Few things excite Honda enthusiasts as much as the thought of increased power and performance options right from the manufacturer itself. If you’ve been around for a while, you no doubt remember the stranglehold that the B-series swap placed on the Honda community. It quickly became an almost mandatory transplant during its heyday. When Honda introduced the K-series powerplant, history once again repeated itself, and it didn’t take long for our swap-happy community to figure out a way to make it work in an older chassis. A topic of discussion in 95 percent of Honda performance-related conversation, it wouldn’t be out of line to suggest that engine swapping, as American as apple pie, has had the largest impact on Honda performance over the last 20 years. With the introduction of the K-series generation, the saga continues.
Pricing for the K-series family is a bit tricky. You can search the various engine suppliers and classifieds forums online and sniff out a good deal on the longblock and transmission, but there’s much, much more involved in putting together a complete swap. When the first wave of K-series motor conversions hit the streets, much of the process involved heavy amounts of custom fabrication. Some did it well, others poorly, but the end result was more interest and a tidal wave of aftermarket support for the K20 and K24. In fact, a number of companies have jumped on board to offer products that simplify the process, and look good doing it. Gone are the days of hack job mounts and “make it fit” radiator setups—at least we hope. Rather than throw some random parts at you that you’ve probably already seen or heard about through the web, we handpicked some of the crucial components needed to complete the K swap. Essentially, these are the ones that will make your life easier during the process, and produce a much better outcome. Many of the parts listed are focused on the incredibly popular ’92–’00 Civic and ’94+ Integra bodies, but if you’ve already completed the swap on your project car or perhaps you’re driving an RSX or newer gen Civic Si, some of these parts can help make it that much better.
Beyond the act of basic swapping lies a massive lineup of high-performance aftermarket goods to take power output to the next level and beyond. Our sister publication, Import Tuner, has stepped up to provide a comprehensive breakdown specifically geared toward making more power with the coveted K swap, and you can read through it in their March issue.
Let’s get started…
To get started, you’ll of course need the engine and transmission. There are a number of importers across the country that secure highly sought-after Japanese market motors. There are also junkyards chock-full of K24 donors due to the U.S. market CRV, Accord, and Element, and don’t forget your favorite Honda forums classifieds section.
Zerolift Autolab JDM K20 approximately $4,800
Specializing in importing used and rebuilt Japanese engines and transmissions, handpicked from Japan, huge inventory, price match guarantees, rapidly growing customer base, massive inventory of JDM engines, interior, and exterior goods
Obviously the factory mounts won’t work for this swap, so you’ll need to source a set of swap-specific motor mounts. Various durometers, materials, and colors are available giving you a number of avenues to completely customize your setup. For the RSX and Si crowd, upgrading mounts can help curb engine movement and revitalize tired stock mounts.
HaSport engine mounts $499–$555
CAD/CAM-designed, 6061-T6 billet aluminum, lifetime warranty, proper engine placement and axle geometry, four different bushing durometers
Hybrid Racing engine mount kits $499
6061-T6 aluminum, CNC machined, .0001 inch tolerances, hand assembled, no-tear/tapered polyurethane with vibration suppression, DuPont industrial powdercoated, lifetime warranty
Power Rev Racing (P2R) “CRV” bracket for K24 swap $69
6061 aluminum, only 310 grams, inexpensive alternative to the OEM CRV bracket from the dealer
Dealing with the K series’ inherent “return-less” fuel injection in comparison to the “return”-type system that most Honda enthusiasts are accustomed to, an aftermarket fuel rail is typically utilized. Many of the more popular fuel rails incorporate options for a gauge, custom fitted lines, fuel pressure regulator, etc.
K-Tuned fuel pressure regulator and gauge $199
Full billet housing, adjustable bracket for easy mounting, 30–100 psi adjustability, includes gauge, bracket, and fittings
Karcepts fuel rail $125
6061-T6 aluminum, large bore design, tucked fuel line option for a cleaner appearance, various colors available
Hybrid Racing K-series fuel rail (universal) $160
6061 aluminum with T6 heat treatment, compatible with -8AN fittings, anodized finishes, 1/8-inch NPT hole for gauge mounting directly to the rail
This can often be the priciest portion of all K swap necessities. Although you can use a stock ECU and ’02–’04 RSX wiring harness in most mid-/late-’90s chassis, you will need to worry about the factory immobilizer. That is, unless you opt for an immobilizer bypass box, like those offered by Hybrid Racing and K-Tuned.
