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Do the oil pump, pan, pickup have to be from a 2.0 or will a 2.3 work as well?

 

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Is that 2.5 crank forged?

 

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is the stroke the same in the 2.3 and 2.5?

did you key the balancer pulley?

did you mod the timing chain tensioner for high rpm use?

 

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The main journals are the same and the rod journals are different. you can put a 2.3 crank in a 2.5 block or a 2.5 crank in a 2.3 block with the right piston rod combo.

Can you elaborate on this?

Also, you didn't answer my question on the timing chain tensioner.

 

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So, did you overbore the 2.5 block to stay at 2.5 or is this a 2.4?

 

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So, what is the advantage to using the 2.5 block if you are still running a 2.3 crank, and have a minimal increase in displacement?

I am not trying to be critical, I just want to understand the advantages as from what you've said so far it seems like you are reinventing the wheel somewhat.

 

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So, playing devil's advocate:

Going N/A you're going to have to rev the hell outof it anyway. Why not go with a 2.5 block and a forged 2.0 crank (fairly cheap from a miata engine)?

I believe you would need custom rods, but this is one of the lightest cranks available, it would decrease piston velocity, the larger bore would optimize the dispersal of the intake charge, shorter stroke would improve vibration of rotating assembly and promote longer life at high rpms, and you would still end up somewhere between a 2.1 and 2.2 (I didn't do the math, correct me if I am wrong).

 

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I am not trying to be difficult, I just want to understand the thought process involved in the part selection for this engine.

Though, 9000 rpms is (in my world) reving the hell out of an engine. I believe that is what this one spun to on the dyno sheet.

 

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You are being difficult. I think a discussion of thought process is good.

Agreed. Your points about bearing speeds, valve spring stress, and heat are well-taken...and things I didn't ponder.

That being said, I enjoy high RPM n/a engines much more than I enjoy turbo engines. I definitely see the advantages to a setup like this. I do think the build requires more in-depth discussion as to the 'why' it was done the way it was...so people can make informed decisions.

 

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If 220 whp is your goal, FI is the easiest and most economical way to get there. As far as I know, the FSwerks setup is quite reliable and well sorted.