Transmission – Automatic to Manual Conversion
Website design By BotEap.comWhen I bought my EG4 Civic hatchback in 1998 I loved everything about it, the interior of the body and the engine were in excellent condition. However, there was one thing I would not have chosen: automatic transmission. The original engine was a JDM D15B SOHC VTEC, rated at 130bhp, especially for a 1500cc!
Website design By BotEap.comSo I started my research on the net to find out my options regarding converting the car to a manual transmission. In my search, I discovered Eric’s B16A site and the hybrid site, among others. So I started thinking why bother changing the transmission on the 1500, you could do that too and put a DOHC 1600cc VTEC and gain 40hp in the process. I considered a B18C but those engines are rare and expensive in Trinidad. In any case, the second generation JDM B16A makes the same horsepower, with slightly less torque. From what he had learned on the internet, he knew that the engine would be a good fit. Also, since my car originally came with a VTEC engine, I knew the wiring wouldn’t be too difficult.
Website design By BotEap.comI read everything I could find on trading and tried to plan the trade to the best of my ability. Let me point out that there is no substitute for good information, so if you are planning any kind of hybrid, read as much as you can BEFORE you start; websites, FAQs, articles, magazines, you name it. I chose to have a local shop with considerable Honda experience do the work and was able to locate the engine from a local importer.
Website design By BotEap.comMY MISTAKE
I knew that the best thing would be to buy the engine and accessories as a package, and that is what I did. But I zeroed in on the big items, engine, Y21 LSD transmission, ECU, complete engine harness, axles, and in doing so I didn’t even realize the engine was missing the mounts! (There’s no AC unit either!) Now, even though we have pretty fast traffic in JDM parts back home, some things are almost impossible to get, like mounts! Website design By BotEap.comThe solution? Modify stock D15B brackets to fit. That mistake caused a project that would have taken a little less than two weeks to take five weeks. You can imagine how my wife loved me for this! Website design By BotEap.comSTART UP
The assemblies took a long time to complete and also, as expected, my car was not the only one in the shop! Anyway, it turns out that the rear (middle) engine mount could be used on the B16A. I was able to get a front drive mount, leaving three mounts to custom fit. By the way, the front lower motor mount/AC mount on the B-series motor is totally different than the D-series mounts, so I fabricated an adapter flange to accept my old AC unit. (I had no intention of buying an air conditioner in any way.) Website design By BotEap.comAfter adjusting the mounts and positioning the motor in its proper place, the shaft hardware was mounted in a jiffy and the necessary fluids and hoses were connected. All electrical system plugged in, including new computer. The only difference was that the D-series engine had the MAP sensor fixed to the throttle body, so a remote unit was added for the new engine. The engine started, no problem. By the way, you guys should hear how the beast sounds with just the tri-y headers! Since the headers were longer than stock, I had to adjust the length of the exhaust so it could bolt onto the headers. Website design By BotEap.comDETAILS Website design By BotEap.comElectric
Now the automatic specific facts. Remove the automatic gear stick and throw it away! There is a plastic slider underneath that is connected to the car’s harness. This slider needs to be set to the PARK position and locked there somehow. The guys at the store put a big bead of silicone sealant on mine. This is necessary if you plan to take the key out of the ignition after driving! Also on the plastic slider, there are two wires soldered near the center of the device (yellow, black/green). When these wires are shorted, they activate the reverse lights and chime. (At least my car has a reverse chime.) My advice is to find the reverse sensor on the transmission, trace them to the jack joint on the right side of the engine bay, then run a couple of wires from the reverse sensor to the plastic slider. Ready! Your reverse lights will work just fine. Website design By BotEap.comI had to add a knock sensor wire and an O2 sensor wire as detailed on the hybrid site. However, I still got a code 23 after driving the car for a few minutes. Then it occurred to me that the computer still thought the car was automatic. Now, I really tried to find the Transmission Control Module, but I couldn’t for the life of me. Maybe you have to remove the hyphen from something extreme. Anyway, with the help of a B16A2 wiring diagram from my friend Christian in Austria, I was able to identify the ECU wires that were no longer needed. Just cut the wires and tape them down! The first four are the TCM wires; the other two go to AT sensors for which I don’t have the German translation 🙂 Website design By BotEap.comECU wires
B3-green/blue Website design By BotEap.comB4-green/black Website design By BotEap.comB7-grn Website design By BotEap.comB13-grn/orn Website design By BotEap.comB17-green/black Website design By BotEap.comB19-yellow Website design By BotEap.comMechanic
Of course, when you remove the automatic gear stick, there will be a big hole under it. I found my car did not have mounting holes for the shift linkage. This is nice in a way, as you get to choose where the shifter will be located. I used a CRX shifter on my application and just bolted it through the sheet metal into the floor arch. Depending on the linkage you use and the plastic trim you choose to place over the shifter, the linkage length may need to be adjusted. Website design By BotEap.comYou’ll see a picture of a CRX pedal box on the left. If you’re really watching, you’ll notice that this pedal box is made for a clutch-by-wire system. The verdict: scrap the idea of changing the pedal box. The guys sawed off the clutch pedal and welded on a hinge so it could be used to actuate the plunger in the clutch master cylinder. We use a soft line to connect the slave cylinder (in the transmission) to the hard line, which connects to the clutch master cylinder. Very simple. In the picture of the interior you can see the large brake pedal (AT) next to the clutch. Website design By BotEap.comTHE RESULT
The car runs wonderfully and is a joy to drive. All functions and sensors are operational. Since I kept the stock AT casing around the shifter, I didn’t lose one of my favorite features of the car; the fold in cup holder! The gear stick boot is custom made with Italian leather. I also got the white faced indicators with the deal! Website design By BotEap.comI would really recommend against switching in the other direction though, as all the wiring in the car behind the firewall would have to be changed to get a fully functional (all functions working) automatic.
