Honda Powered Build Thread - K24 / TSX
I've mentioned in my project log thread about going to the Honda motor. This thread will show my progress as I do this swap. Mind you, I'm a privateer doing this in my garage with the help of a few friends... I'll outline the process as best as I can so that other DIYers who wish to tackle this can do so as well.
With a internally stock K24A2 and a GT35R, 91octane pump gas, and a conservative tune: 425whp / 333tq (Ford Duratec: 435whp / 400tq)
Curb Weight: 2348lbs (w/ Ford duratec: 2450lbs)
Things That Will Not Work With This Swap:
- Tach. Or at least it won't read correctly as it sits. You can likely change a few dipswitches on the back of the tach to make it see a 4cyl rpm pulse. I ultimately bought a new tach from the original makers and had them make me a 10k tach, with the proper 4cyl pulse already set
- Coolant Gauge. The factory gauge doesn't read the Kpro signal
Why a Honda K-series motor?
- K engines can be found from $700-$2000 at your local junkyard, since they've been in almost every Honda since 2002.
- K20 and K24 motors are notorious for putting down very good power. Most boosted setups without doing pistons or cams have netted anywhere from 400whp to 750whp, and did so as street cars, reliably.
- Part availability is the best in the business. Need twin-disc clutch? Get it in two days. Want a sequential gear box? $7K later you have it.
- Reduced engine bay temps. Removing a turbo helps a lot. Add in that the exhaust ports are positioned next to the intercooler box, you won't have a turbo heating up the cabin
- Reduced weight. You eliminate a turbo, a manifold, the coolant hoses, the oil feed line, the intercooler piping from the front turbo to the IC, 2 cylinders, part of the exhaust system, etc
- Remaps are simple and can be done in your garage. The KPro ecu is very easy to work with, allowing boost by gear options, CAN export, datalogging, etc. Not comfortable with tuning, go to a dyno and 9 times out of 10, they've tuned a Honda motor.
- No more stalling or idle issues
- No more AC cutting out because of heat issues
- Heat management is MUCH easier
- Parts are insanely cheaper
- Can rev to 8000rpms
- No more oil starvation issues, since baffled pans are everywhere for Honda motors
- Possible resale value? Not sure how this would play... I know I would have paid more for a Honda-powered Noble when I was looking.
- Will not sound nearly as awesome, exotic, amazing.
- K series gearboxes aren't as strong and start shearing gears at 400ft-lbs (plus side, hardened gears are readily available).
Here is the parts list so far: Engine
- 06-08 K24A2 - $1400
- RBC intake manifold; bored out to 70mm - $310 ($235+$75 for boring)
- Skunk2 70mm TB - $360
- Karcepts RBC Adapter w/ ports - $70
- 45' VTC - $235
- K20 oil pump kit w/ Tensioner - $345
- Moroso Oil Pan - $350
- Thermostat, K24A2 - $25
- Water Pump, K24A2 - $35
- Starter, K20A - $80
- Alternator, K20A - $100
- AC Compressor -- Using the Noble one, will custom make a bracket
- Power steering pump - $60
- engine / charge harness - $100
- Gearbox; X2M5 w/ PNN4 LSD (K20A2 w/ K20Z3 LSD); $1780
- Competition Clutch stage 4 w/ 8lb flywheel - $630
- K20A Intermediate shaft (used) - $125 (Ebay)
- Drive Shaft Shop Level 3.9 axles - $1550
- Gearbox sheared 4th gear, so a Quaife Sequential gearbox is being used - $7500 shipped from UK.
