Stock 7 hole nozzles will flow more fuel than most systems can actually control anyway. (Thermally)
Unless you're running compound turbocharging or a very well setup single, you can't run the stock nozzled injectors Wide ass open without overheating, so why go bigger for towing?
What I'm saying is, you could go bigger and tone them down with tuning, but you will likely never actually have the ability to use more fuel per time than a stock 7 holer can give you in a true towing scenario where durated egt
simply must remain under 1250 degrees.
Now with that having been said....
I have been towing decent loads (15,000 - 22,000lbs) for years now on larger nozzles with ZERO egt
issues. I mean wide open throttle and no egt
issues, no pedal modulation necessary. Just mat it and forget it.
My tow program (An actual tow program, not something simply labeled as such) will produce just over 300rwhp and run a durated, fully loaded temperature of 1150-1200 degrees at wide open throttle from one coast to the other. It usually runs 1100-1150 uphill and 1000 on the flats. I run right at 30lbs of boost in that program when towing at full load.
My nozzles are Extrude Honed 7 holers and are just less than .007" per hole.
There is no smoke when I'm on boost towing. I'm not sure what the milage is, but durated driving at an actual 300rwhp simply cannot be good for milage
Long story short.....if you honestly just want the best towing you can get.....I would run the stock 7 holers and never look back. Honestly.
I made 428rwhp on those nozzles. If 428rwhp can't keep your load moving you need a bigger truck anyway.
I would suggest 175-180cc's and a stock nozzle. Like swamps 175/146 injector. Although I really see no reason why you can't run say a 238cc hybrid and a .146^2 nozzle either. I am towing on a set of BD's FWIW
. Just towed back from the farm this weekend at about 15-16,000 gross and ran 75mph with the cruise control set. Never exceeded 1150 degrees. And the turbo whistle was DEVASTATINGLY crisp on every hill, lol. I had truckers wide eyed and starring at me blowing their doors off with the compounds SCREAMING uphill.