K-Series Currently Supported K-Series Engines, Transmissions, Shifters, Wiring, etc

The K-series spans many years. Unlike older Honda engines there are more parts variation in the K-series engine / transmission family. This makes supporting the K-series swap more complex than older swaps as there are many variances to account for.

Some difference examples of this are:

• Block heights (K20 vs K24)
• Head castings
• Oil pans
• Shifter arm configuration
• Transmission case (RSX/Civic SI, Accord/TSX, and AWD)
• Intake manifolds (PRB, PRC, RSP, RBC, RRC,  RBB, etc.)

For the initial K-swap kit release Prelude Engineering LLC will support a few specific engine/transmission/wiring configurations:

• 02-04 RSX Base - Engine, transmission, wiring (K20A3, ~160hp, 5-speed transmission)
• 02-05 Civic SI - Engine, transmission, wiring (K20A3, ~160hp, 5-speed transmission)
• 02-04 RSX Type-S - Engine, transmission, wiring (K20A2, ~200hp, 6-speed transmission)

These setups are fully supported right now. Just buy a complete swap from one of these cars and you will be able to complete your K-swap with minimal fuss.

The swap brackets and traction bar WILL still allow you to physically swap in other K-series!

However, some things like wiring, intake manifold clearance, shifter setup, radiator hose routing, etc. has not been fully "figured" yet.

Some examples:

• You want to use an 05-06 RSX Type-S engine harness with your swap; you will need to figure out how to adapt the engine harness to the car yourself.
• You want to run a K24A engine; the radiator hose ports are oriented different so you will need to make adjustments for that.
• You want to run an RBC intake manifold; the the stock radiator will not fit, you must use a tucked radiator for clearance.

These are just some examples of what you might have to deal with if you are swapping in something that isn't listed as fully supported above.

We have started a Facebook group just for discussing these type of issues here: https://www.facebook.com/groups/8891hondapreludekseriesswapcommunity

Engine and Transmission Compatibility

Here are the engines and transmissions that are physically compatible with the swap brackets and traction bar. The ones known not to be compatible are also listed.

Engine years: Select 2002-2011 Honda and Acura models
Engine codes: 

• K20A
• K20A2
• K20A3
• K20Z1
• K20Z2
• K20Z3
• K20Z4
• K20Z5
• K24A
• K24A1
• K24A2
• K24A3
• K24A4
• K24A8

Not compatible: K20B, K20C, K23A, K20Z (Earth Dreams), K24Z, K24W, K20Z5 from 2023+ Honda HR-V.


Transmission source: 02-06 RSX and 02-11 Civic SI manual transmissions only.
Transmission codes:

• X2M5
• Y2M3
• NRH3
• NPR3
• NPQ3
• NSN4
• PNN3
• PNN4
• W2M5

Not compatible: This kit does not support Accord or TSX transmissions at this time (support planned in the future!). It also will not work with any AWD transmission.

Not sure if your transmission is compatible? Check the mount points on the rear of the case:

Engine Brackets

There are different K-series post mount brackets out there. You need to use a specific one depending on if you are swapping a K20 or K24. Here are the Honda part numbers and which vehicles they come from:

K20 Requires: 11910-PNA-000 (02-06 RSX, 02-05 Civic SI)

K24 Requires: 11910-PPA-000 (02-06 Honda CR-V)

The RSX / Civic SI style transmission will also require the aluminum mounting bracket:

50825-S7C-000 ( 02-06 RSX, 02-05 Civic SI)

Other Engine Parts Needed

The engine sits as high as possible for maximum ground clearance. This requires running a low-profile oil cap and dip stick. The OE cap and dip stick will dent the hood if you try to close it on them.

We recommend the Hybrid Racing oil cap and dip stick:

A low-cost alternative is simply cutting/trimming the OE pieces to make them shorter. Because of the tight clearance we recommend carefully closing the hood rather than letting it slam shut.

If your K-series has an oil cooler then you will need to run a shorter 02-06 Honda Insight oil filter for subframe clearance:

Headers

You can't use any OE K-series headers because their exit angle is incompatible with the subframe. You will need to run a K-swap header. Here is a list of headers that will fit directly or require minimal mods to fit:

Skunk2 Alpha - This fits as-is. Least amount of work.

K-Tuned 4-2-1 (304 or 409 stainless) - This is a good value header. Requires trimming the lip on the rear subframe.

Stay away from any header that has the primary tubes overlapping each other by a lot. A header like that would require serious trimming of the subframe.

You can see the Skunk2 header has all the primary tubes next to each other, that gives it good clearance with the subframe. If you look at the K-Tuned header you can see the primary tubes are "stacked" over each other. This pushes them closer to the subframe and requires minor trimming.

Here is an example of header primary tube configuration that is almost certain not to fit without serious cutting:

Here is an example of the kind of clearance issues you are likely to run into with this style header. The tube interfere greatly with the rear subframe:

Intake Manifolds

There are a number of different intake manifolds available for the K-series both O.E. and aftermarket. We have tested some, but not all of them. If the manifold isn't listed here then it hasn't been tested for fit yet.

Intake manifolds can be sorted into two major categories:

• Manifold fits with the stock radiator
• Manifold requires an aftermarket/tucked radiator

Manifold fits with stock radiator:

PRB - This is the manifold the initial K-swap was built around. As you can see the upper radiator hose must take a very tight turn and comes very close to the manifold.

Consider this the "benchmark" manifold that others here will be compared to as far as fitment goes.

PRC - The fit on this manifold is the same as the PRB above.

RBB - This manifold tucks downward so it has a good fit.

Manifold requires an aftermarket/tucked radiator:

RBC - The shape/length of this manifold means it will interfere with the upper radiator hose and tank, requiring a tucked radiator setup. The brake booster port on the RBC manifold will probably need to be bent away from the hood or relocated.