- KPro PRB V4 - $1150
- Hondata 4 bar MAP - $100
- PLX wideband - $200
- EP3 Sub Harness (for OBD connector, as well as Honda E plug and C101) - $35
- GT3582R twin scroll - $1630
- 1300cc deatschwerk injectors - $380
- Synchronic 50mm Wastegate w/ boost control - $850 ($390 + $450 w/ bc & flanges)
Exhaust -- All Custom
- T4 Divided Flange Merge Collector, cast stainless - $150
- T4 copper gasket - $10
- Header flange, 3/8" 304 Stainless - $45
Miscellaneous BS That No One Ever Tells You That You'll Need/Want
- Blox oil filter relocation kit - $80
- Hondata intake gasket - $35
- throttle body thermal gasket (70mm) - $15
- Vacuum Manifold - $40
- Oil block cross, 1/8" NPT (for oil feed and sensors) - $6
- 1/8" NPT to 3/8" barb (for brake booster) - $5
- GT35 Oil drain w/ 1/2" NPT - $12
- 1/2" NPT to 5/8" barb for oil drain/return - $20 (for 2)
- 3" V-band for GT35 to exhaust - $20
- O2 sensor bung - $5
- K tuned map plug - $12
- Custom IACV block
- Custom IAA plug and cap
- Oil Feed Fitting for GT35 w/ restrictor, inlet is -4
- Oil Feed Fitting, -4 to 1/8" NPT (connects oil feed to oil cross) - $6
Things That Need To Be Done To Complete the Swap
- These need to be custom made. Pretty straight forward, place engine in engine bay, line up hub holes with gearbox, making sure everything is straight and level. Honda engine sits at a slight angle, tilted towards the exhaust side (rearward of the car).
- Using Drive Shaft Shop level 3.9 axles with the road race grease/setup. My measurements have the axles at 17" for driver (left) side; 20.75" for passenger (right), but this is based on the placement of the engine
- Need to reroute the cable to the left side of the engine bay. Throttle body actuates from the left side of the engine vs. Ford's right side. The hole for the throttle cable on the cam on the throttle body needs to be enlarged just slightly for the Noble throttle cable to fit. Then a bracket will be made to hold the cable at an appropriate angle and distance to ensure full range of the pedal. There's no change to the cable itself.
- The Honda slave is threaded for m10x1.25, the Noble clutch line is -4an. Buy a fitting (make sure it's reversed flared) and you now have your Noble clutch line.
- Noble shifter pivots above the linkage, thus pushing forward pushes the linkage. Honda shifter pivots below the linkage, thus pushing forward pulls the linkage. This means, you flip the Honda shifter 180', then have the cables come in from the front of the gearbox to drive the shifter mechanism
- I'm using a K-Tuning shifter box and the RSX shifter cables.
- Cut the ends off, tap the ends with 1/4-28 thread, add some rod/heim ends, bolt it up.
- On the gearbox, cut the studs off the gear selector mechanism, drill holes, add 6mm bolts to mount the rod ends with.
- Alternatively, find larger rod/heim ends for the larger studs on the gearbox.
- Finally, build custom brackets to hold the cables in place.
- Using the Honda AC compressor. The lines are tube fittings with 8an and 10an. Went to a junk yard and found some OEM fittings from an Accord, cut off the ends, brought them to a shop to have male AN fittings welded on.
- Using a Honda PS pump, requires a fitting to connect the Honda pump to the Noble lines. The pressure side is a fitting from an Accord, cut then an an6 male end welded on.
- Alternatively, use an electric powered hydro pump, wire up as necessary.
*** Wiring ***
- Biggest item, since it'll take the most time.
- Make sure you have the Noble build manual. It'll save you a TON of headaches.
- You'll need the EP3 Civic under dash harness. Look for 2002-2003 Civic Si, and make sure it has the E plug, the C101 plug, and the OBD2 Port. It should come with a set of relays (Main, Fuel / Main 2, and AF relay)
- Starter Relay: You can use the Noble's or use a Honda one. I choose the Honda one, just to keep everything similar. Easy to wire up.
- AC Relay: Again, Noble or Honda. I choose Honda. Run the chassis signal to the relay, then the output to the ECU. Then have the Vtec Pressure control engage the AC clutch.
- Main Relay: Honda. Wire it up as identified in Hondata's site
- Fuel Pump Relay: Honda. Same, send the fuel pump signal to the Noble fuel pump.
- O2 Relay: Optional... but required if you want to use Honda's primary O2.
- Reverse Relay: Noble has the reverse wiring in the chassis harness. Honda has it in the engine harness. Connect the wires together between the reverse switch on the Noble side. Cut the wire near the tunnel, run the signal wire to a relay. The input of the relay is from the ECU (C101 pin1). This gets a signal from the reverse switch. Ground C2 somewhere. When you engage reverse, it grounds the relay and you now have a reverse light.
Random Wiring Thoughts
- Ignition signal is on the Noble RR03 plug, that'll connect to the Honda's E9 pin
- Starter. Noble has the starter solenoid mounted on the chassis, uses the starter signal wire from the relay and energizes the solenoid to send power to the starter via the thick wire on the opposite pole. Honda has the starter solenoid attached to the starter. I'm using a relay (as mentioned above) to energize the starter.
