Hybrid How-To No.16: K-series engines into the EK (1996-2000) Civic's chassic

WHAT AND WHY
Face it, the D series in your Civic is far from anything special. It's a fuel economy engine. If you want more power, it's forced induction or a swap. Installing a B-series swap is easy, but Honda hasn't made a B series since model year 2001. Supply is shrinking and they're getting pricey. The future of Honda engines is in the new K series, under the hood of the Accord, Element, CR-V, TSX and RSX. Figure more than 400,000 of them are sold each year. They're already in junkyards and the minimum power is 160. Plus, the 2.0-liter version has lots more torque than a B-series swap and the 2.4 even more still. The EK Civic is the last generation with an double wishbone front suspension instead of cheap MacPherson struts like the 2001-and-up models, and the handling potential of the EK models is well beyond that of the newer cars. It's also lighter and has lots of non-engine-related performance and bling-bling parts available.

PICKING THE CHASSIS
For starters, Hasport, one of the best-known names for Honda swap parts and engine mounts, has engineered the K swap into the 1996-to-2000 Civic chassis. Any of the Civics (except a Civic that has a Continuously Variable Transmission, CVT) made in these years can accept a K-series engine. A Civic with an auto tranny will work too, but the kit is made to drop in a manual transmission K engine. You'll have to add the clutch pedal yourself. The leanest, meanest car for speed would be the 1996-to-1997 CX hatchback. It has the lowest weight, least emissions control, a relatively rigid body (since it has no moonroof), and is still relatively available. Next would be a coupe, like an HX, but even a 2000 sedan with its 300 extra pounds will suddenly wake up, especially if you drop in a torquey K24.

PICKING THE ENGINE
There are several versions of the K series. Any of them will fit, but some are better than others. The K20A2 powers the RSX Type-S. It's the best of the U.S. engines, mainly because it has the real VTEC, with high- and low-rpm lobes for both intake and exhaust valves, as opposed to the sissy eco-version that only acts on the intake cams and has no high-rpm lobes. The A2 also packs the highest compression, is built to withstand higher revs and comes bolted to a six-speed. Unless it's cheap, a K20A3 engine from a Civic Si or base RSX is probably one to skip. You can beat it with a B20 VTEC and save the trouble of the wiring harness. It'll go in just like the K20A2 shown here, but unless being different means more to you than being better, why bother? The K24s from the Accord, Element and CR-V are all basically the same, but different intakes and emissions components can complicate things. The Accords and Elements have the most emission control stuff. The CR-V is called a "light truck" by the EPA and will have less crap to hook up, notably EGR. All California cars will have more emissions crap. Consider a K24 for a swap because it will have great torque, responds well to turbocharging and paves the way to a future upgrade with an RSX Type-S or TSX head. That leaves the K24A2 from the TSX or the JDM ITR engine, called simply the K20A. The JDM K20A is the best OEM version there is, with 20 more factory hp and a limited slip. The TSX is so new you likely won't see one in a yard for some time. The TSX also uses an electronic throttle that could cause other problems. But either of these engines follows the same installation as laid out here.

PICKING THE TRANSMISSION
If you're polling the yards for complete swaps, you may not have a choice, but there are some diamonds out there. The best of them would be the six-speed from the RSX Type-S, Japanese Type-R or TSX. Either is good, with the TSX being geared for the torque of 2.4 liters and the Type-S and Type-R geared for high-revving powerbands. It's all the other trannies that present you with choices. There are no CR-V two-wheel-drive manuals, but the Element has some short (high numerically) gears. It might make for a nice, all-motor gearbox. Next is the Civic Si. Nearly an exact match for the RSX, it has lower first and second gears, but a higher final drive. The Accord tranny is about fuel economy. It's the easy choice for turbo application though, where short gears just mean wheelspin. See the transmission ratios table for all the details. Gears and final drives of all the five-speed boxes are interchangeable, as are the six-speeds. But you can't swap parts between five-speeds and six-speeds.

ENGINE REMOVAL AND PREP WORK
This is kinda old hat by now. The D-series engines that originally came in these cars are tiny little guys that come out easily. A lift makes things easier since Honda motors go in and out the best from the bottom. When you're buying your K motor, make sure to get everything attached to the engine, including the engine wire harness and the engine charging harness (battery cable and alternator wires), since it's a separate piece on K engines. The batteries are in different places in the K-powered cars and you're going to need its charging and power distribution harness for the EK. The other must-haves are the ECU, an original key and the transponder from the steering column. Since 2000, Honda has built all its cars with a coded key and transponder system as an anti-theft device. ECUs are matched to keys and can't be reprogrammed without a lot of documentation and an understanding dealer.

