08 5.7 hemi fuel economy... and fuel type?

ram5.7hemi · Nov 8, 2013

what type of gas is best for the hemi? i have an 08 5.7 laramie. 4x4 20 inch rims, volant cold air intake.. and a dual exhaust... not sure if its stock or aftermarket dual exhaust.. does putting 91 octane fuel in your truck give you better performance and better mileage?

NWRQC · Nov 8, 2013

If it's tuned for 91 octane then yes it will give you better performance. The manual calls for 89 octane so I would run that. You can run 87 octane, but the ECM will pull timing which will affect power output and fuel economy slightly. Running fuel with a higher octane than needed will only empty your pocket faster. Octane doesn't create power, it creates a slower burn which allows you to get more aggressive with your tuning.

ram5.7hemi · Nov 8, 2013

NWRQC said:
If it's tuned for 91 octane then yes it will give you better performance. The manual calls for 89 octane so I would run that. You can run 87 octane, but the ECM will pull timing which will affect power output and fuel economy slightly. Running fuel with a higher octane than needed will only empty your pocket faster. Octane doesn't create power, it creates a slower burn which allows you to get more aggressive with your tuning.

I understand it won't get more power running 91, i was just wondering if it would help fuel economy any? where i live the 91 isn't much more than 88... i can't find 89 in town. the closest options are 88 and 91 octane.

ram5.7hemi · Nov 9, 2013

does anyone know if there is negative effects to running 91 without a performance chip? i just have a CAI and dual exhaust.. would 91 hurt my truck? or get better MPG?

jacobsjl88 · Nov 9, 2013

I run 91 octane on a 91 tune and I get roughly 13.5 in the city. That's with my heavy foot and a good strong wind here in OKC. Plus I have a K&N CAI and dual exhaust.

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MegaMouseGW · Nov 9, 2013

In truth 91 octane is not worth the extra money spent for a couple more mpg and hp. The gains are so slight it is much better to get a tuner and tune for 87 which will give better gains over just running 91 octane.
Save your money and get a tuner, it is far more worth it than running higher priced gas.

NWRQC · Nov 11, 2013

Nothing will happen to your truck if you run 91.

namccanna · Nov 11, 2013

Most of the 91 octane by me is ethanol free! That's why I run it. Plus my truck is tuned for 91. That extra few $$ at fill up is well worth keeping that garbage out of my engine!

Performance wise without a tune, it does nothing! Good or bad.

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Trupiano · Nov 11, 2013

hen I had my 11, I used 89 nothing less. But yeah, if it's tuned ensure you use the recommended octane.

Alex · Nov 11, 2013

I ran the 91 tune for a while with the Trinity, then realized I was being stupid spending the extra money for 91 on a daily driver haha. Switched back to the 87 tune, barely a noticeable difference, and WAYY cheaper at the pumps

HemiLonestar · Nov 11, 2013

Which ever is best for your tune: 87 if tuned that way, 89 for stock, 91+ if tuned that way. As for fuel economy, Dodge Ram fuel economy is a contradiction in terms....

08 5.7 hemi fuel economy... and fuel type?

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