Octane question for BB tune

[Justin]

You *can* run 87 octane on the 2007+ 5.3L, but you would be more than likely spending more money and getting less performance than on 89 octane. I have yet to encounter more than a handful of 07+ 5.3L engines that do not ping profusely when on 87. Fact is that the engine is really well suited for 89 octane and above due to the compression ratio and GM only requires a minimum of 87 to appease the vast customer base that would balk at running a higher octane.

Run 89 octane or above at all times and you'll likely see a 2-3mpg gain. With the tune installed, performance will be quite a bit better as well, as there is simply no room for more power to be made on 87 octane since it is not capable of operating at peak efficiency on even the OEM tune.

---------- Post added at 04:50 PM ---------- Previous post was at 04:48 PM ----------

My owners manual says to use REGULAR unleaded gasoline..octane 87 or higher

I believe that the owners manual says to use a MINIMUM of 87 octane. This rings true at high elevation as well, as 85 octane is not acceptable due to the ECMs ability to compensate for altitude changes by increasing ignition timing.

 

[YukonXL04]

You *can* run 87 octane on the 2007+ 5.3L, but you would be more than likely spending more money and getting less performance than on 89 octane. I have yet to encounter more than a handful of 07+ 5.3L engines that do not ping profusely when on 87. Fact is that the engine is really well suited for 89 octane and above due to the compression ratio and GM only requires a minimum of 87 to appease the vast customer base that would balk at running a higher octane.

Run 89 octane or above at all times and you'll likely see a 2-3mpg gain. With the tune installed, performance will be quite a bit better as well, as there is simply no room for more power to be made on 87 octane since it is not capable of operating at peak efficiency on even the OEM tune.

---------- Post added at 04:50 PM ---------- Previous post was at 04:48 PM ----------



I believe that the owners manual says to use a MINIMUM of 87 octane. This rings true at high elevation as well, as 85 octane is not acceptable due to the ECMs ability to compensate for altitude changes by increasing ignition timing.

Would this be true for my 04 as well? you have already tuned it. We stuck with the 87 octane.

 

[JennaBear]

Would this be true for my 04 as well? you have already tuned it. We stuck with the 87 octane.

The 85 octane concern does matter for the 04, but not 87. The 04 has a lower compression ratio and 87 octane is just fine as a result