Early proposal: FA20 with a FB25 shortblock, .5l more displacement anyone?

[Basti]

Anyone got new insights on this matter already?

Also, what about the piston rods? What would be the problem if they were cockeyed? And are they, now?

[Kostamojen]

Surprised there isn't any more input on this...

[zephyr69]

i'll be trying to search through some japanese sites and see what they have to say. will post here if i find anything from any crazy japanese NA builds in development for the FA20

[zephyr69]

Found this on one a blog of a individual Japanese tuner:


８６のＦＡ２０エンジンというのはＦＢ20エンジンのほぼフルチューン化（というよりはスポーツエンジン化 ）されています。

Toyota 86's FA20 engine is essentially a FB20 engine that is fully tuned (essentially a sports engine version).


インプレッサやレガシィのエンジンＥＪの時よりも数段エンジンの組み付け精度をあげているのとすべての部品 において軽量化と低フリクション化されているので環境対策エンジンながらもリッター100馬力達成していま す。

In comparison to the Subaru Legacy's EJ engine, FA20 level of intricacy is much higher. Many parts of this engine are lightened and friction is reduced which is why they have been able achieve 100 horsepower per liter.

ただこのＮＡのままでは改造の余地があまりありません。

There isn't really much room to play with engine in terms of an NA build.

ＮＡエンジンらしくもっと高回転まで突き抜けるようなエンジンがほしい！

I want a higher revving NA engine with more thrust and responsiveness!

となるとＦＡ20では不可能だと思いました。

However, I don't think it is really possible with FA20.

[zephyr69]

I wish they worked with yamaha to build 86 engine instead of subaru..zzzz

[regal]

Originally Posted by zephyr69

I wish they worked with yamaha to build 86 engine instead of subaru..zzzz

Best bet with this engine is to run the piss out of it and hopefully in a few years there will be a good solution. I remember not buying an MR-S because of the engine, only to wish I had when the 2z kits started to appear.

[Kostamojen]

Surprised none of the tuners have tried this yet...

[DoctorNick]

I guess too busy putting LS and 2jz motors in instead

[Kostamojen]

Originally Posted by DoctorNick

I guess too busy putting LS and 2jz motors in instead

LMAOOOOOOOO!!!

[Sonolin]

This is a very interesting thread. I would be very interested in an N/A build if remotely affordable for a decent power increase. Unfortunately, I have little to no knowledge of engines other than mine has 4 cylinders, lays flat, and is 4 stroke lol.

[fa5tco]

I wonder if the E257 bottom end would mate tp the fa20 heads? minus the di of course. Could buy the ej257 bottom end for cheap and have the exhaust/turbo/ic piping all custom done for cheap too

[Kostamojen]

Originally Posted by fa5tco

I wonder if the E257 bottom end would mate tp the fa20 heads? minus the di of course. Could buy the ej257 bottom end for cheap and have the exhaust/turbo/ic piping all custom done for cheap too

No not even close.

[s0sl0w]

Surpirsed this hasn't been determined but I'm 95% certain that the FA20 uses the same cocked bottom pistons as the fb20.

The biggest issue I could see standing in the way is the fact that the FB25 is made to bolt up to a subaru specced/sourced transmissions whereas the FA20 is bolting up to a toyota sourced transmission. I wouldn't be surprised if the bolt pattern is different between the two.

It shouldn't be too pricey to find a wrecked Forester FB25 and get to work honestly.

Some quick research indicates a FB25 can be had for around ~$3000, assuming you can afford to take your car off the road for a winter and do the work yourself, you could feasibly do this swap for about the same as some of the supercharger kits are going for.

[jet86]

So guys I have acquired a fb25 short block and I've got numerous fa20 heads. I threw the heads on the fb25 block and well.. they fit quite well. Only issues I can see with this setup is the combustion chamber may need to be ported (probably cnc) a you have to take it out 8mm bigger. And the other thing is the starter motor location is missing off the fb25. Everything else is identical.

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