how much hp can PM rods take before catastrophic engine failure? any first hand experiance? i know there are ALOT of rumors floating around, BUT i want to find out what the real deal is.
i have been through google and here for atleast an hour and found ALOT of technical articles But no : the PM rod failed at 7000 rpm : we were on the dyno and were cresting 500 hp and the rod flew out of the intake!!! or something to that effect. nothing but rumors.

i have heard
that they break not bend
cant live in a high hp motor
cant spin high RPM's

i dont know about break not bending but it sounds about right 'cause the big end is "cracked"
the corvette GS came with them and it has 330 hp
(and GM supposedly underrated the LT4 but what do i know? i dont have one )
the corvette GS came with them and it has a 6300 redline

 

Just a factory performance rod. Nothing special. Buy some 4340 rods if you want strength. A little bit cheaper are 5140 rods. Both are stronger than any factory rod.

I abused some factory rods myself. For the last 2 years I've used 4340 I beam rods with no problems. The new engine has some aluminum rods in it.

 

but what can they take?

 

They are the same rods in ZZ4 motor. Thats the shortblock i want to run i think. I wanna put a set of trickflow heads and superram up top but i to wanna know what power it will hold.

I hear 450hp. the superam intake combo i wanna run should be pushing 400+ hp so i am worried. i wanna spin it up to 5500rpm at least.

 

FWIW, the GMPP 383 Fastburn crate, 425 HP, uses the PM rods.

 

I also believe that the Super AFR ZZ4 460 hp at 6100rpm crate utilizes the PM rods. I dont know if i would push that.

http://www.sallee-chevrolet.com/Chev...s/safrzz4.html

 

To quote Salee's description: "Connecting Rod: 10108688 Powdered Metal".

Hey, if they're not worried, why should we????

 

you want a definitive answer?...go to www.camaroz28.com...there are guys with over 400 RWHP with stock bottom ends and 847 cams spinning to 6,800+...
there "rated" to 450 but imo, just like anyother rating its on the safe side...also the first thing to break will be the rod bolts not the rods themselves...put in some ARP bolts and youll have to have some big power to break them...they are probley to strongest factory rod ever made..

my LT4 put down 310 with a stock cam and headers

 

The amount of what they can take really depends on how the engine is built and used. A rod won't bend unless there's some sort of internal damage such as a failed rod bolt. The stresses put on rods is expansion and compression.

A heavy piston travelling at high rpms pulls the rod apart when at the top of the stroke because the weight of the piston is trying to go through the head. That's why good rod bolts are required.

When using a power adder, there's an extra explosive force driving down on the piston trying to compress a rod.

During any major rebuild, all rods should be checked for proper length and resized.

Using lightweight pistons and rods help the rotating assembly survive high rpm runs.