KPower Industries K24 swap

[funkjaw]

Originally Posted by captain awesome

Get the 4piston head and call it done. I spent hours researching a more budget friendly option and the only thing I could find was a rare JDM head not sold in the states or the k20z3 head which doesn't net enough HP to justify the work. BUT If you wanna fiddle with the coolant passage differences of a k20a2 head and figure out how to route it, then you could save some coin and add power potential for considerably less.



My invoice from 4piston is $1900 which includes new bronze guides, Ferrea 6000 valves, and Viton valve seals. I plan to assemble myself to save a few bucks and I spent a good amount of time cleaning it before sending off. I'm pairing the head with Drag Cartel stage 4 cams based on other dyno plots from Kpower. My buddy happened to have a brand new set of Supertech springs but was missing the retainers for $200. I bought steel retainers along with new keepers for another $175. There are some deals out there but 4pistons price on these are hard to beat at $380 unless you get lucky. It worked out for me in the end only because I didn't want titanium retainers.



The only thing that sucks about this all is the wait time from 4piston. 4-6 weeks was what I was quoted.

Did you ever get your head back? I just sent mine in, mostly based off your findings so thanks for that. I ended up ordering the combination as seen in the picture. I did a ton of reading on Titanium retainers, and I'm kinda 50/50 if they will be reliable for me or not. I'll check them in about 10,000 miles and see how they look. I change my oil very frequently and my car is daily driver where most driving is between 3-6k RPM, so I'm hoping I won't have longevity issues like some people have reported.

Only thing I haven't decided on is what camshafts to get. I definitely don't want 4P camshafts or the DC elite series as they are reportedly harsh on the valve train. I just want a set of cams that can take advantage of my upgraded valve train while also retaining as much midrange power as possible. But if drop in cams end up being the right choice then I am not opposed to that.

[RedReplicant]

Originally Posted by funkjaw

Did you ever get your head back? I just sent mine in, mostly based off your findings so thanks for that. I ended up ordering the combination as seen in the picture. I did a ton of reading on Titanium retainers, and I'm kinda 50/50 if they will be reliable for me or not. I'll check them in about 10,000 miles and see how they look. I change my oil very frequently and my car is daily driver where most driving is between 3-6k RPM, so I'm hoping I won't have longevity issues like some people have reported.

Only thing I haven't decided on is what camshafts to get. I definitely don't want 4P camshafts or the DC elite series as they are reportedly harsh on the valve train. I just want a set of cams that can take advantage of my upgraded valve train while also retaining as much midrange power as possible. But if drop in cams end up being the right choice then I am not opposed to that.

I'd make a post on K20A with your goals, that LotusElise guy will probably steer you to a set of Todas.

Oil temp followup - I talked to KPower, explained the situation and what I was thinking about doing, and they graciously made me up a patch harness to test out. Was supposed to show up today but Fedex hates me so maybe tomorrow.

It is a shielded wire set w/ ground for the DBW TB to the 54 pin engine harness plug for the DBW signal wires and another set of shielded wires w/ ground for the jumper harness from the adapter board to the Haltech. If this doesn't work I also ordered pins for both plugs and shielded wire to shield the DBW TB power wires.

[funkjaw]

Originally Posted by RedReplicant

I'd make a post on K20A with your goals, that LotusElise guy will probably steer you to a set of Todas.

Oil temp followup - I talked to KPower, explained the situation and what I was thinking about doing, and they graciously made me up a patch harness to test out. Was supposed to show up today but Fedex hates me so maybe tomorrow.

It is a shielded wire set w/ ground for the DBW TB to the 54 pin engine harness plug for the DBW signal wires and another set of shielded wires w/ ground for the jumper harness from the adapter board to the Haltech. If this doesn't work I also ordered pins for both plugs and shielded wire to shield the DBW TB power wires.

Please keep us updated, and also how painful it was to install!

[captain awesome]

Yeah I've got it already. I wanna say it took right around a month full turn around?



Toda as mentioned will be the general consensus for mid range by a couple guys on k20a.org. I went with the DC stage 4 due to the dyno number/curve that Kpower got with theirs.

Originally Posted by funkjaw

Did you ever get your head back? I just sent mine in, mostly based off your findings so thanks for that. I ended up ordering the combination as seen in the picture. I did a ton of reading on Titanium retainers, and I'm kinda 50/50 if they will be reliable for me or not. I'll check them in about 10,000 miles and see how they look. I change my oil very frequently and my car is daily driver where most driving is between 3-6k RPM, so I'm hoping I won't have longevity issues like some people have reported.

