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How To: Swap a K20A into a CRX (CRXBart)

8973 Views 14 Replies 13 Participants Last post by  Baker
This is more or less a copy of Bart's article on his website. He has given permission for it to be posted here, I want to keep relevant links like this around.


Starting things off I'm going to do a brief overview. A K series engine swap is no harder than any other. There are a few more things to address, but it really isn't that hard. This swap will require welding of the passenger side mount, and modification of the rear crossmember. The new shift linkage will also be obviously engine mounts will have to be changed. The only manufacture making mounts for this swap is HASport.

First off pull the engine, and remove all the wiring from the bay, and pull it into the cabin. A K swap is the perfect reason to do a wire tuck since none of the engine wiring is reused. For the wiring, you have 3 choices, custom, HASport, or Rywire. I chose Rywire for he custom builds them for his customers, and it is plug and play. He made mine for me to turn on my fan with the Hondata, and made it to work with the wire tuck. Newer Hondas have immobilizers, and Hondata K-Pro does away with that, plus it is programmable. The other option is a non programmable JDM ECU.

Now that the engine bay is empty it is time to remove the passener side mount from the engine bay. This can be achieved by using a spot weld cutter or other methods. Next you bolt the mount tower to the frame rail with the 12mm battery tray bolts. Figure out where you need to grind, mark it, remove the tower. Grind it, reinstall the tower, and weld in the tower. HASport says just to weld in the holes, but I seam welded the whole tower in. That is what everyone I know has done as well.

Welded in the mount should look like this. Note also there are other areas I welded holes shut for a smooth shaved bay. It is a lot of extra work, and not worth it in my opinion, but I went the extra mile.

Next we shift our focus the the rear crossmember, the area in the squares needs to be dented. The blue area needs dented a lot like 1-1.5" I also cut the upper lip, and seam welded it shut. I did the same to the other side too for the header clearence, but it really wasn't necesary with my SSR header I used. Speaking of headers, the SSR, and the DC (HASport) header are the only units I know of to work on the CRX chassis, although SMSP is working on one that might work. SSR offers a 4-1, and a 4-2-1. I have the 4-2-1, it is what most use for more midrange power.

At this juncture your engine bay should look like this. I bolted in the rear mount, the pass side tower is welded in, and everything is prepped, and ready to paint, well mabey not in this pic. At this point I would reccomend installing the engine for a test fit, and then working out any clearence issues. Thats what I did, and I had to dent my crossmember more. Plus it gave me a chance to work on my EP3 Shifter assembly, to make sure it would work well. You will also notice the Z10 traction bar setup. A stock crossmember will not work with a K swap. Z10, Full-Race, and Explicit Speed crossmembers are known to work. Jim fab bars, that are no longer made, don't work. I also had to cut my headlight bucket to clear the alternator for the 3 pulley setup.

Speaking of shift linkage that is something that is to be addressed as well. Lots of people use the DC5 Integra unit, and they make kits to mount them to the floor, or some modify the floor, and weld it to accept the shifter. I on the other hand, had preference for the dash mounted shifter in the EP3(02-05 Civic Si). So I purchased a Buddy Club short shifer assembly, and EP3 shift cables. You cannot use DC5 cables, with the EP3 or vice versa. Most people will not go this route, and will use the DC5 stuff. I will add that info later but for now this is how I did mine. I fabricated mounts, and welded them to the radio mounting area. Oh yeah my car has no heat. I'm pretty sure if you were to retain heat this would be very dificult if not impossible. I actually ran my shift cables through the heater core holes .

You might have noticed all of my brake lines were removed. I relocated my brakelines under the dash, and mounted the prop valve there aswell. You don't have to do this but I did for a cleaner install. I did this after I painted my bay, and before I reinstalled the engine for the final time. The other option is to bend the lines, and have it hang back. Once again I didn't do that but I will add info on how to do it on another date. So now we install the engine, and start hooking stuff up, thats where we are at now. The Rywire harness is simple. You run the engine harness into the cabin, and plug it in. You have to run the o2 sensor, and the fan switch wires out, and connect them. Next you will have to adress the fuel lines, radiator, intake, install your header and axles.

The fuel system is simple, but a little costly. I ran a fitting On the OEM fuel feed, and adapted it to 6AN, then I ran AN lines to an Areomotive filter, and then to the regulator. From the regulator you run to the rail, and plug the other end. The return line, then comes from the bottom of the regulator. I used Aeromotive for this aswell, but AEM is another good choice. Whatever you do don't buy a cheap filter I got one from Jegs and it was a peice of crap and clogged almost immediately. Now for the rad in my above pic you will notice the ugly peice I used. I since then converted to a 91 VW GTI non-AC it fits like a champ. I also had to use a inline fillneck to fill for the rad is made for a remote fill. The rad will have to be custom mounted. I got all the fuel stuff from Jegs.

