How much boost is to much boost?

[turbobuick4life]

I posted a question then i never got a question to. I built a 231 with a GN bottom end with forged 7.5:1 c/r pistons from PAW. I am running 9 lbs of boost because i know that this is a safe level.

I am looking to run higher boost How much boost can this crank take before it falls apart. I would like to run some where around 18 if at all possible. I was thinking about spending a few grand and getting custom forged bottom end <connecting rods, Crank>
But i don't see why I should it the crank will be able to handle it. So please help!!!!?

-Chris

 

[8URCBR]

Im a bit confused....is it a GN motor? turbo? injectors? if its a GN motor from top to bottom with 7.5:1 compression......turn that puppy up! Give us a few more details so we can help you out some more.

 

[turbobuick4life]

okay

The motor is a the block out of my 79 regal. I put a gt 42 turbo with poston headers a turbonetics wastegate. 65 lb/hr injectors <fast sfi system> wiend intake modified to except injectors. i bought the crank and the connecting rods from the local gm parts place the pistons are forged 7.5 c/r from paw. the heads are the same iron heads as it had i had they valve size upped and had them deburred and them ported, the bump stick is an erson with 1,500 rpm -5000rpm,fast bleed hydraulic lifters. Ta rocker arm assemblies TA bottom end girdle. Stock oil pan Ta performance oil pump and pick up. The block was machined .003 over the two middle mains i had the oil passaged drilled bigger to get better lubrication. a griffin intercooler plus water injector<only used at track or on hot days> . modified water pump to pump more water threw the puppy. 160 degree thermostat The exhaust is 3" piping with cat co performance cat 3" two car chemistry glass packs in the rear... That is almost all the info i my car that i think might help.... Thank you much

 

[kjhansen]

Ah, but the question remains: did you get a GN or Turbo Regal specific crankshaft (they are different than the stock 3.8L crank)? I've run 24psi of boost on my TR with 116 octane, 21psi with home-brew Xylene mix and alcohol injection, and 19psi with alcohol injection alone--all with no retard or (so far) damage to the crank (that I know of). A stock crank would have failed by now.
Keith

 

[turbobuick4life]

oh i got yeah

they said it was the stock bottom end for a gn 3.8 turbo. if that helps lol. -chris