I knew that the best thing would be to buy the engine and accessories as a package, and that is what I did. But I zeroed in on the big items, engine, Y21 LSD transmission, ECU, complete engine harness, axles, and in doing so I didn’t even realize the engine was missing the mounts! (There’s no AC unit either!) Now, even though we have pretty fast traffic in JDM parts back home, some things are almost impossible to get, like mounts! Website design By BotEap.comThe solution? Modify stock D15B brackets to fit. That mistake caused a project that would have taken a little less than two weeks to take five weeks. You can imagine how my wife loved me for this! Website design By BotEap.comSTART UP
The assemblies took a long time to complete and also, as expected, my car was not the only one in the shop! Anyway, it turns out that the rear (middle) engine mount could be used on the B16A. I was able to get a front drive mount, leaving three mounts to custom fit. By the way, the front lower motor mount/AC mount on the B-series motor is totally different than the D-series mounts, so I fabricated an adapter flange to accept my old AC unit. (I had no intention of buying an air conditioner in any way.) Website design By BotEap.comAfter adjusting the mounts and positioning the motor in its proper place, the shaft hardware was mounted in a jiffy and the necessary fluids and hoses were connected. All electrical system plugged in, including new computer. The only difference was that the D-series engine had the MAP sensor fixed to the throttle body, so a remote unit was added for the new engine. The engine started, no problem. By the way, you guys should hear how the beast sounds with just the tri-y headers! Since the headers were longer than stock, I had to adjust the length of the exhaust so it could bolt onto the headers. Website design By BotEap.comDETAILS Website design By BotEap.comElectric
Now the automatic specific facts. Remove the automatic gear stick and throw it away! There is a plastic slider underneath that is connected to the car’s harness. This slider needs to be set to the PARK position and locked there somehow. The guys at the store put a big bead of silicone sealant on mine. This is necessary if you plan to take the key out of the ignition after driving! Also on the plastic slider, there are two wires soldered near the center of the device (yellow, black/green). When these wires are shorted, they activate the reverse lights and chime. (At least my car has a reverse chime.) My advice is to find the reverse sensor on the transmission, trace them to the jack joint on the right side of the engine bay, then run a couple of wires from the reverse sensor to the plastic slider. Ready! Your reverse lights will work just fine. Website design By BotEap.comI had to add a knock sensor wire and an O2 sensor wire as detailed on the hybrid site. However, I still got a code 23 after driving the car for a few minutes. Then it occurred to me that the computer still thought the car was automatic. Now, I really tried to find the Transmission Control Module, but I couldn’t for the life of me. Maybe you have to remove the hyphen from something extreme. Anyway, with the help of a B16A2 wiring diagram from my friend Christian in Austria, I was able to identify the ECU wires that were no longer needed. Just cut the wires and tape them down! The first four are the TCM wires; the other two go to AT sensors for which I don’t have the German translation 🙂 Website design By BotEap.comECU wires
B3-green/blue Website design By BotEap.comB4-green/black Website design By BotEap.comB7-grn Website design By BotEap.comB13-grn/orn Website design By BotEap.comB17-green/black Website design By BotEap.comB19-yellow Website design By BotEap.comMechanic
Of course, when you remove the automatic gear stick, there will be a big hole under it. I found my car did not have mounting holes for the shift linkage. This is nice in a way, as you get to choose where the shifter will be located. I used a CRX shifter on my application and just bolted it through the sheet metal into the floor arch. Depending on the linkage you use and the plastic trim you choose to place over the shifter, the linkage length may need to be adjusted. Website design By BotEap.comYou’ll see a picture of a CRX pedal box on the left. If you’re really watching, you’ll notice that this pedal box is made for a clutch-by-wire system. The verdict: scrap the idea of changing the pedal box. The guys sawed off the clutch pedal and welded on a hinge so it could be used to actuate the plunger in the clutch master cylinder. We use a soft line to connect the slave cylinder (in the transmission) to the hard line, which connects to the clutch master cylinder. Very simple. In the picture of the interior you can see the large brake pedal (AT) next to the clutch. Website design By BotEap.comTHE RESULT
The car runs wonderfully and is a joy to drive. All functions and sensors are operational. Since I kept the stock AT casing around the shifter, I didn’t lose one of my favorite features of the car; the fold in cup holder! The gear stick boot is custom made with Italian leather. I also got the white faced indicators with the deal! Website design By BotEap.comI would really recommend against switching in the other direction though, as all the wiring in the car behind the firewall would have to be changed to get a fully functional (all functions working) automatic.