I was curious to know what the max boost on stock injectors would be.

If ALL fuel and flow modds where done then what would be a safe boost level for the 450 injectors?

So please keep the responses true to the question.

Thank you in advance.

My buddy is running 22psi of boost on his 450's with a walbro 255 and a FPR and he's had no problems so far.

It's going to be different for everyone, so don't just crank it to 22 because someone else does.

Use a logger.
Turn the boost up in steps.
Tune out the knock.
Get your injectors to 80% IDC.
The end result will be the max boost for your setup.

If you're on stock turbo, and stock pump, stock FPR, I wouldn't go any higher than 17psi...that's what I ran at the time.

Fuel is delivered to amount of air measured. Not how much boost you are running. 15psi on a 14b and 16g are different amounts of air.

Look at Injectcor Duty Cycle to let you know how much more airflow you can use.

If you have a wide band you can take out fuel until you reached your target A/F Ratio.

If not, you can use 02 voltage. .92 was roughly 12.x:1 on my car. Your car may be different depending on the age of sensor and other random variables I can't think of right now.

Keep an eye on timing. If it's being yanked your knocking. You probably went to lean.

If your reaching 100% IDC you can up your fuel pressure to get a bit more out of the injectors.

If you have nothing to monitor the ECU then just run whatever the wastegate is set and order and AFC/Logger/DSMlink/Stand alone.

Although my car seems to be a lil freak on occassion, I have tuned it to 20psi, stock fuel rewired pump only, stock 450s, with Inj DC's, of no more than 80-85%.
This is with NO KNOCK straight through 2nd-4th gear WOT pulls.
Every car is different though, I have only a newer version MAF-T to tune with, watch the logger and crank it up in steps.
ps. I've got a 14b for now, so I dont run 20psi daily, it was just to see if I could.

yes you will need to get a logger to findout exactly what is going on, like it all depends on the size of intercooler and fuel pump and fpr. like my set up with a large front mount a 18g and walbro 255 and fpr. i was running 22-23 psi no problems. and no knock at redline at 3 and 4th gear pulls. and thats always on 94 octane.

Is it just me or did he forget to mention what turbo he's running? as that should make a big difference. When I had my evoIII set at 15.5 psi (with stock injectors) I saw just over 31 lb/min of airflow and the duty cycle according to dsmlink was about 107%.