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K Series Engine Swap Research

6.8M views 2.3K replies 159 participants last post by  mcmcmc  
#1 · (Edited by Moderator)
Last Update: 3/12/2014

"Getting closer and closer, Thanks to all who are helping make this a more manageable task for others"
Mounts: Solved
Shifting Mechanism: Solved
Axles: Solved, Updated 3/12/2014
Wiring: Researching, Updated 3/12/2014
Radiator Hoses: Solved
Heater Hoses: Solved
A/C: Pending Updated 3/12/2014
Throttle Cable: Pending Updated 3/12/2014
Fuel System: Solved
Exhaust System: Solved, Updated 3/12/2014
Anti-Lock Brakes: Solved
Power Steering: Solved


General Info: Always Read First...!
Well, I have been gone for a long time and will try to keep this updated. Sorry about the delay as I am in a transition period and can't work on the swap.
Also some really big information the innovative mounts put the engine so far forward that only the PRB intake manifold off of an RSX type S will fit.

BottledFedMR2 has confirmed this and it's been verified. So anything else will require the firewall to be cut or the manifold to be shortened. This sucks but at the same time it's nice to have the engine weight as far forward as possible as it puts it more centered.

I will have CONFIRMED next to everything I know for 100% is correct information.

Mounts: CONFIRMED
Recommends 75 was told by innovative that it's the same as a 65a poly used by
other companies. Theirs is pure poly so 65a could sag over time.
http://www.innovativemounts.com/ProductDetails.asp?ProductCode=90551

Shifting Mechanism: CONFIRMED
Use the Factory MR2 cables and this bracket will make them interface with no other mods.
http://www.innovativemounts.com/ProductDetails.asp?ProductCode=50507
**Note: 2006+ Civic SI transmission will require the shift "Arms" off of an RSX type S transmission. You will then be able to
hook up the innovative shift Mechanism as it would be on a normal RSX-type s Transmission.


Axles: CONFIRMED
Axles can be ordered through Drive Shaft Shop they now have part numbers on file though they are not on their website.
Part Number: RA9040x2 and RA9041X2

Wiring:
There is much debate about the wiring so far it's every man for himself. I haven't actually started the physical wiring so I can't confirm anything or have a proven design. There are a few that have completed their swaps and have them running and driving but they all sort of do wiring differently. Monkeywrench racing is working on a full swap kit and will be selling the parts all separately. I talked to them and they will be offering a wiring solution. Right now this is known for a fact!

If you want the car to fully function like a stock spyder you will need to shotgun the ECUs (Factory Toyota ECU and Honda ECU) if you don't care and want to replace your cluster then you can run a straight Honda ECU but don't expect it to be very easy and you will need to know wiring to do it. You will also find it a lot harder to get the A/C running correctly without redesigning the whole A/C wiring system.

Now if you just run the Honda ECU by itself and keep your factory cluster you will lose your TEMP gauge and a few other idiot lights.


Old Info 3/12/2014

ABS:

I have found in theory that the ABS is almost completely independent of the engine control unit there is one wire going to the ECU and from talks with people its a input to tell ecu that ABS is active.

P/S:
The P/S system isn't too much of an issue in my eyes as it will keep running if you don't give it any signal from ECU. So at the basic level, you have P/S no matter what. Now if you want to operate factory style then you need to configure Kpro to see the signal from the pump to IDLE UP on the current draw which is PIN E3-25.

There is also a pin on the ECU for turning the pump on and off while the engine is running/off. This pin is E3-19 on the ECU. From what I understand if the Power Steering ECU doesn't see any input on this pin it will just stay on all the time with the car in ACC/ON position. As for any speed variance to Pump pressure adjustments, this is all done between the P/S ECU and the ABS ECU (as the ABS ECU supplies the speed signal).

A/C:
I am working with innovative and when I start my swap will be using a prototype A/C adapter plate. You will want to keep your 1zz compressor as it will be the easiest by far to adapt to work. The K-series compressors are bigger and right now the 1zz one will barely fit.

I will be running wiring straight to the HVAC controls so that I can bypass the Toyota multiplex system and in essence just hard wiring the functions like Honda has in its cars all the way up to 2002. I will be recreating the same system they used in the earlier model civics that did not require any type of digital electronics.

At the back of the Toyota Hvac controls the A/C switch comes out as an analog +12 or Grounded signal that goes to the combo meter where it is processed and sent to the ECU on a multiplex. I will just be wiring straight to this output on the HVAC control and cutting the meter and associated multiplex functions out of the circuit. I will then create a patch harness for the A/C compressor that contains the High/Low switch relays to cut the clutch and also figure out a way to wire a freeze-out switch into this same harness.


