Octane question for BB tune

[Texastoad]

I have a 09 yukon 5.3L flex fuel motor...I have signed up for a BB tune in Houston in March. I normally run the 87 octane gas in my Yuk...is that ok for the tune. Should I be running the Higher octane gas? I would think I should do the tune with the 87 octane since thats what I run all the time...Ive had no issues running the lower octane so far

 

[07Burb]

If you run 87 now and choose to run 87 going forward that's fine. Justin can tune to fit your needs and wants. You'll love how your Yukon performs once tuned!!

 

[JennaBear]

You "can" run 87, but there is probably some pinging/detonation going on. For your engine compression, a minimum of 89 is recommended.

You can be tuned for what best suits you, but since you are getting an AutoCal, you can get a tune for the higher octane should you decide to run it.

I would recommend you run a few tanks of 89 and see if you notice a difference. You should see a peppier response as well as better MPGs.

 

[Texastoad]

thanks for responses

Thanks guy

 

[OHSIXX]

Get it tuned for premium fuel and both your and your vehicle will love it
Best bang for your buck IMO

 

[MudnRox]

Get it tuned for premium fuel and both your and your vehicle will love it
Best bang for your buck IMO

X2.......I totally agree

 

[ccapehartusarmyINF.(ret)]

you should only run higher octance gas if the manufacter recommends or youve added forced induction otherwise your wasting your money
the technical reason is higher octane gas is for engines with compression ratios above 10.5:1 typically. so if you have a compression ration above that
higher octane doesnt not mean better it has a higher flashpoint then regular gas.
that engine has a 9.9:1 compression ratio regular is just fine

 

[Texastoad]

flex fuel

My yukon is flex fuel...so doesnt that mean I can run either or fuels???

 

[Big Buttons]

Flex fuel means you can run E-85 fuel

 

[Texastoad]

owners manual says

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

 

[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