the K and F are basically the same engine. Main difference is the K has variable cam timing and the F has stronger rods from the factory. Maybe pistons too but not sure on that.

 

Been told this is a K20 A2 out of a 2004 RSX. Does this look right to you guys?

Confused about the open deck configuration and its ability to hold high HP (turbo power). I can see if it was sleeved!

Good topic for sure! (caught my interest)

 

The K-series is better than the F as an overall package, and this is coming from a former S2000 owner and F20B enthusiast (I had one for my beater EG hatch but never went through with it), it's simply newer and more advanced. I loved my stock AP1, but there is a reason why anyone who is serious about competing with a N/A S2000 goes to the K24. It kills the F20/F22 in area below the curve with the cam phasing and has much more aftermarket support, not to mention availability. For big power turbo usage on stock engine, sure the F is going to hold together longer, but I don't know many people who would risk blowing up an F2x with today's pricing. I'd also argue the 6-bolt 4G63 can go even further than the F2x - a stock 6-bolt shortblock DSM has gone to 749 whp with a 9.28 @ 154 pass. It's very common to get a 6-bolt DSM, strap on a $1,000 turbo kit with a Holset HX40 and cast manifold with a mildly built automatic for easy and cheap 10s. They take nearly any type of abuse except for tuning mistakes. Anywhere a K-series or F-series has gone, a 4G63 has already gone before. I'll maintain that the 4G63 cannot touch either one in N/A form (and N/A Hondas are seriously underrated around this forum for fun-to-drive factor), and a small turbo K-series will feel great because it will make more power off-boost, but for brute force power production, it's impossible to beat the 4G63 overall, and especially when considering cost involved.

 

From what ive seen on YouTube, K series, particularly the k20a2 (USDM) or the JDM k20a respond very well to boost, can rev to 9k and make power there without any internal mods. There is plenty of youtubers (check out boostedboiz, humble performance to name a couple) that have made 500+ WHP on stock internals. That Racing Channel is currently building an AWD RSX and its looking like a beast. They did some testing stock, stock block w/ turbo, and in the process of testing with AWD and sequential trans. Very impressive to say the least.

The K24 engines and make similar power with more torque. They just cant rev as high due to the rod ratio. Most people ive seen replace the oil pump from the K20A and they can rev to 7500-8k safely.

I would not dare say which is better, but they are both very good and both have been proven to make plenty of power both stock and built. Ive been a big fan of Honda and recently sold my RSX type s. And own an evo, so to my biased opinion they are arguably some of the best 4cyl engines ever made.

 

I think the previous 2 posts sum it up the best. Both are great engines and make great power.

 

Looks like a K20Z1 from 05-06 RSX-S, the stamp is right in front of the starter hole.

 

Yes very similar with F having better head flow and VE, can fit larger intake valves because larger bore/chamber area, better rod ratio (k20=1.62, F20=1.82, F22=1.65) and some advantages in the crank like wider rod journals for more support/surface area in bearings and thicker rods. F has stronger forged pistons/rods/crank from factory. Really the only advantages of the K is cheaper more available parts, aftermarket support and ivtec.

Salute fellow s2k owner ivtec is a major advantage I will give you that, but even with ivtec it will never flow as much as a F20/22C at high rpm in stock form. Porting is a wash, ivtec giving the edge in area under the curve. All of the advantages that the K have over a F (besides ivtec) are all external factors that are not directly related to the Ks design. See above for some advantages of F over K design. The thing holding back the F platform from realizing its full potential is cost, availability of parts, and aftermarket support as you said. If I was building a project car with a honda engine I would go with the K for those reasons only. Nobody is willing to take the F as far as they have taken the K because it doesnt make sense from a $/hp standpoint with current aftermarket and oem parts support. I dont think that makes the K a better engine design than the F.

 

My main concern is the open deck design. Not a good comparison between the closed deck 4G63 & this open deck design. The K20 seems to need a sleeve job to be able to hold high turbo type HP.

But from a NA point of view, Im sure, based on all the great comments that this NA motor is just one of the best!

 

Even open deck it still holds massive power, I think people only really sleeve when going 800+whp. But it can pretty reliably hold 500 even open deck. Honda's rod ratio and mean piston speeds are what make them work so well and be so reliable even with big power. I've seen plenty of people make around 500 with single cam D-series open deck blocks. Honda just take abuse and asks for more.

 

under normal circumstances yes, open deck can take basically the same power as closed. Its when an issue arises, running too lean/rich, detonation ect where the closed deck will be more likely to sustain possible engine failure that the aluminum open deck head surface/bores would warp/crack under.

 

K series > 4G63 as far as head flow go
The biggest advantage a 4G63 have over K series is the AWD system that is intended for performance application from get go with active center differential
K series AWD stuff AFAIK is all derived from CR-V or something along the line of that which is more like a band aid for low traction situation rather than performance enhancing system

 

Kinda have to put bounds on a question like this.

Are we talking which is better at holding 300, 500, 1000hp? Or which can take more abuse without major potential for damage.

Which has the best oiling system?

 

4g63 <<< 3 Leading F&F roles* Also that Fq400 video on top gear *Chef's kiss*





* AFAIK, maybe more? I stopped watching them after PW passed.

 

This is an impossible question to answer really. Both engines do their jobs and make power, without really having any major inherent design flaws (the K will need sleeves at some point, but thats any modern aluminum 4 cylinder built for economy cars).

If you were looking for a used 4 cylinder to throw in a project car and make a bunch of power, K for sure because a 4g is ridiculously expensive. But I certainly wouldn't put a K in my Evo. And likewise, if I had a civic with a K, I wouldn't be looking to put a 4g in it.

 

Actually there is a 5th gen hatch for sale rn with a full evo 8 motor/drivetrain! 25k