuner/manufacturer. The three Calvert brothers behind the operation combine a cumulative 85 years of design and manufacturing experience in the racing industry. Not long after opening, they teamed with Pankly Racing and quickly began supplying F1, IRL, WRC and other elite racing teams with pistons. Their pistons for the K series come in three compression ratios and include pistons for the K24 with a Type S head, all in stock bore sizing.
JE714/898-9763 * www.jepistons.comChances are we don't need to explain to you where JE ranks in the piston world. They've been making pistons for over 50 years for the likes of NASCAR, NHRA, IRL, IHRA and others. All JE pistons are forged and can be custom-designed using Ultra Crown, the company's proprietary digital 3D piston crown machining process and Finite Element Analysis (FEA). FEA is a computer process where stress and fatigue are tested on a computer model before it goes into production. Their standard K pistons feature CNC diamond-turned skirts to reduce friction, forced pin oilers and a machined side relief with lower support band for extreme HP applications. Ring kits are also available directly. $123 per piston.
TODA714/327-0181 * www.todaracing.comTODA offers high compression forged pistons for the K20A Type-S and Type-R engines. The kit comes complete with forged pistons, rings, clips, and heavy-duty wrist pins. These are the same slugs used in their Japanese N+ circuit cars that maintain Honda's factory piston-to-wall clearance. The basic form of the piston is an elliptical barrel. This forms the basis from which each part is subjected to high loads and measured for thermal expansion to accuracy of 1/1000mm. The top edge of the piston uses a castellation design to reduce sticking, improve lubrication and sealing. The design also acts as a scuff-band to reduce run-in time. Redesigned oil channels improve oil drainage and reduce piston weight during engine operation, key if you're looking for high rpm. $1,080 for the complete kit.
HyTech949/581-2181 * www.hytechexhaust.comStarting life as a Wiseco piston, HyTech orders up a custom slug with strutted forgings for the highest strength and lightest weight. They're available in two and three-ring designs and feature a unique ceramic heat prevention coating. Bores range from stock (86mm for K20; 87mm for K24) all the way to 90mm overbore with any choice of compression ratio. HyTech will also match the piston top to a custom-shaped chamber or "bowl". $499/set.
CONNECTING RODS
Crower619/661-6477 * www.crower.comCrower's all-motor rod utilizes the company's new Maxi-Light shape that features a unique Radial Beam design. The RBT design is a Crower exclusive that features less overall material without compromising overall strength. The result is a con-rod approximately 100 grams less than Crower's standard forced induction/nitrous designs for greater throttle response because of lighter rotating/reciprocating mass. It's also usable in moderate boost/nitrous applications (15 lbs/75 shot max). Made from USA-milled 4340 steel billet and machined in-house at Crower, these rods feature 220,000-psi rod bolts, notching the big end for added piston oiling and extra wide pin width for added wrist pin stability. $711 for all four.
Cunningham310/538-0605 * www.cunninghamrods.comPeople are going to be mad, but Cunningham is something of a trade secret in Honda land. They're basically a custom, made-to-order, rod company, very small and very focused. They've built rods for Lisa Kubo, Papadakis, Alaniz, R&D Dyno and many more successful shops and racers. They also make rods for well-known companies who label them as their own. Cunningham believes the I-beam style rod is better than an H-beam because it has the most material on the sides of the rod that receive the greatest side loads (the same side loading that causes cylinders to oval). The other big trick up their sleeve is a separate casting for the rod cap. This ensures the metal's grain is oriented correctly and the memory effect will not cause the crank end to go out of round. Cunningham has been building rods this way for 30 years and doesn't claim anything supertrick. It's just plain experience. $200 each forged, $475 each for titanium.
HyTech949/581-2181 * www.hytechexhaust.comAsk HyTech's John Grudynski about rods and he'll quickly tell you that they're one of the weakest links in a Honda motor. They're a lot stronger than the rods in the engines of other automakers, but they'll still break under the high-rpm stresses that Grudynski routinely subjects his engines to. The key is not only in the design of the rod-an "H" design-but in the rod bolt size. HyTech rods feature oversized 3/8 rod bolts with 220,000-psi tensile strength bolts-the largest available. Custom lengths and journal sizes available. Special oil shedding coating is also available. $1,200 for four.
TODA714/327-0181 * www.todaracing.comThe JDM guys at TODA use their I-beam rods in their N+ endurance engines. These rods are constructed of 100-percent chrome-moly steel for maximum strength and TODA says they're also 17 percent lighter than the factory rods (489 grams vs. 589 stock). $1,840.
OTHER STUFF
HyTech949/581-2181 * www.hytechexhaust.comOil starvation is a huge issue in a road racecar. High g forces from cornering push oil away from the pump, and with no oil pressure, you'll soon have a lump of molten aluminum. HyTech has devolved an oil pan baffle and control insert. Five trap doors contain the oil near the pick up and control oil starvation. Easy bolt-in installation. $249.
HyTech949/581-2181 * www.hytechexhaust.comHyTech was the only company we found offering cranks for the K series. Honda cranks are incredibly stout and HyTech's are just as tough but also come in strokes of 86mm, 90.7mm, 95mm and 99mm, allowing you to make a very custom K engine (like HyTech's K23) for whatever application you're dreaming of. Cranks are hand-profiled, lightened and coated for reduced oil drag. $1,000.
Spoon707/584-9300 * www.opakracing.comFrom the factory, the USDM RSX Type-S sports an 11:1 compression ratio, while the JDM Integra Type R stretches to 11.5:1. Want that little extra? A Spoon 2P head gasket should do the trick. Thickness is 0.45mm, which should bump compression about 0.4. $210.
TODA714/327-0181 * www.todaracing.comTODA takes the same approach with its thinner head gasket for all K20 engines. Designed to also increase compression 0.4, TODA offers a 0.3mm thick gasket. Thin is in, baby. $220.
TODA714/327-0181 * www.todaracing.comOne of the coolest tools since the advent of the MAC tool truck. Changing springs on a head typically means removing everything so that these kinetically-charged coils don't make a beeline for your head. Leave it to a Japanese racing products company to come up with a very unique tool to swap springs with the head left pretty much intact. It's compatible with all K-series engines, as well as the F20C (S2000) engine. $400.