"Diablo Tune" vs "87 octane" tune --- 07 silverado 5.3

[04silverado4.8]

Any opinions on performance/mileage/price at the pump?

My impression is the Diablo Tune is 91+ octane...


07 Silverado 5.3 v8

Thanks,
Scott

[Vas@Diablosport]

The Diablo tune is a Premium fuel tune, 91+ octane. Diablo and 87 tunes should both give you roughly the same MPG boost over factory, which is about 1-2.

[04silverado4.8]

Thanks, that is what I needed to know. I've got a 4 door z71 so if the mpg bump is about the same I would just being paying more at the pump for performance only, which I don't really need; I'm not racing anybody I'll stick with the pep I got with the 87 tune.

Merry Christmas!

[Copperhead]

But the 91+ tune is advantageous if one it fueling regularly with E85. Since all I ever fuel with anymore, because of the lowest cost per mile, is E85, just makes sense to have a tune that more closely takes advantage of the fuel. So, in essence, I am not paying the premium price for premium performance. God, what a country!

[Mike_Levy]

But you're getting much worse economy on E85, so you're definitely paying a premium. Even with the cheaper fuel, the mileage is so much lower that its unlikely that you're actually saving money. I was seeing about 40% less mpg with my Denali on E85 vs 93 octane, and was certainly paying more than 60% of the price.

[Copperhead]

No, I am not paying a premium even if I am getting lower mpg. You fail to look at the cost per mile. Like a lot of folks, you are only focusing on the mpg number. In my area premium is pegging $3.80. E85 is pegging $2.45. I get about 17 mpg on premium and around 13.5 on E85. The vast majority of my operation is rural two lane type of highways and gravel roads with a little bit of in town thrown in. Premium therefor costs me are hair over 22 cents a mile. E85 costs me a hair over 18 cents a mile, a net savings of 4 cents a mile. True, others will experience different numbers, and they will have to determine if it is worth it.

So, how am I paying a premium by using E85 again?

[Silver2011]

I would be cautious using the 87 octane tunes if others are anything like my 2013. I actually lost power vs. my stock tune with the 87 octane tune due to lower timing. I don't have the logs in front of me but torque was way down. I was getting as low as 10* of timing advance in some frames. Diablo made the tune leaner but by dropping the EQ ratio down it also drops you down to the lower timing in the PE Correction table. The PE Correction table needs to be adjusted by Diablo.

[06MonteSS]

No, I am not paying a premium even if I am getting lower mpg. You fail to look at the cost per mile. Like a lot of folks, you are only focusing on the mpg number. In my area premium is pegging $3.80. E85 is pegging $2.45. I get about 17 mpg on premium and around 13.5 on E85. The vast majority of my operation is rural two lane type of highways and gravel roads with a little bit of in town thrown in. Premium therefor costs me are hair over 22 cents a mile. E85 costs me a hair over 18 cents a mile, a net savings of 4 cents a mile. True, others will experience different numbers, and they will have to determine if it is worth it.

So, how am I paying a premium by using E85 again?

it's not that you're paying premium prices.. but the savings negates itself, because you get worse mpg with e85 crap, so you have to fill up more often

thus, you're paying the same if not more, because you have to fill up with e85 more often than if you just used good normal 91+ octane gas that gets you better mileage..

so you're not really saving anything...

[Copperhead]

I am having a rough time figuring out how some can't see, since I stated the numbers, how using E85 at a cost of 18 cents a mile (based on E85 mpg at $2.45 a gallon) vs. using premium at 22 cents a mile (based on premium mpg and $3.80 a gallon) is a losing proposition. I really figured this didn't take a course in statistical mathematics. Even though the mpg is less with E85 in my vehicle, the actual cost per mile at that lower mpg is less as well.

Let's remember our grade school math, boys and girls....

E85.. $2.45 divided by 13.5 mpg is 18.15 cents a mile.

Premium.. $3.80 divided by 17 mpg is 22.35 cents a mile.

Now... 22.35 cents minus 18.15 cents is 4.25 cents. So, the savings to me by using E85 is 4.25 cents a mile.

I guess it is just the business guy in me that finds this easy to calculate. When you do statistical averages of cost per mile on commercial trucks it is not hard to jump over to something simple like a pickup. I really expected this would not be such a problem for some to grasp. I guess I assumed too much.

