Performance Tune And Octane?

cujo8 · April 4, 2009

I'm getting a Black Bear Performance tune in couple of weeks and I have a couple questions about the 87, 91, & 93 Octane tune options. It is my understanding that octane is added to gasoline as an anti-knock additive or in other words the octane level is directly proportional to the fuels flammability. The higher the octane-level the more energy that is required to ignite the fuel mixture. Usually higher compression, high performance engines need higher octane gas to prevent the gas igniting too early in the combustion chamber, so my question is what is the benefit of running say 93 octane gas in an engine that was designed to run on 87 octane? If the gasoline is equivalent in every other way except the octane level it should give similar performance as long as it has sufficient octane to prevent pre-ignition (knocking). I know they call 93 octane gas "premium", but is there something else in this higher octane fuel to warrant the name "premium"? From what I've read so far they put the same detergents in to all grades and the only difference is the octane rating.1. If I tune my 2006 GMC w/ a 5.3L L33 V8 with the 93-Octane tune will my truck have better 0-60 times than it would get if I went with the 87-Octane tune?

2. If I drive my truck in a similar conservative manner, will I get more MPG running 93-Octane fuel with a 93-octane tune or with 87-octane fuel with an 87-octane fuel?

From the limited web searches I've done on regular vs premium fuels, I've found it written that regular and premium gasoline all contain the same amount of energy per unit volume and the only difference is the octane rating. They go onto say the only reason to go for the higher octane fuel is if your engine is knocking and that the higher octane will help to eliminate the knocking. They also say that if your engine is not knocking with 87 octane and you start running premium the only difference you'll find is in the weight of your wallet .

Unless someone can convince me otherwise, I am leaning towards getting the 87-octane tune. Lets here your opinions.

L29er · April 4, 2009

personaly getting the 93 tune in my experience netted better mileage, making it actually cheaper to fill with premium. beleive it or not...

matt3 · April 5, 2009

The detergents are a little different in different grades of gas. Also, I'm pretty sure that they are different blends as well. The gas you get at the pump is not just 1 stream coming off of a distillation tower. It is a number of products that are in the gasoline boiling range. Some solvents are used as well as alkylate and some other gasolines from other areas of a refinery.

I am a operator in a alky unit which produces 1 component of the blend stock (alkylate). If your really curious just PM me and I will call the blender at the refinery where I work and ask him for more specifics.

Just from me talking to Justin @ Blackbear, he told me that typically you will see some performance increases as well as slighty better mpg's going with a higher octane fuel. As I understand it (I may be wrong) the only time your wasting money with running a higher octane is if your truck isn't specifically tuned for it.

Whoever is tuning your truck will walk through all your options and explain the benifits to the different choices.

mattgob86 · April 5, 2009

Well what if you truck requires premium, would you net better mpgs from a high octane tune

cujo8 · April 5, 2009

personaly getting the 93 tune in my experience netted better mileage, making it actually cheaper to fill with premium. beleive it or not...

So did you once have a 87 octane tune from Justin before you got the 93 octane tune? If I actually could better mileage with 93 octane than that's the way I would go for sure. I estimate it would cost me ~ $5 more to fill up with premium (93) over the cost of using regular (87). So here's the math for my truck right now using 87 octane gas I'm getting ~17.5 MPG so,

17.5 MPG x 26gallon tank = 455 miles/tank

Gas has been $2.06 for 87 octane and $2.26 for 93 octane where I buy it these days.

26gallons x $2.06 = $53.76 / tank, which works out to $0.12 / mile for me right now.

That would mean I would need to 489 miles/tank to break even and get $0.12 / mile using 93 octane. To do this I would have get 18.8 MPG running 93 octane to break even or an additional 1.3 MPG. I have not used 93 octane gas in my truck yet, but the engine was designed to run 87 octane, so it may not get better MPG with 93 octane. It actually could get worse mileage for all I know. Has anyone seen any mileage benefits by running 93 octane in your truck designed to run on 87 octane with the stock tune?

cujo8 · April 5, 2009

Well what if you truck requires premium, would you net better mpgs from a high octane tune

My trucks manual states that my 5.3L engine requires 87 octane fuel, but it yours says it needs high octane than I think you would get better MPG w/ a tune. Justin could even tune your truck to run on 87 octane if you wanted.

mattgob86 · April 5, 2009

well my truck is not here yet but the 6.2 supposedly requires premium

66nova · April 5, 2009

personaly getting the 93 tune in my experience netted better mileage, making it actually cheaper to fill with premium. beleive it or not...

So did you once have a 87 octane tune from Justin before you got the 93 octane tune? If I actually could better mileage with 93 octane than that's the way I would go for sure. I estimate it would cost me ~ $5 more to fill up with premium (93) over the cost of using regular (87). So here's the math for my truck right now using 87 octane gas I'm getting ~17.5 MPG so,

17.5 MPG x 26gallon tank = 455 miles/tank

Gas has been $2.06 for 87 octane and $2.26 for 93 octane where I buy it these days.

