I've spent the last couple days reading over the forum and I'm interested in building a 818c for a weekend car, autox, and maybe some track days. I've spent most of my life over the last 8 years racing autox and roadracing motorcycles. Upon researching if I thought I could tackle a 818C build in the garage it came to me of how come no one mentions or has built a K24 with a K20a head and put it in a 818? I raced S2000s for most of my autox career and after owning 4 of them I'm blown away by how reliable and easy to work on everything honda. Also hondas aftermarket is very broad. A K24 with a K20a head is easily a 500whp+ car and I've seen build sheet of almost 1000whp from a build that had a stock ported K20 head. The parts are available and also cheap.
The K24/K20 is about 275/300 LBS which is what I was finding the WRX STI motor weights.
Problems:
who makes a Adapter plate/flywheel?
Is there room for the motor? (K24 is 26" high, 20" long, and 16" deep)
How big is a EJ207 (that's the 2007 WRX STI motor right?)
Wiring should be easy because the K24 is often used as a swap to several cars so the aftermarket makes harnesses and other parts needed. My problem with the WRX motor is I've had a few people blow them up around 400whp which is a far cry from the reliability you would get with simply going to a honda motor.
LS3 would be nasty but I don't forsee that fitting.
I say do one, and we can all watch and learn! It would be near impossible to get an engine with a cg as low as the subie motors. Also, 300 HP is all this little car needs. As far as engine reliability, as you read further, you will find that most problems occur because ppl buy worn out junkers and drop the motors in one of these cars, then take it out for a proper beating. They are quirky motors and aren't easy to rebuild, so most ppl just try finding a low mileage donor car.
a 500-1000hp k24 is going to have an unusable power band in an 818. unless you are dragging the car, in which case a 500-1000hp k24 is going to have an unusable power band in an 818.
however a 300hp k build would be a nice setup in the 818.
I don't know if you'd want to adapt to the Subaru gearbox. using an rsx trans and custom axles and cable shifter would probably be easier.
A well stocked beverage fridge is the key to any successful project.
The guy from Sugarugears said he can make a adapter plate and a flywheel to mate engine to the sti trans. I didn't think about using a RSX trans which is what the lotus guys do. I'd say if the engine fits in the lotus and the ecoboost fits in the 818 I'm sure the k24 will also fit in the 818. The attractiveness of going with a wrx trans would be the mounting,shifter, -!: axle setup are already done. You would just need engine mounts and a wiring harness. Going to a RSX trans would eliminate the adapter plate and flywheel but would require a custom setup for the shift linkage, trans mount, and axles.
Going to a RSX trans would eliminate the adapter plate and flywheel but would require a custom setup for the shift linkage, trans mount, and axles.
And a lot of frame and suspension re-work! Frank818 originally considered mounting his VR6 sideways in his 818 with the VW transaxle, but realized the entire rear suspension would need to be redesigned to accommodate a transverse drive-train layout. His VR6 fits, but he ended up with a longitudinal orientation, bolting it to a Porsche transaxle, IIRC.
And a lot of frame and suspension re-work! Frank818 originally considered mounting his VR6 sideways in his 818 with the VW transaxle, but realized the entire rear suspension would need to be redesigned to accommodate a transverse drive-train layout. His VR6 fits, but he ended up with a longitudinal orientation, bolting it to a Porsche transaxle, IIRC.
Exactly! So the question is, what is the physical size of the 2007 WRX STI motor and will a K24 block fit in the same space without having to move anything; I.E.-the trans back.
I wouldn't want a 800whp or 1000whp but mid 600 with an borg warner EFR turbo with a anti-lag setup similar to Robert Thornes S2000 CR and the car would be nasty with very little turbo lag.
I'm still confused on why no one has done this yet.
Your dimension above is 20", so it won't fit without mods to the rear firewall.
The trans is about as far back as it will go.
The adaptor plate might also make this worse.
You'd also have to mod or relocate the tank,
and motor maintenance in a C would be tight.