Here is the GTi Rad, and the custom hoses, and fill neck. The GTi rad is mounted upside down, and the sensor hole will need plugged for it is not needed. Also Note the custom Air Intake. I built it from a 3" U bend cut, and welded, and a 3" K&N filter tops it off. Most people just make them sit in the engine bay sucking in all the hot air. I wanted to do away with that so I made it go where the washer tank was. I have since scrapped this, and I'm building a custom airbox, with a ram air velocity stack feeding it. Also note the catch can installed running to the PCV valve, and the custom oil cap to clear the hood courtesy, of John Ward. All the little parts were from Jegs, once again.

Next install the axles, DSS are what I used,, fill up the fluids, and connect the brake booster vaccumm line. Double check all of your work. Go have some fun. This motor is tall and will hit an OEM hood. I have a JDM hood with trimmed webbing and it fits just fine. Fiber Images offers hoods for the USDM, and JDM frontends, and they clear aswell. This is only true with a k20, k24s will require, a custom hood. Some other items you should install would be some upgraded brakes, and a car alarm. Oh and as far as I know the only strut bar that clears the K series is a Cusco Type-ST. For your speedometer to work you will either need to use a electronic VSS cluster or, a speed sensor from a cable speedo tranny. Your exhaust will have to be modified to fit the K header. It is in a totally new location. I hope you enjoy this, and found it insightfull. If you need anything I can be reached by email.

Ok now it is time for a little preaching. I obviously went the most expencive route on the engine. The K20A is about $1200 more than the A2 from most importers. For the extra $1200 you get a LSD, lower FD, 4.7, over a 4.3, a half a compression point, and some bigger cams. Worth the extra money in my book. Also it should be told I did not spend $10,035 on my swap. I should have, but I didn't I got the first three items, and the axles, and pulley for $6500 picked up used off of a friend on There are deals to be had if you look around. Just don't go cheap where it matters. I also got a deal on the Hasport mounts too from a H-T member. The Hasport header is cheaper, but makes less power, my fuel system is expensive, but bullet proof. My axles, could be better, and soon I will upgrade to stage 3's.

Price List
K20A Complete Swap $5500
DTR SSR Header $1175
Hondata K Pro $1000
HASport motor mounts $750
Rywire Harness $350
Drive Shaft Shop Axles Stg 1 $300
Buddy Club Shifter EP3 $150
Aeromotive Fuel Regulator $150
Fuel Lines, and fittings $150
STR Pulley Kit $150
91 GTi Non A/C Radiator $130
Aeromotive Fuel Filter $80
Radiator Fill neck, and Hoses $75
Air Intake filter and 3" tube $75
Total $10,035
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I love his car....what ever happened to his build?
well detailed article.

I like the "k-series powah F--- enzo" on the dusty windshield!

If anyone can provide close up shots of where the rear crossmember needs to be notched that would be very helpful :D
In this picture you can see where it looks a lil rough and shiny on the driver side. Mine just needed to have the lip on the top of the crossmember pounded/cut off. I cut the lip off of mine so it was flush. Hope that helps.
Any one doing this swap, plan on testfitting. A hydrolic lift makes it so much easier. I can only imagine doing it by myself in a driveway...I dont think I have that much patience lol.
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I would do this swap it it didn't cost near $10k.
It doesn't really cost that much, you can find the USDM type-S motor swap for 3500 and get a DC swap header for like 300, that will save you almost 3000 right there...a lil research and shopping around will save you a lot of money :wink: You can save in other places too, from the fuel system, to the axles, to the radiator...there are just so many different options and parts you can use...You can do the swap for cheap if you put your mind to a wrecked RSX-S and sell everything but the swap parts you need, make your money back that way.
It can be done for much less, this was done with allot of the best parts available. I bet u could do an a2 for around 6000 running. maybe even less. I have much less in mine, because I bought allot of the parts second hand.
CRXBart said:
It can be done for much less, this was done with allot of the best parts available. I bet u could do an a2 for around 6000 running. maybe even less. I have much less in mine, because I bought allot of the parts second hand.
why dose the shifter sit so fuckin high?
Heath said:
why does the shifter sit so [potty mouth] high?
Because he wanted it to.

I on the other hand, had preference for the dash mounted shifter in the EP3(02-05 Civic Si).
If it helps anyone that is looking into this swap, I compiled a lot of links together and created a DIY and FAQ Section on
i just drooled on my keyboard... must rob bank... must buy new welder...
DeepBassAddictions said:
i just drooled on my keyboard... must rob bank... must buy new welder...
K swap is way easier to do now. Side note where is Bart? I miss some of his Ohio meets.
DeepBassAddictions said:
i just drooled on my keyboard... must rob bank... must buy new welder...
It's a little bit more affordable now and easier to do, especially as time goes on and parts become more commonplace.

Here is a nice detailed write-up.
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