08 Silverado 4.8 (LY2) daily driven. 4l80 swap, triple disc stall, KB t72 intetcooled. Question is what is the most psi I can run without meth? (Using it for insurance not power) I got arp studs n ls9 gaskets. Lunati dual springs high lift. Looking into alky control kit. But just want to be safe until I buy it. Thanks guys.

 

Depends on how your IATs act.
its kinda a loaded question, but if your tune is good and you use good gasoline. prolly say around 10-15psi.

how big of injectors do you have?

 

Oh yeah planning on 12# total but don't know if it needs meth at that psi

 

My tuner says below 11psi meth/water injection isn't really needed. So per his suggestion, my plan is to run a street boost setting of 5-8psi w/o injection, and a spirited setting of 12-15psi w/ injection. But as mentioned, there are many other variables, so I might end up spraying at both settings.

 

10 is a pretty solid number.

 

i was going with 10 without. 63# injectors. thanks guys just trying to get a feel for what everyone is running

 

I run my Methanol starting to spray 10% at 6psi since thats max boost with the cutout closed and for towing.

 

It would concern me to run methanol in this manner. If you only use it for high boost then you cant tell if you have a problem until you have very high cylinder pressure and then it might be too late. However, if you use it progressively ( a little on low boost and increasing as you go ) you could tell if it wasn't spraying properly before your under heavy load. My experience is that methanol pumps would rather be used on a more frequent basis to extend their life. If you only use it for high boost you could go days, weeks, or months without activating the pump, and by then it could be seized and you wouldn't even know it.

 

Mine starts about 5psi and sprays with the number 1 Injector duty cycle. The harder my injectors work the more the pump works. Keeps egt's down while towing and racing. It's a win win.

 

^^^^ hmmm interesting