How much boost can i throw at stock pistons?

[andrew_mx83]

hey guys

i come from the land of the GE, built plenty of 7m's but not a boosted one yet. im a huge fan, got my own nuts 9000rpm race motor slowly in the build.

i am doing a GTE for a customer, he is on a budget and im just wondering what the limit on stock (new) slugs is? it has some huge f*ck off turbo and ext gate etc and a computer.

he wants 300rwkw+ so i guess we are looking at 20psi or so? will stockers be upto this with a 2mm MHG and a good tune?

looking at throwing rod bolts in it too as ive seen too many spun big ends recently (this one too -it also detonated 4 pistons)

 

[bioskyline]

whats the fuel system mods? even with a piggyback or standalone, 10psi is max for the stock fuel system.

Regarding stock vs forged pistons, it don't matter which pistons you use when boosting up to 20psi as long as you don't have detonating/knock condition. It's usually caused by too low grade fuel, even 93oct premium is way too low for 20psi runs. Just that forged piston can handle detonation much better than stock

if the fuel system is upgraded to 550cc, lex, AFPR, wideband etc, 15-17 should be on on pump gas. you can even get a knock gauge that will let you when detonation/knock is occuring and then back off.

 

[andrew_mx83]

full aftermarket ecu with map sensor (no afm)

has a fuel pump, not sure about injectors. prev owner claimed 270rwkw so... hoping its upto the task

will be dyno tuned for afr's on (aussie) 98RON


basically fuel/tune is not an issue, its more a matter of when do the stock units give up the ghost (powerwise)? do we need forgies for 300+?

 

[bioskyline]

stockers are good to the 400hp range, from 450 up forged is needed

 

[andrew_mx83]

sweet thanks

 

[ValgeKotkas]

Where's the guy with 782 (?) rwhp with stock internals...

E: 753rwhp and http://www.supramania.com/forums/member.php?2595-X-man

 

[mk3_7m]

What kills the pistons is pre-detonation from lean tunes i believe.

 

[bioskyline]

Where's the guy with 782 (?) rwhp with stock internals...

E: 753rwhp and http://www.supramania.com/forums/member.php?2595-X-man

very nice, but yeah with a good tune im sure they will hold up, aslong as you can avoid detonation.

stock parts normaly are rated to double stock hp, then forged internals are recomended. the more power your making, more stress on parts, and the tensile strength of the material comes into play.