- In KPro, you can use the VTEC Pressure to activate the AC Clutch. I'm spliced the wire in the Honda engine loom and ran it to the AC.
- In KPro, you can use the Purge Solenoid to run the Boost Solenoid. I've spliced the wire at the ECU plug and ran the wire along the chassis to the solenoid.
- Add a LED for the "Check Engine Light", this will make it OBD2 compliant, as well as helpful if there's an issue with the engine
- So it can pass smog, as well as the other benefits of the OBD2 port.
- Most of these wires will be wired to the ECU.
Last edited by Driven; 03-09-2017 at 12:53 PM.
So, I opted for the K24A2 out of a TSX, mainly because it'll have more torque than the K20s. Other benefit of the K24A2, specifically, is the oil squirters. The '06-08 also have stronger rods, so, '06-'08 K24A2 purchased.
Next up was a gearbox. I had a guy in Florida build me a gearbox from a RSX-S, but add a LSD from a factory Civic Si. I used the following guide to determine what gearbox to use. If this gearbox fails, I may move to a 5 spd, since the gears will be thicker, thus stronger.
I didn't have a good basis for this, so I asked around for recommendations. I went with a Garrett GT3582R (aka GT35R).
I wanted the same feeling that the Ford motor had with the GT28s, near instant spool and scoot. I got this turbo with a twin-scroll, so hopefully it'll match the responsiveness.
Also bought a Synapse 50mm wastegate with their boost control solenoid. I'm running a single wastegate with the twin scroll, which means I'll have to keep the divided primaries separated all the way to the wastegate valve.
This will be the most difficult part of the entire build... building a turbo manifold with divided exhaust ports to the turbo, and have those divided sections separated to the wastegate. To help with the divided collected build, I bought a divided collector with flange:
Engine Support Mods
The K24 has an oil pump that will cavitate at around 7500rpms, so I went with a RSX-S oil pump and baffles. The pump requires a minor modification to bolt up to the block, which takes all of 5 minutes with an angle grinder. The RSX oil pump also requires a K20 oil pan. Since I was already looking at buying a baffled pan, I ordered the Moroso pan, which has fittings for an oil return (for a turbo), a magnetic plug, and another bung for an oil temp sensor.
The K24 has proper IVTEC, so it allows the cams to be adjusted up to 25' or so, while the K20 allow up to 50' adjustment. To get more power, the additional timing is required. HOWEVER, the K24 will have valve interference if timing ever hits 50' or so. In KPro, you can limit the timing to 45' (safe region), but this will NOT prevent overrevs/misshifts. Best, buy a VTC gear mechanically pinned to prevent it from achieving 50' worth of timing.
The K24 intake manifold is suppose to be pretty good for making mid-range power, but an intake manifold from the 06 civic si makes more power (RBC intake). I opted to get that intake, as well as a 70mm throttle body from Skunk2. I then sent the intake manifold to be bored out to match the throttle body.
Aslo needed injectors to help with the fuel requirements, 1300cc injectors are being used. These might be a bit overkill for the power I'm shooting for, but I can always add more and not need to redo the fuel system
Wiring is another challenge, since I'm using a Honda engine harness to mate to the chassis harness/relays of the Noble. First thing though, need an ecu to control the engine, simple enough, KPro.
K motors have two engine harnesses...
1. Engine harness. This is the wiring that pulls together the injectors, the coil packs, etc and connects it to the ECU.
2. Charge harness. This is the wiring for the starter and alternator. Also, I believe includes the knock sensor.
The engine harness has two plugs for the ECU, A-plug, and B-plug. The E-plug is attached to the chassis harness. What you need to complete the wiring is wire the E-plug up to whatever requirements it needs (integrating it with the Noble chassis wiring), as well as another plug, called the C101 plug. More on this later, as I'm still working thru it.
I'm also working on having a proper OBD2 port, so I can connect dongles for datalogging, MIL, etc.
Ideally, you use the engine/charge harness for the ECU. I'm using a PRB ECU (02-04 RSX-S), so you want 02-04 harnesses. For the K24, you'll need to repin a few sensors on the engine, which is pretty straightforward. Once I get to that, I'll post the specifics.
