Second Gen Swap? FA24

[Ashikabi]

Originally Posted by Dzmitry

I believe this was a mistake when the BRZ launched or a simple mistake made by someone that ended up widespread all over. Toyota claims it to be 12.5:1 and I believe there was a collaboration of both not too long ago also mentioning 12.5:1 - which I would think is the correct CR. It would also make more sense for them to stick to 12.5:1 rather than complicating things more with the engine.

13.5 in a cheap sports car like this would be pretty crazy.

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[Dzmitry]

Originally Posted by Ashikabi

13.5 in a cheap sports car like this would be pretty crazy.

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True, but with modern technology, even cheap cars like Mazda seem to do it just fine. So I wouldn't think it to be impossible, but rather cool and beneficial in terms of NA. But as you said, it's a cheap sports car, and also a fairly cheap gen 2 upgrade, so I wouldn't expect them to make a major change like a 13.5:1 CR as this would require some more extensive work on the engine.

[Ashikabi]

Originally Posted by Dzmitry

True, but with modern technology, even cheap cars like Mazda seem to do it just fine. So I wouldn't think it to be impossible, but rather cool and beneficial in terms of NA. But as you said, it's a cheap sports car, and also a fairly cheap gen 2 upgrade, so I wouldn't expect them to make a major change like a 13.5:1 CR as this would require some more extensive work on the engine.

Mazda is just over there doing freaky Mazda stuff. How many other cars under 100k have that CR?

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[Dzmitry]

Originally Posted by Ashikabi

Mazda is just over there doing freaky Mazda stuff. How many other cars under 100k have that CR?

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I hear ya! I'm simply saying I wouldn't take it to be impossible, but definitely less likely when they've managed with some struggles on 12.5 in gen1.

[Ashikabi]

Originally Posted by Dzmitry

I hear ya! I'm simply saying I wouldn't take it to be impossible, but definitely less likely when they've managed with some struggles on 12.5 in gen1.

It's certainly possible. Just not plausible

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[NoHaveMSG]

Originally Posted by Dzmitry

True, but with modern technology, even cheap cars like Mazda seem to do it just fine. So I wouldn't think it to be impossible, but rather cool and beneficial in terms of NA. But as you said, it's a cheap sports car, and also a fairly cheap gen 2 upgrade, so I wouldn't expect them to make a major change like a 13.5:1 CR as this would require some more extensive work on the engine.

Direct injection helps a lot in making this possible. The D4S system works very well.

[irax]

Originally Posted by NoHaveMSG

The FB25 has a worse rod to stroke ratio(the FA20's is already not great), thinner rods, and thinner rod bearings then an FA20. Pass.

Like i said you swap out for the fa20 crank and fa20 aftermarket rods.

[NoHaveMSG]

Originally Posted by irax

Like i said you swap out for the fa20 crank and fa20 aftermarket rods.

If you want to go that far you might as well do pistons since the FA/FB's are cast. At that point you are better off putting that 2500 extra towards a K swap.

[irax]

Originally Posted by NoHaveMSG

If you want to go that far you might as well do pistons since the FA/FB's are cast. At that point you are better off putting that 2500 extra towards a K swap.

FB25 short block $500
Having your FA heads and timing cover cleaned and prepped $800ish
FA20 OE forged crank $400
FA20 aftermarket con rods $300-600
FB25/FA24/FA20 custom sized pistons $600+
ARP head studs $250
FB25/FA24 HG $100~

So you really are only at like $3500 or so in extras before the normal cost of a rebuild which can be like $3500 or so.

So like $7k

Can you do a full K swap for $7k And have boost ready internals?

[NoHaveMSG]

Originally Posted by irax

FB25 short block $500
Having your FA heads and timing cover cleaned and prepped $800ish
FA20 OE forged crank $400
FA20 aftermarket con rods $300-600
FB25/FA24/FA20 custom sized pistons $600+
ARP head studs $250
FB25/FA24 HG $100~

So you really are only at like $3500 or so in extras before the normal cost of a rebuild which can be like $3500 or so.

So like $7k

Can you do a full K swap for $7k And have boost ready internals?

A new OE crank is not 400, it is about 650. Don't forget rod bearings, main bearings, ARP case studs, full seal kit.

I am not saying you can't do it and be under a K swap. I am saying the savings isn't worth what you are left with. If it is that good and easy they why aren't people doing that over a K swap?

[irax]

Originally Posted by NoHaveMSG

A new OE crank is not 400, it is about 650. Don't forget rod bearings, main bearings, ARP case studs, full seal kit.

I am not saying you can't do it and be under a K swap. I am saying the savings isn't worth what you are left with. If it is that good and easy they why aren't people doing that over a K swap?

Sorry last time I looked at them they were like $400ish
https://www.subarusource.com/oem-par...aft-12200aa490

Right, those rod bearings, main bearings, case studs, and seal kit would go along with everything else in a normal rebuild.

Also I'm under the impression that ARP case studs aren't needed until you break into the 600whp range.

[NoHaveMSG]

Originally Posted by irax

Sorry last time I looked at them they were like $400ish
https://www.subarusource.com/oem-par...aft-12200aa490

Right, those rod bearings, main bearings, case studs, and seal kit would go along with everything else in a normal rebuild.

Also I'm under the impression that ARP case studs aren't needed until you break into the 600whp range.

I'm of the opinion of "while I am in there." Especially the abuse from tracking my car. Personally if it was me I would probably do springs/retainers and a rocker retainer kit too, which I should have delivered today for my FA.

[irax]

Originally Posted by NoHaveMSG

I'm of the opinion of "while I am in there." Especially the abuse from tracking my car. Personally if it was me I would probably do springs/retainers and a rocker retainer kit too, which I should have delivered today for my FA.

Fair enough.

What retainer kit did you get ?

[radroach]

@irax pretty sure the FB engine has a different timing cover design and wouldn't fit FA20 heads. This was evident during the J02 recall since the FB engine recall procedure was much simpler than the FA20.