I want to build a k24a2 as something fun to do. I left the car world years ago and I miss wrenching. The end goal is turbo k24 into something when it's done, but the main thing is just finding the correct engine to start with. I was a vw guy so Honda is new to me and vtec versions are foreign to me.



Is this the correct engine to start with? It's the same as a k24 block with a k20 head essentially? The performance vtec not the economy one?



https://www.japandirectjapanese.com/...2004-2008.html



or this https://www.jdmsource.ca/products/jd...ca78aa7d&_ss=r



or this which looks to have no accessories and is the wrong head, it's the non-performance vtec head?

https://www.japandirectjapanese.com/...2003-2011.html

 

K24A2 TSX engine is the one you want. The last engine you listed, the Element engine, has the economy oriented i-VTEC.

And yes, the K24A2 engines have heads that flow just as good as a K20. The price on these engines is also great right now.

Edit: It looks like I was wrong about the A2 head flow.

 

The USDM K24A2 or JDM equivalent K24A is an excellent "all-around" choice for a mid-power turbo build. If you intend to run above 700 WHP, the TSX head will start to get in the way, so a K20A2/Z1 would be a better choice... OR if you are building anyway, you might consider the K24A1 (CR-V) engine with a VTEC killer type camshaft package... the ports are really large on that head too.

 

From what I understand its the worst flowing of the "proper VTEC" heads. Which is why a lot of people opt to just get a cheap K24A4 and put a K20 head on it.
I personally didnt want to mess with all that, so I got a K24A2 (Its a JDM K24A, but its close to the A2). But I suspect one day Ill be tempted to put an RBC head on it.

 

I think the move is pull a CRV k24 from a junkyard. Get it bored and honed and find a k20 head. I don't plan on 700hp but I mean, you never want to limit yourself if it's something as simple as the base head you start with if it's going to cost the same. I've found a bunch of super cheap k24 CRV motors locally, and if it's the same bottom end more or less, I guess it doesn't matter if I'm going to swap heads. The compression will be the same 10-1 or whatever it is on the TSX motor, correct?

This is either going to be a big turbo motor or a 10k RPM ITB motor.

 

I wouldn't say you are wrong Chance EG... the framing of the information is the problem I think. Let's consider the intake runner cross-section of a K24A2 and a K20A2 much like that of comparing throttle bodies: The K20A2 intake runner cross section IS larger just like a 70mm throttle body is larger than a stock 60mm one. If you install a K20A2 head on a K24A2 stock short block, what you will get is an engine that makes literally identical peak HP numbers (maybe 1-3 HP more at best) and a WHOLE LOT LESS midrange torque than the stock K24A2 head. A stock B,D, or H series engine with a 70mm throttle body performs basically the same way: The engine doesn't draw air fast enough through the large throttle body to create air velocity that maximizes engine efficiency until nearly redline... creating a loss of power throughout the midrange and reaching "even money" (same HP) near redline with the stock throttle body.
Once an engine's breathing capabilities have been improved enough to out-flow the stock throttle body (or intake runner size in this discussion), a larger one meets the requirements while minimizing the efficiency loss in the midrange. So, if you are building a high compression, big cammed K24 with all of the trimmings, the K20A2 head will certainly make more peak power over the K24A2 head with limited power loss between 4000 and 6000 RPM. However, if you plan to use a stock short block and add a K20A2 head with stock or mild to moderate cams, you will make almost the same peak power as if these same mods were done with the K24A2 head... and a loss of as much as 10-12 HP in the midrange.

In short: For a mild to moderate build, I would suggest using the K24A2 head. It will be far more enjoyable to drive every day. If you are building a Drag Race car... then go with the K20A2 head.

 

Thank you very much for taking the time to expand the details on that, I'm glad to know now.

Do you know how the K24A2 heads respond to port and polishing versus a K20 head? I've mistakenly thought this whole time they were more or less identical.

 

Opening them up will make the K24A2 head perform "more like" a K20A2/Z1 head. Certainly not worth the cost if you have a stock K24A2 bottom end or a relatively mild build... but it could be a viable path on a big power forced induction application or a salty NA build.

 

4piston has a port program for the TSX head that improves it a lot, but their ported K20 heads flow better. There is some kind of limitation with the water jacket or something IIRC.

 

Thank you, that explains why I've seen these K24 heads used on big WHP all motor builds. In a lot of ways I wish I went K24 NA on my own hatch, but I'm sure the boosted B will be a lot of fun too.

 

K series stuff is really starting to come up cheap.

 

Been a few weeks since I've looked at the K market, but yeah it's seemed that way for awhile. Doesn't seem like the K world got hit as hard by the lockdown market either, probably because at this point there's more old K series engines out in the wild, and in US scrapyards than the ancient B series.

D is dead, B is headed the same way. K truly is the way now, from almost any way you try to look at it. Can be about the same price as a B swap or possibly even cheaper depending on how you do it, better aftermarket support, more OEM parts availability and support, VTC, more displacement, super strong stock sleeves, etc etc...

RIP B ;_;

 

And more torque than the B could ever dream of making. MmmMmm torque.