K20 vs K24

[adam]

I've got some proper geek questions, so prepare yourself

You've got the K20 engine (a 2 litre) and the K24 (a 2.4), hence the naming convention. If you look at Atoms for sale, at least the 3.5 from what I've seen, some will have the K20 and some the K24. Yet both are always advertised as 245bhp or 310bhp SC upgrade. Is this really true? You get no bhp performance difference between the two?

I've heard the K20 offers a better driving experience in terms of power delivery and feedback, is this true? Or is this one of those "yes but in reality you won't notice the difference unless you're <insert F1 driver of choice>"? Anyone experienced both?

Assuming I'm accurate so far, what's the advantage of the K24? More options for tuning if you choose to pursue that route?

Aside: Given the Atom naming convention and the fact the 3.5 was the 3.5 as it was a chassis improvement but same engine (so couldn't be the 4), why wasn't the K24 version of the 3.5 the 4 and the latest version the Atom 5? (Yes, these are the questions that keep me awake at night)

Cheers

[markwetherall]

My Understanding is:-

K20 was the better engine for the Atom. The K24 was for the nomad. They run out of the K20's so as a stop gap they installed the K24's in a few Atoms while they were waiting for the Atom 4 to be ready. K20 is better suited to the Atom and the K24 is better suited to the Nomad.

Differences between Atom 3 and 3.5 were additional bracing on the frame, headlights and a new dash. A lot of 3's have been upgraded to 3.5 over the years

[speedmachine]

@adam


Also there are multiple versions of the k20 installed, the later being the least desirable, but only thin margins. K20 is more of a sporty engine and likes the revs, straight out of a type R and than most times supercharged on top.
The k24 is an accord engine, not built for a type R and is a bit more torqy, but doesnt like the revs as much as the k20.
Some tuners combine the 2, heads and stuff from k20 on a k24 shortblock, this will give max power I think.
H
In short, you want the k20.
Or actually you want the k20c1, thats the Atom 4

The 3.5 with k24 is not called atom 4 as that would suggest it is an upgrade, but it rather isnt, so they kept it quiet.

Hope you can go back to sleep now

[adam]

Ahhh... I had not considered the stealth influence of the PR & Marketing department on an otherwise logical naming convention!

Thanks for the info all.... Goodnight

[revvhappy]

There are multiple variants for both K20 and K24 engines, both having low and high hp versions. The revvy nature of the K20 comes from the square bore/stroke (86x86mm), while the K24 spins slower with more torque from increased displacement primarily from longer stroke (87x99mm). The big power differences between models of each engine come from the head design, with the higher hp coming from full v-tec on both cams. One version of the K20 head is the best flowing of all the K20/K24 variants (rare RSP from the JDM Type R), but the PRB and RBC aren't too far behind.

I ran a K24A2 (USDM Acura TSX from 2006-2008) in an endurance race car for years that was internally stock with an S2000 header, 3" intake, and Megaquirt engine management. It easily made 220hp at the wheels with minor tuning in endurance trim, and was still building power at the rev limit that I set (7200rpm). In sprint form it probably would have made 240hp over 8000rpm.

I second the installation of the K20C1, it's an absolute ripper in my Civic Type R with gobs of torque and HP. You can buy a new crate K20C1 from Honda and have 200k mile reliability. Of course it would cost nearly $10k for the swap. : )

[adam]

Is the turbo version _that_ good? I've not bought the car yet so getting a 4 over a 3.5 is an option.

I'd heard that although the turbo is really good, the SC 3.5 was actually the better driving experience?

[markwetherall]

Is the turbo version _that_ good? I've not bought the car yet so getting a 4 over a 3.5 is an option.

I'd heard that although the turbo is really good, the SC 3.5 was actually the better driving experience?

The Atom 4 is a massive step up on the 3.5. Engine, chassis massive improvement over the 3.5. If you can afford the 4 then well worth it.

[adam]

My wife is gonna be so annoyed at your advice!

But I thank you