Goodmorning,

i have a fully built 2.0L 4g63 with the following setup:
- Wiseco HD pistons
- Manley H-Tuff rods w/ ARP2000 rod bolts
- L19 headstuds
- Mainstuds
- GSC S2 camshafts
- GSC valves
- Kiggly Beehive springs

So my limiting factor in this built are the rods with the rod bolts.
I rev the engine to about 8500 rpm.
From what i've read and hread the H-tuff rods are not strong enough for over 700hp.
Even though the sales pitch says 750hp for the arp 2000 and 950 for the arp 625+'s.
Has anyone used these rods in 700+ applications? Manley doesn't answer any of my e-mails.
I plan to keep torque to 550 ft lbs MAX anyway.

Any input is appriciated.

 

I haven't used them but I think your best bet is to keep trying to get ahold of Manley if you can.

That said, I did a quick google around and see that with the standard ARP2000 rod bolts, they should be limited to about 750 crank horsepower.
You don't mention if the numbers in your post are wheel or crank but there is a pretty large difference; something like 25-35%, between those 2 values. Taking their 750 crank horsepower rating and applying the estimated driveline loss, they max out somewhere between 487-562 wheel horsepower applying 25% and 35% lose respectively. Honestly, those numbers seem a touch low to me but Manley is the best place to get that answer.

 

Power ratings are a CYA and requires some reading between the lines. Rod bolts only fail under tension, the only time a rod sees higher tensile force is from higher engine speed, so if you aren't increasing your redline then better rod bolts are not going to make your engine magically hold more power.

Would I trust the H tuffs to 950? Probably not, but it really depends on where peak power is at what RPM as well as what peak torque is since torque is what kills rods.

 

100% they are a CYA but its a starting point. Yea, the rod bolts thing it always a little funny to me too but I figured I'd quote it as they have it posted for info.