KPower Industries K24 swap

[jflogerzi]

Originally Posted by RedReplicant

It doesn't really work when you need to have a few tunes for optimizing power to weight classes or similar. Also, without getting too far into it my experience there was pretty much the tipping point that had me say fuck it and pull my FA20/Harrop for the K.

If I need to drop 5whp or pick up 5whp it takes me two minutes in Haltech without talking to a tuner.

yes that make sense... I guess it depends on what and how your using car. cant argue with you on that point

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[Tokay444]

Originally Posted by jflogerzi

I don't see many drawbacks. The Oil issue is already can be fixed. Honestly for those who can do alot of the labor and fab work, K24 is a great option. But let's not deny that FA24 NA running on e85 and can get about 240WHP and a healthy 200 WTQ tuned. Yea its early, but my gen 1 motor running e85 and boost for a period is still ticking out on track near 100K on ODO. As Gen 2 motors get cheaper, I still stand by my statement that in my situation the FA24 is the better option.

How do you fix the oiling issues?

[series.trackday]

Originally Posted by Tokay444

How do you fix the oiling issues?

For the FA20 you have to add in an oil passage and restrict the flow on another to allow the journal bearings to be fed equally. A description of that issue is found on this very forum:

Look at the FA20 crank mains and the rod journals and you should spot something unique where I oil starved the rod bearing. The third main from right to left has a larger oil port. Why? Because it has to feed two rod journals where all others only feed one rod journal. What happens to oil pressure when you increase the oil port size? What happens to your oil volume requirements when you need to feed two journals with one main? Guess which one failed?

Additionally, there is problems with the design and manufacturing of the oil pickup tube which can be solved by swapping to the KillerB unit.

Finally, the oil pan capacity isn't really sufficient when pulling sustained lateral G. It's just a physical limitation of the horizontally-opposed design and gravity. A baffled oil pan can help some but you're safer with a higher-capacity baffled pan and/or an Accusump accumulator.

When someone mentions the "inherent issues with a boxer engine design" the obvious comparison - Porsche - comes to mind. Well, for their high-performance engines (most 911 models) they use a dry sump system from the factory. For the "lower-performance" early-gen watercooled engines in the Cayman and Boxter, their oil capacities were gigantic compared to the FA20 - almost 8 quarts of oil in the Cayman vs. 5.8(ish) for the Twins. And that's leaving aside design differences in oil supply and routing.

As far as I know - I haven't researched it as much as I wasn't even planning on build an FA24 - Subaru/Toyota didn't do anything to address the preexisting issues with the FA20's oiling, and in fact made it worse with the change to a multi-screen plastic oil pickup design. The addition of the now well-known issue of too much RTV being applied from the factory causing the oil pickup tube to become partially or completely clogged muddied the waters a bit, but overall it seems these issues will persist on stock engines.

[Tokay444]

Originally Posted by series.trackday

For the FA20 you have to add in an oil passage and restrict the flow on another to allow the journal bearings to be fed equally. A description of that issue is found on this very forum:


Additionally, there is problems with the design and manufacturing of the oil pickup tube which can be solved by swapping to the KillerB unit.

Finally, the oil pan capacity isn't really sufficient when pulling sustained lateral G. It's just a physical limitation of the horizontally-opposed design and gravity. A baffled oil pan can help some but you're safer with a higher-capacity baffled pan and/or an Accusump accumulator.

When someone mentions the "inherent issues with a boxer engine design" the obvious comparison - Porsche - comes to mind. Well, for their high-performance engines (most 911 models) they use a dry sump system from the factory. For the "lower-performance" early-gen watercooled engines in the Cayman and Boxter, their oil capacities were gigantic compared to the FA20 - almost 8 quarts of oil in the Cayman vs. 5.8(ish) for the Twins. And that's leaving aside design differences in oil supply and routing.

As far as I know - I haven't researched it as much as I wasn't even planning on build an FA24 - Subaru/Toyota didn't do anything to address the preexisting issues with the FA20's oiling, and in fact made it worse with the change to a multi-screen plastic oil pickup design. The addition of the now well-known issue of too much RTV being applied from the factory causing the oil pickup tube to become partially or completely clogged muddied the waters a bit, but overall it seems these issues will persist on stock engines.

