S14 SR20DET into DOHC S13 Swap
I hope this is helpful to those interested in doing this swap.
Ok, so as most of you know I did this swap recently. I looked all over the internet for people who had done the swap and how to wire it. Well after trying what I found on my own I realized how wrong most of the “free” information was. I didn’t want to buy a wiring DVD and I also didn’t want to spend $350 to have the wiring done by someone else, when I know I could do it on my own. So being armed only with the Factory Service Manual (FSM) for both cars (which are available upon request here on NICOclub) I wired it all on my own.
With that being said I am going make a disclaimer, this is the way I did it in my personal car, some may have done it differently than I did. However my car runs great has no check engine light/fault codes. Also for the SOHC owners out there… the write up will work for you but you will need to pinout your own SOHC S13 interior plug. However, the wire colors are the same on both DOHC and SOHC interior plugs. This means you should be able to match up my diagram with the correctly colored wires on your SOHC plug. Also the SOHC cars will need a DOHC Tach/cluster in order to read the tach signal of the SR. Now for the full disclaimer.
***I AM NOT RESPONSIBLE FOR WHAT HAPPENS TO YOUR CAR IF YOU USE THIS GUIDE, IT IS FOR INFORMATIONAL PURPOSES ONLY!***
ALSO, if you aren’t wiring-savvy, want a factory-looking engine swap harness that’s plug-and-play, or you simply don’t have the time to mess with all that spaghetti, contact the guys at Wiring Specialties. They make some beautiful engine swap harnesses that look better than the factory ever made!
Ok to start off, my swap was from a JDM Zenki S14. They are the 1st generation S14 motors so this guide is for these motorsets only. The mechanical portion of this swap is all bolt on and drop in, meaning the motor/tranny mounts are all the same for S13, S14 and S15. So the motorsets will fit no matter what chassis they are in. The stock KA drive shaft fit fine, however I had to remove the tranny dust cover in order to push it all the way into the tranny.
Start with pulling the stock KA motor, trans, wiring harness and ecu. All the smog equipment on the KA can be removed with the exception of the charcoal canister. Leave that behind since it’s doesn’t affect power/reliability and is used for removing fuel vapors from the fuel tank.
Here you see I removed the hood for more clearance.
Here are the S13 power plugs that lead to the KA ECU, these need to be spliced into the S14 power wires.
Behind the glove box you can see the interior plug for the DOHC S13 motor (it’s the brown plug) and this will be spliced into the S14 interior harness wires. On SOHC cars this plug will be white. Ignore the ****ty stereo wires as they were there before I bought the car lol.
More parts removed from the car.
Once everything is disconnected from the car you can loosen the motor/tranny mounts and pull it from the car.
Now we are ready to put the SR in. At this point remove the S13 KA temp sender from the the KA motor, it is a single pin sender located on the coolant inlet of the intake manifold. Then take the temp sender from the S14 SR out, which is located under the throttle body. Replace it with the KA temp sender. This will make your temp gauge on the dash function correctly.
Here you can see I removed the stock clutch fan because I have no use for it since I already have a set of Altima electric fans.
All done and bolted in!
Here are the stock SR heater hose lines. As you can see in the pic these can be cut and routed right to the stock USDM S13 heater core connections. I chose to use the hoses that came with my swap since they were in great condition. However there are a set of hoses you can get that are preven and fit the S14 SR heater location perfect. I will posts those numbers later.
Here you can see the stock S13 throttle cable lock nuts are too small for the S14 bracket which is why the S14 grommets must be used.
These are the stock S14 throttle cable grommets, the one on the left needs to have a slit cut into it like the one on the right to work with the DOHC S13 throttle cable. On the SOHC cars I am not sure if this will work since I dont have a SOHC and the cable is a different length (IE: you may need to get a DOHC KA throttle cable).
This is the grommet after it has been modified to slip over the throttle cable.
Throttle cable installed and routed. Also you can see the DOHC KA brake booster vacuum line, all you need to do is trim it to length to fit the SR motor.
My new Koyo S13 SR20 radiator, an SR20 rad is needed cuz of the different inlet location on the SR vs. KA, otherwise you will need to make a crossover tube. Beware tho, SR’s like to run hot especially when they are running on a stock KA rad. You should really run a better radiator for this swap.
At this point you can hook up the power steering lines, on the DOHC S13 the high pressure line will fit perfect, however the return line will need to be trimmed to length to fit the SR pump location. From what I have been told on the SOHC cars you can simply buy the DOHC high pressure line and swap it over.
Here is where it gets a bit interesting, the S13 and S14 SR motor’s have different plumbing/routing for the charge pipes. The BOV’s are on different sides and the stock SMIC’s sit in different spots too. So you can use the S14 SR charge pipes but you will have to drill holes and make your own mounts to make it all fit and work. In my case I already had an S13 Greddy FMIC kit, so I ended up using a combination of the stock S14 hot pipes and the Greddy piping as well. Then I bought an after market S14 piping kit to complete the piping for my motor. Some people say buy the S14 Greddy kit and you’re good but again not all of the piping fits right either. So you’re pretty much gonna need to custom cut/make all the charge pipes.
I had to reposition my battery to drill a 3 inch hole for the intercooler piping to pass thru.
Now for the really fun part… the wiring.
Ok since I didn’t want to kill a good KA wiring harness I opted to get a spare wiring harness. You are basically going to fully destroy your KA harness and rape it for connectors/shielded wires. If you’re ok with this then use your harness, otherwise get a spare one. The good part is the power plugs are the same on the KA DOHC and SOHC harnesses, the bad part is the interior plug is different on them. So you really need to a harness that fits your chassis.
