+625 rod bolts overkill?

LumpyVR4 · Oct 29, 2019

I am big into overkill when buying engine bits. Sometimes spending money I don't need to. At the moment I am collecting bits for a 94mm stroker build. I am planning on 500 - 600 HP at the FW courtesy of a 12cm hx35 huffing through a ported head with 264/272 Kelford cams.
I picked up a sett of second hand, new in box BC H beam rods, that I am teaming with Manley stroker pistons. They came with the standard ARP2000 bolts. They are rated at 175hp with these bolts, which has me covered. I talked to BC about my build and they recommended +625 bolts for trips to 8K. Overkill or good insurance?

I have searched and have seen guys having no dramas with the 2000s. I just want to be really sure that they will be fine. I cannot afford to lose a big end and have it destroy rest of the engine.

Canadian_CD9A · Oct 29, 2019

Strange that BC only rates them to 175 hp per rod. From any other manufacturer, ARP 625+s are absolute overkill for the 500-600 HP range.

DSMPT · Oct 30, 2019

LumpyVR4 said:
I am big into overkill when buying engine bits. Sometimes spending money I don't need to. At the moment I am collecting bits for a 94mm stroker build. I am planning on 500 - 600 HP at the FW courtesy of a 12cm hx35 huffing through a ported head with 264/272 Kelford cams.
I picked up a sett of second hand, new in box BC H beam rods, that I am teaming with Manley stroker pistons. They came with the standard ARP2000 bolts. They are rated at 175hp with these bolts, which has me covered. I talked to BC about my build and they recommended +625 bolts for trips to 8K. Overkill or good insurance?

I have searched and have seen guys having no dramas with the 2000s. I just want to be really sure that they will be fine. I cannot afford to lose a big end and have it destroy rest of the engine.

Some people would say yes, some would say not. The ARP2000 will be perfectly fine for your goal. What should care about is the engine speed rather than the engine power. When you exceed around 9000rpm you will start to have more stress on the rod bolts and caps.
If you don't feel the price difference is not too much for you then go with 625+ wouldn't be a bad idea. I use the 625+ or L19 since I have experienced a bolt issue with the ARP2000. But it doesn't mean the 2000 don't work. Like you said it's an insurance, I'm purchasing a sense of security. I don't feel wasting money if I consider the total cost and time of rebuild.

babyviper · Oct 30, 2019

I put down well over 500whp on an eagle h-beam with ARP2000 bolts, i'd say you're fine.

GST with PSI · Oct 30, 2019

LumpyVR4 said:
I am big into overkill when buying engine bits. Sometimes spending money I don't need to.

I hope that carries over to the drivetrain department. 500hp from a stroker = transmission eating torque.

I'd say you'll be fine with the standard ARP fasteners, but like others have said, it's cheap insurance. I will say, most for the rod failures I've seen start at the cap, or the pin. Doesn't hurt to keep the cap end a bit more secure, IMO.

donniekak · Oct 30, 2019

Rod bolt power ratings don’t apply to forced induction applications really. We kill rods in compression, naturally aspirated engines are more likely to have a rod, or rod bolt fail in tension.

The back pressure in turbo setups keeps pressure on the piston at all times softening the “pull” of the piston on the rod at the top of the exhaust stroke.

I have arp 2000 rod bolts in an engine running 7’s.

LumpyVR4 · Oct 30, 2019

GST with PSI said:
I hope that carries over to the drivetrain department. 500hp from a stroker = transmission eating torque.

I grabbed one of the last evo 3 first gear sets, and am getting the box rebuilt with those plus 4x spider gears and a LSD. The car already has a rebuilt 4 bolt rear end with an evo 3 LSD.

rabenne · Oct 30, 2019

Which LSD did you choose?

GST with PSI · Oct 30, 2019

LumpyVR4 said:
I grabbed one of the last evo 3 first gear sets, and am getting the box rebuilt with those plus 4x spider gears and a LSD. The car already has a rebuilt 4 bolt rear end with an evo 3 LSD.

You'll be on borrowed time.

https://www.dsmtuners.com/threads/building-a-stronger-5-speed-transmission.525839/#post-153741194

LumpyVR4 · Oct 30, 2019

Well I guess I'll sell off the evo3 gear and beg ppg for a fellow aussie discount.

babyviper · Oct 31, 2019

There's a brand new PAR EVO3 dog-box gear-set on ebay right now! big discount

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+625 rod bolts overkill?

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