I've read that using a pressure box with after market injectors is not generally recommended by the injector manufacturers What is anyones opinion on this matter? Thanks

 

Now don't hold me to this, but I think this may be right......
When the nozzles are enlarged it means less material in the tip. The bigger the hole(horsepower), the weaker the tip, generally. If you put too much pressure on a large injector it can break the tip off. I don't think you would have to worry unless you're running HUGE injectors.
Maybe I'm right, if not someone please educate us both!! lol

 

I have ddp 90's and they say not to run more than 26k lbs of pressure. Whole injectors may be different but just honed tips cant take all the pressure

 

When you put a set of sticks in pressure falls of significantly and a upgraded pump or pressure box may be used to bring pressures up to recomended levels. Industrial claims its not the pressure that does it they can take the pressure for extended amounts of time its the spiking pressures that will do it, if you were to take an empty coke can and squeze it then pop sides back out over and over again it will eventually crack and leak somewhere but if you just crush it up once you generally wont have a crack develope. I have heard this from other companies too not just II. Just my .02