Unless I am missing something and by all means correct me. I see that if you completely remove the factory Toyota ECU the only things that will not work are the A/C, Temp gauge, and Some idiot lights and that is it. Everything else can be wired/jumped to function like normal.

The Temp gauge is on multiplex along with some of the idiot lights and A/C. You could make these work using the factory ECU as a multiplex conversion box and feed it the K-swaps sensor signals and hope they are in the same range as factory Toyota's or hook up factory Toyota sensors in addition to the Honda ones on the engine. IE: two oil pressure switches, two temp sensors ETC...

My goal is to make it as streamlined and simple as possible (Wiring/Electronics). That is why I want the Toyota ECU to be completely gone and all functions controlled by the Honda ECU.

Overall I am getting more and more done day by day and hope to start buying parts soon. I wanted to figure out most of the wiring before I even took the first bolt off the car. I'm hoping to have some of the conversion harness already made before I even start working on the car. "


Throttle Cable:
Was informed that if you buy a Cruise Control delete it will allow the factory cable to bolt in no major mods are needed. Getting verification but should be for a 00-04 RSX.

Radiator Hoses: CONFIRMED
He also said that the K-series and the 2zz are very similar in where all the hoses route. Since this is true He has confirmed the fact that in the swap in the lotus all the hoses fit up 99% perfectly.

He said cutting one hose 2 inches is all that is required on the lotus. Since the engine is what determines the placement of hoses then the spyder should be no different than what's required for a 2zz swap.

Heater Hoses: CONFIRMED
Read Radiator Hoses Same applies.

A/C System:
Again BottledFedMR2 is the guy to see, he is working on bringing an A/C bracket to production. He is close to having it ready and I myself will be buying one.
It will use the 1zz compressor, he says it will be a little lower than he would like but it doesn't seem to be a big issue.

Tim said they are in the works to make a bracket for the Lotus with Kswap. So He says he doesn't see why the spyder wouldn't be able to use it. Again like the throttle cable he would need someone to test fit it and confirm or send it back to have it modified till they get it right. But it is doable and not a big issue.

The Lotus has issues with A/C line clearance and he said that is one of the problems they are working on. When I asked him if the Lotus and spyder have very similar bay layouts I didn't know for sure but he said the way the firewalls are the spyder might actually have more room for the lines. Like everything though he can't say for sure.

Exhaust System: CONFIRMED
PPE makes a Header now for MR-2 Spyder with Kswap and is also available through MWR.
The collector size is 2.5" and the overall header is longer than the stock one so will stick out further than the factory.
Still waiting to get info on if you can use a downpipe to make it line up with the rest of the factory system.

Fuel System: CONFIRMED
You will need to run a return of some sort. You will need to also get a fuel regulator. I am still a little iffy on this from a basic swap standpoint because Honda uses a returnless system factory so you might not need to do this if you're just going to OEM performance.

Extra Notes:
I will update this a little more in a few days. I wanted to get something new on here as I have been away from the forums for a while and people might like to see a summary of the events going on with the Kswap. The main thing that is missing is the wiring. Once there is an agreed-upon design that everyone thinks works and is simple as it can be will the swap gets easy enough for everyone.
 
#2,194 ·
Intake Manifold Cheatsheet

Performed on a K20, compiled from here:
 
#2,198 · (Edited)
My alternator looked the same. I used a rubber mallet to get it to this...

This is Skunk2 Pro manifold, no massaging and slight paint scratch. I did hit it a few times to try to avoid that slight contact.

I smashed the turbo firewall (RBC mani) the same with no noticeable issues so far. It didn't seem to make contact with the top of the firewall and I can get my finger around the TPS.
 
#2,200 ·
My alternator looked the same. I used a rubber mallet to get it to this...

This is Skunk2 Pro manifold, no massaging and slight paint scratch. I did hit it a few times to try to avoid that slight contact.

I smashed the turbo firewall (RBC mani) the same with no noticeable issues so far. It didn't seem to make contact with the top of the firewall and I can get my finger around the TPS.
Thank you for the feedback.

I'll probably pick up a pro. I am tempted by the ultra, it seems like it's got even more clearance, especially since it tapers and the vacuum ports are closer to the motor. Anyone ever try running these?

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#2,201 ·
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I did a lot of massaging due to watching both your channels! With the Skunk2 pro copy IM on K24 there was plenty of clearance. The closest was the TB with about 1.5”. Just enough to reach the TPS bolts. My only clearance issue turns out to be with the AC compressor pulley. Only about 1/2” and it hits slightly on hard braking. Let me know if you have a solution for this.
 
