1. do these pumps need to have a pressurized feed, or do they produce the X psi stated on their own.
2. if on thier own, the "self-priming" feature will pull the water from an un-pressurized tank, correct?
3. was there ever a decided psi range for h2o injection for us?
4. what GPM range is adiquit for a good DIY system?

thre are a few pumps on here for good prices, but different psi and gpm. look at bottom of the linked page as well.
input?


http://www.northerntool.com/webapp/wcs/stores/servlet/ProductDisplay?storeId=6970&langId=-1&catalogId=4006970&PHOTOS=on&productId=357081&categoryId=1546

h20injection.com

i used the info on there to set up mine :thumbsup

1. do these pumps need to have a pressurized feed, or do they produce the X psi stated on their own.

YES

2. if on thier own, the "self-priming" feature will pull the water from an un-pressurized tank, correct?

YES

3. was there ever a decided psi range for h2o injection for us?

The stated 60psi from the one you linked I would think would be enough. probably depends more on the noozle you plan to use.

4. what GPM range is adiquit for a good DIY system?

I'm pretty sure you'd want to use the noozle to regulate the amount of water and not the pump. cause at max flow rates those RV pumps 'pulse' alot.

all my above statements are just from first hand experience going on vacations in an RV.