ok im looking to boost an ls and i wanna keep all internals stock,and my question is what is safe to boost on a stock ls.ive seen people run 4-20psi on stock ls and im wanting to run about 14psi.basically i want a very low 12 high 11 second car

 

That is a vague question. 20 psi is completely different between turbos. You can get over 300whp out of an ls, but for how long is the question. I would look into a rebuild someday. 14psi out of an of the shelf kit like the greddy kit is doable.

 

im not looking to buy a complete turbo kit. i feel i can just peice together a t3/t4 setup for alot cheeper and produce more power.im planning on getting quality parts, im not a fan of ebay.everything will be quality so i dont have to worry about having it take a **** on me 1000 miles down the road.

 

True. I wouldn't either.

 

like said above its not the psi you should worry about, its the size of the turbo and how much power you are looking to make. in order to get an ls in the low 12's its going to take 15psi minimum more then like, assuming you run a .57 trim turbo. that will put you in the low 300's for hp.