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Originally Posted by getrdunn
(Post 4667787)
If I'm not mistaking MT is trying to say that the 4.5" stroke is bringing peak hp down with the said duration @.050. Without looking into it more I would guess with a 4" stroke 509 ci would likely make peak hp above 7k. That's a given. |
I've have a little different opinion but do realize it's not just displacement and duration that dictate peak hp RPM. Obviously there's other variables. Intake runner length and port volume, int & exh port cc, head degree, LSA, cam timing events/overlap, etc etc. Know you can take a 565 CI with a little 236/244 + - and have peak hp @ 6k. Just so so I understand what your saying though is a 4" stroke, 4.5" bore 509 build would peak hp as a 4.5" stroke, 4.25" bore with same components. Not arguing at all just always like good topics.... |
I shoulda reread before asking but was that cam installed straight up? |
Originally Posted by hogie roll
(Post 4667793)
No, it’s not a given. In fact it’s wrong. A 509 created via a 4.5” bore x 4” stroke would make the same power within the measurement variance. |
Originally Posted by hogie roll
(Post 4667776)
i don’t agree. Displacement is displacement regardless of the bore stroke combo. The head only flows based on the pressure drop created below it. That pressure drop will on average be equivalent for the same displacement at the same engine speed. The only caveat is that the larger bore combo might create a better flowing chamber. Id attribute the 6400 peak to the very tight lsa. Wider lsa’s can hang on up top better. The pistons position in the cylinder, varies based on those variables. Therefore, the valves need to compensate for those changes. |
:A custom cam grinder wouldn't even grind a cam if you didn't give him the stroke in your combo. Ah just don't worry about it dude I said it's gonna be a 572. I mean wtf... What difference does it make how I get there? :sport009: Just throwing some Saturday humor out there. Winter sucks monkey balls. |
Originally Posted by MILD THUNDER
(Post 4667817)
You forgot one part. The motion of the piston. A half inch change in stroke, as well as a change in rod angle, is a big player in what the piston does, and when it does it. The pistons movement/speed, plays a big part in cylinder filling. If it didnt, variable camshaft timing wouldnt exist.
The pistons position in the cylinder, varies based on those variables. Therefore, the valves need to compensate for those changes. chevy high performance October 2000 |
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