AC - I'm planning on using the Honda AC compressor. Just need to wire up the AC Clutch line (using the VTEC Pressure switch)
PS - I'll be using a RSX-S PS pump
Alternator - Again, using a RSX-S unit, since the wiring will be for a RSX-S. It should bolt up without any issues.
Engine mounts will be custom made. I asked a few of the other shops who have done this if they would sell me the mounts, but alas, they would only sell if you have them do the entire swap.
Drive axles. Once I get the engine mounted with the engine mounts, I'll be able to do proper measurements and have Drive Shaft Shop make me some custom units. Will be using RSX-S inners with Noble / Mercury Cougar outers.
Last edited by Driven; 01-13-2016 at 08:29 AM.
Awesome project, there's no doubt the Honda K series engines are the truth. There are definitely a lot of pros related to this swap, arguably more than the cons as you mentioned. I think I decided to stick with the Ferd engine just to preserve the novelty/originality of this car.
Another benefit you forgot to mention is that it's a Honda meaning oil is pretty much optional. WEIGHT REDUCTION!
Well done for being so adventurous. I think its a wise choice with endless resource availability. The ford we have may perform well, but it has too many shortcomings imho. If anything it's a bitch to work on. Just the other day I tried to check all the turbo and manifold bolts. Looks like a rabid dog got a hold of my arms.
i think you are going to have a bulletproof setup. Keep the pics going and good luck.
Its an interesting choice and I do understand the reasons for doing it, frustration as to how poor the standard tuned setup can be and how little variation on the tuned packages there are unlike the engine you have picked.
I went a different route and designed my own single turbo engine package for the V6 (twin scroll similar to yours) meaning it revs to 8100rpm with a new stand alone ecu... I then developed my own triple clutch and flywheel and remade the rear chassis so I could remove the engine in under 3hrs on my own. Also a new design of sump to stop the standard big wing sump surging in some corners (as they do).
Biggest weak point of the V6 is the box, its a lottery due to the way 5th is spun welded on, some are good (like mine) some last just days at half the power I run.... Id be happier if another box option was available
Looking forward to seeing the progress you make with this... following with interest
One of the things that I can't foresee is the image and potential value change the Honda motor would cause over the Pherd.
Originally Posted by Darbid McYeezy
Thanks and I know the feeling. a few weekends ago, the front turbo seal went out during my first session on a Saturday of a two day track weekend... and I was asked if I was going to swap out the turbo.
Originally Posted by veteran
Yeah, no... pulling the front turbo is about as fun as being asked to binge watch Housewives of Atlanta.
I was initially thinking of going the single turbo route, but, the tuning aspect creeps back up. Which of the three or four people in the USA do I use... vs. with the Honda setup, which 300-400... or do it myself.
Originally Posted by andygtt
The Honda gearbox is pretty weak too, limited to maybe 400tq before gears get sheered off. Thankfully, stronger internals are readily available and replacement gearboxes are a junkyard away. Although, to the MMT6's defense, it's incredibly easy to pull apart and rebuild. Just make sure you have the parts to do so (which is less easy for us based in North America).
Week 2 Update
Did some small things while I wait for the engine to arrive. One, made a break in the wiring loom for the taillamps. Since I'm no longer using the starter signal wire, I yanked that from the taillamp harness, as well as connected the reverse switch wiring together, since these will be managed via the engine harness on the Honda motor. Which means, I have an uninterrupted wiring loom from the fuel cell to the clam connector.
So, since I love modular wiring and wiring that is a bit more hidden, I redid the loom for the taillamp harness, ran it thru the chassis brace, added connectors on either end. This does a few things:
- hides the hideous wiring loom
- allows the chassis brace to be removed without having to cut a dozen zipties
- simplifies the reverse signal wire
- simplifies the chassis harness near the fuel tank
Also laid out the chassis harness so I can remove/add whatever I'll be needing. For instance, I'm using the Honda Main and Fuel Pump relays, so I can get rid of the Noble relays. This allows for clearer wiring near the ecu, as well as gets rid of a lot of wiring mess near the battery.
Finally, started to lay out the ECU, relays, fuses, and OBD2 port... all of which will be housed behind the passenger seat.
Some pictures of what I'm doing with the ECU.
