High RPM Rods?
02-05-2019, 05:38 PM
#3
ModSquad
iTrader: (6)
While the overall rod design does play into the high rpm equation, especially for windage, I’d pay attention to the rod cap fastener as well.
02-06-2019, 05:59 PM
#7
For the past 16 years and 300+ runs at 780HP and 8400 RPM in my 18 degree SBC, I've run old CAT-Pep (no longer in business) China 4340 I-Beam rods that are an older Oliver copy.
While I certainly don't recommend it, these have worked OK for me. I never expected them to be in the motor this long. But every time I take it apart, the housings stay round and the bearings look good. I did upgrade to an ARP2000 bolt from the standard 8740 bolts this last time, mostly out of guilt I guess.
A big factor in rod application is not only RPM, but the component weights that these rods are trying to control. I have rather light pistons/pins which helps my situation.
I wouldn't buy a rod based on what the windage characteristics are, buy it based on the strength required.
Watch out for the L19 fasteners though. They are VERY sensitive to moisture, handling and contaminants in the engine oil. If a stronger bolt is absolutely needed, I'd lean towards the CA625 bolts.
While I certainly don't recommend it, these have worked OK for me. I never expected them to be in the motor this long. But every time I take it apart, the housings stay round and the bearings look good. I did upgrade to an ARP2000 bolt from the standard 8740 bolts this last time, mostly out of guilt I guess.
A big factor in rod application is not only RPM, but the component weights that these rods are trying to control. I have rather light pistons/pins which helps my situation.
I wouldn't buy a rod based on what the windage characteristics are, buy it based on the strength required.
Watch out for the L19 fasteners though. They are VERY sensitive to moisture, handling and contaminants in the engine oil. If a stronger bolt is absolutely needed, I'd lean towards the CA625 bolts.
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02-06-2019, 06:02 PM
#8
For the past 16 years and 300+ runs at 780HP and 8400 RPM in my 18 degree SBC, I've run old CAT-Pep (no longer in business) China 4340 I-Beam rods that are an older Oliver copy.
While I certainly don't recommend it, these have worked OK for me. I never expected them to be in the motor this long. But every time I take it apart, the housings stay round and the bearings look good. I did upgrade to an ARP2000 bolt from the standard 8740 bolts this last time, mostly out of guilt I guess.
A big factor in rod application is not only RPM, but the component weights that these rods are trying to control. I have rather light pistons/pins which helps my situation.
I wouldn't buy a rod based on what the windage characteristics are, buy it based on the strength required.
Watch out for the L19 fasteners though. They are VERY sensitive to moisture, handling and contaminants in the engine oil. If a stronger bolt is absolutely needed, I'd lean towards the CA625 bolts.
While I certainly don't recommend it, these have worked OK for me. I never expected them to be in the motor this long. But every time I take it apart, the housings stay round and the bearings look good. I did upgrade to an ARP2000 bolt from the standard 8740 bolts this last time, mostly out of guilt I guess.
A big factor in rod application is not only RPM, but the component weights that these rods are trying to control. I have rather light pistons/pins which helps my situation.
I wouldn't buy a rod based on what the windage characteristics are, buy it based on the strength required.
Watch out for the L19 fasteners though. They are VERY sensitive to moisture, handling and contaminants in the engine oil. If a stronger bolt is absolutely needed, I'd lean towards the CA625 bolts.
02-06-2019, 07:08 PM
#9
That is good advice.
Run a small journal rod... Callies does this. It reduces the rod weight significantly as well as the crank weight.
JE has some very light asymmetrical pistons as well. Really good pins are also a good idea.
I'd talk to HPR about it. They've given me a few quotes on higher RPM setups with the Callies SJ setup with the Dragonslayer and Ultra I-Beam. They also have some custom lightweight Wiseco pistons with a .180" tool steel pin I believe (not the heavier .200" wall shelf part) that works well.
I'd also look at the Dart center weight crankshaft that would be good for high RPMs. HPR does these as they need special machining to fit the stock blocks.
Run a small journal rod... Callies does this. It reduces the rod weight significantly as well as the crank weight.
JE has some very light asymmetrical pistons as well. Really good pins are also a good idea.
I'd talk to HPR about it. They've given me a few quotes on higher RPM setups with the Callies SJ setup with the Dragonslayer and Ultra I-Beam. They also have some custom lightweight Wiseco pistons with a .180" tool steel pin I believe (not the heavier .200" wall shelf part) that works well.
I'd also look at the Dart center weight crankshaft that would be good for high RPMs. HPR does these as they need special machining to fit the stock blocks.