The rods let go at about that hp but what do the stock pistons let go at?

There's no guarantee that a six-bolt will hold 400hp. That depends on your maintenance and wear-and-tear on the parts. But if a six-bolt block can handle the power you mentioned, the pistons are part of the block so isn't that sort of a strange question?

If anything, I'd be worried about running lean and melting my piston rather than a power figure.

Red97Eclipseboy said:

There's no guarantee that a six-bolt will hold 400hp. That depends on your maintenance and wear-and-tear on the parts. But if a six-bolt block can handle the power you mentioned, the pistons are part of the block so isn't that sort of a strange question?

If anything, I'd be worried about running lean and melting my piston rather than a power figure.

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No there is not but it is possible. Tuning factor aside, the rods go first. I wanna know the point at which the pistons are gonna fail.

I know they can fail at stock or 450, thats not the question though.

That is a good question. I have seen cars with bent, broken, or stretched rods on cars running in the 425+ whp range with good tunes but I have never heard of a broken ring self or a cracked oem piston on a high hp engine with a good tune. My brother made 472 AWDHP at 7500 and after the fifth pass on the track his 1st and 3rd rods where bent but the pistons where in good shape, this was with a 11.5 target AFR and high timing but very little knock.

I understand your question, but I think that most piston failures are due to a shit tune... or no tune at all. I'm not sure if there's a definitive power number related to six-bolt piston failures.

spoonman said:

That is a good question. I have seen cars with bent, broken, or stretched rods on cars running in the 425+ whp range with good tunes but I have never heard of a broken ring self or a cracked oem piston on a high hp engine with a good tune. My brother made 472 AWDHP at 7500 and after the fifth pass on the track his 1st and 3rd rods where bent but the pistons where in good shape, this was with a 11.5 target AFR and high timing but very little knock.

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EXACTLY what i wanted someone else to type.

Its always the rod that fails, the piston only fails due to the rod, tune, or knock, maybe valve float.

With all your maintenance done here is your answer.
http://www.dsmtuners.com/forums/articles-engine-fuel/96677-engine-limits-psi-cfm-horsepower.html

joe said:

With all your maintenance done here is your answer.
http://www.dsmtuners.com/forums/articles-engine-fuel/96677-engine-limits-psi-cfm-horsepower.html

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Wow completely missed the point.

silver bullit said:

Wow completely missed the point.

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Not to bash but I agree partly with this. I know some are looking for a number, but a large number of parts in our engines are cast, and being so, each part the factory cranked out is not the EXACT same. You can have (depending on the tune, driving style, servicing, etc.) a motor hold 500hp or 350hp. I don't think anyone is going to put a number out there in fear that it would be misleading. Hope this helps a little at least.

Anyone knows the Hp limits on the stock pistons?

silver bullit said:

Anyone knows the Hp limits on the stock pistons?

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Really depended on the tune. Pistons rarely fail from too much HP. Usually crappy tune. Some have gone well over 400 and into the 500 HP range (some into the 600 territory?). I know some one putting out a little over 400 hp on the stock bottom end, daily driven, with 168,000 miles (6 bolt)

On the other hand, I bent one of my rods with stock tune and a T-28. over revved the piss out of it accidentally, and two weeks later the engine went... pulled it apart and the rod was bent, but the pistons were fine... and with my highly calibrated butt dyno, I can tell you I was pushing LESS than 250hp.

I personally think that older the rods/more miles, the less power they can handle. Rods are subjected the much more stress in a multitude of different angles. After time they loose integrity. Pistons are subjected to mainly heat, and stress in one direction.

If you take brand new rods with brand new pistons and keep adding HP to the engine with a perfect tune, the pistons will go before the rods. Now do that with rods and pistons with 150,000 miles on it, and I'd be willing to bet the rods go out before the pistons.

But as far as a number, I wouldn't take stock internals above 400 ponies for the fact that I wouldn't want to rebuild the engine. But thats not to say that you can't.

T is for TURBO said:

Really depended on the tune. Pistons rarely fail from too much HP. Usually crappy tune. Some have gone well over 400 and into the 500 HP range (some into the 600 territory?). I know some one putting out a little over 400 hp on the stock bottom end, daily driven, with 168,000 miles (6 bolt)

On the other hand, I bent one of my rods with stock tune and a T-28. over revved the piss out of it accidentally, and two weeks later the engine went... pulled it apart and the rod was bent, but the pistons were fine... and with my highly calibrated butt dyno, I can tell you I was pushing LESS than 250hp.

I personally think that older the rods/more miles, the less power they can handle. Rods are subjected the much more stress in a multitude of different angles. After time they loose integrity. Pistons are subjected to mainly heat, and stress in one direction.

If you take brand new rods with brand new pistons and keep adding HP to the engine with a perfect tune, the pistons will go before the rods. Now do that with rods and pistons with 150,000 miles on it, and I'd be willing to bet the rods go out before the pistons.

But as far as a number, I wouldn't take stock internals above 400 ponies for the fact that I wouldn't want to rebuild the engine. But thats not to say that you can't.

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Once again.....
Where not talking about the rods.



LET ME REITERATE:

VERY IMPORTANT READ:

THE PISTONS- at what hp do these fail? Not the rods!

I know the rods go before the pistons. Where not gonna factor in a crappy tune because i dont run that shit in my cars.

Is this question to hard to understand?
Or am i using more than 5 letters in a word and people cant understand?
Or do i gotta type this in hard core ghetto E-thug for everyone to understand?

Haha, I think the definitive answer is who knows? I think most people end up getting new pistons when they get new rods. So it's hard to tell exactly when an OEM piston fails. And when it does fail it is always attributed to knock or tuning. When people say they melted a piston, the answer is "you're tune sucked".

Sorry for not having an answer, but the general belief is: pistons go from detonation or lean mixtures. And anyone running enough power to truly break (not melt) a piston already has aftermarket forged pistons.

silver bullit said:

Once again.....
Where not talking about the rods.



LET ME REITERATE:

VERY IMPORTANT READ:

THE PISTONS- at what hp do these fail? Not the rods!

I know the rods go before the pistons. Where not gonna factor in a crappy tune because i dont run that shit in my cars.

Is this question to hard to understand?
Or am i using more than 5 letters in a word and people cant understand?
Or do i gotta type this in hard core ghetto E-thug for everyone to understand?

Click to expand...

I think you my friend are missing the point of what others have told you so I will go ahead and tell you once more.

It all depends you will never find a exact answer. If you really want to know build a motor with new internals and use oem pistons and see if they fail otherwise quit asking the same damn question over and over again hoping to get a different answer.

Thread over.

droppinbottom said:

I think you my friend are missing the point of what others have told you so I will go ahead and tell you once more.

It all depends you will never find a exact answer. If you really want to know build a motor with new internals and use oem pistons and see if they fail otherwise quit asking the same damn question over and over again hoping to get a different answer.

Thread over.

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I'm gonna have to agree.