Most of the cars I own and drive have engines with compression ratios similar to the pressure of a firm handshake, or perhaps the effort needed to squish a ripe peach in your hand until it erupts its sweet, sticky juices, which then coat your fingers and one determined rivulet trails down the underside of your arm to your elbow, where it then drips, now free. This generally means that gasoline octane levels don’t matter that much to me. I just get the cheapest 87 octane juice.
But there are people with modern cars with genuinely impressive compression ratios that want nothing to do with knock or pre-ignition, so they need gasoline with higher octane, and so buy the rich, creamery fuel known as Premium, which has an octane rating of 91-94 and, I believe, smells like sex and leisure time.
That just leaves the middle grade, 89-90 octane “mid-grade” gas. Who buys this stuff? I mean, okay, there have been some cars that specify mid-range, 89 octane gas, but there weren’t that many. In fact, for cars currently being sold today, there are precisely nine cars that fit this requirement, and they are all either RAM 1500 trucks, Dodge Durangos, or one lone Jeep Grand Cherokee, all of which have the same Mopar 5.7-liter V8 engine. So, really, just one engine requires it.
Here’s another secret: there really isn’t any midrange gas. There used to be, but now it’s most often just a cocktail of 93 and 87, and in most cases is mixed in the pump, right there while you wait. I think they use bartender-trained elves chained up in the pump to do the mixing; I haven’t checked.
You can see how rapidly gasoline refiners have decreased how much midrange gas they produce here:
This cocktail of fancy and cheap gas is only purchased by about 7% of consumers, too.
So, who is buying it? And why are they buying it? Is it just based on the assumption that because it costs more, it must be a bit better? But not, like, rich-guy-premium better? Some of our writers mentioned in Slack that they had cars that knocked on 87 but were fine on 89, so perhaps that’s what the 7% is made up of? Car geeks with engines that have juuusssstttt too high compression for the cheap stuff, but don’t need the good stuff?
For most people, mid-range seems like a waste of money. But maybe there are some justifications for it? More mellow flavor? Deeper color? Who knows? If you have thoughts or justifications or just want to defend mid-range gasoline, now is your chance! Have at it!
Top graphic image: depositphotos.com
There are far more comments of people saying they buy mid grade than I thought. I figured it was no one.
The people who buy it are people with engines where 89 octane is recommended… such as vehicles with the modern Chrysler 5.7L Hemi V8:
https://www.allpar.com/threads/ram-1500-premuim-or-midgrade-5-7l-hemi.241038/
Remember when Sunoco had seven buttons on their pumps?
The variable speed pumps earned their keep in those stations!
The manual for my 1996 Trooper calls for it, so may as well.
My in-laws buy mid-range. Their Lexus manual says the car should get premium, but mid-range is acceptable, and the dealer told them it doesn’t make a difference.
I have a 2011 Lexus rx450h.
I tried all three for several tanks each. Low grade gets worse fuel economy and a slight reduction of power… Mid and premium get the same power and fuel consumption… so I buy mid grade.
My Lexus has the same power and economy no matter what grade or brand of gas I put in it. I had expected a noticeable difference, which could be compared to the difference in price, but there was none.
Every gallon of gasoline has the same amount of energy, but the higher octane rated fuel combusts more smoothly and is less likely to ping if the timing is too far advanced. Higher octane allows earlier spark timing and therefore more power, if the engine is tuned correctly.
My 05 Dodge Ram 2500 Hemi recommends 89.
I run 87 most of the time, especially if it’s just doing light work. On road trips towing the car trailer I usually run 89 or higher because I know it’s going to be low rpms and high loads for hours on end.
I pretty much exclusively get midgrade for my fr-s and my old 1.8t jetta. both called for 91 which was never available, and I could never afford 93, so midgrade it was. Never seen any performance or fuel economy difference compared to 93 unlike 87 which they both drink like crazy to avoid knocking
Mind you this was on a high school and now college budget so splurging was never really an option like most people would
I put mid grade in my Subaru.. premium is recommended but not required and buying the cheapest option seems like a cop out so mid grade it is! The Mustang gets 93 all the time since it’s tuned for it.