Gotta figure out how to make this rat's nest:
...talk to this rat's nest:
... and live happily and without domestic violence.
the work bench:
Have printouts of:
- RSX-S ecu pinout (from Hondata)
- EP3 C101 / E Plug pinout (from the internets)
- Noble chassis wiring (from Noble)
I'm using all new looms, shrink wrap, soldering connectors as needed, and using techflex sleeving where applicable. I'm doing my best to route the wires as cleanly as possible around the ecu, relays, and fuses. A lot of effort that'll hopefully pay off with a clean install.
Just in case you don't also have these pin out schematics:
Finalized my shifter, more or less. The RSX-S has reverse passed 5/6th... using the Noble shifter doesn't give me enough room to engage reverse due to the design.
Background info... the M400 shifter has one of the shift cables attached BELOW the fulcrum on the shifter. This means, that regardless of orientation, 1/3/5th gear selections PUSH the shifter cable.
RSX-S shifters has the attachment ABOVE the fulcrum. This means, in FWD layout, selecting 1/3/5, PUSHES the cable. Flip that badboy 180' and now you are PULLING the shifter cable.
On the MMT6 gearbox, in FWD layout, the cables run from the rear of the gearbox... likewise with the Honda FWD gearboxes.
So, instead of running the shifter cables from under the gearbox and around the back, Noble translates the PUSH action into a PULL action with clever levers... mainly because there's no room in front of the gearbox to run the cables straight to the gear selector. BUT, the Honda gearbox has the position of the gear selector in a much more ideal position.
What does this all mean?
Well, if I install a RSX-S shifter box, I can run the shift cables straight to the gearbox, with a simple bracket holding the cables, attached to the front of the gearbox. No levers are needed. AND, the RSX-S shifter box fits with very minor trimming to the hard plastic base of the shifter box to clear the opening of the shifter hole.
Other minor modifications are needed, but all very simple. Now that I have a mounting bracket for the shifter box, I can use any of the handful of billet shifter boxes and short shifters available for the RSX to improve the shifting feel, if it's not up to par.
Downside, the RSX-S shifter box, when in FWD layout, is bent towards the driver. In RWD layout, it'll be bent towards the passenger... this is an easy fix with a vise and a hammer or large pipe.
Basic process so far:
- Remove shift knob
- Remove arm rest (PITA, as the four little nuts are nearly impossible to get to, even with the engine out. A LOT of cursing and wobbles; Also, ebrake cover is held in place with safety wire, so flip the ebrake inside out, cut wire, remove ebrake cover)
- Remove the four nuts that hold the knee pads to the center tunnel
- Remove four screws for the rubber shifter surround
- Pull carpet from the tunnel, as far back as the center upright. This allows you the room to get to the screws and bolts holding the shifter bracket and cover
- Remove the four screws for the shifter cover
- Remove four bolts holding the shifter bracket in place
- Remove shifter cables from shifter
- Remove rear cable stay, there are four bolts holding it to the center tunnel
Install of RSX-S shifter box
- Get an aluminum angle piece from Lowes/HomeDepot
- Cut to xxx (measurements to be provided later). The rear bolt holes used for the Noble cable stays will be used for the rear of our new brackets
- Drill holes for the RSX-S shifter box to mount to the brackets
- Install studs or rivnuts into those holes, this will allow for easier install from the cabin
- Drill two holes in the side of the tunnel, 140mm down from the top of the tunnel. Drill these holes between the two holes that held the Noble shifter cover bracket in place.
- Install all of the bolts and drop the RSX-S shifter into place. Connect cables, and test.
Viola, you know have a RSX shifer box in your Noble that'll make the next process MUCH easier... which is mounting the shifter cables to the gearbox to operate the gears.
The wiring schematic I made for the start/ignition and firewall connector I have for the rest of the chassis wiring. I'm using a delphi HES circular plug that will be mounted to the firewall for quick connect/disconnect from the cabin, if I ever need to change things.
All the parts, minus the engine:
Oh, and the engine temporarily mounted:
Need to finalize that exact placement of the engine and to avoid too much of an alignment difference with the axles.
I have plenty of room in the clam to raise the engine, very little to lower, since I'm using a moroso oil pan, which is a bit lower than a stock pan.
Right now, I have about a 3" height difference between the gearbox and the hubs. I'll have to put the car on the ground to see how the suspension will settle to determine if I need the drivetrain lower.
Last edited by Driven; 12-09-2015 at 09:54 AM.