The single shots and Swamp's tuning got me my best single tank ever -28.2 MPG.

All INTERSTATE at the posted limit - mostly 70.

Circuit testing in progress.

Real interesting...

I'm watching.

First fillup on my normal circuit: 27.67 MPG.

That's up 0.4 MPG from split-shots.

Or less than 1.5% change on your 'normal' route from the old tips.
Keep reporting the most comparable results.
Do you have some data from a similar trip with the old tips to which you can relate the all interstate 28.2 in post #11?

Not to be pessimistic, but I just want to make sure I understand this correctly. You improvement came from replacing worn out injectors with new ones, changing to the single shot tips and having some "tuning" done?

From the info you have can you differenciate the difference between replacing worn out injectors and going to single shot?

You said part of the reason they went to the split shot was to quiet it down, do you hear a difference in engine noise now?

very interesting stuff... I am still trying to determine if I am glad I have the single shots or not.

Mr_C

A 100% Interstate run 315 miles, driving the posted limit both ways. One way splits, the other way single shots.

Split shots: 27.8 MPG
Single shots: 28.18 MPG

In my normal circuit (30% Interstate, 35% city/suburban, 35% rural roads)

Split shots 27.24 MPG (average of three tanks)
Single shots 27.65 MPG (one tank only so far)

"Highway" improvement: 1.35%
"Combined" improvement: 1.48%

Look at the graphs of MPG in various contributors garage entries. Notice how much inherent variation there is with no concious driving difference or vehicle adjustments. Your change of less than 1.5% is effectively no change.
If you have less noise, or lower smoke output, or other benefit that is more difficult to measure, that's great. But mileage improvement? Statistically unchanged.

True, but Dave's pretty consistent at home about using the same place for his fill ups. However, this might have been different. Dave will have to elaborate, and whether the effectiveness of the tune is correct? I don't know. More data is needed.

Considering what Dave does with his pick up compared to my Excursion, he's about 10MPG ahead of me, still. I'm taller, wider tires, geared shorter, different shape. I'm still pretty impressed with where he's at.

I never claimed this is necessarily a winner. I?m testing it out. I have tried many things that didn?t work or didn?t do much. Free-flowing intake and exhaust didn?t help a bit. A chip helped only 0.75 MPG. A 203 degree stat was good for 0.5 MPG. Synthetic oil goes a very long way between changes but didn?t help MPG. An air dam and side skirts got me 0.6 MPG.

But actually in the MPG game there aren?t too many real silver bullets. I got 3 MPG improvement from my gearing and a total of 3 MPG from my bed cover but other wise all the improvements have been 1 MPG or under. If you are looking for a single silver bullet, you might be on a fool?s errand, but cumulatively I get pretty good performance.

I got these injectors in exchange for some thorough testing so my testing season is completely eaten up for this summer. The weather will turn in about six weeks and my MPG will roll off. I look to peak out at about 27.75 MPG this summer, and that will set the bar for more stuff next summer.

Dave, have you considered the idea that there might be carbon in the combustion chamber too? On the last legs of my bus, I looked for an additive to attempt to clean things up. Have tried a couple of things, but I have no specific results without physically taking things apart.

Might skew your results, per se. But, on the topic of experimenting...