You are already at a loss because you bought the tune! Seriously, you can also factor in cleaner injectors and intake valves so just DO IT!

 

Well, the tuner started saving about 1 MPG when I bought it, so it's already paying for itself. I'm just looking for some type of formula to give me some solid numbers. But you're right, I'd love to run premium for just the added detergents alone; but with my gas bills, I'm a little uneasy about taking the plunge, unless I'll get some money back.

 

I can't say or sure what you'd see with a hypertech, but my truck was custom tuned for 93 octane and I see at least 1.5mpg increase over 87 octane. I NEVER run crap 87 in my truck for other reasons as well, but I would definitely give it a shot.

 

I do not have a tuner but I found it interesting at one of the tuner sites, one of the things they want you to do is drive the vehicle with a scan tool installed and look for "knock retard" counts. If you see numbers climbing or knock retard activity, you need a better grade of fuel. LOL!
I have seen on my truck, while driving in hot summer weather, that my fuel mileage goes up slightly and I have MUCH better "tip in" throttle response.

 

You are looking at a 6% increase in cost so you would need to get 6% better fuel mileage. 13 mpg plus 6% would be 13.78 MPG.

 

I don't have a tuner but am running premium gas through mine and I have seen easily 1 mpg gains since i have started. I am getting 350 to 375 miles a tank. I spend between $1000-1500 a month on fuel and definitely feel that the extra $50-100 a month extra for premium is well worth it not only for the gain but for the cleaning properties as well.

*edit - sorry just saw what section this was in! Different engine but I still noticed a difference

 

how big say average fill up of 20 gallons?

 

Most of my fillups are 18-20 gallons. Thanks for the great info, Gordon! 6% doesn't seem too far-fetched, when you combine the power of the tuner with the benefits of Premium gas. I'll have to give it a shot on my next fillup.

 

Premium costs about %6 more than regular so you would need an increase of at least %7 in MPG to start getting your money back. This %1 increase equates to about 3¢ savings per gallon bought.

A hypertech programmer costs about $300 so you would need to burn through 10,000 gallons of gas to get your money's worth. We all know this is not realistic so what gains should we expect to see in order to make it worthwhile?

Say you want the programmer to pay off within the average lifetime of your truck and average lifetime ownership is 5 years. The Federal Highway Commission spent our tax dollars to figure out that the average American driver burns through about 729 gallons a year.

Multiply 729 by 5 and you get 3645 gallons in five years. Or put another way, this is what the average American will burn through in the average lifetime of his/her vehicle.

But we need to modify this because we are talking about trucks that get about half the fuel economy of cars so lets double 3645 and we get 7290.

But you also do a lot of plowing and heavy hauling so lets add another %20. That gets us to 8748 gallons of fuel that you; Spanky, will use in five years of your truck ownership. So in order for you to make your money back on a $300 programmer using premium gas (in five years), you need to save 3.5¢ per gallon on fuel. That ain't much at all; about %1 of a gallon.

Then, if you get at least a 1/2 mpg increase, you'll pay off the programmer in a year!

You asked...

 

here is what i came up with it might not be 100% accurate but i think this should work...shows that you will average your cost of fuel out if you gain 1 MPG...the tuner was an expense to get you there and i wouldnt worry about that or anything else you do but your orignal question states how much would you need to gain from a tuner to not notice a difference at the pump between regular and premuim...I hope this helps lol...but if you dont get any increase in MPG you will spend about 200 dollars more a year, but who cares about 200 dollars over the corse of the year now a days?

 

Great post, WN! Thanks for the math help. This makes me want to race down the freeway and burn off all the gas in the tank, just so I can switch to premium! We'll see how it goes. Thanks for all your help, guys. I don't do any "regular" driving in the winter, since half the time I'm either idling, plowing, or spinning the tires :twisted:. But, if I could keep my summer average during the winter, while using Premium gas, I'd consider that an even trade.

 

I just switched to premium from 87, after running the Diablo Predator Performance Tune. Before my MPG display always read one number, 15.7MPG. Occassionally, it would go to 15.9MPG, but usually right 15.7MPG.

But after the tune, it now fluctuates, but stays around 13.5MPG. If I hit the highway, or coast for a while it does go up, sometimes as high as 18-19MPG.. So I'm not sure if before I had an avergae being displayed or what, but I'm going to start watching how far I make it one tank. I never fill up either, always getting $10-$15 at a time when needed. I'll do a full tank filling over the weekend, and then start measuring to check against distance..

