Stock Internals and Turbo

[Mishakol129]

I'm wondering how many HP and LB of boost stock internals will handle with no ill side effects. I would like maybe 250 hp. So can it handle it? Oh and its an automatic transmission.

[ErMMaC]

I'm wondering how many HP and LB of boost stock internals will handle with no ill side effects. I would like maybe 250 hp. So can it handle it? Oh and its an automatic transmission.

Searching just "turbo" gives like 20 pages of this question lol

As for now I can tell you the most common feedback you are going to get.
Stock internals were not meant for boost, they are made of cast iron, eventually you WILL break a ringland (weakest point of the piston on our cars). There are a bunch of people who boost on stock internals ranging from 5 psi to probably like 20 psi. The main problem nobody knows how long it will last. It could last you 2 years with no problem! Or it could break once you hit boost the first time.

As for 250hp it is doable, but you need a quality tune to make it somewhat "safer." As for it being an automatic, I'm not sure about that. I'd say it's not a good idea because I'm assuming it places a lot stress on the transmission as well. Don't quote me on that though as I've never owned an automatic lol so it's just theory

If this is a daily driver I don't recommend it because you rely on it.

[Mishakol129]

Searching just "turbo" gives like 20 pages of this question lol

As for now I can tell you the most common feedback you are going to get.
Stock internals were not meant for boost, they are made of cast iron, eventually you WILL break a ringland (weakest point of the piston on our cars). There are a bunch of people who boost on stock internals ranging from 5 psi to probably like 20 psi. The main problem nobody knows how long it will last. It could last you 2 years with no problem! Or it could break once you hit boost the first time.

I put entirely different pistons in (Silvolite) and they have a different design than the OEM pistons, so I'm guessing the ringlands are stronger.

Pic of one,

As for 250hp it is doable, but you need a quality tune to make it somewhat "safer." As for it being an automatic, I'm not sure about that. I'd say it's not a good idea because I'm assuming it places a lot stress on the transmission as well. Don't quote me on that though as I've never owned an automatic lol so it's just theory

If this is a daily driver I don't recommend it because you rely on it.

I've heard ups and downs to AT turbo. You may have a valid point there but who knows.

[ErMMaC]

Those are definitely better than 20 year old pistons, but if they are still cast iron then they will break those are not meant to hold the stress of boost.

Yeah like I've seen AT with turbo, but with like 5 psi? Lol and with that I doubt you will reach 250hp

[Mishakol129]

Those are definitely better than 20 year old pistons, but if they are still cast iron then they will break those are not meant to hold the stress of boost.

Yeah like I've seen AT with turbo, but with like 5 psi? Lol and with that I doubt you will reach 250hp

These are hypereutectic pistons and are made of aluminum not iron. The sleeves are iron though.
It says they have "reinforced top lands".

http://www.kb-silvolite.com/silv-o-lite/index.html

-UEM has been manufacturing aftermarket pistons for automotive, light truck, -popular import and heavy duty applications since 1922. We offer over -485 OE -replacement pistons. These features include the following:
-Reinforced top lands (they mean ring lands right?)
-Coated skirts
-Floating wrist pins where applicable
-Application specific aluminum alloys
-Diamond finished skirts
-Pin hole accurate to +/- .0001


Here is the exact piston:

http://www.kb-silvolite.com/silv-o-l...tails&S_id=300


It does say though,

NOTES
Hypereutectic. F22a1 Engine. Accord All Except Se. 2.840' Dia. Head Recess .130' Deep W,4 Valve Reliefs. Not Intended For Racing Applications.

[ErMMaC]

Holy shit, I been saying cast iron pistons, I meant to be saying cast aluminum! Sorry about that mix up

And yeah the side note would include turboing lol

[Joey GT-R]

These are hypereutectic pistons and are made of aluminum not iron. The sleeves are iron though.
It says they have "reinforced top lands".

http://www.kb-silvolite.com/silv-o-lite/index.html

-UEM has been manufacturing aftermarket pistons for automotive, light truck, -popular import and heavy duty applications since 1922. We offer over -485 OE -replacement pistons. These features include the following:
-Reinforced top lands (they mean ring lands right?)
-Coated skirts
-Floating wrist pins where applicable
-Application specific aluminum alloys
-Diamond finished skirts
-Pin hole accurate to +/- .0001


Here is the exact piston:

http://www.kb-silvolite.com/silv-o-l...tails&S_id=300


It does say though,

NOTES
Hypereutectic. F22a1 Engine. Accord All Except Se. 2.840' Dia. Head Recess .130' Deep W,4 Valve Reliefs. Not Intended For Racing Applications.