I buy mid-grade sometimes because I feel so bad for that middle button with its smudge free surface while the other two are blurry with the fingerprints of popularity. Also, during the pandemic, I figured that was safest button to touch.
My Stihl and Echo 2 strokes both call for midgrade. So, negligible use, but some use.
I used to go to the one station around me to get ethanol free 94 for my 2 strokes. Now that I’m down to 1 chainsaw and 1 weed eater I just buy a bottle of premix that generally last me the whole year. Not cheaper but honestly it’s a couple of dollars a year and far more convenient.
I buy midrange because I can. Envy me puny mortals. Actually I buy what is specified in the manual but occasionally I will buy my babies a take of ethanol free to clean out corn. I mean we humans need bran but do our cars?
I don’t know how many octane one loses over a given amount of time but generally I got with the highest octane ethanol free gas I can buy.
Who knows how long it’ll end up sitting for, or how old the gas I’m getting out of the pump is.
I can’t wait til I’m no longer burning through a tank every 4.5 days, like clockwork.
My B5 Audi S4 used to require 91, but I would normally buy 93 because that’s what was available near me. So when I’d come home to visit, I’d buy 91. Or, if I had a partial tank full of 93, I would buy 89 to top off. I replaced that car with a Golf so 87 for that car.
My C5 Corvette gets 91-93 depending on where I am, but one time I was up in rural Maine with the car and I needed to fill up. 89 was all they had. I figured I wasn’t doing a track day and I had some 93 in the tank so why not. I made it all the way home and there was no knocking on 89 so that was good enough for me. Otherwise I’ll use 91 just for casual driving. For track days I use 92-94 depending on what’s nearby the track.
I used to run mid-grade on a few cars that I had tuned with HPTuners to run on 89 octane. I started with a tune for 91 octane and played with the fuel trims and timing and didn’t see any losses moving down to 89 because the engines were mostly stock. One vehicle I picked up about 15hp on the dyno, though the other never saw a dyno so I don’t know how much I picked up on it. In retrospect, the power gained was nice, but likely not worth the extra money spent on each gallon of mid.
I also had a car that stated 90 octane minimum, which was odd, but would accept 88-89 octane at higher elevations.
The people buying mid-grade are the automatic V6 Mustang and Camaros owners who use the phrase “this baby is too good for regular”.
And really they aren’t
Mid-grade fuel for mid-grade cars…
My 3.5 Intrepid called for midgrade, and I genuinely got better fuel economy on it. I have not bought 89 since then.
I get mid grade because I have a Ram with a hemi. It’s not a high number of vehicle models that require mid but they sold millions of them between 2004-2024 and quite a few are still in the road. I get premium in my Civic because it’s the sport and apparently that’s how I get the additional 8 HP over the run of the mill 1.5 turbo.
Came here to say the same. I added an ’18 Ram with a 6.4 Hemi to my fleet this year and the recommended fuel is mid-grade. I use it whenever practical, and absolutely if I’m towing or hauling a big load with it. I’ll use regular in a pinch and it doesn’t seem to mind, but the ever accurate seat-of-the-pants-o-meter says it’s happier with 89.
I bought MidGrade on a road trip, because the station I stopped at in Bumblefuck, WY, was out of Premium, and my car wants 91 minimum. Looking back that was fuckin’ dicey because who knows how long the MidGrade had been sitting there, shoulda just put in the 87 which at least would have been fresh…
If they didnt have premium they didnt have 89 either as its a mix of premium and “low”.
I’ve rarely used mid-grade gas, precisely because it’s mixed at the pump and you really just have to trust the gas station that the ratio is correct enough to be getting your money’s worth.
I don’t recall ever owning any cars that had call-outs for mid-grade gas in their owner manuals. Most have been fine with 87. A string of Chevys, Jeeps, Subarus, an older Dodge minivan and even a big Chevy 454-powered motorhome all were fine with the cheap stuff. Now, the Land Rover Discovery 1 with its Rover/Buick V8 specifically required 91 octane or above. (And using lower octane was known to flirt with getting burned valves.)
