Do you really need forged pistons?

[fivepointhustla]

If you control detonation under boost or spray do you really need forged pistons?

Could you just have the cast pistons crogentically frozen to increase strength?

[SappySE107]

To an extent, yes. Do I know the limits of hyper pistons in a 60V6? Nope. I don't know if cryo treating the pistons will increase that limit either. I know it works well for brake rotors though.

What are you doing exactly?

[3400-95-Modified]

Well I have sucessfully run a 100 wet shot on Hyper pistons in a 3400 for quite some time... Dynoed at a 62whp gain.

I have over 6-8 visits at the dragway, one day being 13 runs, others around d6-8 runs, all being sprayed, also the daily squirt once and a while on the road when there is juice in the bottle, and this was all on a stock un-tuned 95 ECM... I still have good compression and have never fouled a plug or seen any KR while running at the strip. 50k on the motor now and it still has good compression on all cylinders.

To be specific these were Sealed power Hyper replacement pistons .030 over.

[bjornmk1]

say..did you post on the pennock fiero forum about
supercharging the engine with a m90 >interesting

I can give you some tips,cause I am building one myself

BTW I'm going with the forged pistons myself..just t be on the safe side.

[fivepointhustla]

yes I am goatnipples2002 on pennocks.

I plan on running a 200shot nitrogen push system, until I get boosted. Since I have the juice now. I have been running a 100 shot for now.

[bjornmk1]

well I am sc-ing mine with a ford m90.
it is going where my airco pump used to be.
doing that you'l need a relocator kit for the oilfilter.

I shortened the snout of my sc-er to get the fitment I need.
that way it wont suffer from the heat of the exhaust as much
as the set up in the picture.

I'm aiming at 240-250whp at aprox. 10-12psi.
ported the alu heads an manifolds.
350cc fuel injectors.
audi s4 intercooler.

what is yours going to be like

B

[fivepointhustla]

new thread

http://60degreev6.com/showthread.php?p=313160#post313160

[MidnightriderZ24]

ive been running 12 psi on stock 3400 pistons for awhile and no sign of slap or any piston noise. really the only noise is the timing chain is a little loose. with my built 3500 i plan on runnin 20+ psi

[farmerz24]

yes i was running 10 psi for not a long time but did you see my piston cracked and the only thing holding it together was the cylinder wall? if i had kept goin it would have ended up like 89jyturbos and shattered.

forged are a must, especially if you want to be reliable.

[AaronGTR]

I think there definitely is a HP limit to what the pistons will take, even without detonation. You have to remember that HP is the result of increased cylinder pressure pushing down on the piston and eventually it will reach it's limit. That said, I also don't think there is a definitive HP number that can be used. Given the low tolerances and variences in metal quality and grain of stock pistons, the limit could be different for every engine. This is evident when some people run 12psi with no problems and other break a piston at 10psi. Obviously the one that broke at a lower level had some flaw from the factory.

I would say just for peace of mind and to lower the risk of damaging the rest of your engine with a blown piston, you should probably consider forged pistons for anything over 10psi or approaching 300whp.

[rickykline]

there have been several break 350whp with stock pistons.. i plan to upgrade to forged soon just so i can push the envelope

[geoffinbc]

I think there definitely is a HP limit to what the pistons will take, even without detonation. You have to remember that HP is the result of increased cylinder pressure pushing down on the piston and eventually it will reach it's limit. That said, I also don't think there is a definitive HP number that can be used. Given the low tolerances and variences in metal quality and grain of stock pistons, the limit could be different for every engine. This is evident when some people run 12psi with no problems and other break a piston at 10psi. Obviously the one that broke at a lower level had some flaw from the factory.

I would say just for peace of mind and to lower the risk of damaging the rest of your engine with a blown piston, you should probably consider forged pistons for anything over 10psi or approaching 300whp.

Not entirely true. The largest factor is going to be fuel ratio and timing while under boost. Thats will be the difference between a failure and a reliable motor. Sure metal flaws might be a factor. But it is not the most important one. Also depending on the temperature of the boosted air you might not have any problems at 15 PSI on one setup but might be overwhelmed at 9PSI on another setup

Every piston and bearing surface is imediatly suspetable to failure under detonation. Every piston top is going to run excessivly hot under a lean condition even if there is no detonation.

Heat makes power. But too much melts stuff

[boostedrs]

ive gone 18 psi + 35 shot of nitrous on my engine once,and ive continously run 18 psi on the motor without the nitrous,and its held together,on stock pistions.the main weak point is the top ringland,open up the ring gap a bit and u should be fine ,as long as ur tune is good .
i have had only one pistion falure between 3 diff motors,and it was due to going dead lean @ 20+ psi and detonating to hell (wastegate came unhooked).

[MidnightriderZ24]

Not entirely true. The largest factor is going to be fuel ratio and timing while under boost. Thats will be the difference between a failure and a reliable motor. Sure metal flaws might be a factor. But it is not the most important one. Also depending on the temperature of the boosted air you might not have any problems at 15 PSI on one setup but might be overwhelmed at 9PSI on another setup

Every piston and bearing surface is imediatly suspetable to failure under detonation. Every piston top is going to run excessivly hot under a lean condition even if there is no detonation.

Heat makes power. But too much melts stuff

totally agree here. im running 12 now, dyno'd 358whp with 9 psi. i am intercooled and have a way better tune than kenton (89jy). i think i could easily run 15 psi but im not going to, traction is limited at 6 psi, try 12 psi!! a limited slip should fix that soon.

[boostedrs]

totally agree here. im running 12 now, dyno'd 358whp with 9 psi. i am intercooled and have a way better tune than kenton (89jy). i think i could easily run 15 psi but im not going to, traction is limited at 6 psi, try 12 psi!! a limited slip should fix that soon.

358@9#'s???? it took me 18 psi to hit 412.what size turbo u running?

edit nm i just noticed its a 3400 motor,mine was done on a iron headed 3.1,though im in the middle of a 3xxx swap now and switching to twin turbos