Other than that, go for it. Frank818 has proved anything can be done with enough perseverance
From the firewall to the center of the suspension mounts is 26" . You have some room to play with, some 2" or so. So without doing surgery to the firewall and relocating the gas tank you have 26-28" to play with.
From the firewall to the center of the suspension mounts is 26" . You have some room to play with, some 2" or so. So without doing surgery to the firewall and relocating the gas tank you have 26-28" to play with.
My bad, I took the question to be a Honda engine mounted north/south with a Subaru transaxle.
There is a fair bit of suby gearbox in front of the suspension mountsWP_20160625_002.jpg
Last edited by DodgyTim; 12-16-2016 at 01:03 AM.
Reason: wrong photo
Yea I would mount it longitudinally so the 20" length mentioned would come into play of how much space we would need past the end of the wrx trans. Not counting a spacer which is another 2" or so. If that motor you listed above fits is 18.3" we need roughly 4" past that to fit it.
I don't see the K24 being much longer than a 2.3 ecoboost and they made that fit so I'd say it's possible.
I'd skip the powder coated frame, since you'll be modding everything. In fact, I'd ask if FFR would sell me only the tacked-up frame and the body panels. Everything else will change. Do it!
I'd skip the powder coated frame, since you'll be modding everything. In fact, I'd ask if FFR would sell me only the tacked-up frame and the body panels. Everything else will change. Do it!
A tacked-together frame is not a good idea. Without the frame jig FFR uses, the finish welds will pull everything way out of square. It's not much more work to cut and modify a finished weld.
We are installing a k24 in our endure Miata (in know, just stop it with the new cars) and we are very excited about this engine. If you could make up and adapter for the Sti trans, I would go that way in a path of least resistance. Considering that there is already a Miata adapter, how difficult could it be?
I'd skip the powder coated frame, since you'll be modding everything. In fact, I'd ask if FFR would sell me only the tacked-up frame and the body panels. Everything else will change. Do it!
FFR will not sell an unfinished, partially welded frame in any shape or form. I tried my best to get them to just tack on the front end.
While I like the idea of a Honda motor in an 818 (I have S2000 spindles on the front of mine) I don't think the boxer motor should be ruled out. Which begs the question of whether a Porsche motor/tranny would fit?
As mentioned here and repeatedly elsewhere, people tend to overwork and/or overboost a tired, stock Subie motor and have it fail fairly quickly.
Oiling issues during cornering G's is well-known and fixable.
They may be different, but I wouldn't call them quirky. I have built a few now, with forged pistons and sometimes better rods. I just pulled a motor from my STi track car that was built from a new factory STi shortblock with plain CP pistons, ARP studs and an 11mm oil pump with one 1mm shim. That and slightly improved heads for more R's. It had 70+ track hours on it and all that was wrong was I had started to burn two valves due to a lean condition that developed because of the fuel pump getting clogged. This engine produced 395 WHP or about 500 crank HP and 393 FPT on a regular basis and for two track events was boost-creeping to 26 PSI and there were no ill effects. This at 7K RPM! It was a great, screaming workhorse of a motor! I could have slapped on heads and kept going. I think the key to longevity was the KB pan, external oil filter, big Setrab oil cooler, Accusump and nine quarts of (race) oil capacity. That and a good breather/catch-can system that did not allow oil blown out to return to the intake.
I have Subie track buddies with similar successes.
There are some places however, that cannot build a reliable built motor. Be very picky about who you let build a high HP motor and use some common sense about it. My tuner knew how to work magic, as well. He would not wring the last 10 HP out of the motor on pump gas because he knew I would be asking a lot of it on the track; not just as a stoplight/drag burst. BTW, there is tons of good information on NASIOC, IWSTI and a few other Subie forums.
I'm also quite interested with this option. I have a 2002 Acura RSX type S. I bought it second hand and it has been a super reliable car, but due to high mileage (225,000 miles) it's really not worth anything to sell. I'd love to use it as a donor car for engine and transmission and whatever else might be usable.
I did the Mott College Build school for the 33 Hot Rod recently and it gives me some confidence that a build is do-able, though I'd be going outside the box with this.
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Originally Posted by josh7owens