By far the most popular tuning options are Hondata’s K-Pro (FlashPro for RSX/Si) and AEM’s EMS. Both offer users the ability to customize their setup whether it be NA, boosted, nitrous, utilizing ITBs, etc. Both eliminate the need for immobilizer work abounds, and they have a massive following among Honda enthusiasts.
Hondata K-Pro $995–$1,595
Fits inside the ECU, USB connection, built-in data logging, TPS-based table for ITBs, expanded fuel and ignition tables, built-in calibrations for common engine combinations, engine protection from over boost and lean protection, etc.
Hondata FlashPro for RSX/Si $695
Full user tuning and data logging, USB 2.0 connection, no ECU mods necessary, 90-second programming time, check and clear diagnostic codes, custom laptop gauges, dual calibration storage, 20 hours onboard data logging memory, etc.
AEM EMS $1,400
Complete engine control using factory harness and sensors, individual cylinder fuel/timing trims, base maps included, Windows-based software, onboard data logging, forced-induction compatible, 16/32 high-speed processor, etc.
K-Tuned immobilizer bypass $199
Allows the use of OEM K-series ECU, disables both the immobilizer and the factory multiplexor system, quick installation, simple work-around
In the early days of K swapping, custom axles were the only option to force the conversion to actually work. Currently there are off-the-shelf axles for various applications available in a number of strength and sizing options.
HaSport “entry level” axles $333 available for multiple chassis and engine combinations
Custom-length shafts available for an exact fit, 12-month warranty included, all 2.9 and above series axles produced by The Driveshaft Shop and also include a 12-month warranty
Driveshaft Shop axles $799+
Level 0 “basic swap” axles for street cars, 2.9 for higher-powered street cars that see track time, 3.9 for up to 600hp, 5.9 for over 600hp
A number of companies now offer street and race exhaust manifolds for K swap vehicles in different sizes and lengths. While some incorporate a catalytic converter, others specify off-road-use only.
Blox Racing K swap header for ’92–’00 Civic/Del Sol, ’94+ Integra chassis $829
4-2-1 design, 16 gauge, T304 stainless steel equal-length mandrel-bet tubing, CNC-machined flanges and TIG welding for additional strength
K-Tuned 4-1 race header $549 (picture not available)
100 percent TIG-welded, CNC-cut flanges, 2.5-inch high-quality flex and outlet flange, two oxygen sensor bungs, full stainless construction
K-Tuned ram-style race header for ’92–’00 Civic/Del Sol, ’90+ Integra chassis $999
Long-tube 4-2-1 design, 304 stainless construction, equal-length tubing, stepped design, 2.5-inch exit, three “true” merge collectors, excellent ground and shifter box clearance
Chassis-specific radiator options were scarce in the beginning, but are commonplace nowadays in both half core and full size units. For those looking to eliminate as much as possible under the hood, custom “tucked” versions have also made their way into the market.
Hybrid Racing radiator $399–$499
Full size and half core units available, integrated bungs to mount coolant temp sending unit and fan switch, grounding bung on lower end tank, all-aluminum TIG-welded construction, no need for custom mounting brackets on most chassis
Crossflow design, lengthened coolant path, dual pass partition, precision hand welds, billet-aluminum filler neck, 1/8 NPT female bung for aftermarket temp gauges
All-aluminum/military-grade, deep drawn tank technology, B-tube technology, wind tunnel tested for efficiency, Master-class TIG welding, CNC-machined brackets/fittings, all-aluminum drain plug
K-Tuned passenger-side radiator kit $399
High-quality aluminum radiator, original passenger-side mounting retained with zero modification, custom-fitted hoses, stainless steel T-clamps, slim design fan and mounting ties included
Rywire “tucked” radiator $425
Dual-core and dual-pass, -16 bungs for AN fittings or traditional slip-over hose compatible, front-mounted drain plug for easy coolant removal
In order to mate the factory K-series engine harness to the dash harness in your particular chassis, a harness or adapter is needed. This will allow all of the factory electrical functions to relate with the new swap, including your gauge cluster, fuel pump, sensors, etc. Most kits are almost entirely plug-and-play.