The lower engine harness for the KA will plug right into the S14 SR motor, all you need to do is drill to enlarge the hole on the KA Alternator power wire ring terminal to fit the size of the stud on the S14 SR Alt. The S14 SR tranny plug ends will need to changed over to the S13 plug ends or vice versa, I decided to just change the plug ends on the tranny sensors so that I could reuse the lower harness on my S13 KA tranny later. Some people say you can simply take the sensors from the S13 tranny and use them on the S14 tranny… I have not verified this but it does appear that they can swapped. The Speed Sensor from the S13 Tranny must be used since the S14 will not read the right speed.
At this point we have to wire the main harness… it’s not as hard as it seems but it was a PITA for me to do since I ripped my harness apart using other wiring info on the net which turned out to be WRONG! So I had to repair my harness first, then deloom it entirely and wire it up my way.
Where you should start is by delooming and rerouting the harness connections on the motor to fit the LHD configuration of the USDM S13 chassis. Route it however you want… but you must do this first. This is so you know what wires need to be extended to meet their respective connections. In my case I extended the MAF, Boost Solenoid, Power Steering Switch and I also added the stock Boost Pressuse Sensor connection to come out by the TPS plug. I also changed the S14 SR power steering switch plug over to the the KA plug to fit my KA power steering switch.
On a side note the stock boost pressure sensor is plugged into the S14 SR’s fuse box, make sure you get this sensor and plug end when you buy your motorset. I am not sure if this is needed to make the car run right, but from what I read in the S14 SR F.S.M. it seemed to be an important part so I added it to my harness. The boost pressure sensor is easy to wire, all you have to do is tap the power and ground from the TPS to the power and ground from the pressure sensor they are the same colors. This is the way it was from nissan as well, just the location of the sensor is different. Then with the remaining signal wire extend and run a sheilded signal wire back thru the wiring harness to the white wire on the S14 SR interior plug, this leads to Pin 35 on the ECU. Make sure that you use a shielded wire for all the signal wires, you can get shielded wires off of your old KA harness.
Here is the S14 wiring harness unmodified.
Here is the harness after I de-loomed part of it, the blue plug with the larger gauge blue wire is the ignition coil relay, the other is the ecu relay. Finally the white plug is the S14 SR interior plug, this is where most of your connections will be made.
USDM S13 DOHC and SOHC power plugs. The main power wires are the same color on both DOHC and SOHC harnesses, however not all of the wire colors are the same color, but regardless of color of the wire the position of each wire does the same in both cars. You want to deloom this harness and keep as much of this wiring as possible by cutting the wires at the ecu plug. These wires will be reused to power the S14 SR harness, you will route the power wires the same way as they were stock in the stock S13.
USDM S13 DOHC brown interior plug, again the SOHC plug will be white. This is what you make the S14 Sr harness look like so that it will plug into the S13 Chassis.
All of the wiper motor/amp wires can be removed from the S14SR harness as they are not used, at all on the S13 Chassis. Also I did not wire up the A/C because I don’t run A/C in my car, however it should be super easy to connect the correct wires using the wiring diagram from both F.S.M’s.
Now we come to the actual wiring of the harness. I made this in the easiest format I could, hopefully everyone understands it. Additionally I made the same wiring diagram in microsoft word for download and I also included the microsoft excel pinouts that I used to help wire my car. The links for these files are below.
My Wiring info, Download here —>http://mestiso.net/photogaller…3.doc
Decoded JDM Zenki S14 Sr20DET pinout, Download here —>http://mestiso.net/photogaller…d.xls
USDM S13 DOHC pinot, Download here —>http://mestiso.net/photogaller…t.xls
S14 SR20DET Circuit Diagram:
S14 SR20DET Main Power and Ground Diagram:
S14 SR20DET ECU and Coil pack relay Diagram:
USDM S13 KA Gray Plug at the front right side of engine bay to the S14 SR20DET Harness wires.
Back of plug pinout.
USDM S13 KA Brown Plug at the front right side of engine bay to the S14 SR20DET Harness wires.
Back of plug pinout.
USDM S13 Interior Plug behind the glove box on DOHC S13 Chassis to Interior plug wires on S14 SR20DET Harness wires.
Back of plug pinout.
S14 SR20DET Interior Plug.
When you get to the S14 SR wiring harness firewall boot, you will need to pull all the tape off of it and then you can slide the boot out of the way. Once you get the boot moved you will see a bunch of black goop all over the wires, you will need to individually pull the wires out of this black stuff so you can move the boot to where you need it to be on your harness. Now you can loosely tape up the harness so it fits everything right, then connect everything to the car and motor. The reason I say to loosely tape it is so if something is wired wrong it will not be hard to go back untape it and make the corrections.
Now once you have plugged everything back in to where it goes, ***MAKE SURE YOU HOOK UP ALL THE GROUNDS***, finish all the charge piping, vacuum lines and fill with fluids. If you wired it right, the ECU & IGN coil relay’s will click when you turn the key to the ‘ON’ position, as well as you should hear the fuel pump priming the fuel lines. If it all works you can try to start it. My motor is wired this way and fired up on the first try. Hopefully your’s will too! Once you get it running good and there are no check engine lights then you should be able to tape/loom everything back up and finalize all the installation.
Questions or comments about this article? Here’s a discussion thread you’ll want to check out: SR20DET into S13 swap