Here you can see the RBC silhouette vs. the PRB: 

RRC - This manifold has a very similar shape to the RBC so fitting it should be the same.

Skunk2 Pro Series - The shape of this manifold is similar to the RBC and it has the same clearances issues.

The Skunk2 Pro silhouette vs the PRB:

Shifter / Cable Setup

We are designing shifting setups for this swap that look OE on the interior. That means you will be able to run the factory console and a shifter boot.

If you don't care about those items then you can use any shifter or cables setup you want (like a fancy billet shifter) just drill new holes for the shifter you choose and bolt it down.

However, if you want that OE look then here is what we are supporting right now, "PE" is short for Prelude Engineering LLC:

• 02-06 RSX / 02-05 Civic SI trans. > PE cable bracket > OE 3g Prelude cables > PE shifter base with 90-93 Accord shifter.
• 02-06 RSX / 02-05 Civic SI trans. > OE cable bracket > Hybrid Racing cables  > PE shifter base with 90-93 Accord shifter.

Both of these setups fit under the factory console. More information will be provided soon.

Engine Harness and ECU

Grab a used OE engine harness from one of these models, or buy a new aftermarket (Rywire) 02-04 RSX Type-S spec aftermarket harness:

• Civic Si 2002-2005
• RSX Base 2002-2004
• RSX Type S 2002-2004

You can use any of these harnesses with any transmission. However for 6-speeds if you want the reverse lock-out to work then you must use a RSX Type-S harness (or modify a 5-speed harness).

You will need a Hondata KPro compatible ECU with KPro installed. This is required for disabling the immobilizer, multiplexer, VTEC pressure switch, etc. by using the KManager software. It also has the same issue as the harness in regards to the reverse lock-out; the ECU must be from a 6-speed in order for the reverse lock-out to work.

Hondata lists these ECUs as compatible with KPro:

• PRB (A01-A12 & 305)
• PND (A01-A09)
• PNF
• PRA 
• PRC (JDM DC5 Integra Type R) 
• PRD 
• PPA (A0#, A5#)
• PPL (A0#, A5#)

Or to go by the models they were offered in:

• Civic Si 2002-2005
• Civic Type R 2001-2005
• RSX Type S 2002-2004
• RSX Base 2002-2004
• Integra Type R 2002-2006

Please contact a Hondata KPro dealer to make sure you get the right ECU.

Throttle Cable

The Prelude cable is too short to reach the K throttle body. Use this part number from Hybrid Racing (56.5" Long):

• HYB-TRC-01-05

This info applies to left-hand drive cars only. RHD may be able to use the OE cable or one of the longer offerings from Hybrid Racing.

Oil Pans

You will want to use either of these pans for this swap:

•     11200-PRB-000 Aluminum (02-06 RSX Type-S)
•     11200-RAA-A00 Steel (02-06 RSX Base, 02-06 CR-V, 03-07 Accord, 02-05 Civic SI, 03-11 Element)

I recommend going with the steel pan if you are buying new. It has slightly more clearance since the steel wall is thinner, and it should deform rather than crack if it does take a hit. 

The pan that you do NOT want is the K20Z3 "11200-RRC-000" aluminum pan. This pan is deeper and will reduce available ground clearance. If your engine has the K20Z3 setup on it then it can be converted to the shorter setup by switching to a K20A2 oil pump and either of the previously listed pans.

Fuel System

You can use the O.E. Prelude fuel supply system all the way up to the fuel filter exit if you desire. From the filter to the fuel rail will need a custom line made.

A cleaner setup is to remove the O.E. filter and run a new line right from the firewall fitting. You just need to install an inline filter somewhere in the pressure line before the fuel rail.

The K-series fuel rail is set up for a return-less system (aka. dead-head system). That means there is only 1 port on the factory rail for the pressurized fuel to enter and they do not have a fuel pressure regulator or return port.

There are a number of ways to go here but the simplest configuration would be a firewall mounted external fuel pressure regulator. Run the pressure line to the regulator, then to the rail. The return line will also connect to the regulator. Here is an example image Radium Engineering:

Another alternative is using an aftermarket fuel rail with a port for a return line. You will still need to install a fuel pressure regulator somewhere though.

We recommend avoiding fuel pressure regulators that are mounted directly to the fuel rail, due to hood clearance concerns.

Air Conditioning

If you want to have A/C you will want to use a 02-06 RSX compressor and compressor bracket, these part numbers:

• 38810-PND-006 - Compressor
• 38930-PNC-000 - Compressor Bracket

We sell the conversion A/C and wiring kit you will need to get the A/C hooked up. 

It's possible our A/C will work with other compressors than listed but we can not guarantee anything.

Power Steering

All of the K-series hydraulic engine driven pumps are too large, they don't fit under the hood. You will need to use an 02-05 Civic SI / EP3 style idler in place of the power steering pump on the engine.

Here is how bad the fit on the K-series pump would be, the pulley and feed fitting would stick out of the hood:

For the pump itself you will need to convert to an electric hydraulic pump.

We sell a mounting bracket for the electric power steering pump that came on the followint Volvos:

• 2004-2013 Volvo S40 C70 C30 V50

There are two styles; one with a screw on cap and one with a tube top (the tube would run to a remote reservoir on the Volvo).

You can use either one, the tube top ones tend to be a little cheaper, but you will have to figure out your own cap solution.

The Volvo part numbers are:

• 5N513K514 - Cap top
• 4N513K514 - Tube top

Try to order one that comes with the connectors already, otherwise you will have to pay more for new connectors. You don't need the black mounting bracket they are sometimes listed with, just the pumps as shown above.