 

Maybe I'm wrong, but it kinda sounds like you had the average number being displayed with your regular tune, and then once you switched to the premium tune, the DIC displayed the instant MPG.

 

I run 87 in my truck all the time and average 15.8 mpg. when I run premium i do notice better performance but my mpg goes to 15.9. Not worth running premium alle.

 

I dunno, I'd have reservations breaking even with the exception you'll have better combustion processes due to better anti-knock fuel and with the additives some premiums offer do some decent fuel system cleanup. You'll definitely have cleaner power!

I just wish they'd stop offering the V-Power, Techron and other additives in just high octane, or it's what gives it it's octane rating.

Oh and Jrluz14, 87 octane isn't crap gas, crap gas is crap gas. It goes BOOM just as well as higher octanes, just not as well behaved while doing so. :mrgreen:

 

Well, I burned through my first tank... I'll be lucky if I got 10 MPG, but 1\3 of that is from plowing. I doubt that I'll be able to get a good reading until spring, since I'm either driving around with the plow on, or actually using the plow. Oh well, at least the extra boost in power\tuning helps mitigate the weight of the plow!

 

I just switched to premium from 87, after running the Diablo Predator Performance Tune. Before my MPG display always read one number, 15.7MPG. Occassionally, it would go to 15.9MPG, but usually right 15.7MPG.

But after the tune, it now fluctuates, but stays around 13.5MPG. If I hit the highway, or coast for a while it does go up, sometimes as high as 18-19MPG.. So I'm not sure if before I had an avergae being displayed or what, but I'm going to start watching how far I make it one tank. I never fill up either, always getting $10-$15 at a time when needed. I'll do a full tank filling over the weekend, and then start measuring to check against distance..

Are you looking at the instant MPG or the average?

Do you reset your MPG when you fill up? I reset all the DIC counters every time I fill up, so I can keep better track of what the truck is doing.

The winter gasoline mix in the northeast is not as efficient as the summer gasoline - and you can expect 2-3 MPG drop when the filling station makes the switch. Kind of like running the lower octane flex fuel - it's cheaper but you don't get the same MPG's out of it.

Also, manually calculate your MPG's - the DIC is not always accurate. Mine always indicates about 1 MPG higher than actual.

 

Hey, if it works *better* that's good IMO. :mrgreen:

 

Are you looking at the instant MPG or the average?

I'm guessing the instant, because it does change as I drive. It used to just show an average. The first time I reset it, it now shows the instant. I don't know how to go back to average.

Do you reset your MPG when you fill up? I reset all the DIC counters every time I fill up, so I can keep better track of what the truck is doing.

No, but I will start doing so. I do look at it usually once a day at least, and always when I add gas.

The winter gasoline mix in the northeast is not as efficient as the summer gasoline - and you can expect 2-3 MPG drop when the filling station makes the switch. Kind of like running the lower octane flex fuel - it's cheaper but you don't get the same MPG's out of it.

That I do know, but I didn't know it was so much. I figured maybe 1mph, but 2-3 is quite a bit. Hopefully things will change post-Winter.

Also, manually calculate your MPG's - the DIC is not always accurate. Mine always indicates about 1 MPG higher than actual.

I did try that recently, but I'm still relying on the truck to measure it. I looked at how much gas I had used, and reset a trip meter. A week later, I checked the new fuel used number, that gave me how many gallons I used. I did some math with that number and the mileage number, but it only came out to 9.5...so I'm not sure I did that right. Or the truck is still lying...because the meter last read was 12.8mph. I'm starting to not care, even though I asked tehe question to start. I bought a truck knowing it was a gas whore.. Then again, gas was $1.75/g when I bought it. Still though, I wouldn't trade it for anything..except maybe a new truck, with missles!

 

no mater what tune i used 93 got better gas milage on my 5.3l. I played with it all spring and found the 93 custom tune I had was the best to run.

 

One thing I did notice was that the DIC would show better instant MPG when I first switched to the 91 octane tune. I don't consider this hard evidence at all, but it's something to build on! This was without the plow on; but I'd like to burn through some gas in the spring to see what happens.

 

When I fill my car up premium usually nets me a minor increase if im not too hard on the throttle. ;D

 

I'm extremely heavy footed, which I know is killing me. I have been slowly trying to ease away from a red light, but still find myself pulling away 50 yards before the next car even starts moving...

 

after reading through this thread, i'm almost convinced to switch to 93octane.

 

If you can afford the extra $0.20\gallon, and have a tuner like mine, go for it. I LOVE the extra power, and I'm sure it will help at the pump someday... just not right now, since I'm using the truck mainly for city driving and plowing.