#2,204 ·
I’m running the z3 head on an 08 k24a2 bottom end. Most internet searches will say the z3 head flows marginally better than the k24, that is false. The diameter of the throats of the k24 are about the size of a quarter, the k24 next to the z3 head, the z3 are obviously much bigger. The z3 head next to k20a2 or k20z head the ports look exactly the same.
EnDyn said the z3 head is the best out of the box 🤷‍♂️

as for the intake manifold I have the ultra STREET but it’s CNC ported, as they come from skunk the diameter of the runners were 1mm smaller than the rsp manifold I was replacing. Anyone interested in that manifold I strongly suggest getting it ported.
look up perfect circle engines in Winchester, Virginia for a good price on that with fast turn around.

as for clearance, I have good bit with minimal firewall bashing. You really only need a little bit near the TPS
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#2,243 ·
Can you send me that diagram too?
Not sure what you are referring to. Which diagram? If you do not have wiring to the wideband you can find it in the RSX-S wiring diagram, though it should have come with your Honda wiring harness.
These may help:
 

Attachments

#2,250 ·
Not sure what you are referring to. Which diagram? If you do not have wiring to the wideband you can find it in the RSX-S wiring diagram, though it should have come with your Honda wiring harness.
These may help:
If I remember, the diagram to get rid of the power draw on the battery when not being driven. I am just about to start working on/finish my turbo build.
 
#2,214 ·
In my experience, if you're not driving at least 3-4 days, disconnect the battery. With both, RSX-S harnesses and custom harness, the battery would be completely dead within 2 weeks. I can't find anything "wrong" so I assume it's just a flaw in how everything works together.
 
#2,223 ·
It's hard to believe it's been over 10 years since I started this project, so I figured it's time for a "where I am now" post. This journey has been an incredible learning experience, full of highs and a few lows. I've met many fellow Spyder owners, shared fantastic experiences, and navigated through challenges. Your feedback over the years has been invaluable, helping to shape and improve the swap and related products. Here are some key updates and changes:

Engine Mounts
I switched from powder-coated steel to 6061 aluminum, which eliminates chipping and rust, while also being lighter and stronger. Initially, there was an issue with the welding process that shrunk the distance between two metal pieces by a couple of millimeters. Additionally, I addressed concerns about the driver side mount not being pre-shimmed by adding that feature, and I created a shim kit for those wanting the engine to be level. This kit is compatible for users not running AC, as the engine's position accommodates the AC pulley.

Shifter
The original Innovative design was complex and not cost-effective, especially with the reverse throw. To simplify things, I completely redesigned it, fabricating a new shifter cable to match the Honda setup and creating new brackets. The first design used steel and powder coating, but for the RSX version, I improved the powder coating and switched to 6061 aluminum for the brackets, enhancing strength and durability. I plan to phase out all steel parts in favor of 6061 aluminum, which offers better precision in production. The Civic SI shifter setups now combine stainless steel and 6061 aluminum for weight reduction and strength.

AC System
Toyota's integration of the DRL and headlights with the AC system was unexpected. We thought we had the BEAN system figured out until someone turned their high beams on. This led to reprogramming the MIMs to prevent AC issues unless the high beams are on. We're also updating the MIM to restore speed-based power steering, similar to the 1zz. Additionally, to address space constraints for the AC pulley, I made the AC brackets thinner by 0.125 inches. Early versions of the bent bracket failed due to poor steel quality, prompting a switch to a different supplier and, recently, to stainless steel to eliminate powder coating.

Axles
A small percentage (5-8%) of users reported the driver side axle being too long. Despite the challenge of gathering precise feedback, I began producing shorter axles by about an inch. This will be a trial-and-error process to find the optimal length, though I'm concerned it might cause some axles to pop out if they're too short.

Wiring
Wiring was the first component I tackled for the swap, and it’s been a learning process. I’ve improved the manufacturing process, now outsourcing the crimping so wires arrive pre-crimped, except for the PCB header which I cut and solder myself. These improvements have reduced the risk of pin breakage. The battery drain issue was solved by adding our own relay to control power distribution, addressing the problem caused by the Spyder’s opposite power configuration. Sourcing engine harnesses has been challenging since Honda discontinued them, but aftermarket options are manageable. We're also moving towards using the LinkECU standalone system due to its advantages over the PRB ECU setup.

Exhaust
Initially, I collaborated with Paul @ PPE to create a temporary header based on the 2zz design. Despite the availability of more elaborate and expensive headers, the PPE exhaust performs comparably well, only yielding 4-5 hp less than costlier alternatives. The shorter length of our exhaust systems, compared to Civic/RSX systems, likely reduces the need for larger designs. The main change has been shortening the header to improve ground clearance.

