so, how much boost are you guys usually run with GT30 or 35R with water/meth injection?
i guess it really depends on how much power i am shooting but...
what's the census? 24lbs? 26lbs? higher?

 

i run 28 psi on straight 93

i would run 30-33 psi with meth

 

i have run 30lbs on a 35R with meth.

 

I run 27 psi without meth injection on straight 93.

 

i would guess 28-32psi on a stock block

 

It's not just about how much boost - it depends on how much air your engine can pump through itself, ie the power you make.

With the power level (lbs/min airflow) you can then read a compressor map. At say 500 hp, which could be roughly 52 lbs/min calculations say you need around 30 psi of boost. This gets you on the choke line of a GT30R. Can you run 30 psi on a GT30R at around 500 whp - yes. Will you be overspinning the turbo and doing damage to it - yes.



A GT35R though is much more willing to give out 30 psi and not choke.

 

thank you for the response.
i need to look at the graph little more carefully...

 

Actually boost is a big consideration. 500whp w/o meth on a 35R is safer compared to a 30R. Boost pressure and air temps have a direct relationship, so as you have more boost you have higher temps, and thats the reason for meth injection. The 30psi is more likely to cause detonation/preignition with the 30R, doesnt matter how much power you are making.

The 30R is also capable of higher PRs than a 35R, but mass airflow is lower.

 

We're basically saying the same thing...

I'm talking about given the airflow/power levels, high boost levels may choke the turbo (over spin it), especially the 30R. If you are not making huge power, and flowing lots of air, you can actually run high boost on a 30R as you said, it just depends how many lbs/min your setup can flow and where it puts you on the compressor map.

 

i was running 27-28lbs with green and injection, i guess 27lbs with 30R should be OK with injection, right?