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-   -   87 or 89 Octane in Hemi? (http://www.jeepgarage.org/f108/87-or-89-octane-in-hemi-31851.html)

fotomatt1 11-30-2011 12:50 PM

87 or 89 Octane in Hemi?
 
I'm picking up my JGC Laredo X tonight, and I'm just curious what everybody fills up with? The manual suggests 89, but also says 87 is acceptable. Has anybody noticed a performance or mileage difference between the two? Any feedback is appreciated!

tyresmoker 11-30-2011 12:59 PM

Re: 87 or 89 Octane in Hemi?
 
I fill it with 87 and let er rip...

HemiHog 11-30-2011 01:06 PM

Re: 87 or 89 Octane in Hemi?
 
Yeah. I've never noticed any difference in mileage or performance with the Jeep or the 5.7 300C or Ram I used to have. They seem just as happy either way.

billyp 11-30-2011 01:26 PM

Re: 87 or 89 Octane in Hemi?
 
Same here. Tried a couple of tanks of 89,didn't seem to make any difference(at least for my conservative driving style and only very occasional light duty towing). Almost 13K miles so far.....no problems.

peckmv 11-30-2011 01:30 PM

Re: 87 or 89 Octane in Hemi?
 
Higher octane will not give you any more gas mileage or HP. It is an anti-knock additive that is put in gas so the timing can advance without pre-ignition occuring. The timing will advance when a load is put on the engine, such as towing. I run 87 and have had no problems or lack of performance. I do plan on using 89 when I will be towing. Save your money, use 87 and splurge for the higher octane as needed.;)

jeepgrady 11-30-2011 07:07 PM

Re: 87 or 89 Octane in Hemi?
 
Had both an '05 "C" and an "05 WK with Hemis. Always used 87 in both and had no performance problems whatsoever.

Red G8R 11-30-2011 09:08 PM

Re: 87 or 89 Octane in Hemi?
 
87 octane only.

frog_a_lot 11-30-2011 10:25 PM

Re: 87 or 89 Octane in Hemi?
 
Are the US Hemi's different export ones, just because in Aus, the lowest octane is 91, and if i owned a Hemi i would put at least 95 octane, but most probably 98 octane like i use in my WRX, never 91 or lower.

rubicontrail.net 12-01-2011 12:21 AM

Re: 87 or 89 Octane in Hemi?
 
Quote:

Originally Posted by frog_a_lot (Post 525143)
Are the US Hemi's different export ones, just because in Aus, the lowest octane is 91, and if i owned a Hemi i would put at least 95 octane, but most probably 98 octane like i use in my WRX, never 91 or lower.

In the US, our octane ratings are different: http://en.wikipedia.org/wiki/Octane_rating

The owner's manual for the Hemi, suggests mid-grade.

frog_a_lot 12-01-2011 12:30 AM

Re: 87 or 89 Octane in Hemi?
 
Although that suggests that your 87,89 octane equals 91,93 in Aus terms, which is still lower than i would ever use. I am assuming they must be tuned slightly differently, it looks like you guys cant really get what we call 98 Octane, which is 94 in US octane terms.

Kevlars 12-01-2011 01:04 AM

Re: 87 or 89 Octane in Hemi?
 
I put 91 as it seems to me I get smother and better performance...

pwguy 12-01-2011 07:50 AM

Re: 87 or 89 Octane in Hemi?
 
Quote:

Originally Posted by peckmv (Post 524802)
Higher octane will not give you any more gas mileage or HP...

This statement is true for using gasoline with an octane rating higher than an engine is designed for. If you use lower than the recommended octane both power and mileage will be adversely affected. The change may not be noticeable to most people under normal conditions.


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