Do I have forged pistons or cast iron?

Mike_W

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Did I even ask the question correctly?

I have a 2002 GTS that I would like to get S/C some day. Do I have the better pistons, or is that something I need to spend more money on...

Also -

What does it mean when something is blue printed opposed to not being blue printed?

Thanks,
Mike
 

ACR Joe

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Did I even ask the question correctly?

<font color="red"> 2002 has cast pistons.
</font>
I have a 2002 GTS that I would like to get S/C some day. Do I have the better pistons, or is that something I need to spend more money on...

<font color="red"> I understand if the boost is &lt;5 psig, the 00 and newer engines can tolerate supercharging. </font>

Also -

What does it mean when something is blue printed opposed to not being blue printed?

<font color="red"> It means that the engine is completely disassembled and rebuilt to precise OEM specification without any production tolerance (i.e. pistons, rods, valves, etc. have precisely the same weight, cam lobes have the exact same lift, etc. In most cases, blue printing can yield a single digit performance gain.

ACR Joe
</font>

Thanks,
Mike
 

Gerald Levin

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Andrew, I believe with cast pistons if you use too much boost, you end up melting one or more pistons so you are restricted. Am I correct to say that 1999 is the last year of the forged pistons?
 

ACR Joe

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Andrew, I believe with cast pistons if you use too much boost, you end up melting one or more pistons so you are restricted. Am I correct to say that 1999 is the last year of the forged pistons?
<font color="red"> You are correct. 1999 was the last year for forged ALUMINUM pistons! </font>
 

Vipermed 97.01

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There are a lot of misconceptions about these pistons.00 and up came out with a Hypereutectic alloy cast(aluminum)piston.These are a very good and strong piston that are used on many late model high performance cars.The Hypereutectic alloys are much tougher than the alloys used in ordinary cast aluminum pistons. Hypereutectic pistons (which are also cast, not forged) have a very high silicon content ranging anywhere from 16-22%. The excess silicon forms little hard spots in the alloy, giving the piston improved wear and scuff resistance at high temperatures. Another change is that many pistons are getting shorter as the manufacturers reduce deck heights for shorter blocks and reduced hood clearance.To achieve this and produce torque longer rods are used – which requires moving the wrist pin higher on the piston.This leaves less room for the rings, which means smaller rings must be used and crowded together more closely creating the short ring land which in the world of superchargers and turbos is not a good thing.This is why you will find the 00 and up rods longer than the previous years,but what is real strange is that they share the identical casting #s so be carefull.Reducing the thickness of the piston lands also increases the risk of breakage, so that's another reason for using hypereutectic pistons. The harder hypereutectic pistons have less ring groove wear .most modern high performance engines including the viper are also running much closer piston-to-cylinder wall clearances to reduce blowby emissions. Some clearances are .001" or less, which leaves little room for error – or overheating. A tighter fit means there is less room for heat expansion, which is another reason why the vipers and newer high output engines are using this style piston.Hypereutectic pistons expand less than ordinary cast aluminum alloys, and CNC machining of the piston profile allows piston-to-bore clearances to be reduced. This also eliminates the need for steel struts inside the piston to control heat expansion, which reduces piston weight.So when we are talking naturally aspirated high performance motors,this is the way to go.Now when we are talking forced induction where cylinder pressures increase is where the short ring land is not our friend.This is the ONLY reason anyone should consider changing out there pistons to the forged.Also consider when going to the forged pistons with a much larger ring land that ring area must be moved lower which brings it into the wrist pin area creating the need for oil support rails.Sorry for the long winded explanation but i was hoping it would clear the air of fear for these 00 up owners.We have many owners contacting us wanting to change out pistons only because of the stories they haer about these "weak pistons"and most of these people do not plan on forced induction.I hope this helps
 

rcdice

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Vipermed,

Great info! You clearly know way more about this subject than I could ever hope to. Question: In the 00 and later cars not only did they go to cast pistons but DC also put a much less radical cam in the car. "Supposedly" the softer cam is now pushing less mass (cast pistons) and therefore the HP stayed the same. Everything else being equal, if you put a PRE 00 stock cam in a POST 00 car, you should see a nice HP gain as the more radical cam is working with the lighter pistons. Correct? Second question: If someone (me) was going to go to the trouble, would you put a stock pre 00 cam in or something a litter bigger?

Thanks for the insight.
 

Ron

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Thanks Vipermed.

RCDice,

Confused by your comment about the cam pushing less mass as the cam "pushes" the valve train and valve springs. Regarding the lighter cast piston mass, less mass should help spool up and redline, not make more power in and of itself. The rated horsepower stayed the same because earlier GENII Vipers were under rated at 450 FWHP. Do a search on dyno results. The somewhat unjustified creampuff label of later GENII's evolved out of the cam / piston / power changes over the years
 

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