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
I have never used the stuff until I bought a big honking truck that suggested it. I think the trucks sensor must sense the lower octane stuff as the truck does seem slight down on power if 87 is used. I tried the Non ethanol 91 on it after running through a tank of 89 and was surprised it did not change anything noticeable. I know the e85 on the old chrysler my wife had made the engine seem to run better, but it also got way worse fuel economy due to ethanol not having the same energy density and he engines compression ration not optimized for e85 (side effect of flex fuel vs designed only for E85) so I kind of expected a mile or two of Fuel economy change going to 91 with no grain alcohol mixed in. but I could not confirm that.
This may be a uniquely specific problem to Colorado, but the stations here sell 85 octane as regular, 87 as mid grade and 91 as premium. I’m one of the people who is getting mid-grade for our VW turbos that “require” 87 octane minimum, because our regular gas is shit. Would get “regular” if it were actually 87 octane out here.
I used to by mid range gas on my two saab 9-5s. The engine was tuned for 90 (no idea why since that doesn’t exist afaik, maybe in Sweden?) and I found it ran better on 89 than on 87 or 93.
I use midgrade in a few cars. The first is my 78 Impala. Since the engine rebuild, it runs happier on a higher octane gas. I’ll also run midgrade in anything non-truck with a modern 5.7 Hemi, which is factory recommended. My 05 Magnum runs somewhat better on it and my parent’s 13 Charger R/T runs better with it too. The MPG increase is noticeable in the Charger too.
with that many cars, the goal of course is to get whichever does not have ethanol in it as you know at least 2 or 3 of those cars will never run through a full tank of gas inside 6 months. Corn syrup is the result of old ethanol gas.
I use Premium grade from BJs (Warehouse store) for the Jaguar since its the same price as mid grade on my local Mobil gas station. I made the mistake of running regular once and the mpg drop was noticeable.
Premium grade BJs in the Jag seems on brand.
The ethanol free gas around here is either REC 90 or Wawa has 89 ethanol free. My car with a carburetor runs a lot better on straight gasoline. So I end up using mid grade for the ethanol free part, not the octane. It would run fine on 87.
My 1998 BMW 318i recommends 89. My 2001 BMW e46 took 91, which wasn’t available at most gas stations. I’d alternate between 89 and 93. Wawa and some Circle K stations actually have 91.
I do. The recommended fuel for my truck is 93, but I use 89 to save some moolah while avoiding knocking. Luckily my DD Accord takes 87.
This helps explains what I have been seeing on my Tactrix logs. While my Subi says 87 was fine.. I always ran 89. Seemed to like it better and pulled less timing at higher RPM’s. The past few years I have seen it get very grumpy and pull timing at the higher RPM’s even on Mid. Thus I have moved to 91 and made it rev happy all over again.
This helps solve the mystery as to why… I always thought it was just my car getting up there in miles. 300k is a decent amount for a not lightly driven Subi.
Guess the bar tending elves in the pump need more lessons…
In high elevation places low grade is 85, and mid is 87-88. I always ran mid grade when I lived in Utah, because the car asked for 87 so that’s what I would give it. As soon as I moved to normal elevations I dropped to low grade because it’s 87. I know there are all sorts of reasons the mountain regions are allowed to sell the low grade stuff and how it’s supposedly the same, but I always figured better safe than sorry.
Pretty much this. My parents were the original owners of my ’97 ZJ, and my dad would sometimes fill it up on the way home from work. We started to notice knocking whenever he filled it at one of the stations near his workplace. Not wanting to drive too far out of his way, he started filling it with midgrade, and the problem went away. I still mostly use midgrade, especially since it’s not a daily driver.
I used mid-grade in my ’06 Altima and ’98 Chevy C1500 in the summer due to knocking. It’s an easy fix.
When I lived in South Dakota 20 years ago, the mid grade was the only nonethanol option and was the cheapest.
These days, most of the gas stations around me have e10 87 octane and e15 88 octane. One of the gas station chains sells the e15 for around 20¢ cheaper than the e10, so I fill up with that.
Mid-grade has exists to squeeze a few extra bucks out of the sort of people who don’t know cars, and know they don’t, so they follow every car maintenance guidelines they have ever heard. The type that will (only) change their oil at 3000 miles, no matter what, even if they definitely should do it more or less often. The extreme “better safe than sorry” types.
Just put a stupid name on it, like “With Deposit-Blasting Technology*” and they’ll pay for it.
*For port-injection engines only (for best results, read this in end-of-commercial hyper-speed speech).
Because they won’t know if their car has port injection, or that ALL port-injection engines clean the valves by virtue of their function, not because of anything the pricier fuel is doing. Better safe than sorry, right?
