You pretty much need kpro to be able to tune a 2.4 swap to run correctly. It gives the ability to command total control over how the engine runs plus relay vital information that the normal instrument display would not. You can use a stock k20a2 02-04 ecu but it needs an expensive immobilizer bypass and is meant to run a 2.0 motor. If you want your k24 to run properly it’s considered a must have in my opinion although it is a large price tag.

 

You can save some money by using a PND ecu for your core. You have to either run wires from the motherboard to engine harness or put in a constant speed to trick it (auto ecu reads speed differently) which makes the cluster speedo read accurate but the computer thinks the car is always going a set speed to keep vtec operation intact. You lose launch control this way but it was worth paying $800 vs $1000+ for a PRB kpro. Hamotorsports.com is where I bought mine. Running my k24a beautifully on a 6 speed.

 

Hey KBuilt,

Thanks for replying. So from what you said, i can use an RSX ECU with KPro to run my K24 engine? I see KPro sells new PRB ECU`s with KPro on them for 1100 USD. Expensive, but if thats what it takes to get my K24 running with a 6speed. And you said the PRB can be run with the stock K24 engine harness right?

 

You will need an 02-04 rsx (type s if you want reverse lockout, base model if you don’t care ) engine harness to go with the PRB ecu and then you are set to have your k24 running 100% once it’s tuned. Has to be 02-04 same as the ecu.

 

Gotcha. The RSX type S came with the K20A2, right?

 

02-04 is k20a2. 05-06 is k20z1.

 

Awesome. My assumption was correct then . Did look around a bit for a wiring harness and they are quite expensive at 400-700USD. Im guessing this is why a K24 build isnt cheap haha.

 

The type s harness prices are pumped up right now. Just about everything k swap related that is a necessity is expensive currently. It took me a year to put everything together for mine lol

 

Yeah im seeing that now. Like holy cow... 700 bucks for a bunch of wires and connectors. Seems silly to me. If i can, i`d want the reverse lockout. But not if its 500 bucks more expensive vs not having one. Havent found the base wiring harness yet, but i`ll keep looking.

 

I've seen 02-04 rsx tuck harnesses for as low as $400 if you don't care about it not being original.

 

Also, my Prelude`s engine uses a cable to run the throttle. I know the K24 does that by electronics. Does that mean i`ll have to wire up an electronic controlled throttle pedal, or can i modify the throttle body to accept a cable? (I`m assuming modifying cant be done here)

 

You will use a cable driven 02-04 type s style throttle body or an aftermarket equivalent. I chose to use an adapter plate and a b series 70mm on my engine. The tps is much more reliable on the b series and the wiring is even the same colors so it was a cut and splice affair for the map and tps wiring and I have a trouble free throttle body. The k series tps can be problematic.

 

You might also use the Doctronic ProECU-K as an alternative to a KPro for way less (50%) money.
Features are almost the same as they are based on the same Honda ECU. I use one.

Doctronic.at


If you are in Europe, try to find a Civic EP3 Type R engine loom. They are on ebay from time to time from the wreckers.
From there you are almost there. How to interface to the car, you’ll also find on their website in download section.

 

@KBuilt Awesome. Thought i read somewhere they had throttle by wire. Makes things much easier if its cable operated. Might take your suggestion on that B-series TPS.

@Lotus Awesome suggestion on Doctronic. I checked out the site, and i already love the modularity they offer. Prices are indeed much cheaper than KPro aswell. I`ll still compare the 2 just to see what i want/need. I looked up what an actual EP3 looks like.... theres a yellow one near me. I did wonder what it was for a while since the yellow color made it stand out. Anyway, i assume the EP3 wiring loom wont work with an RSX ECU? Meaning if i find one, i`d have to go with an EP3 ECU, correct?

 

The engine comes with a DBW throttle body from factory but any k series intake manifold and TB can be fitted. Most common is the rbc intake manifold with a type s throttle body.

 

Yes, best to use the ECU as a base that belongs to the loom. PRA ECU can read a Wideband lambs controller signal. I mapped my car myself with the Doctronic ECU.

 

depending on space, get a PRC, RBC, RSP or RRC intake manifold. PRB is waste of time.

 

Things have changed in the Honda world drastically in the past few years. Many parts are on back order and as time goes on parts become discontinued typically. Some of this is due to covid and some is due to the increasing popularity of Honda swaps into basically everything it seems. Covid has slowed down exporting parts from Japan because they want to preserve the availability of parts to Japan's Honda owners. Also covid has slowed down shipping all over the world. The popularity of the K24 swap and the K24 owners desire parts from the K20 platforms because they are suited for higher rpm's and the K20's cylinder heads flow more air giving them higher output potential. The K20 PRB oil pump, RBC intake manifold, RRC intake manifold, throttle cable operated throttle body, K20 engine harness, K20 transmission, etc. All of these things put a greater strain on availability of extra replacement parts.