26gallons x $2.06 = $53.76 / tank, which works out to $0.12 / mile for me right now.

That would mean I would need to 489 miles/tank to break even and get $0.12 / mile using 93 octane. To do this I would have get 18.8 MPG running 93 octane to break even or an additional 1.3 MPG. I have not used 93 octane gas in my truck yet, but the engine was designed to run 87 octane, so it may not get better MPG with 93 octane. It actually could get worse mileage for all I know. Has anyone seen any mileage benefits by running 93 octane in your truck designed to run on 87 octane with the stock tune?

There is none! Anyone that claims to see it is either seeing a placebo effect or there is another variable in their better mileage.

As for your tune, the main difference between a 87 and 93 octane tune has to do with the timing and fuel tables. The 93 octane tune will make more power and get better mileage (assuming you can keep your foot out of it), but how much seat of the pants difference and how much better mileage, that will vary for every truck/driver/driving conditions. No one can predict it.

Here is what I would do if I were you. I would have Justin give you a 93 octane tune and drive it for a while (the tune will continue to learn, so you really need to put some miles on it before you decide). See if you like it and see what mileage gain you get. You are paying for tune, get everything out of it you can. Then if you don't get the mileage gains you want, call Justin and have him send you a 87 octane tune instead. Retunes are free.

stadt11 · April 5, 2009

Get the higher-octane dual tune

L29er · April 5, 2009

personaly getting the 93 tune in my experience netted better mileage, making it actually cheaper to fill with premium. beleive it or not...

So did you once have a 87 octane tune from Justin before you got the 93 octane tune? If I actually could better mileage with 93 octane than that's the way I would go for sure. I estimate it would cost me ~ $5 more to fill up with premium (93) over the cost of using regular (87). So here's the math for my truck right now using 87 octane gas I'm getting ~17.5 MPG so,

17.5 MPG x 26gallon tank = 455 miles/tank

Gas has been $2.06 for 87 octane and $2.26 for 93 octane where I buy it these days.

26gallons x $2.06 = $53.76 / tank, which works out to $0.12 / mile for me right now.

That would mean I would need to 489 miles/tank to break even and get $0.12 / mile using 93 octane. To do this I would have get 18.8 MPG running 93 octane to break even or an additional 1.3 MPG. I have not used 93 octane gas in my truck yet, but the engine was designed to run 87 octane, so it may not get better MPG with 93 octane. It actually could get worse mileage for all I know. Has anyone seen any mileage benefits by running 93 octane in your truck designed to run on 87 octane with the stock tune?

Yeah i tied a 87 tune for about a month, and noticed a decrease in economy, lost nearly 50-60miles per tank, and lost the obvious gains in HP.

Jennabear · April 5, 2009

93 octane typically sees 10-15HP over the 87 octane tunes.

cujo8 · April 5, 2009

Yeah i tied a 87 tune for about a month, and noticed a decrease in economy, lost nearly 50-60miles per tank, and lost the obvious gains in HP.

When you did this experiment did you have the stock tune or an aftermarket performance tune? Also what engine do you have?

cujo8 · April 5, 2009

93 octane typically sees 10-15HP over the 87 octane tunes.

Good to know. Thanks.

What are the MPG differences between the 87 and 93 Octane tunes if driven under the same conditions?

Thanks. Jim

Jennabear · April 5, 2009

93 octane typically sees 10-15HP over the 87 octane tunes.

Good to know. Thanks.

What are the MPG differences between the 87 and 93 Octane tunes if driven under the same conditions?

Thanks. Jim

That would be hard to estimate without doing a prolonged test. Would also depend on the driving style, as I can guarantee that most people are not consistently light on the throttle and staying within MPG optimal RPMs.

cujo8 · April 5, 2009

93 octane typically sees 10-15HP over the 87 octane tunes.

Good to know. Thanks.

What are the MPG differences between the 87 and 93 Octane tunes if driven under the same conditions?

Thanks. Jim

That would be hard to estimate without doing a prolonged test. Would also depend on the driving style, as I can guarantee that most people are not consistently light on the throttle and staying within MPG optimal RPMs.

I was hoping for a rough estimate from maybe your own experience. I have not even had my truck for a month yet and I'm pretty good at keeping to the posted speed limit to within 5 MPH, but I have not gotten my best case scenario for MPG numbers yet, because I have been hauling wood and a utility trailer once or twice a week since I picked up my truck. It would be great to see this type of data on your BB Performance tune website, because I'm sure I'm not the first person to ask these type of questions. Maybe you could have your truck tuned for an 87 octane tune and drive it for a month or two while keeping track of your mileage and then have your truck tuned with a 93 octane tune and do the same thing. Then you would have data for both tunes on the same truck and the same driver. Of course you have to post the data with a disclaimer that stated "your results may very", but at least we would have a rough idea of the benefits of each type of tune. Thanks.

Jim