FB25 VS FA20 - Toyota GR86, 86, FR-S and Subaru BRZ Forum & Owners Community

Baramzisyan · 03-13-2018, 09:10 AM

hello! fa20 exhaust manifold to fb25 , will it fit?

celek · 03-13-2018, 09:23 AM

Yes same block height the F series are modular.
you can bolt a set of BRZ heads on a FB25 block, they have the same head bolt pattern.
Unknown at least to me is the front cover bolts and how they line up. between the 2 engines.
I should pop the hood on the 2018 Legacy 2.5i and take a peek at the cover to compare.

Baramzisyan · 03-13-2018, 09:30 AM

thanks! im interesting how brz exhaust manifold better then rxhaust manifold fb25 engine

celek · 03-13-2018, 09:52 AM

Quote:

Originally Posted by Baramzisyan

thanks! im interesting how brz exhaust manifold better then rxhaust manifold fb25 engine

Problem is the exhaust routing and engine cradle location differ in the 2 chassis. Not sure everything will line up the same.

Teseo · 03-13-2018, 10:40 AM

Quote:

Originally Posted by celek

Yes same block height the F series are modular.
you can bolt a set of BRZ heads on a FB25 block, they have the same head bolt pattern.
Unknown at least to me is the front cover bolts and how they line up. between the 2 engines.
I should pop the hood on the 2018 Legacy 2.5i and take a peek at the cover to compare.

Can i use FB bottom end with FA top and will increase the compression?

celek · 03-13-2018, 10:52 AM

Quote:

Originally Posted by Teseo

Can i use FB bottom end with FA top and will increase the compression?

In theory yes. I have been trying to locate a FB25 since about 2013 to confirm fitment. I have not validated the setup yet.

fika84 · 03-13-2018, 12:03 PM

Quote:

Originally Posted by celek

In theory yes. I have been trying to locate a FB25 since about 2013 to confirm fitment. I have not validated the setup yet.

Wrong thread @celek ! Keep your eye on the prize! Back to work!

Teseo · 03-13-2018, 02:28 PM

Quote:

Originally Posted by celek

In theory yes. I have been trying to locate a FB25 since about 2013 to confirm fitment. I have not validated the setup yet.

If the FB have stronger bottom end than the FA i think would be worth to do the search/test.

celek · 03-13-2018, 03:54 PM

Quote:

Originally Posted by Teseo

If the FB have stronger bottom end than the FA i think would be worth to do the search/test.

The FB25 is actually worse shorter rods crappy rod to stroke ratio and smaller thinner rod bearings

celek · 03-13-2018, 03:55 PM

Quote:

Originally Posted by fika84

Wrong thread @celek ! Keep your eye on the prize! Back to work!

I really want to switch it up for a 2.5 build if someone will by my 2.3

NoHaveMSG · 03-13-2018, 04:01 PM

Quote:

Originally Posted by celek

The FB25 is actually worse shorter rods crappy rod to stroke ratio and smaller thinner rod bearings

I was just about to reference your build as I had remembered reading that.

fika84 · 03-13-2018, 04:05 PM

Quote:

Originally Posted by celek

I really want to switch it up for a 2.5 build if someone will by my 2.3

Wouldn't you still use your FA heads off your build? PS - what did you do to your heads at this point? Or has it all been bottom end work thus far?

nikitopo · 03-13-2018, 04:05 PM

The FB25 wasn't supposed to be a performance motor.

NoHaveMSG · 03-13-2018, 04:33 PM

Quote:

Originally Posted by nikitopo

The FB25 wasn't supposed to be a performance motor.

We will not be oppressed !!!

03-13-2018, 09:10 AM	#1
Baramzisyan turbo turtle Join Date: Nov 2013 Drives: exit GT86 enter STI Location: RU Posts: 196 Thanks: 12 Thanked 9 Times in 8 Posts Mentioned: 0 Post(s) Tagged: 0 Thread(s)	FB25 VS FA20 hello! fa20 exhaust manifold to fb25 , will it fit?

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03-13-2018, 09:30 AM	#3
Baramzisyan turbo turtle Join Date: Nov 2013 Drives: exit GT86 enter STI Location: RU Posts: 196 Thanks: 12 Thanked 9 Times in 8 Posts Mentioned: 0 Post(s) Tagged: 0 Thread(s)	thanks! im interesting how brz exhaust manifold better then rxhaust manifold fb25 engine

03-13-2018, 04:05 PM	#13
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