I am especially shocked you couldn't figure this out, Lew. Makes me wonder if I should trust you with a tune!! Just kidding. I am sure you just looked at things in haste and didn't actually reason it out properly.

[Mike_Levy]

LIke I said, I was getting about 40% less mpg, 14 vs 8mpg.
Using your prices
E85 - $2.45 for 8 miles is $0.30 a mile
93 octane - $3.90 for 14 miles is $0.27 a mile

That makes regular 93 octane gas cheaper in my case, even with your prices. Both prices are higher here, especially E85, so the difference would be even greater.

[06MonteSS]

I am having a rough time figuring out how some can't see, since I stated the numbers, how using E85 at a cost of 18 cents a mile (based on E85 mpg at $2.45 a gallon) vs. using premium at 22 cents a mile (based on premium mpg and $3.80 a gallon) is a losing proposition. I really figured this didn't take a course in statistical mathematics. Even though the mpg is less with E85 in my vehicle, the actual cost per mile at that lower mpg is less as well.

Let's remember our grade school math, boys and girls....

E85.. $2.45 divided by 13.5 mpg is 18.15 cents a mile.

Premium.. $3.80 divided by 17 mpg is 22.35 cents a mile.

Now... 22.35 cents minus 18.15 cents is 4.25 cents. So, the savings to me by using E85 is 4.25 cents a mile.

I guess it is just the business guy in me that finds this easy to calculate. When you do statistical averages of cost per mile on commercial trucks it is not hard to jump over to something simple like a pickup. I really expected this would not be such a problem for some to grasp. I guess I assumed too much.

I am especially shocked you couldn't figure this out, Lew. Makes me wonder if I should trust you with a tune!! Just kidding. I am sure you just looked at things in haste and didn't actually reason it out properly.

I don't tune for E85.. so no you shouldn't LOL e85 has a different stoich air fuel ratio than normal gas.. and the canned preset tunes on the tool are not made for e85, nor is my custom tuning...

so if you get a tune from me, you better be using normal gas...

lol

[mikel]

LIke I said, I was getting about 40% less mpg, 14 vs 8mpg.
Using your prices
E85 - $2.45 for 8 miles is $0.30 a mile
93 octane - $3.90 for 14 miles is $0.27 a mile

That makes regular 93 octane gas cheaper in my case, even with your prices. Both prices are higher here, especially E85, so the difference would be even greater.

40% loss = poorly tuned for E85.

Most flex fuel GM trucks lose an average of 30% economy on factory programming. Custom tuning for the E85 can get that down to closer to 25%...

[Mike_Levy]

LIke I said, I was getting about 40% less mpg, 14 vs 8mpg.
Using your prices
E85 - $2.45 for 8 miles is $0.30 a mile
93 octane - $3.90 for 14 miles is $0.27 a mile

That makes regular 93 octane gas cheaper in my case, even with your prices. Both prices are higher here, especially E85, so the difference would be even greater.

40% loss = poorly tuned for E85.

Most flex fuel GM trucks lose an average of 30% economy on factory programming. Custom tuning for the E85 can get that down to closer to 25%...

It was your canned tune, what would you expect. If you're tuning for 91+ octane, of course its not gonna be ideal for E85.

[mikel]

LIke I said, I was getting about 40% less mpg, 14 vs 8mpg.
Using your prices
E85 - $2.45 for 8 miles is $0.30 a mile
93 octane - $3.90 for 14 miles is $0.27 a mile

That makes regular 93 octane gas cheaper in my case, even with your prices. Both prices are higher here, especially E85, so the difference would be even greater.

40% loss = poorly tuned for E85.

Most flex fuel GM trucks lose an average of 30% economy on factory programming. Custom tuning for the E85 can get that down to closer to 25%...

It was your canned tune, what would you expect. If you're tuning for 91+ octane, of course its not gonna be ideal for E85.

but if it was a flex fuel vehicle, it wasnt using anything from the canned tune except the TM setting, throttle, etc.

Spark and fueling are handled separately for e85 on ffv cals

[Mike_Levy]

It was flex fuel, so GMs tuning sucks.