COOLING SYSTEM
This one is a bit of a bugger. Our EK uses an aftermarket radiator made for an RSX (you can use the stock RSX unit as well). The stock lower mounts have to be cut off and mounted further down, but it's very effective and uses stock RSX hoses. The old EK radiator's fan switch and temp sensor had to be moved when we did this as well (and are still needed if you use your EK radiator). This setup means no A/C without the RSX condenser. Another option, if you want A/C, is to make the EK radiator and the A/C condenser switch places (they sit side-by-side, not one in front of the other like most cars). In the stock location, the EK radiator's upper outlet hits the K-series intake manifold. For hoses you can use 1994-to-2001 GS-R upper and lower hoses. The lower hose will require some creative trimming to fit properly. The A/C compressor from the K will work with the EK's condenser, but you'll have to get custom hoses made. Any good A/C shop should be able to do it. If you don't care about A/C and didn't get the RSX radiator, then just move your EK's radiator to the driver's side and plug the gaping condenser hole so air will actually go through the radiator. This car didn't have A/C and so the above suggestions are I-think-so engineering. The K-series compressor will certainly work with the EK's condenser and it will also work with the condenser from the K-series donor car. The question on that one is, "Can you make it fit?"

Power Steering Sorry, this is a no-go as of yet. The problem is that the pulley sticks up too high to clear the hood. Even when you cut hood support beams, there's not enough room. Likely, a carbon-fiber hood company will make a K-series hybrid hood soon. For now, you can just loop the in and out hoses on the steering rack together and get a hell of a workout. You will also need to install the idler pulley from an EP3 (2002-and-up Civic Si) to take the place of the power steering pump.

MOUNTING THE ENGINE
The mounts fit a K20 or the 20mm taller K24. If you're installing a K24, to get the stock hood to shut, some of the reinforcing beams needed to be trimmed. Be careful not to cut too far. If you install a K20, you won't have to do this. When lowering the car onto the engine (remember, that's the easier way) line up the left and right mounts first, getting a few threads into those, but leaving them loose. Then get the top bolt off the rear mount. With the lower bolt out, put in the driveshafts. The lower bolt on the rear mount rotates the motor and can make getting the driveshafts in much tougher.

DRIVETRAIN HOOKUP Damn, the bills are piling up fast on this swap. But no one ever said being the first to do a project would be cheap or fast. Your EK needs new axles, because none of them fit exactly. The Civic Si is the closest fit but still comes up short on one side. The Driveshaft Shop custom-built the axles on this car, but Hasport will have both 250- and 400-hp versions in stock, with 525- and 800-hp models available by special order. Next is the shift linkage. The EK uses big rods under the car and the K motor's tranny uses cables on top of the floor--not to mention the transmission is on the other side of the car. In the world of Honda accidental parts compatibility, the shifter mechanism (the shifter arm and the base its attached to) from a 1990-to-1997 Accord is what you need, plus the cables from the K tranny. The installation problem here is the EK's transmission hump. Sitting the new cable shifter mechanism on that hump makes the shifter so tall, the factory console won't cover it. A solution is to mount it under the car. Doing so means making an enclosure for the mechanism so it's not exposed to the elements. Hasport enclosed it with sheet steel and it worked perfectly. Inside the car, all you see is the stick coming up just like stock. Cables were routed under the car as you would on an H22 swap. The shifter mechanism from any RSX, TSX or current-model Accord will work too, but it's very tall. Enclosing it and putting it under the car may not leave enough exhaust clearance. If you use this, you'll have to be creative or skip the stock center console (perfect for racecars). Finally, you'll probably need a throttle cable from a new Civic Si (EP3). The one in your Civic may or may not be long enough.