Rywire $300 (all Honda chassis)
OEM plugs and wiring used, wiring color-coded according to factory manual, 99 percent plug-and-play, includes C101 harness plug for air/fuel relay and all other necessary functions, diagram included
Rywire mil-spec “tucked” harness $899 (all Honda chassis)
Signature custom-routed wiring harness, mil-spec Teflon-coated wire loom, DR-25 heat shrink covering, adhesive-lined wire junctions to avoid moisture, option for mil-spec quick-disconnect available, easy-to-read identification label for ease of installation, shielded heavy interference connections
K-Tuned $339 ’92+ Civic/Del Sol, ’94+ Integra
99 percent plug-and-play, OEM wire color-coded, nylon sleeves for protection, complete installation instructions and wire-stripping tool included
HaSport ’92+ Civic/Del Sol, ’94+Integra $299
OEM plugs and wiring based on factory color codes, 99 percent plug-and-play, hours of testing on both the street and the track
Hybrid Racing K-series conversion harness ’92+ Civic/Del Sol, ’94+Integra $349
Original Honda style connectors and pins, integrates the factory oxygen sensor, simple installation, complete instructions and necessary connectors included
Shifter Box and Cables
Some shift boxes and cables were unusable on certain K swaps until adaptive shift kits were developed to not only help bring down the cost of the overall swap, but to make your life a little easier.
Karcepts shifter mounting kit $125
Laser-cut stainless steel construction for longevity and to act as a thermal barrier against exhaust heat, eliminates cutting into firewall for cable routing, rigid mounting base for positive shift feel, eliminates the need for shifter box bushings
K-Tuned K20Z3 trans conversion kit $229
Keep the Civic Si shift selector for use with ’03–’07 OEM Honda Accord shifter box and shifter cables, much more affordable alternative
K-Tuned billet shift box $TBD
Complete replacement for any car that uses an RSX-style shift box or shifter adapter, fully produced in high-quality 6061 aluminum
Hybrid Racing K swap bolt-in short shifter $379
Stainless steel and aluminum construction, adjustable throw from 90 percent to 40 percent of stock throw, height-adjustable knob (not included), splined central shaft for added knob placement adjustments, compatible with RSX or Hybrid Racing shift linkage, over 400 possible configurations
Hybrid Racing shifter cables for RSX and K swap cars $349
Replace OEM RSX cables, solid rod ends (no rubber), billet-aluminum bushings, stainless steel cables and guides, wire-reinforced sleeve
And finally, here are a few bits and pieces that can help simplify the swap or give you even more options for expanding on the power front.
Hybrid Racing A/C line kit for ’92–’95 Civic/Del Sol, ’94+ Integra $399
Retain A/C with a complete bolt-in kit, precise measurements used, OEM-quality fittings and lines, designed around R134A
K-Tuned billet TPS sensor (new design for 2012) $159
OEM Honda-spec sensor, 6061 aluminum housing, silicone-filled “pocket” for cushioning
K-Tuned swivel neck thermostat $179
Adjustable for multiple types of water hoses, fan switch port, optional heater hose delete, Stant thermostat included
K-Tuned adjustable EP3 pulley kit $159
Allows the correction of accessory belt length by manual adjustment, keep or delete A/C, available for all K20/K24 engines
K-Tuned vehicle speed sensor $159
Because ’05+ speed sensors aren’t compatible with ’02–’04 ECU, K-Tuned VSS can be used to calibrate the speedometer, simple four-wire installation, instructions, and jumper plug included
Blox throttle body adapter for RBC intake manifold $60
Allows K-series swap to maintain the drive-by-cable operation rather than drive-by-wire, compatible with the RBC intake manifold and the Blox Racing or OEM throttle body
Karcepts throttle body adapters $60
For adapting various OEM and aftermarket throttle bodies to an OEM RBC or RRC intake manifold, 70mm throttle body compatible