No one is talking about swapping an FA20 with an FA20.

[NARFALICIOUS]

I've had some changes in the garage and want to start the K-Swap now so I am deciding on parts. Few questions for you experts:

Oil Pump- As of 2024, KPower has a pan and notched-subframe that allows you to keep stock RBB Oil pump and Balance shafts instead of doing a k20a2 pump.

It feels like keeping everything stock would be better for reliability and reduced NVH, but going K20 pump and balance shaft removal would be better for revs and power.
I've been searching various sites like k20a.org and seemingly the balance shafts aren't *needed*
Is the NVH from removing the balance shafts all that bad? is there a video that demonstrates this?
Can it be that much more NVH than the typical FA20 noises?
Would the fluidampr help with this?

I have a 1JZ in my Supra, and I had an RSX Type S back in the day (k20a2). I fell in love with square/oversquare higher-revving engines, so I'm leaning more towards using a Type S pump to support my long term goals.


Trans - Does the 2nd gen transmission case have basically all the same measurements and mounting points, including shifter?
Planning to keep 1st gen trans for now, but I wouldn't mind keeping an eye out if a good deal comes up on FB, ebay, or the forums.

Thanks.

[RedReplicant]

Originally Posted by NARFALICIOUS

I've had some changes in the garage and want to start the K-Swap now so I am deciding on parts. Few questions for you experts:

Oil Pump- As of 2024, KPower has a pan and notched-subframe that allows you to keep stock RBB Oil pump and Balance shafts instead of doing a k20a2 pump.

It feels like keeping everything stock would be better for reliability and reduced NVH, but going K20 pump and balance shaft removal would be better for revs and power.
I've been searching various sites like k20a.org and seemingly the balance shafts aren't *needed*
Is the NVH from removing the balance shafts all that bad? is there a video that demonstrates this?
Can it be that much more NVH than the typical FA20 noises?
Would the fluidampr help with this?

I have a 1JZ in my Supra, and I had an RSX Type S back in the day (k20a2). I fell in love with square/oversquare higher-revving engines, so I'm leaning more towards using a Type S pump to support my long term goals.


Trans - Does the 2nd gen transmission case have basically all the same measurements and mounting points, including shifter?
Planning to keep 1st gen trans for now, but I wouldn't mind keeping an eye out if a good deal comes up on FB, ebay, or the forums.

Thanks.

Yes, it's bad. This shows up in cabin noise - especially at high revs, vibration you can feel across the entire range, vibration that you don't feel that murders sensors / causes the wiring harness to chafe holes in itself / causes bolts to untighten / pressure plates to develop cracks and come apart, etc.

A Fluidamper or ATI damper marginally help, but does not eliminate the higher order vibrations that the balance shafts counteract.

Yes, the second gen trans and first gen trans are interchangeable.

The K20A2 pump has been shown on the Tuning by Nick channel to be worth like 15whp, but if it were a street car you very much want to keep the K24 pump. The stuff about it not being able to keep up with oiling isn't true, it is fine, even on track. You can do some reading about that over here https://www.k20a.org/threads/is-ther...-built.228355/



ima be real, we're in a different time for these cars now. Unless you specifically want the K for an actual race car you're better off putting a FA24 into these things. It makes more power, it costs less, it's more reliable, it's easier, and it has much better nvh manners.

And yes, I say this as someone that did the swap, tracked the car for two years after, and then went ahead and K swapped another car after that.

[2.2Lude]

Originally Posted by RedReplicant

ima be real, we're in a different time for these cars now. Unless you specifically want the K for an actual race car you're better off putting a FA24 into these things. It makes more power, it costs less, it's more reliable, it's easier, and it has much better nvh manners.

And yes, I say this as someone that did the swap, tracked the car for two years after, and then went ahead and K swapped another car after that.

As much as I love Honda's and K motors this is the truth. The oil pressure issues are close to being resolved so the FA24 just makes the most sense on pretty much every level when compared to a K swap.

When I first got my 1st gen back in late 2023 I began research on a K swap for when the FA20 went but now..there's just no real practical reason to not drop in a FA24 and carry on with the boxer life.