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4th Gen TECH


1988 to 1991 CIVIC/CRX

Ranked from easiest to hardest:



Many Japanese engine importers have been getting Japanese 1.6L (non-VTEC) DOHC motors that bolt right in. They are from '88-91 Japanese Civic and CRX Si. (CRXGuy's page shows that in Japan the DOHC was standard in the Si, while the DOHC VTEC was standard in the Si-R). The ZC motor externally looks almost the same as the 1G Integra but with 4G Civic mounting brackets on it. However, this motor has slightly higher compression (9.5:1), a larger intake manifold and slighlty higher hp cams. This all adds up to stock power of 130ps (about 129-130hp).

The Si transmission is the best choice available. Both the Si and DX transmission bolts right up and keeps the install simple. The DX transmission will sacrifice performance for better fuel mileage and lower freeway rpms. The ZC tranmission has a close ratio 1-5th gear, but a long final drive, making the best transmission still the US Si. For the ultimate acceleration make a Si/ZC hybrid transmission, by taking the Si final drive and put it in the ZC transmission. Or you can do it the other way around, ZC 1-5 in a Si transmission case. Either way, expect 80mph to turn 4300 rpms. However, the ZC transmission requires you to use ZC or 90-91 Integra axles, and a ZC or 86-89 Integra intermediate shaft. Because these axles are equal length, many users report a reduction in torque steer.

For ECUs you can use a Si ECU (7000 rpm fuel cutoff), 88-89 Integra ECU (7500 rpm fuel cutoff) or the JDM ZC ecu (7500 rpm), but the DX does not work. Especially with header, exhaust and intake the Si ecu's redline seems to cut in early. You will not need higher than 7500 with stock cams, and if you decided to chip your ecu, keep the redline at 8000 rpm or below on the stock valve springs. On the DX, the Integra, Si and ZC ecu will plug into the DX wiring harness, but a few wires will have to be changed. See the DX to ZC wiring conversion article for more information.

The motor looks really clean in the engine bay and your A/C compressor should bolt right on (earlier it was thought that a special bracket was needed). The DX throttle cable is long, but will still work. If you're stuck, here is one example of how to route it. Or replace the throttle cable with one from an Si.

While the motor has been advertised for as low as $240 (long block, K.Wantanabe), $400-700 is a more realistic price range, though some have happily paid over $1000. By now, most of the Japanese engine importers know about this motor and get them all the time.

The Integra 1.6L does not bolt in. Compared to the ZC, there is no reason to try to fit a 1G Integra 1.6L. At only 118hp, it's not worth the trouble.

ZC Resources:
ceas ZC page
Jason's ZC for Dummies
Steve Sosteen's ZC page
Hybrid's ZC page



The SOHC VTEC motor from a 5G Civic Si/EX will bolt to the 4G transmission allowing it to drop into the car with no cutting or welding. The 4G intake/fuel system can be bolted to the VTEC block, so that the 4G ecu is retained and there is very little wiring changes. A VTEC controller will have to made or bought. Ideally, the the VTEC intake, fuel system and ecu would be used, if you have the time and wiring skills.STEP by STEP instructions and more information.


Bolt in kit for B16, B17, B18

There are two good bolt in kits on the market. Both have positives and negatives. The jury is out regarding which is the best.

HCP Power Innovations EF-18 Kit

Speed Garage bolt in kitThe HCP Power Innovations third generation EF18 bolt-in kit is distributed by Speed Garage (949.472.8521). EF is Honda's code for the Japanese 4G CRX and Civic, and 18 refers the to the Integra 1.8L engines. The B16A and B17A can also be installed with this kit. The kit includes three motor mount brackets and an adjustable shift linkage. Several improvement were made since the prototype pictured, and the kit is a solid design with many good reviews. No welding is required, but you do have to drill one or two holes. The kit uses the stock 90-93 integra engine mount in the stock Civic/CRX location, which places the motor slightly back. This leaves plenty of space between the block and the radiator for a turbo. HCP has many test cars out there (CRXs, hatchbacks, sedans, and even wagons!!) and they report that although the firewall clearance looks slim, you will not have a problem. For about $160 they have a custom bracket that allows you to mount your A/C compressor so you can keep your cool. Images of the Speed Garage Turbo EF18 CRX

Place Racing

Place Racing makes a well engineered bolt in kit, designed to position the motor like Honda does. However, that may not leave enough room for a big turbo. Additionally, there is no front mount, so the three remaining mounts are filled with a hard rubber, that while controlling the engine motion extremely well, also transmits extra vibration to the chassis. The upside of the firm rubber is that it keeps the engine from banging into the hood or firewall during hard shifts.



also read B16A powered CRX, by Eric Bauer

The B16A1 (160hp DOHC VTEC) from the JDM 90-91 Civic/CRX Si-Rs is being imported in small quantities. The B17A comes from the U.S. 92-93 Integra GS-R and the block is externally and internally identical to the B16A1 block. But they do not bolt in. The stock B16A powered CRX Si-R has many significant differences form the U.S. The most important thing to note, is that the driver's side motor mount is NOT in the same location as the U.S. Civic/CRX.
Si-R vs Si driver's side engine mount
As you can see above, the Si-R B16A driver's side mount is closer to the front of the car. It is also wider, and beefier than the U.S. mount. The B-series mount is designed for a stronger motor, and I suspect that Honda must have put it in that location for a reason.

