Safe boost levels - iron head 3.1

[davida1_hiwaay_net]

This question really has no single answer so I'm looking for opinions. My engine is an iron head 2.8 wih 3.1 crank. It's turbocharged with an air to air intercooler. The block, crank, and rods are stock GM parts from late 80's to early 90's. Pistons are hypereutectic alloy low compression ones; however they are not 'performance' items.
Assuming the engine management system is properly tuned (not lean/ over-advanced; no detonation) how much boost should I be able to put on this engine?
Currently runs 10 to 11 PSI at 5500 RPM. This seems to be the limit where the transmission slips so I plan on reinforcing the transmission. I'd like to push the boost to 15 PSI which is the limit for the MAP sensor of the speed-density fuel system.
Do you think this motor will withstand that kind of power?
Thanks,
David

[X11_STE]

A friend of mine, who's work @ a chevy dealership for nearly 30 years, built a twin turbo citation <project X> and he's pushing 12psi max. According to him, that is the safe limit before blowing the block to pieces. Sorry I cant offer better news, but if you want reliable, build the tranny and be happy.

[sharkey]

you wont blow the block to peices, the stock blocks have been proven to almost 500 wheel hp. the rods should be alright, they are stout peices right from factory, same with the crank. id be worried about the pistons the most. i myself would limit it to 10-12psi.

[ForcedFirebird]

With hyper pistons and a good tune Boosted89rs has gone to 18PSI, good for low 12's in the 1/4. He was on 9" slick IIRC, but started re-working his project before he could get new times with a high stall TC etc. I know his vac line came off the wastegate once and he saw 23PSI,but neded up breaking something because of tune (he's got a MAF).

If you are tunining yourself, DIY Autotune sells a 4bar MAP sensor that would give you more than enough room.

I don't know what you have for head gaskets, but they seem to like to go.

I'm running around 6PSI with a stock tune and larger injectors, so I haven't got enough fuel delivery to go any more

[ezrollin]

With hyper pistons and a good tune Boosted89rs has gone to 18PSI Where can buy hypertec pistons for a 93-95 iron head 3.4 ?

[ForcedFirebird]

With hyper pistons and a good tune Boosted89rs has gone to 18PSI Where can buy hypertec pistons for a 93-95 iron head 3.4 ?

ebay, that's where he got his 3.1 pistons and the KB pistons (3.1 that I'm now selling also).

Haven't seen 3400 pistons come up for a while, but I still keep looking. Aparently, people order them and never pick them up, so the machinists auction them.