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'03 RSX Type S
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Discussion Starter · #1 · (Edited)
Hey everyone! On the way is a JDM K24a (high comp w/ vtec). Sometime down the road I will be swapping it into my stock ’03 DC5. I don’t intend to modify much at all, but I will have a donor K20a2. This will be my DD, so I would like to maintain low-mid torque these engines are built for). After seeing the pics, a few questions have popped up (I’ve searched but haven’t found these specific answers):
  • 1) Will I need to change the lower radiator hose? If so, which?
  • 2) It looks like I will definitely need to change the upper radiator hose (angled water outlet on RBB head – see pic). Which to use (with RBB IM)?
  • 3) I would like to try and use the stock RBB IM. I currently have an Injen CAI and was planning on getting some ebay tubing to make it connect to the upward facing TB. Thoughts?
  • 4) My plan for the throttle body is to get an adapter plate and reuse my K20 TB. Will this hurt performance at all? Is the accord cable driven TB a direct bolt on? Any benefits to this one? I believe it’s 60mm vs 62mm.
  • 5) After the cost of the TB adapter and intake tubing, should I just consider a different manifold? RBC maybe? Other recommendations? I’m assuming my PRB IM would kill low-mid power?
  • 6) I will be swapping my K20a2 pump, however, I hear the idle oil pressure will go down a bit. Is there any cause for concern with a DD?
  • 7) I will reuse my K20A2 oil pan. Will I have any different dimensions to consider? Pick up location and clearances? I have a very tight fitting baffle currently.
  • 8) With a basically stock setup (RBB IM), is there any reason to change the VTC gear? I will obviously have one on hand. With a new IM, I would definitely do it (with limiting pin of course).
  • 9) Will I run into any clearance issues with the AC line running between the radiator and IM that goes over top of the engine (See pics)?
DC5:
Motor vehicle Automotive tire Automotive fuel system Electrical wiring Automotive exterior

Motor vehicle Automotive fuel system Vehicle Car Automotive design


JDM K24A being shipped. Comp test was 180, 180, 175, 175:
Tire Wheel Automotive tire Hood Automotive lighting

Tire Automotive tire Hood Vehicle Motor vehicle

Automotive tire Motor vehicle Bicycle part Rim Automotive design

Camshaft Engineering Nickel Ratchet Machine

Bicycle part Nickel Engineering Auto part Rim

Light Motor vehicle Automotive design Rim Engineering
 

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'03 RSX Type S
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Discussion Starter · #4 ·
Quick add on question: this engine will be paired with a used 09 csx 6 spd lsd transmission. About 100k on it.

Should i replace the bearings or not even bother cracking the case open?
 

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2002 DC5 Type S
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For sure. I just realized i put this under the wrong section. R u able to move it to the correct one?
what section do you want it to go to ? i can move it
 

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2002 DC5 Type S
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Quick add on question: this engine will be paired with a used 09 csx 6 spd lsd transmission. About 100k on it.

Should i replace the bearings or not even bother cracking the case open?
I would not crack it open. I doubt there are bearings needing replacement
 

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Arouse the DAMPFHAMMER!
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Discussion Starter · #11 · (Edited)
You will plant a K20 into that chassis?
My RSX already has the stock K20A2 that I rebuilt several months ago. It's running fantastic, but I wanted to get a backup engine before prices go out of control. With 250k on the odometer, I worry about the longevity of the K20. A k24a is on the way along with a 4.7 FD LSD trans. I will probably wait a while before doing the swap. I tell myself I will wait until there is a good reason, like some sort of mechanical failure... We'll see if I can wait. I'll probably end up doing it when my current clutch wears out, or some other lame excuse to justify it to myself, lol.

I can't help my brain from anticipating new parts needed and other mods necessary to successfully complete the swap. I created this thread to reach out for some help in that regard.
 

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Arouse the DAMPFHAMMER!
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My RSX already has the stock K20A2 that I rebuilt several months ago.
That's great. The NA feeling need revving to the moon :p, which is done on stock material better with the K20. That is really awesome that there are still tough guys resisting the boost or bigger is better trend, which runs heavily up and down the US K-series scene. We have to introduce a K20 NA award here for guys like you 🆙!

Some NA sound :D.

Does rebuilt mean you made also rings or at least a compression/leakdown test?
 

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Discussion Starter · #15 ·
1st off, your build is sick (the good kind). I have the utmost respect for your skills and knowledge. Excellent clip, is that a straight through exhaust?