The slightly silly Grand Caravan R/T in the garage only asks for 87, although it’s flex-fuel rated which would have no problem the higher octane of E-85 or conventional 93-octane gasoline… but it’s more than quick enough on the “cheap stuff.”
My old Z52-package Corsica had the regular car’s owner’s manual, which was written for 87-octane regular unleaded, although feeding it 93 was noticeably better, so that’s what it got.
And the weird one was my ’83 F-150 with the 300 straight six. Sure, the manual said 85-87 was fine — but it would knock like crazy. In the winter, it was usually happy with mid-grade 89… but not always. (Possibly due to bad pump blending.) In hot weather, it took 93 to keep it quiet and smooth. My family bought two more I-6 powered F-150s, both later models with fuel injection and they were fine with 87 all the time. My old, carbureted one was the prima donna.
87 is low grade? I laugh at you lowlanders. Up here, we’re just fine on 85. As to the topic at hand, great question. I’ve never purchased it and I’m not sure I’ve ever seen anyone else hit the button, either.
I used 85 once when I drove cross country in 2000 because 87 was $2 and there was no way I was paying that much for gasoline. The Legacy ran so well on 87, I figured it would be fine with that, too. It was not. Nothing serious happened, but it was very unhappy with me.
the Subarus are notoriously fussy.. had a 92 Legacy turbo wagon that wanted premium, anything less or premium that wasn’t top-tier, and it would hiccup stall surge buck and generally make itself obnoxious..
first car I ever had that noticed what gas it was getting..
Come on down and visit! The oxygen is better, boost pressure is higher, and the horsepower is greater! The only reason 85 is sold up there is because you don’t need as much pressure to detonate the mixture!
Nah, every time I go down there, the air is full of water and I hate that. You have a point about the horsepower, though.
My truck loved 85. Definitely a improvement as 16,000 lbs was my usual total wieght up there. I recall a sign saying i had to pull over at that wieght, so passing the sign under 1/4 tank was kinda important. Like dont get pulled over important since my truck wasnt legal at that.
In Wisconsin the big gas stations offer “mid grade” cheaper than regular. The hitch is it is 15% alcohol vs 10.
E15 is usually 88 octane at Woodman’s.
I have seen E15 88 in MD and PA.
I’ve always seen e15 as 88 octane. It seems like the newer Sheetz Caseys and good2go always have it
I tend to get 89 for the riding mower and generator unless I’m filling up the car at the same time, in which case the small engines get premium too.
The mower and generator are fed from gas cans, so I add fuel stabilizer to the empty cans before heading to the local petrol purveyor. The flow of fuel into the cans is (I assume) going to mix the stabilizer more or less evenly throughout the five gallons.
I put it in my older cars, they don’t need it, but I figure a little extra octane can’t hurt, but I’m not springing for premium
The Hemi in the bf’s 300C runs fine on regular, but Chrysler calls for mid-grade gas. I have a handful of cars that will be very damaged if I don’t run 93 in them, so I do that.
A few stations locally have 87/91/93 which I suppose appeals to the cheapskate who also drives a car requiring premium.
Some cars are calibrated for 91 octane premium, rather than 93 octane premium. That’s good for Western states where 91 octane is often the highest available short of the (also rare) 100 octane street-legal unleaded race gas.
As I understand it, all factory tunes are for 91, for exactly that reason.
I’m on record wishing for more OEM approved 93 tunes for those of us who live where it’s readily available.
A lot of performance cars spec 93 octane but will not explode on 91. They just won’t perform up to advertisements. Seems like the newest Z car gained .3 in the quarter when they retested it on 93 vs 91. Could have been the DA and road conditions too, though.
Often that’s true, but not always. The Subaru WRX STi owner’s manual calls for unleaded gasoline 93 AKI (98 RON) or higher. It also says that 91 AKI (95 RON) “may be used with no detriment to engine durability or drivability. However, you may notice a slight decrease in maximum engine performance while using 91 AKI (95 RON) fuel.”
I guess more precise would have been to say that no car I’m aware of is unable to run on 91.