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Ideally you don't want to go above 550hp at engine with stock forged I beam conrods, stock conrod bolts if engine is driven hard lap after lap on a racetrack.
Stock forged I beam conrods with upgraded conrod bolts (ARP, Tomei, etc), Tomei forged pistons can handle up to around 700hp at engine on the dyno and has been proven many times over (some lasting up to 100,000kms). But when look into how those cars have been driven, that's only a few hard laps on racetrack and they pit, mainly street driven, not lap after lap after lap for 40 laps or more.
Revs is what damages conrods (inertial load). If want to make the hp you keep revs low and use the boost level to make the hp (also cams, camtiming helps) instead of revs as you would with NA engine. Bonus of having a turbocharged engine. The increased load from the increased boost level is supposedly less than reving the engine more.
All parts fatigue and once excede it's max load rating it's only matter of time before it fails. I know Nismo crack test, shot peening, etc each conrod for the N1 RB26 engines and use the best 6x conrods and those engines have been known to handle up to 700hp on stock bottomend (I think was a engine dyno). Around 500hp at engine is the limit for longevity in a 24 hour race for a N1 engine (not exactly a factory engine as found in most production based GTR's, as the piston ringland design is different, block design as far as coolant, oil galleries, etc are different, etc).
Stock forged I beam conrods with upgraded conrod bolts (ARP, Tomei, etc), Tomei forged pistons can handle up to around 700hp at engine on the dyno and has been proven many times over (some lasting up to 100,000kms). But when look into how those cars have been driven, that's only a few hard laps on racetrack and they pit, mainly street driven, not lap after lap after lap for 40 laps or more.
Revs is what damages conrods (inertial load). If want to make the hp you keep revs low and use the boost level to make the hp (also cams, camtiming helps) instead of revs as you would with NA engine. Bonus of having a turbocharged engine. The increased load from the increased boost level is supposedly less than reving the engine more.
All parts fatigue and once excede it's max load rating it's only matter of time before it fails. I know Nismo crack test, shot peening, etc each conrod for the N1 RB26 engines and use the best 6x conrods and those engines have been known to handle up to 700hp on stock bottomend (I think was a engine dyno). Around 500hp at engine is the limit for longevity in a 24 hour race for a N1 engine (not exactly a factory engine as found in most production based GTR's, as the piston ringland design is different, block design as far as coolant, oil galleries, etc are different, etc).
Turned out pretty damn good for a 130xxxkm head thats been sitting for three plus years.
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