Only thing I haven't decided on is what camshafts to get. I definitely don't want 4P camshafts or the DC elite series as they are reportedly harsh on the valve train. I just want a set of cams that can take advantage of my upgraded valve train while also retaining as much midrange power as possible. But if drop in cams end up being the right choice then I am not opposed to that.

[funkjaw]

Anyone know if the grams 72mm throttle body is direct plug and play on this kit?

https://gramsperformance.com/inducti...w-frs-brz.html

[Ebush]

Originally Posted by funkjaw

Anyone know if the grams 72mm throttle body is direct plug and play on this kit?

https://gramsperformance.com/inducti...w-frs-brz.html

I use it. I've had it on since I completed the swap last November.

[ML]

Thinking about going to a 40 weight oil. Last track day I was seeing oil pressure going down to 15 psi at idle after really hot sessions. oil was getting to 230-240, which isn't even really bad. Anyone else experience this or run a 5w40 or something? this is still just a junk yard motor with refreshed timing components and a 4piston oil pump.

[funkjaw]

Originally Posted by ML

Thinking about going to a 40 weight oil. Last track day I was seeing oil pressure going down to 15 psi at idle after really hot sessions. oil was getting to 230-240, which isn't even really bad. Anyone else experience this or run a 5w40 or something? this is still just a junk yard motor with refreshed timing components and a 4piston oil pump.

Currently I run 5w-30, and when I change it out after only 1500 miles it is nearly water thin. This can't be good for my engine, so next oil change I am going 10w40. Like yours, my engine is a junkyard engine so I am sure the bearings are well beyond needing OEM viscosities.

[funkjaw]

Originally Posted by Ebush

I use it. I've had it on since I completed the swap last November.

Did you have to make any changes to the idle control circuit from the base map?

[Ebush]

Originally Posted by funkjaw

Did you have to make any changes to the idle control circuit from the base map?

No, it's a plug and play replacement on the fa20, so I treated it the same way with the k24. Just do the DBW calibrations like normal.

[FrickingReallySlow]

looking at some of the K24 videos online, some builders get new chains and guides in addition to new tensioners when doing the cams. Is that necessary, are you guys doing that too?

[funkjaw]

Originally Posted by FrickingReallySlow

looking at some of the K24 videos online, some builders get new chains and guides in addition to new tensioners when doing the cams. Is that necessary, are you guys doing that too?

1. Guides - from everything I have seen these generally never fail. The one exception is in a racing car running pure methanol. The methanol fuel tends to mix a little bit with the oil and under prolonged use can eat away at the guides. This doesn't apply to most people but just keep this in mind. Regardless, since you are in the timing area of the engine anyways when doing this swap, I personally recommend just replacing all the guides so you don't have to worry about it.

2. Chain - ABSOLUTELY replace the chain with a brand new unit. The K24 chains are incredibly notorious for stretching out: causing power loss of anywhere from 5-30hp+ and at worse, destroying your engine. Oddly enough K20 chains generally don't have stretching issues like K24 chains.

Here are the part numbers for everything:

14401-R40-A01 - Timing Chain
14540-RAA-A02 - Top Cam Guide (Updated Version)
14520-RAH-H01 - Chain Tensioner Guide (Updated Version)
14530-RZA-A01 - Cam Guide

[funkjaw]

Decided on Toda D cams to go with my 4pistons TSX head. While I don't think they will be the best combo with my current stock block, down the road when I build a block with high compression and a stroker kit they will be perfect. Really good mid range torque with a focus on power below 8200 rpm.

[RedReplicant]

I made my NASA classing dyno pulls today, so this would be pretty comparable to anyone else using those settings. In effort to drag my classing horsepower down (it is done with a formula to get an average) and reliability I set the limiter at 7800. NASA average was 196whp, coincidentally same as my old S2000, which is absolutely perfect and what I wanted.

So, since everything here is fairly comparable I give you:
* note: K24 and S2000 dyno graph scales go to 9k, both FA BRZs go to 8k

My dyno today - bone stock KPower K24 swap, pump 91


Full bolt-on first gen BRZ NASA TT5 car, pump 91


Stock plus Cleib catback and air filter second gen BRZ NASA TT5 car, pump 91


Full bolt-on AP1 S2000 TT4 (lol) car, pump 91




As for the electrical interference stuff, Fedex legit ate the harness KPower sent me so I filed a claim with them. KPower was kind enough to send me another harness which showed up yesterday, I will test it tonight.