I would suggest collecting extra OEM parts for your engine, transmission, drivetrain, and any parts that are typically referred to as service parts. The cost of the parts are going up and the supply is not meeting the demand, being that the Kseries is over 20 years old now that does not help. Other members on K20.org and I have already started collecting extra parts for our future servicing. Some of the more popular parts are :

1) K20 PRB oil pump, S2000 oil pump
2) Timing Assembly parts
3) OEM sensors
4) K20a PRC flywheel
5) RBC and RRC intake manifolds
6) K20 water pump

In general the Kseries engines and transmissions are going up in value and availability.

 

Alright. I`ll have a look at the intake manifolds, see if i can find something usefull. The guy im buying the engine from doesnt have one depicted in the pictures, but he did say it was a complete engine with extra parts.

As far as i can see on the picture he has

• Engine block
• Valve cover
• K24A3 Camshafts
• Camshaft housing
• K20A2 oil pan
• K20A2 oil pump
• K20A2 camshafts
• K24A3 plastic engine cover
• New head gasket
• A whole bunch of new seals varying from rear main seal, to O-rings etc
• NGK sparkplugs
• ACL race thrust bearings
• ACL race crankshaft bearings
• Oil dipstick
• K24A3 waterpump with pulley
• Ignition coils
• Several engine mounting brackets for stuff like power steering pump, alternator, etc
• VTEC Solenoid
• Timing cover

Im pretty sure he has more parts than listed above because the K20A2 stuff he only mentioned in his description, not shown in his pictures.

He said the engine ran fine before he took it apart, and has ran for 157K km or just under 100K miles.

@Them Witches Thats a good tip. I`ll keep a look out on K20/K24 parts, but gonna focus on what i need first to complete the engine.

 

you could also consider buying a K20a2 swap package that includes loom, ECU etc.
Then build a frank K20/K24 and sell the left overs.
This will save you lot’s of hassle with the electrics.

Or buy an entire Civic EP3 type R and sell the left overs if you have the space.

 

@Lotus Civic EP3 Type R`s go for atleast 4.5K euro over here, and as with 2K euro for a swap kit, it seems alot of money to spend to me just for the harness and ECU. If i got the PRB ECU from Doctronic and a PRB harness id be out 1200 euro give or take. Though thats if i go for the harness with reverse lockout. Can be cheaper if i got a base PRB harness.

As added info, the gearbox i have now is the GZT5. I will put a Turbo on the K24A3 either while im building, or later. You think its worth putting an LSD in there? As its a 2nd hand gearbox, i will change the seals and open it up just to inspect for any damage. It seems to shift well, though cant be too sure.

 

2003 Accord 5dr Wagon Type-S and Executive (Chassis CM1 CM2)
K24A3 6-speed manual non-LSD United Kingdom (built in Japan)
Transmisson code - GZT5
1 3.533
2 1.880
3 1.354
4 1.027
5 0.825
6 0.659

Short 1st, looong 6th. 4.3 FD
For a turbo or heavy car ok.
for a turbo, definitely LSD.

if you want all that, you need a healthy budget.

 

Car weighs about 3000lb so yeah, a heavy car. Transmission indeed came from a Honda Accord Tourer 5dr. And yes, i know im gonna have to spend money. But i have everything out now so might aswell do it all as good as i can

 

Not in Europe.no one sells aftermarket

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I bought from the Litauen chap before.all legit and good.
Also saves VAT if you are located within the EU.

with this loom, you might have to swap the crank sensor, and a PRA ECU and a Wideband Controller you get the k24 to run in your car.

 

I just picked up the engine. Engine is complete without ECU, wiring loom, and has no intake manifold, and throttle body. So now im left wondering what intake manifold would suit the RBB head best? Its stamped RBB-1 on the side.

 

If you want to get more power up top but sacrifice a little bit under 6k rpm or so then an RBC manifold is what you want. If you mainly will drive the engine in the lower range and aren’t concerned with what’s going on higher than 7k rpm the original RBB manifold will be better. Or depending on availability the k20z4 RSP intake may offer the best of both worlds. I have a stock k24a with an rbc manifold and it still has plenty of low and mid range power although I haven’t put any other intake on to see the difference.

 

Hey guys still new to this whole Honda stuff, i have a K20a engine puled out from a FD2R swapped into my DC5/RSX using a Links G4X DC5 ecu , will a 02-04 DC5 work on the engine that is swapped?

 

DC5 ECU?