The other differences are that the passenger side mount, and the front and rear cross members are different. You can import the crossmembers, but the driver's side and pasenger's side mounts would have to be removed and new fabricated mounts welded in. So, contrary to what you may have heard, there is currently NO WAY to mount a B-seies motor in the same location as the factory, without a bolt in mount kit or welding in new mounts.

Keep in mind, that all B-series motor swaps that use the US drivers side mount will position the motor closer to the firewall than Honda intended.

The B16A1 is almost identical to the 160hp U.S. Del Sol VTEC (B16A2). The Del Sol motor does NOT bolt in either. Since the D-series transmissions are not compatible with the B-series motors, you should purchase the Y1 transmission along with the motor. If you can, buy the motor and transmission as a package, not separately. Some of the Y1s have the highly desirable factory LSD. LSD should be imprinted on the transmission casing, so search carefully. If a Y1 is not available, a 90-93 Integra LS transmission will work, but the gear ratios are not designed for the high rpm VTEC engine and will hurt acceleration. With either tranmission you will need to modify the shift linkage to fit. A few people have managed to get Si-R shift linkages from Japan and these work perfectly.

For engine control, you have three choices. Use a stock Si-R ecu, which requires some wiring changes. Use the stock Si ecu, reprogrammed for a higher red limit and the use a external rpm switch for VTEC activation. Or use a Del Sol VTEC engine harness and rewire the engine compartment and dash to use the Del Sol VTEC ecu. With either the Si-R or Del Sol ecu, note that there is a speed sensor in the transmission that tells the ecu that it is okay to activate the VTEC. If it doesn't see that signal, you get no VTEC and a slow motor. I am sure you can fool it if you know what you are doing. The Del Sol VTEC service manual should be able to guide you through the wiring. This can be the hardest wiring install, since you are combining the parts from three different cars (U.S. Civic, JDM/U.K. Civic, and Del Sol).


1.8L Integra non-VTEC

The non-VTEC Integra engines fit, BUT this is not a bolt in swap. The D-series transmission is not compatible with the Integra motor, so all four motor mounts must be modified to fit in the bigger motor and transmission. Use 88-89 Integra axles and you will have to modify the shift linkage. All these things are necessary to insure proper alignment of the axles so that the car will drive straight and shift correctly. In the past, poorly done swaps, would cause the car to pull viscously to the side. So make sure the shop you choose knows what their doing. Prices for a non-VTEC swap start at around $1000 (not including the engine, transmission and other parts needed). But prices vary widely.

The ecu plugs into the under dash harness, but the color coding and pin location is different. The manuals for both the cars will be necessary to map out the changes.

The transmission from the 94+ Integra uses mounts that are significantly different than those in the Civic and uses a hydraulic clutch, so the swap gets very complicated and ugly. However, the 90-93 Integra transmission will bolt to the 94+ motors and has a cable clutch like the 4G civics. This will allow you to use the 94+ non-VTEC motor. You will need to use a 90-93 ecu.


B16A2, B16A3 and B16ASpecR

The B16A2 from the Del Sol VTEC makes 160 hp, and the B16A3 from the JDM 5G Si-R and Si-RII make 170 ps. There is a slight difference in compression ratio, but not ten hp worth. Perhaps the difference is in ecu tuning because of the higher octane gas available in Japan. For this reason, only use the US Del Sol VTEC ecu with these motors. Both motors are externally the same, and should install similar to the B18C below. The block is slightly shorter, than the B18C, but not enough to justify choosing the B16 over the B18C.

The should also fit if you can manage to get one.

B18C VTEC, US and JDM B18CSpecR, JDM B16B

These VTEC motors are taller than the other B-series motors. The extra height requires creativity and a few more compromises. The rails under the hood can be trimmed to reduce interfered with the motor. The motor can be shimmed downward to clear the hood. However, placing the motor lower puts it close to the radius rods and the engine will probably bang into them [bad!]. Refer to these pictures for some of the challenges. A custom bumped hood, or an Si-R hood can give you the extra clearance you need. Be warned though that a JDM Si-R hood doesn't match up with the US front end.



The 2.2L and 2.3L Prelude motors can be stuffed in the 4G engine bay with cutting, pounding, welding, and basic indifference to structural safety. We highly advice against it.

A normally aspirated fully built H22A VTEC motor would be very strong, and should be capable of low 12sec slips. However, very few H22As are actually faster than built B18Cs.

The prelude motor is significantly heavier than the stock 4G motors, and the additional front weight bias will spell u-n-d-e-r-s-t-e-e-r. If you love the way your car handles now, think twice about the big 'lude swap. If you do, you must get bigger front brakes, or at least aggressive pads, to haul you down without drama.

Which motor should I get?

For a daily driven car that is your sole mode of transportation, I highly recommend the 1.6L DOHC ZC motor, or the SOHC VTEC. They both bolt right in, fewer parts are changed and its not very expensive. But its nowhere near as fast as the 1.8Ls, and the ZC is harder to find, especially outside of SoCal.

The B16A will be a time consuming wiring challenge, but should be very rewarding.

The Integra motors create a lot more torque than the 1.6Ls. A streetable, built non-VTEC can generate 150+ hp at the wheels and modified B18Cs can generate push 170s-180s, even high 190s. Either one is capable of tire smoking power that will have your friends calling your car 'Monster'. But since the install is much harder, the cost is usually much higher than the bolt in swaps. And with modified motor mounts the risk goes up that the car won't be Honda-smooth and relatively vibration free.

For an all out racer, fully built Turbo/NOS B18A, H23 or H22s have all been successful.

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