89 octane

Colin_5.7 · Jun 21, 2016

My truck says its recommended to use 89 over 87 or even 91. What do you put in your Hemi?
My truck: '03 1500 Hemi

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ST-8 · Jun 21, 2016

I use 89. Haven't ran less than 89 in the 6 years I've owned it

roastpuff · Jun 21, 2016

87, it says 89 recommended but 87 is acceptable. I fill up with 89 or 91 when towing or hauling a large load.

blackbeautyhemi · Jun 21, 2016

justin13703 · Jun 21, 2016

89 or 87. You won't get anything out of putting higher octane in it unless it's tuned for it.

usaf2006 · Jun 21, 2016

I run 89 if i have it tuned for 87. I use 93 when it's tuned for 91.

jslowell · Dec 5, 2016

My book says 89 octane. Why cheap. What will you save by using 87 octane. Maybe $5.00 per fillup. The 5.7L hemi is a performance engine not a four banger.

BAMF · Dec 5, 2016

I use 89...that's what ram recommends.

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Lufty · Dec 5, 2016

Every fill has been with 91 (premium)... only because it's 100% gas... no ethanol

smiley · Dec 6, 2016

justin13703 said:
89 or 87. You won't get anything out of putting higher octane in it unless it's tuned for it.

You can totally feel the difference between the 2 at least on my truck. 87 acts like turbo lag. 89 is much more consistent. It could be something with setup but I can tell every time.

cgeorgemo · Dec 6, 2016

Octane isn't power, its anti knock. Without adjusting the engines tune running higher octane than needed gets you exactly nothing but a psychological boost.

I wonder what this button does?

HemiLonestar · Dec 6, 2016

jslowell said:
My book says 89 octane. Why cheap. What will you save by using 87 octane. Maybe $5.00 per fillup. The 5.7L hemi is a performance engine not a four banger.

Actually the 3rd gen 5.7 isn't lol. Fairly low compression ratio and small cam. The Chrysler engineers have stated that the 5.7 was meant to be the high volume pedestrian V8 engine as opposed to the SRT engines. The 4th gen 5.7 is closer to being an actual performance engine in design (VVT, higher compression, heads more like a 6.1/6.4). That being said, since I have it tuned for 91 I use 91-93.

smiley · Dec 6, 2016

cgeorgemo said:
Octane isn't power, its anti knock. Without adjusting the engines tune running higher octane than needed gets you exactly nothing but a psychological boost.

I wonder what this button does?

The computer has to compensate when using lower octane to prevent knock so doesn't that actually relate to power because the computer is essentially lowering performance of the engine that is tuned for 89 from the factory. Your statement would be true in an old non computer controlled engine or an engine that is tuned for 87????

89 octane

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