FUEL SYSTEM This is either pretty simple if you live in a non-California-emissions state or really tough if you're in California. Most of it has to do with fuel vapor control. Take a look in the manual at all the controls on the car your K engine came from and you can see about matching them up with your Civic chassis. The 1999-and-2000 cars may have all the matching controls, but certain models may not. The 1996-to-1998 cars will be tougher to match and may require pulling parts from other Civics. If you don't have them and must put them in to pass emissions, you can probably find a newer sixth-gen. chassis that has the corresponding parts. An example would be a fuel tank pressure sensor. This is on all K-engined cars and 1999-to-2000 Civics, but not our 1996. You have to look at all the emissions control stuff on the K-engine donor car and match it part for part to your car if you want to pass the California smog test or any state that follows California's rules. The other challenge is the fuel return system. Your EK Civic has one, but the K-series engine doesn't, plus the K-series operates at a constant fuel pressure, rather than following the intake manifold pressure like the EK's engine did. An adjustable pressure regulator does the trick--just set it to the pressure in your K-series manual. Fuel comes into the regulator from the filter, pressure is set and goes out to the fuel rail. Excess fuel from the regulator is sent back to the tank via the EK's return line, which is attached to the second output of the regulator. Mounting the regulator on the firewall close to the fuel filter means just a couple of custom hoses. Don't hook up a manifold vacuum line. It will freak out the K-series ECU.

INTAKE
Obviously, short-ram intakes designed for the K-series engine are going to be the easiest. But they aren't very good to begin with, since they typically put the air filter on top of the hot transmission. A better way is to work some custom cold-air piping into the pocket in front of the driver's tire and the bumper. Just like an EK cold air, but on the other side. As this swap becomes more common, companies will likely make these, just as AEM does for B- and H-hybrid swaps today.

EXHAUST
This is now on the firewall side. Because of the very different crossmember on the EK, the stock exhaust won't work, nor will any aftermarket exhaust. Hasport has long tube headers available that terminate into a 2.25-inch collector. You can use the stock EK cat and exhaust, but will need to shorten the B-pipe. The O2 sensors on K-series engines are unique. Be certain to get at least the front or first sensor when you buy the engine. The catalytic converter is useless. It contains another 12 inches of pipe before the cat, but the front O2 sensor is a full wideband unit and the ECU expects readings from it, not the narrow band sensor that came with the EK.

THE WIRING
If you thought it was tough getting the right engine with all the right parts and then getting it in the car, grab a drink and sit down. Realists, add $399 to your budget, send the stock EK engine harness, the K engine and charging harnesses to Hasport as a core and get back the plug-and-play version. More time than money? Here goes. Order the service manual and electrical trouble shooting manual for your chassis and the year and type of car your engine came from at www.helminc.com. Helm makes all the OEM manuals for Honda and they're cheaper there than the dealership, even with a shop discount. With all four of those in hand, you can follow along. These notes are for a 1996-to-1998 chassis; 1999-or-2000 models may be different. Here are your biggest challenges: The EK has a single harness for the engine and for the charging system. The K has separate harnesses. The EK has a conventional dash and the Ks use a multiplex (multiple signals sharing one wire) system to drive the speedo, tach, water temp and more. The EK has relays that operate differently than a K. The K's engine harness comes through the passenger's side of the firewall with all its wires, the EK has most of its wires in the same place, but there is one critical plug at the driver's-side shock tower. There are also signals that are in the EK cabin harness that need to go into what would be the K's engine harness. Some things, like the engine temp, have to be wired directly into the dash because, although it gets into the K's ECU, there isn't a separate output wire. The water sensor on your stock radiator will need to get wired directly to the dash via the driver's side shock tower plug (see wiring charts). Most importantly, make sure to get what the K manual refers to as the E-plug on the K-series ECU. When the junkyard guys send the ECU, just have them cut it with as much wire hanging from the E-plug as possible. They likely will because there are only three plugs for the ECU and the other two are on the engine harness.

ECU
You need the ECU, key and transponder that match your new K engine. However, Hondata does have a reflashed RSX, RSX Type-S or Civic Si ECU available with dyno-proven results. It also has a fully programmable version based on the RSX Type-S ECU that gives you control of ignition, fuel, i-VTEC, idle, redline, nitrous control, boost and more. If you want the Hondata, the best way to go is the fully programmable unit because it's the only one that can disable the error codes associated with missing emission controls. Be sure to budget at least $400 to $500 for dyno tuning. Hondata will also sell you a brand-new ECU if you're moving from a non-Hondata compatible ECU (Accord, Element, CR-V) to a programmable or reflashable unit. Hasport has ECUs with the immobilizer removed, but you'll be expected to provide full documentation (including VIN numbers) of where you obtained your swap engine. If you source your own ECU, you'll need the matching VIN number as well or a new ECU receipt. The purchaser's info will be shared with law enforcement upon request.

TEST DRIVE
If you're still excited about this swap with all its complexity and mass of odd or custom parts, then you'll love the result. If it's 160 hp from a K20 or the super low-end torque of a K24, this is a great swap. The lucky few who get K20A2 motors will really love their new EKs.