FD3SEvo8

What is the average limit hp wise for a gen 4 rod with a forged piston strapped to it? Or oem for that matter.

krazy4

iTrader: (5)

Depends on a lot of factors. People get away with around 1000hp.

I would say 600-800whp is pretty safe.

Bazman

I was told 650rwhp is the safe limit if you lean on it often or for long periods... I'm down 10-15psi on 1 cylinder after 1 or 2 too many backfire pops. I ran at 663rw so wonder if the safer limit might be 600rw tops. I think mainly street plus the odd track pass could get away with more, but I do road course hot laps and week long closed road events so that's pretty tough on a stock motor - lots of heat issues to work through. I'm going to forge and add oil coolers asap.

ChopperDoc

Here's some good info on the subject. Piston is the weakest spot. They break around 1000 HP. Cranks and rods can take more, but not sure how much. If you are swapping pistons, why not do the rods too? Worth the extra $$$. Texas Speed has some good stuff, always been happy dealing with them.

FD3SEvo8

About to just pull the trigger on a set of forged rods. Problem is, i already have them in a .945 pin, so K1 makes a set that will work. I was going to use a gen 4 rod, but for another $600, why gamble? Its a 2 year build plan and I'm a month in and almost done with the motor already lol.

yenkomike

iTrader: (2)

hard to put a hp level on the rods as the tune has everything to do with if it lives or not. on that same note the best pistons and rods you can buy will not live if the tune is bad and it detonates. . there are plenty of these engines in the 8s with stock lower ends. and they live a long time. I have run a few with hp in the mid 700s at the wheel. and they live for years . if you build a gen 4 engine get the bearing clearances right and the ring gaps opened up a bit and the tune is on you will have an engine that in my mind is hard to kill. but the supporting parts need to be there. it needs good fuel and supply a good oil pan and a good tune. I have not seen one fail that did not have a fuel system or tune issue.

FD3SEvo8

So I might give it a shot with the forged piston and gen 4 rods. My fuel system will be a solid setup. And ill get adequate injectors for my goal.

http://www.radiumauto.com/Fuel-Hange...-FD-P1390.aspx

I am aiming for 800 whp, but not constant. Just when I want the extra power. I will be set up on an ebc so i can switch with ease. And I trust my tuner. I just dont want to build a decent motor and the weakest link be the rods, ya know? I was mostly curious more than anything..

Mavn

iTrader: (3)

You don't need Forged pistons. Gen 4 rods and pistons are good for 1000 wheel with a tuner that knows how to keep them alive. I'd spend the money on forged pistons else where. If it's on e85 with a GOOOD tune you're set for 800 wheel reliably

panda240ss

i was looking around and i think gen3 are 700 750 the safe limit. and 4 gen are 800-900. but yeah pistons are the weak point after oil pressure

FD3SEvo8

The only reason I went for a forged slug is because I had to bore my cylinders. They were pitted. Thats why I found a set of forged pistons that could be used with the .945 wrist pin of the gen 4 rods.

SLOW SEDAN

iTrader: (13)

Gen4 pistons are plenty strong, you will bend the rods before you hurt the piston with a good tune.

Exactly! I've run them way over 700, no issues until you really start leaning on it. And by leaning on it I mean maxed out billet Borg, and even then the pistons were fine, crank was fine, headgasket fine, just wrinkled a few rods but somehow still ran fine just noticed it on winter teardown.

Yup, throw boost at them and not timing and it'll reward you for a long time.

SLOW SEDAN

iTrader: (13)

Pistons are the weak link for tuners that think 20+ degrees of timing on boosted SBE are the hot ticket lol

yenkomike

iTrader: (2)

a lot of the ones I have been on the dyno with lately I have been getting 720 to 780 hp at the wheels with 15 degrees timing and 20 ish # boost on e85. they live a good long life at that level with afr in the 11.7 range on the gas scale.

ddnspider

iTrader: (26)

hellbents-10

Gen 4 pistons and rods are both strong enough to sustain 1400+hp for a 1/4 mile blast at a time. Jon was putting 100+ passes on his running 170-178mph through the stripe shifting at 8200-8400. The only time he has bent them in the last 300ish passes doing this is when he lifts the heads. He believes he is simply "hydroing" them when the water starts entering the chambers.

FD3SEvo8

Good to know.

On a side note, what is everbodys opinion on oil squirters by Get M' Garage? Good to have for cooling, or just go without them? Its not uncommon in the Honda world (where I'm from lol) to block them off at higher hp.

Bazman

Wow... I should take up drag racing lol.

Road racing sure heat soaks after a few miles and at 11:1 on 93 pump I am staying well under those power levels. E85 would sure help though

slowlsx

iTrader: (28)

Those rods bend when ur tuners talent runs out.

ddnspider

iTrader: (26)

Na, usually that's when you get a hole in a piston or a popped ringland

BCNUL8R

iTrader: (2)

I agree...If the pistons come out fine and you have a bent rod I would guess the tune was pretty good and you just reached the limits of what the rods could take.