Have noticed a post or 2 that people talked about running 87 octane. Bad Idea!! Chrysler calles for 89 and up. This is for a reason, spark advance and compression. When I had my HEMI at first I was running 87 octane Gas for id say the first 5 months or so and couldnt figure out why my mileage was always in the 8 mpg range, and why I was always hearing a ping at high rpm's? Well come to find out it was all because of the 87 octane. I switched to 89 and in a few tanks I was noticing better throttle response, the pings were gone and my fuel mileage shot up to 14 mpg.

Remember detonation blows head gaskets.

 

When i first got my hemi i ran 87 octane manual says ok but 89 is preferred. On 87 octane my truck ran fine.
I thought i would try 89 octane because everyone was talking better mileage.
It's been 6 months now and my mileage is still the same as it was when i ran 87 octane.

 

If you're noticing pings then sounds like you have other issues to worry about. I've been driving just fine on 87 octane.

 

I used the 87, but the 89 is an improvement in mileage and the way it runs.

 

Not talkin like a Huge detonation. Not like a turbo car. Slight ping you can pick up with a trained ear... At any rate Im sure you all have read this but here it is anyway... Enjoy

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