Any Disadvantages Tuning To 93?

PFF09Sierra · June 21, 2010

Sounds like some of you have had your trucks tuned to 93 and some for 87. Around MD we have 87,89,93 (Unless certain gas stations sell 91 that I haven't seen). After E-mailing Justin at BB he had told me that Tuning for 91 would yield better performance because of the engines compression ratio. Im not sure if he didnt know MD had 89 and 93 but just wondering which Octane would be the best. Im leaning for towards 93 but havent heard any bad things from the 87 tunes. Is it true that running higher octanes will result in a dirtier engine in the long run (Cant remember where I heard that) because of the increase in carbon build up?

Also, im on my seconed tank of 93 in preperation for the tune and have noticed a SIGNIFICANT decrease in performance and MPG. I took my first road trip in the truck and it just happened to be on the first tank of 93 and saw a decrease of 2 full MPG. I was thinking I would get the best I had ever gotten because of the long straight roads but I got 15.5 from 18.7?? Also the truck seems to have slower acceleration and just plain dead off a light. Any suggestions.

Thanks for all the help!!

David

Doug_Scott · June 22, 2010

Sounds like some of you have had your trucks tuned to 93 and some for 87. Around MD we have 87,89,93 (Unless certain gas stations sell 91 that I haven't seen). After E-mailing Justin at BB he had told me that Tuning for 91 would yield better performance because of the engines compression ratio. Im not sure if he didnt know MD had 89 and 93 but just wondering which Octane would be the best. Im leaning for towards 93 but havent heard any bad things from the 87 tunes. Is it true that running higher octanes will result in a dirtier engine in the long run (Cant remember where I heard that) because of the increase in carbon build up?

Also, im on my seconed tank of 93 in preperation for the tune and have noticed a SIGNIFICANT decrease in performance and MPG. I took my first road trip in the truck and it just happened to be on the first tank of 93 and saw a decrease of 2 full MPG. I was thinking I would get the best I had ever gotten because of the long straight roads but I got 15.5 from 18.7?? Also the truck seems to have slower acceleration and just plain dead off a light. Any suggestions.

Thanks for all the help!!

David

What was the alcohol (methanol) in the fuel you bought? There is more to the "need" for higher octane fuel than just the tune. To take full advantage your engine should actually require it in the first place. I think in your case you got a tank of 10 or 15% aclohol. And chances are you have not used that blend before. I tried running the Sunoco 94 we have up here in my 00 GTP with a smaller pulley on it, and got 10 to 15% less economy compared the Esso Premium (it does not have the alcohol in it). Personally, I would do what Justin recommends, and if you cannot get 91 octane, aim for the 89 that you can get.

I am not sure why the FTC (or whatever department it is that regulate advertising) even allows fuel companies to sell higher octane fuel as "premium" or "super". It is not premium in the traditional sense of the word. It is not better, or even a higher grade of fuel. It simply is a blend that resists ignition by compression better. That also means it is harder to ignite, unless you have the extra boost of higher compression (or a smaller pulley on your supercharger) to help you out.

PFF09Sierra · June 22, 2010

I believe it says the fuel contains up to 10% alcohol. Any truth to running higher octane and having more carbon build up? I just E-Mailed Justin to confirm but I just thought it was odd that it ran so poor with 93!

jfm1982 · June 22, 2010

I believe it says the fuel contains up to 10% alcohol. Any truth to running higher octane and having more carbon build up? I just E-Mailed Justin to confirm but I just thought it was odd that it ran so poor with 93!

Please let us know what Justin tells you?

I'm going for the mid range tune. I think is the best bang for our buck

Jennabear · June 23, 2010

Remember, it boils down to quality as well. You could be getting premium fuel, but a poor quality, which will cause your vehicle to run poorly.

jro909 · June 24, 2010

unsure about other places but here ethanol is only put into regular and mid range gas not the top end premium stuff

Ahsmo · July 18, 2010

I believe it says the fuel contains up to 10% alcohol. Any truth to running higher octane and having more carbon build up? I just E-Mailed Justin to confirm but I just thought it was odd that it ran so poor with 93!

There is no truth to that. Octane rating boils down to rate at which the fuel will burn. 93 Octane will burn slower than 87 Octane. Engines with high compression ratios require fuel with a higher octane rating due to the increased heat of compression. Our engines get along just fine on 87 octane. Some have theorized that running higher octane in a car meant for lower octane will cause damage from unburnt fuel exiting the combustion chamber. Unburnt fuel could possibly burn up exhaust valves.

I have an 87 octane BB tune just because I am weary of fuel quality inconsistencies that exist everywhere in this country.

Ethanol has a much higher octane rating than standard gasoline. So companies add it gas to raise the octane rating and they probably get some kind of subsidy for using ethanol.

ColoradoSkiCountry · July 18, 2010

Until you've had the tune done, you can expect poor performance by running 93 octane. The engine was designed to run off of 87 (if you have a 5.3L or 6.0) Once you get the tune i'm sure everything will be fine.

Just consider this though: 93 Octane is not available everywhere. Some states and cities may only sell 91 Octane as the premium fuel.