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Musing on displacement.

3461 Views 56 Replies 17 Participants Last post by  tdbunch
I wonder if there is enough room in the block to replace the crankshaft with a 3.55 mm increased stroke. That would bring the displacement to 2.5 liters. I know that would require a re-tune, but it would also increase the H.P. above 250 and further increase torque. I believe the factory induction components should still be sufficient to feed the added volume.

Then again, would a current production Subaru 2.5 liter crankshaft fit the bill. Or would our induction and and long block components fit on a 2.5 liter short block?
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From the Wikipedia:
  • 2.0 L (1,998 cm3) (FA20)
  • 2.4 L (2,387 cm3) (FA24)
Cylinder bore
  • 86 mm (3.39 in) (FA20)
  • 94 mm (3.70 in) (FA24)
Piston stroke86 mm (3.39 in)
ValvetrainDOHC 4 valves x cyl. with AVCS
Compression ratio10.6:1, 12.5:1

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