What fuel octane do you use?

[303 Mopar]

Here in Denver we have 85, 87 and 91 octane. Some say the altitude effects the burn so it's equivalent to 87, 89, and 93 at sea level but I'm not sure about that. My Ram 1500 5.7 owners manual says 87 is acceptable but 89 is recommended so I round up and run 91. On the 392 Hemi in the Cuda I always run 91 because it's the highest. For the 505 in the Charger and 318 in the Sport Satty I also run 91 because it's the highest octane. I've heard there are 2 other stations in the metro area that offer 93 octane and one offers leaded fuel one Saturday's only or something like that.

So I'm curious what octane do you run on your e-body and on your daily.

[Cuda Cody]

91 is the best we can get around here.  That's what I use in my E-Bodies. 

[Brads70]

In my neck of the woods I always use Shell premium (91) as it has no ethanol. There is higher octane fuel available at other brand stations(94?)  but it has ethanol.  This is in the Challenger, my other regular vehicles get the cheap stuff. LOL

[GoodysGotaCuda]

The altitude to octane differences are real, I'd be fine with 87 in the ram, especially if it's not modified.

I run 93 in the 'Cuda, but I likely don't really need to given it's not a high compression engine. It just makes me worry less about knock since I haven't fully dialed in my timing tables. My smog 360 Warlock gets 89, mostly to just help with carb heat soak/vapor locking. My Subaru and BMW get 93, both are factory turbo 4cyl cars and need the knock protection.

[RUNCHARGER]

We get 94 up here, expensive but it doesn't matter.

[Spikedog08]

I run 94 and turbo blue 110 mix in the hardtop and 94 in the convertible.  Cost about $100 for a tank in the hardtop.   

[70/6chall]

In my Challenger 87 is just fine for the old lean over.     Thanks,   Al

[Chryco Psycho]

THe altitude has a real effect , as there is less air pressure @ 5000 ' , sea level is about 14.67 psi while @ 5000" you have 12.23 PSI
so if you have a 10:1 compression engine you should have 146.7 psi pressure in the cylinder while at 5000'  you should have 122.3 psi under perfect conditions so you need less octane as there is less pressure / heat
BTW here 91 octane is regular & 95 premium

[cudabob496]

87 may have the most ethanol.
Junk.
At least run 89.
You'll probably notice better performance in going from 87 to 89.

[Topcat]

I add Torco booster and then add Redline leaded substitute since I still have stock heads on the Hemi.

91 is the highest unless I go to the high Octane gas station.

[cudabob496]

I add Torco booster and then add Redline leaded substitute since I still have stock heads on the Hemi.

91 is the highest unless I go to the high Octane gas station.

I've read you really don't need the lead additive.

[Crash520]

Down here in Aussie land we still have 95 and 98 at Caltex

[Chryco Psycho]

I add Torco booster and then add Redline leaded substitute since I still have stock heads on the Hemi.

91 is the highest unless I go to the high Octane gas station.

I've read you really don't need the lead additive.

& you believe everything you read ? Without lead the exhaust valves will weld to the seat & tear away material every time they open , you either need stellite seats or some kind of additive , I have seen valves recessed over 1/4" deep into the head .

[Racer57]

Doesn't do much good posting what octane your using without saying what engine you have. 

Stock HP383. I use 89. Plugs look great.     91 is probably overkill and I have used 87 without any knocking.

[Topcat]

I add Torco booster and then add Redline leaded substitute since I still have stock heads on the Hemi.

91 is the highest unless I go to the high Octane gas station.

I've read you really don't need the lead additive.

& you believe everything you read ? Without lead the exhaust valves will weld to the seat & tear away material every time they open , you either need stellite seats or some kind of additive , I have seen valves recessed over 1/4" deep into the head .