hi guys, I was just wanting to know what boost levels people are running with standard internals on their 4G94 enginges, at current I am running 7psi but I am told that I can run up to 10psi safely without changing internals.

thoughs and comments would be appreciated.

 

I'm running 5.5 lbs non intercooled. I'll be turning it up though when I go intercooled this winter. I'm hoping to push a lil more than 7 and go stage 2.

 

10 psi on stock internals isnt exacly safe for stock internals yes it can be done but will need extensive tuning

 

With enough fuel and a little timing pulled it should be fine. The issue is knock. If you're not knocking then there's relatively little danger.

 

I'm sorry, but that just isn't true at all. Take for example a popular stg2 turbo kit that runs 11pounds on stock internals fine, and the same with a stg2 supercharger kit.

In fact, I believe someone upped theirs to 13 pounds for testing purposes before stuff started going wrong (floating valves, etc). It all comes down to the tuning and if you have enough fuel and what not.

 

It is not just how much fuel, it is the octane too.

 

alright i guess i was wrong i take back my comment

 

I was going on the assumption that Aussie CG's smart enough to use the highest unleaded octane available.

 

I think the guy in charge of building my car is talking about running 15ish. He says the internals are forged so I'll be alright with it.

 

Note to GreenPsycho and Johns Slow ES:

Give up arguing over it. It's just luck, for the most part. Some people run 11 psi daily, others blow up on 6 psi. It all depends on the particular car, particular mods, and particular tune.

*and I'm out*

 

compressor wheel efficiency and rated CFM plays a big part in this as well. i'd imagine it's possible to be running more boost the smaller the turbo gets depending on efficiency.

 

not arguing just adimiting that i was wrong

 

Not singling you out. Just saying that it's hard to give a solid number.

I don't think it's fair for anyone to ever say "this level of boost is safe." The answer should always be "it depends."

 

^agreed

 

yeah, I agree too and for the record, wasn't trying to be rude or anything to slow ES, sorry if it came off that way.

I think the single most determining factor is: the tune. You got a solid tune (enough fuel and in the right places), and you can start working miracles for pretty much any setup. black is right though, you can screw up even at 4psi or so if you don't give it enough fuel or have a crappy tune.

Just a word to the wise for hte custom turbo guys: piece it together yourself, but get a solid tune