Likely the first FA2/4 hybrid incoming
 

Ordered a brand new FA24 short-block once the part numbers were published. It is due to arrive November 15th.

Plan is to build using the FA24 short-block with FA20 heads, similar to the EJ20/25 hybrid builds done on the older WRX's. This will be installed in my 2013 BRZ (using the 2015 wire harness, coils, sensors, etc) and run with an Ecutek tune.

Lots of unknowns with this...good news is the cylinder heads share the same oil and coolant passages and the head gaskets, when laid on top of one another are identical other than the bore size. The short block external size is identical to the FA20, The cylinder heads are very, very similar to one another (FA24 uses slightly different intake port sizes and shape and has a slightly longer intake valve length, and there are some changes to the oiling system on the FA24 that may require some other parts mingling between the two...

Currently on order:
FA24 Short-block
FA24 Engine Gasket set
FA20 Rocker cover gaskets (different than FA24 because it uses plastic rocker covers)
FA20 Intake Manifold gaskets

Expect to need, haven't ordered:
FA24 front timing cover/oil pump
FA24 Upper oil pan
FA24 Oil Baffle
FA24 Oil Pickup
FA24 Oil Pan (Very similar looking, but different part number)

Watch along and see what happens...if it all goes together, if it runs, what parts from each series are needed, what power can be wrangled out of it and more....

So far I've started tearing down the donor FA20 waiting for the FA24 parts to arrive....

What's the purpose of using the FA20 heads? So we know that they flow better than the 24s?

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When I saw Hybrid I thought you connected an electric motor between the engine and transmission. This a Frankenstein like the K20/K24. Glad to see someone doing this swap so soon. I’m sure this thread will be super helpful for many people.

Didn't realize the short block part numbers where available. I will be watching this intently. Curious if the 2.4 piston clears the cylinder head and what the CR would be. There looks to be plenty of room to mill them if need be.

subbed! living vicariously through all you trailblazers!

Biggest question I think is the timing cover! better hope no holes were changed on the upper oil pan/heads

Unless you know one head flows more than the other there is no point unless chamber artificially raises compression? Just flow the K24 versus k20 heads before you get carried away.

Yeah I agree about the timing cover. I was kind of surprised to see the upper oil pan/pickup change.

Per the service manual, all the mounting holes, etc are in the same place. Will know for sure once it arrives.

Don't think this is for flow reasons. Its a cheaper alternative to get a "built" block for FA20 but also gain 400cc. if successful you get to use the same cam sensors /vvt /engine harness and FA20 ECU that is already supported for tuning. I wonder if the wrx STI FA24 short block might even fit in here

It could become a good upgrade for Gen1 instead of getting like a crawford / IAG built block

Also his FA20 heads are probably free haha... so many blown FA20s

Had them available, cost savings and compatibility with the '13-'16 harnesses, OCV triggers, etc.

That makes sense

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Subbed!!

I shall dub this build.....

Franken-Opie

Good luck!

Yesss!

Eager to see if this is a viable option in the future

Fropiestein's monster?

They changed the oil pickup and location of the pickup mounting to the side. They must;ve read all our oil starvation / cavitation threads :D. Maybe also changed those oil return galleries you showed me on that video you made

Great idea. Following!

Interesting you say about the different size and shape of intake ports as I was hoping the FA20 PD Superchargers will be a straight fit or need minor milling, but seems less likely now. I'll wait for Edelbrock and Harrop to confirm!

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Subbed for a potential alternative for a K-swap.

What exhaust are you planning to run? Do we know whether the FA24 stock header will bolt onto the FA20 & overpipe? I'm hoping for a factory-looking header solution that removes the torque dip :-)

The exhaust ports on the head are the exact same size and shape as the previous version. Exhaust manifold gasket is the same part number.

Will be running the exhaust I already have (unless someone wants to give me some JDL parts to try :D ), MXP Unequal length & overpipe, Berk front pipe and TOMEI Expreme Ti Titanium Exhaust Type-80

Is there a way you can help me find the new intake manifold and gaskets part no and the old 2015 MY ones.


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its right there on the Subaru parts website. 14035AA800

2013-2020 with plastic intake manifold - 14035AA610
2017-2020 with aluminum (red) intake manifold - 14035AA720
2022+ - 14035AA800 as dragoontwo posted

This was my biggest concern. I have an Edelbrock and it is going to be tough if it doesn’t match up. I suppose I could sell my FA20 Edelbrock to finance the FA24 short block and machining, then add another PD SC down the road.

Decisions, decisions….
@Opie Are you considering the upgraded transmission, too?

interested in where this goes

Subbed.

Lemme know if you need any extra brain meat to figure any issues out. I'm deeply invested into seeing how this will pan out.

I guess I'll be the first to ask, how much for the short-block?

That's actually really reasonable

A bargain compared to alternatives.

So it’s basically the same price as the FA20 short block. I got FA20 short block through a friend at a dealer for around 1800. I suspect the FA24 could be had for similar discounts if you know the right person.

Curious about @Opie plan for the heads to get compression back to 12.5 The FA20 heads will actually introduce a quench/squish area when paired with bigger bore of FA24 (which I guess can be desirable for velocity and mixturing). Probably also need a head CC kit to get compressed volume even across all 4 heads if material is taken out.

Surprisingly so. Probably looking at three grand once you account for the ancillaries. Then what else do you need?

-Header, if you're still stock?
-Tune? Which might become available off-the-shelf in the not-too-distant future

If that works out, it might yield 250 OEM-like hp for the price of a decent supercharger. N/A, with a "new" engine, higher reliability and less weight.

Speaking of which, interested in seeing the weight penalty between FA24 & FA20 short blocks. Probably less than an FI kit anyway.

I doubt it’s much more. I guess the steel sleeves are larger but could that really add up that much?

Not until/unless the current one breaks

I'm gonna assume the weight penalty is approximately one large dump after taco night.

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Is it not the FA24 short-block longer? Hope you don't have clearance issues.

No. It should be the exact same size externally.

It has the same casting and same stroke , no change. Only bored wider.

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