Which engine? Subaru 2.5 STI/Subaru 3.0/Honda j35/ Honda k24, Building a weekend/track car, help me pick the engine Options

[rupert14]

I am trying to decide which engine to swap into my 914. In the past I put a honda J35 in a baja bug and it would roast 33" tires all day long. It was a great engine for a baja bug. I have a local shop that is pushing me toward a subaru 2.5L STI turbo motor. I have also read about very happy owners of 3.0 flat six suby engines in the 914. A buddy of mine that runs NASA has a k24 in his car that puts almost 250hp to the ground with just cams. The good part about the k24 is that it is light.

I plan to just use it as a fun weekend car and once a month or so on track here in AZ for HPDE4. I am currently running a 2001 BMW 330ci at the track but I also have a speck e30 and a few street e30's. I want to be around 300hp (stock J35 is 300hp/300tq) and I am ok swapping the trans if necessary. My trans was recently gone through at a Mr. Evil gathering and is a strong side shift.

I realize many of you have more experience than me with these engines so what is your vote? I will be adding a wide body and the fattest tires I can stuff in there.

1. Subaru 2.5 turbo STI motor
2. Subaru EZ30R 3.0 six
3. Honda j35 V6
4. Honda k24 inline 4

[technicalninja]

I vote K24 as well.
That motor is possibly the best 4 cylinder ever built by ANYONE!
They can go 500 NA and above 1K blown.
Nothing else comes close to IMO.

That motor that fasthonda listed should have 300+.

Something about it is not optimal.

Most K24 with K20 headed mixes go 300+

Maybe it had to meet certain criteria for its class of racing.

Overall, besides the wimpy dyno sheet that looks like the BEST K20 swapped K24 I've seen yet.
I wonder what that will go for?
I'd guess 5-6K...

I am trying to buy a used K24-A2 from a friend. I don't really have a home for it yet. It's a "maybe" for either a 914 or a NB Miata. Doner car is a 05 TSX and I believe it's the highest HP variant to start with. It has individual exhaust ports and requires a dedicated header.

Those "Z" variants (like the auction) have a single rectangular exhaust port which makes installing into other vehicles EASY. It also makes adding a turbo easy as well.


Now, it's not the "optimal" motor as it was not designed by "German rocket scientists".

If I had unlimited funds, I might buy a late model (or NEW!) 4 cyl 718 Boxster/Cayman and just "back half" it, swapping everything past the firewall over to 718 junk.

If the non-S is used the 2.0 badging would still be correct!

Can you imagine the conversations with others?

Yep, it's just a 4 cyl 2 liter...


I'm with Chris916n6 regarding the 986/987 Boxster/Cayman stuff.
I'm under the impression that it will fit with ignition modifications.
It's supposed to be super tight and require engine manipulation to do any work on it all.
Now, I haven't actually tried yet and I'm betting the fit is tight enough that some cars won't clear.

Clay was the first person to put the "Just back half it" into my thoughts...