Tuning the 3 power outputs from the latest 2.4 motors

[PAJ]

It was while is was waiting for the build of my Atom to start that another forum member made me aware that Ariel had switched to the K24, seemingly nothing changed, with the 3 previous options of power output remaining the same, albeit now with some extra torque and the big disappointment of losing the top off the rev range
    However, having read about the K24, there seem to have been challenges with tuning them, but they've been around for a few years. I'm totally unclear on what gets changed from standard spec to release this extra power, and I never like to bother those busy men at the factory with questions that don't really matter, other than to satisfy my own interest. Does anyone know what is changed, and who does the work. Does Ariel receive standard engines, bolt of a few revised parts and remap the ECU for these specific 3 outputs ? Or did I hear that TDiNorth do some of the engine modding ? I've a sneaky suspicion that the outputs will be the 235 / 290bhp of the Nomad. I'm guessing they still do the 'R' at 350bhp ?

[kelvin12382003]

I was told that K24 still offer the 3 options of power output. I would assume your k24 atom will have the same horse power as the Nomad!!

I just think that people would choose k20z over the k24  ( anyone?)

[John Scherrer]

I heard at the factory that they were reserving some k20 engines for the 350R orders ..

[PAJ]

Really So all that money for a car, then pay another £10,000 and they'll give you the engine you ordered in the first place ? Disgusting !

[alanoo]

Challenges are with the k24z versions with the integrated exhaust manifold.
They are still able to do 230/240 hp N/A and close to 300 with SC, but having more needs a less restrictive head. Well at least that's the current state of mind in the Honda tuning community

[PAJ]

That's slightly worrying since I indicated to Tom that I may upgarde to 350 BHP when funds permit, but that was 13 months ago when the 2.0l was still routine fit. Hopefully it's still possible when having bought a 310. There are build photos of a 3.5R on the forum at the moment, it's a 2.4l, does this have a different head ?

[Rocket Man]

eddie hill has a 2.4 for sale in US with 365HP. it appears they turbocharge the 2.4 over there

[GraemeW]

PAJ Tom told me some months ago when i enquired, that the new NA K24 in the Atom they tuned it to get slightly more than 245 BHP and the same torque output as the the SC K20.  It is however rated as 245 the same as the 2 litre engine.  Although I didn't discuss the SC 2.4 I assume its rated 310.  This is to be clarified in a press release sometime.

My K24 245 is about to go into build or has already started.  I note that you have SC your 2.4?  I hope to do the same later after driving one...an experience I will not forget.

[PAJ]

Maybe I'm just getting confused with the Nomads outputs, making the assumption that their 235n/a (I think that's correct) and the 290 s/c will be the same as the Atom, maybe they're tuned differently. I'll be pretty pleased if 310 means 310.

[GraemeW]

yes my understanding that although they use the same engine in both cars they are tuned differently

[jpswift]

I have no idea re the technicalities but Tom says the 2.4 is quicker

The 235 bhp output figure seems to be at a much lower rpm for the 2.4 lump than the 2.0 one

[Peter255]

[quote="justin swift"]
I have no idea re the technicalities but Tom says the 2.4 is quicker

The 235 bhp output figure seems to be at a much lower rpm for the 2.4 lump than the 2.0 one
[/quote]

Whilst that's good for general road use, that's not good for track use when you should be using low gears and high revs to maximise acceleration. I suspect the 2.4 would be quicker only in some situations. But as I have said before you need to compare dyno outputs across the rev range to fully understand.

We need to do a dyno day to get to the bottom of this with some 2.4s to compare to some older 2ltr cars.

[PAJ]

You would imagine that just by the nature of this being a larger, but related engine to the K20Z, that Ariel would have been able to revise the three power figures upwards. It seems that there are limitations in tuning the K24. Without knowing what the new motor was, and being told you're getting another 400cc, we should have been clapping our hands and expecting 25bhp to appear over and above the existing figures for the K20, the nobody would be wondering which engine would produce the faster car

[PhillipM]

Unfortunately the longer stroke of the K24 means you have to bring rpms down to limit the piston speeds  if you want to keep things reliable, which is why peak power remains similar (although it's still actually faster as the engine has more power everywhere in the rev range)

[John Scherrer]

.. more torque everywhere in the red range .. presumably?