87 or 89 Gas which do you use?

[Drivinfast247]

Was using Premium, but now that it's $5/gal. here in Michiganistan, I'm using $4+/gal. mid-grade. I fill up every 5 days.

 

[Redfour5]

I use 91/92 because of my tune.
I used to only fuel up at Costco, I stopped because hemituner stated whatever fuel I used was crap.
So I ran two tanks of chevron through before redoing my new data log.

The Costco having bad fuel, or should I say the local one, that surprised a little bit.

Me too...

 

[Scap]

Mid grade (89) Sunoco, only.
This is a screenshot of 90+% highway miles. I started a new job that has me driving against the traffic, so I'm setting cruise control and enjoying the ride.

 

[LakesAZ]

I use 87 but at my elevation, 5,000+ ft, its not a problem. However if I am towing or on a trip I use 91. I use Costco almost exclusively so I am surprised to hear about a bad gas problem with them. I have never in the 20 years plus that I have been using Costco fuel have I come across bad gas from them.

 

[Levi Morgan]

I use 87 because I could tell absolutely no difference between it and 89 or 91.

 

[BowDown]

I use 91/92 because of my tune.
I used to only fuel up at Costco, I stopped because hemituner stated whatever fuel I used was crap.
So I ran two tanks of chevron through before redoing my new data log.

The Costco having bad fuel, or should I say the local one, that surprised a little bit.

I use Costco in my 12.6:1 Z06 with no issues, now Kroger gas, thats a different story

 

[BowDown]

I use 93 because I fill up at Costco and their 93 is cheaper than 87 or 89 everywhere else. I've tried 87 and lost 1-1.5 mpg which impacts me by 23-34 miles per tank or about $3-5 per tank which is about the difference in price between the two

 

[Redfour5]

Mid grade (89) Sunoco, only.
This is a screenshot of 90+% highway miles. I started a new job that has me driving against the traffic, so I'm setting cruise control and enjoying the ride.
View attachment 102298

Downhill both ways?

 

[Scap]

Downhill both ways?

Uphill both ways in knee deep snow, while wearing shorts and flip-flops.

 

[McBroom]

87. When I tow heavy I use 93

2020 Lonestar

 

[Sal731]

93 octane either shell or Sunoco. Been using it since first fill up. Probably stupid of me but my truck cost 70k so probably shouldn’t be cheap when it comes to the fuel

 

[Redfour5]

87. When I tow heavy I use 93

2020 Lonestar

In my 2015, I was 87 for daily driving and 89/90 for towing. I never had any knock. It always gets weird in certain mountain states where they drop the Octane essentially saying you do not need it as air pressure...blah blah blah. Montana never went the 85 octane route thank goodness but some others... I always went mid grade there usually 88 but want to go 90 or whatever the highest is. But, I have to gulp when paying although lately I gulp all the time... The prices really jump in those states I noticed if you go above "regular/85." Here is an article on it regarding CO. Of note are the comments regarding modern day cars vs ones made prior to 1984... https://www.denverpost.com/2006/10/16/some-knock-states-lower-octane-levels/

 

[Trippi]

was using 87 but the manual recommends 89 for the Hemi so that is what I use now. Can't say I notice any difference but for the pennies difference why not?

 

[johna151730]

89 Mobil always. $3.19 a gallon in Mass.

 

[KWKSLVR]

Mid grade (89) Sunoco, only.
This is a screenshot of 90+% highway miles. I started a new job that has me driving against the traffic, so I'm setting cruise control and enjoying the ride.
View attachment 102298

What speed do you set the cruise control at?

 

[Scap]

What speed do you set the cruise control at?

68 for the 65 speed limit and 72 for the 70 limit.

 

[HoosierTrooper]

93 from Sams most of the time, it’s generally cheaper than 89 at the Marathon or Shell stations nearby. My wife and I have burned up a whole lot of gas from Sams in our vehicles and have never had an issue.

 

[Andymax]

I use 87 because I could tell absolutely no difference between it and 89 or 91.

This. Only difference is in the wallet. Manual clearly states 87 is fine. I drive 90% highway and regularly attain 20+mpg with no knock, no ping, no nuthin. Truck runs great.

 

[RAM Patriot]

The HEMI is 10.5:1 compression ratio. 89 octane fuel is recommended for optimum performance and fuel economy by Mopar.



Fuel Based On Compression Ratio

87 Octane
Gasoline with this octane number is proper for engines with compression ratios of 7:1 to 9:1.

89-90 Octane
Gasoline with this octane number is good for engines with compression ratios of 9:1 to 10:1.

93 Octane
Gasoline with this octane number is advisable for car engines with compression ratios of 10:1 to 11:1.

Based on this information our trucks will run optimally with 89-93 octane fuel. Without having to advance or retard the timing.

 

[BowDown]

This. Only difference is in the wallet. Manual clearly states 87 is fine. I drive 90% highway and regularly attain 20+mpg with no knock, no ping, no nuthin. Truck runs great.

Not true.
87 only allows for X ignition advance which is what creates low speed torque and upper room horse power.
Lowering the ignition advance decreases torque output requiring more throttle, more rpm and more fuel to accelerate to a specific speed.

We may only be talking 20-30 lbs ft of torque but over the course of a tank of fuel you'll consume more.
My previous truck averaged about 1.5 mpg less on the highway alone and I've seen the timing impacts on Dyno in my car