impressive! i am a bit jealous, with our 30' ( oal ) toyhauler i got 8.5 mph to mt rushmore not fighting wind and 65 to 70 mph at only 7500lbs and 12'6" tall. no shortage of hills up that way either. now cruising around ( sight seeing ) custer state park and surrounding area, at 900 rpm to 1500 rpm ( in mostly high gear ) for 200 miles, i got 20 mpg.

 

When testing, keeping all of the variables the same from injector to injector is the goal. The resolution of your measurement is also important because you may not pick up on subtle data changes, but that doesn't mean they aren't there. I suspect the fuel pressure has the most to do with refilling of the barrel since the plunger has to compress the fuel to be discharged from a properly working nozzle once it hits the break over pressure. I run 75 PSI on my 7.3 and I believe both of our HEUI flow benches are right around 60 PSI.

 

This is interesting to me and I couldn’t help asking about it. Do you see improvements with higher pressure?

 

60-65 is perfectly adequate fuel pressure. Any claims to gains in improvement from going above that is simply a pixie dust fairy telling story

 

VERY well said. I'd like to print this and email it to everyone with AD's that calls in wanting 180/30% because it's the cool thing to do.

Any reason why you don't run lower pressure in your truck, or higher on your bench? I would think you'd test what you run, or run what you test, no?

I won't speak for Matthew, but I dynoed my truck years ago with the only change being fuel pressure and even fuel pumps. What I found was the 7.3 likes 60 psi to 65 psi. When I dropped it to 50 psi it lost about 8 hp, and when I bumped it to 75 psi it lost about 8 hp. These were back-to-back-to-back runs with the only change being a few tweaks on the regulator. I will imagine (or insist!) that every truck is different, but nothing at all wrong with just picking 60 to 65 psi and forget about it.

Eh, there could be variables that might show otherwise, but I've seen a LOSS in hp doing so, never a gain, so I stick with a good, well-known pressure that won't put extra strain on the pump and shorten it's lifespan.

 

75 PSI is what we run on the Vegistroke and it just happens to be what I adjusted the diesel side to as well. That is all.

 

makes sense.
So as I understand it [ def could be wrong ] stock nozzles are expected to achieve best mpg based on atomization, 30% next best, but can plug up easier. Again, in my case only, with an adrenaline hpop and stock injectors, would that produce slightly higher icp to better drive the splits w/o tuning? I only ask as that should be slightly better atomization imo. i'm simply curious if 30% tips are really more beneficial then a better hpop? i have already made the change and i'm not going back, but, for anyone reading this wondering where their money is better spent.

The reason I asked about stock injs when I bought mine ,was not only quieter/smoother but based on re sale as well as fear of relying on a tuner. It was pointed out i could send the ecu in and have it flashed. Based on what a few members have reported on stock injs [with decent tow tunes,] its possible stock injs/sxe 363 would've been sufficient for the toyhauler I currently tow. with my 34' wolf pack 295 fifthwheel toyhauler 12'2" tall, stock required 80 hp tow on cooler days and 60 tow on hot days.

based on my current experience, the difference between stock ab's [ e99 ] the new hybrid 205/30% injs, adrenaline hpop , sxe 363 running whats called stockish tune, i pulled my 30' [ oal bumper hitch] 12'6" tall toyahuler across neb to mt Rushmore at 65 to 70 mph in stockish vs 80tow in stock configuration. Ya sous. Old habits die hard lol
I do not know how much additional power my current configuration produces in stockish mode vs a bone stock but it seems substantial.

 

Sure, the most restrictive nozzle should have the highest injection pressure. Tuning should clear up any haze you have. Driving habits are what change MPG.

 

out of curiosity, when it comes time to replace your injectors, are you considering a cnc fab or adrenaline hpop to better supply the split shot injectors?

 

I will either go with a Bosch OEM replacement or a CNC stage 1 HPOP when it comes my time. Adrenaline is too much money for me and my intended use.

A friend of mine is going to sell me an old HPOP as a core, so that I have injector cores and a HPOP core on hand. The first sign of failure from either, they are being replaced. Maybe sooner if the budget allows. Then I would let the new part sit on the shelf in a vacuum sealed bag until the first sign of failure.