The NA feeling need revving to the moon
No greater feeling. Still brings a smile to my face taking her to 8.5k. I longed for this exact car when it came out in '02 in the US. I finally got one in 2013 (Yes it took that long to find one, once I could afford it) and since then I've had no intention of ever getting rid of it. Hence the rebuild and now back up engine.
resisting the boost or bigger is better trend, which runs heavily up and down the US K-series scene
To me forced induction is cheating. There's something more pure to an NA build and tuning. Seems like more of a craft to squeeze every bit of power from the engine. Forced induction is basically a 30 to 40% boost in power with a bolt-on kit. To me this completely changes the dynamic of the engine and overshadows it's subtleties and characteristics that make it what it is. call me a purist, idk
Does rebuilt mean you made also rings or at least a compression/leakdown test?
I did a literal leak down with the head off and compression was + or - 5% across all four. I ended up lapping some valves but ultimately decided to keep the pistons in the block since compression was good, leaving the original rings. 250k and pulling stronger than ever. You were a big part of my thread several months ago: Service/Rebuild after low oil pressure K20A2 stock
 

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Arouse the DAMPFHAMMER!
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I have no glue about chassis things, I never had a Honda chassis. But I can suggest some engine performance approaches/suggestions/answers :).

I would like to try and use the stock RBB IM.
Great idea. Put the 64 mm TB from the K20A2 on it a 2.5 or 3.0 CAI with an perfect cold air induction then you will see the good results after tuning. Check out what it was worth on a 500 ccm/cylinder engine here: Skunk2 K-series Manifold Test Fit | Page 28 | Honda / Acura K20a K24a Engine Forum

5) After the cost of the TB adapter and intake tubing, should I just consider a different manifold? RBC maybe? Other recommendations? I’m assuming my PRB IM would kill low-mid power?
You will loose a bunch of midrange at low speed cam with an RBC or PRB IM. They just add power after 7000 rpm, which is always an application thing to decide if useful or not over the loss in the mid.

6) I will be swapping my K20a2 pump, however, I hear the idle oil pressure will go down a bit. Is there any cause for concern with a DD?
Yes, pressure will be lower, the gear ratio of the K20A2 gear set is lower for high engine speed reasons. A K20A2 survive it, why not a K24?

8) With a basically stock setup (RBB IM), is there any reason to change the VTC gear? I will obviously have one on hand. With a new IM, I would definitely do it (with limiting pin of course).
Yeap, the reason is moooooooooooooooooooooooooooooore midrange :). Tuning is definitely your way to go after the hardware is done.
 

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Arouse the DAMPFHAMMER!
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1st off, your build is sick (the good kind). I have the utmost respect for your skills and knowledge. Excellent clip, is that a straight through exhaust?
Thanks, it has an Euro 3 emission-CAT, a 62.5 mm piping and an absorption technology muffler. Nothing special, but still does support 142 Nm/Liter and 155 hp/Liter :p.

To me forced induction is cheating. There's something more pure to an NA build and tuning. Seems like more of a craft to squeeze every bit of power from the engine. Forced induction is basically a 30 to 40% boost in power with a bolt-on kit. To me this completely changes the dynamic of the engine and overshadows it's subtleties and characteristics that make it what it is. call me a purist, idk
Five hearts of five! I was involved in engine developments with 2-staged turbo-charging with Formula 1 combustion technology with up to 108 psi of boost and around 50 % of efficiency. This are amazing numbers but nothing special compared to an NA engine development where no more boost compensate evtl. hidden non-optimal design aspects. NA engines are the reference for any engine builder and designer.

I did a literal leak down with the head off and compression was + or - 5% across all four.
That sounds pretty healthy for a Quarter Million miles engine.

I ended up lapping some valves but ultimately decided to keep the pistons in the block since compression was good, leaving the original rings. 250k and pulling stronger than ever. You were a big part of my thread several months ago: Service/Rebuild after low oil pressure K20A2 stock
Yeap, there was something, sorry for missing that.
 

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Discussion Starter · #19 ·
Follow up question. What types of upgrades would constitute the need for larger injectors (rdx)? Also, are the blue densos the exact oem rdx injectors? Are these still the go-to or is there a better aftermarket option?
 

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Arouse the DAMPFHAMMER!
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What types of upgrades would constitute the need for larger injectors (rdx)?
Depends on your fuel pump, your aimed fuel pressure and fuel you are going to feed in that engine speed master. The spray pattern of the RDX injectors (= blue Denso injectors, but please state the part number here for comparison) is superior to most of the aftermarket stuff, which is interested mostly in balancing of injectors.
 
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