Hi, I have been slowly reading up on forced induction and just had a simple question; can you run a turbo without forged piston?; if it is possible to run without forged pistons, how much pressure can stock pistons resist? thx.

8psi safely. Its in the stickies

There is no exact number anyone can give you that will insure safety on any specific engine. Every engine is different, and may react ever so slightly differently. Not only that.... "8 psi" on a T3 is going to be less power than "8psi" on a T3/T4. It depends on the size of each turbo individually what "# psi" will yield for power.

For your other question, yes you can run a turbo with stock pistons. It is recomended that you run less boost through it though, than you would with forged pistons/rods. Also depends ALOT on your tune. One person could have a fully forged bottom end and a crappy tune, and blow it up, whereas someone with a stock engine and a very good tune running equal power out of the turbo, could have a reliable car with virtually no problems...

Jazer is right. There is no exact number. I've seen cars with a good tune last well past 10psi on a stock bottom end, and I've seen cars that grenaded on only 4-6psi. Tuning has a lot to do with it.

It has to do with the integrity of the rods/bearings/pistons all together. If you have a weak rod, doesn't matter how good the tune, once you break the threshold of it's maximum power it can handle, it will break... it's all about horsepower and forces that are going through the internal components. Rods are supposed to be good to 275HP on the LD9. 2.2L Ecotec got up to 380 some HP on nitrous, when all four rods snapped simultaneously.


2001 Olds Alero (LD9)
650 whp / 543 ft-lb
@turboalero

GM snapped the Eco rods/wrist pins at 280ish with nitrous.

i ran 13psi on a stock eco block for a year and a half..no worries on that block..tune was impressive


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04 Cavalier Turbo r.i.p my baby
2nd place 2009 GM tuner bash qwick 8--holla