Basically you bought Aftermarket Replacement Pistons. I've never heard of the company, so I cannot comment on their reputation. However, to be honest I would trust your used OEMs over those. That's just my gut feeling.

Just like ErMMac said, it is not a question of if the pistons will fail, it is when. It could be as soon as you pull out of your driveway, accelerate on an entrance ramp to your local highway, or months later you're headed home from work. If that is the route you want to take, all I can say is you might want to keep some extra cash in your savings account, or an extra F22 in your garage.


You're also creating a bigger headache with an automatic transmission. They simply can't hold up to the boost. I think the most I've personally witnessed a transmission last was for 4 months on 220whp. 2 of those months he only had 1st-3rd gear. When we removed the transmission he had hairline cracks around the block, so pretty much after 4 months of boost all he had was a rolling shell.

Now you can build a transmission to withstand high boost, but I'm guessing if you had that kind of coin we wouldn't be having this conversation in the first place. Not to mention that very few tuners can tune an automatic setup to begin with. Those who can, know what they are worth, and you will pay them handsomely for their time and skills.


To be honest we might as well place a bet, "Which will go first? The engine, or the transmission?".

[SOHC-FTW]

Maximum i've seen on a stock auto F trans is around 250whp. Now with that being said if the trans is in good shape invest in a trans cooler and better fluid (Perfomance oriented) this will keep heat down which is really what kills them. 200whp will be a good solid goal that should last aslong as you aren't being a fool/ricer and nutral droping it as far as the trans goes.

[DunKrS]

In the V8 domestic world, KB Silvolites are pretty well respected, Not the highest dollar piston and not typical for performance builds.

But while we're on the topic of hyper-eutectic stock replacement pistons...


I think Sealed Power has a pretty well respected name, and beings that the stock pistons real weakness is ring lands. Would a pistons like this be suitable for boost around 9-15lbs? It appears to have larger ringlands although I can't tell if it's just a stock photo or an actual picture of this specific piston. If it were to have beefier ringlands and a tuner were to be careful not to detonate, could this be a budget solution for a mild turbo build?

http://www.summitracing.com/parts/sl...p/media/images

I know hyper pistons aren't ideal for boost but don't dsm and other oem turbo cars utilize hypers and still retain strength and longevity? (volvos, subarus, dsm)

[evil_demon_01]

It says they have "reinforced top lands".

That means exactly what it says, The TOP land.
Judging from the pic, the ring lands (between the oil and compression rings) are the same as stock.

Do it once, Do it right.

[SOHC-FTW]

Ringland's look no different than my nippon's which are pretty damn close to my OEM set.

[wed3k]

yea id stay away from hypereutetics.

you need more clearance and they tend to rattle at start up which ends up killing the rings.

so hello oil consumption. forged or cast.

[deevergote]

So the first question asks about the "stock internals", when you've replaced them with non-stock internals. Already, this thread is off topic.

Stock pistons, or stock replacement pistons, are made of a fairly fragile cast aluminum. Perfectly strong for their intended purpose, but not made for turbo. Even if the ringlands were larger, the metal is still likely no stronger... and something will give. Brand new internals will probably last a bit longer than 20 year old stuff... but they will eventually break.


So to answer your question: there is no "safe" limit of boost you can run on stock internals. The lower the boost, the better. The more appropriately sized the turbo, the better (too small, you'll be blowtorching your internals. too large, and "low boost" will still be creating a pretty good amount of force... 1psi with a small turbo is not the same as 1psi with a large turbo.) And of course, as long as your fuel, spark, and tuning are all spot-on... because a "safe" amount of boost with a bad tune or a faulty fuel system can go boom very quickly.


Basically... if you're asking this question, you either haven't done enough research, or you're far too interested in cutting corners and hoping for the best. Either way, it's a recipe for disaster.

[Quashish]

you either haven't done enough research, or you're far too interested in cutting corners and hoping for the best. Either way, it's a recipe for disaster.

Remember he tried repairing his AT casing with jb weld

[toycar]

I always wonder what gives when people buy an OEM replacement piston and then think it will be stronger than OEM.


I bet the OP paid half to two thirds the price of forged pistons, for OEM replacements.


Silly if you ask me.