This project has been a remarkable journey, especially considering my lack of background in electrical engineering, manufacturing, and related fields. I've learned a lot along the way and enjoyed every moment. Unfortunately, Kenny, the original poster, can't access his account to update the original post, but we're moving forward with these new developments and improvements.

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#2,229 ·
Well, you can't move the suspension mounts without major body work, since the struts and control arms mount to the body. The engine position cannot change the suspension geometry, since the axles are articulated at both ends, and the suspension is fixed. If the axle was too long, that might bind the suspension, but I would expect that you would feel that when it happened.
 
#2,230 ·
Always nice to see updated products!

I know you said selling mounts separately is a pain, but I would like the new rear mount (subframe) to replace the old rear MAP mount. I'll pick up a new AC bracket too. Also, with the MIM update, is the connector and wires beefier by chance? If so, I'd grab a couple.
 
#2,233 ·
Always nice to see updated products!

I know you said selling mounts separately is a pain, but I would like the new rear mount (subframe) to replace the old rear MAP mount. I'll pick up a new AC bracket too. Also, with the MIM update, is the connector and wires beefier by chance? If so, I'd grab a couple.
When the mounts are made I need to order them in sets of 50, if I sell 1 or 2 then it throws off inventory and I am left with partial sets which will never sell. That equates to money wasted, so I cannot sell separate pieces. The steel mount's which is likely what you have, I did have a few extras made a while ago, that are for sale on the website, but the 6061 stuff I cannot sell separate.

The only think different on the newest AC mount is I replace the powder coated steel for stainless steel.

The MIM container is the same, I haven't had any issues with the connector or the wires or seen a reason to change them. The wire size is sufficient for the amperage they carry by electrical standards. The only update was to the actual programming to address issues with the high beam involvement into AC system.
 
#2,246 ·
I'm seeking advice on the parts I'm missing, suggestions, etc. to complete my k24 swap. I have the check-marked items. I already committed to a K-swap, and I should probably be committed to a mental institution as well.

If I'm posting this in the wrong spot, I'll take it down:

I have a google sheet link below where anyone can comment.
If you take the time to offer advice, thank you in advance.
Of course there are typos.



Photo of list as well:
Preview of gallery image.
 
#2,248 ·
I'm seeking advice on the parts I'm missing, suggestions, etc. to complete my k24 swap. I have the check-marked items. I already committed to a K-swap, and I should probably be committed to a mental institution as well.

If I'm posting this in the wrong spot, I'll take it down:

I have a google sheet link below where anyone can comment.
If you take the time to offer advice, thank you in advance.
Of course there are typos.



Photo of list as well:
Preview of gallery image.
I PM'd you my lists. They're not individually complete but together should cover most.
 
#2,247 ·
  1. Personally I would skip the ATI super dampener for a street car.
  2. Be sure you want the K20A transmission. You're paying a hefty premium compared to a K20Z3 transmission and the MAP Z3 adapter pieces.
  3. The TSX thermostat fits the spyder without issue.
  4. I went with Kpro, but it doesn't do DBW and there isn't a stock Kpro calibration for the 06-08 TSX engine so you'll need a tune to get the benefits of the 06+ cams and larger valves. UNLESS it's actually a JDM which I usually assume when I see "60K miles"
  5. If you are doing the swap yourself you should consider building and welding your own exhaust.
 
#2,249 ·
Only thing I'd add after tabKola's comments is if you're going K24 with K20 oil pump, get the ATI damp. Street car means you'll daily it when you're in the mood and you will not want all the extra vibrations. MAP/stock mount would be good too. I tested my turbo setup with this combo and didn't notice any vibrations...practically OEM smoothness.
 
#2,252 ·
The crank damper does not have any real effect on the vibrations you feel. It is a torsional damper that minimizes the effect of torsional twisting (worst case at the rotational natural frequency of the crank assembly). It protects the crankshaft from failing in fatigue. I agree, you want the OEM mount (internally-damped) on the passenger-side because that mount transmits most of the engine vibrations to the chassis. Huge difference in NVH between the OEM mount and a 70a Urethane mount in that location.
 
#2,254 ·
Sorry folks I think it's wrong to a bit of a dead-end to equate the OEM K-series Denso Wideband with safety at big power. There are better options available with aftermarket controllers, aftermarket ecus and even considering the idea of Canbus lambda control with aftermarket ecus. Kpro and Doctronic are good but not fully aftermarket, but do support 0-5v wideband controller outputs like the lsu4.9. They're also both based on the now ancient stock ecu. Consider options like link g4x and haltech...