Keep a vehicle for 200,000 miles and there’s no such thing as “too often” oil changes. The only thing you’re hurting with over-maintenance is your wallet.
And your time.
When I was driving my BMW e36 328is, I would buy mid grade for it as that is what it called for. If I had a car that called for it, I would run it.
Theoretically the Renix ECU in my 90 Jeep MJ would take advantage of the extra octane as it simply uses a knock sensor to advance the timing until it knocks. The only time I’ve run higher octane in it though is when Sheetz is offering a killer deal on e15 which is 88 octane.
I toss in 89 octane mid-grade into my 2019 Golf with the 1.4T. It does seem to build boost a bit better than with 87 octane, going from “anemic” to “eh, it’s fine” levels of torque. I also used to run it in my Shelby Z Daytona, and at the time one of our regional chains would sell a 10% ethanol blend that was rated at 90 octane for the same price as regular at other stations. The mileage wasn’t quite as good as with 91 or 93 octane premium (no ethanol) or 87 octane without ethanol, but the performance boost was VERY welcome to 19-year old me!
I have a ’22 Ram with a hemi and it says in the manual that 89 is preferred but 87 will work. You will just get less mpg. So I always run 89. The mixing at the pump thing is something I learned reading this though. I’ve always thought that different stations seem to have shittier quality 89. Kroger gas generally gives me less mpg while somewhere like Sheetz give me what I expect. I bet Kroger mixes more 87 in than somewhere like Sheetz so they can save a buck or two.
Having grown up seeing a 10 cent difference between regular and premium grades, I always figured mid-grade was an excuse to jack up the price of premium while maintaining that 10-cent gap people were already used to.
Ahh, the not so old days when the premium was $0.10 per gallon difference between the grades, unlike the ~$1.00+ per gallon difference between 87 and 91 these days.
I run 89 in my Dodge Journey. It’s a prefacelift so it has the 3.5l V6 and the owners manual recommends mid grade but emphasizes that premium isn’t worth it and no performance gains will occur. I will say that the engine seems to run a little bit better with it. That tidbit about the 5.7l Mopar V8 that debuted around the same time requiring mid grade as well makes me think it is or was just a Mopar thing to require it.
I buy the cheapest ethanol-free option.
Holy Crap! I’ve been putting 87 gas in my 2019 Ram 1500 since I bought it new in 2018. And it’s “the engine” that needs 89. And I wonder why at about 40,000 miles it has this crazy ticking sound? Hmmmm….. Uh oh.
Don’t blame yourself, it’s a RAM a ticking at 40,000 miles while not good is typical.
Exhaust manifolds if you’re lucky, cam lifters if you’re not, regardless it’s not due to the fuel octane being used.
hemi tick is pretty normal and I still think it is a result of the 10K oil change regimen they suggest. though it could also be from the type of oil used if you are taking it to a Jiffy Lube type place. MS 12633 material standard for the oil is generally required. Mobile 1 Euro and Pennzoil Ultra are the two that I can think of that meets this standard. though I will tell you, I have used Royal Purple Euro Formula in my 6.4 Challenger since I purchased it and it has over 80k miles with no tick. But it also has a manual trans and thus no MDS and the MDS is the reason for the tick in these things.
When the pig swill at altitude regular is 85 octane like where I live, then you get the mid-grade.
85 at altitude is identical to 87 at (or near) sea level, don’t sweat it!
It was strange seeing 85 octane the first time I drove through Colorado. I filled my tank with it once I looked up that it was the same as 87 at sea level!
Nebraska used to have mid grade filled with ethanol (made from corn) and would subsidize the price so it was less than regular. So as a teen growing up in Omaha I would buy it for my Ford Probe GT.
I put at least 87 octane in two of our current vehicles, which at higher altitudes means mid-grade.
I use it in my wife’s Mini S. It calls specifically for 89, and in the summer on 87 it’ll definitely pull timing. I use whatever the highest I can get in my Clubman JCW, but it’s also modded and making maybe 350awhp.
People who don’t understand how octane impacts engine performance are buying the midgrade. They think the regular stuff is “cheap,” the midgrade is average and the premium is expensive. They don’t want to put cheap gas in their car but they don’t want to pay for expensive gas so they get something in the middle.
Kinda like, I don’t want to pay for a Rolls Royce but I don’t want to drive an econobox so I bought a Lexus.
They don’t understand that higher octane does not equal higher performance. Even a lot of car people don’t get this. They see 100 octane racing fuel and think that gas makes the engine put out more power when really what it does is keep the higher compression engine from detonating the fuel air mixture too early in the compression cycle.
The only times you might legitimately buy the mid grade stuff if you know what you’re doing is when you live in the mountains and are taking a trip down to sea level (octane requirements rise with lower altitude due to air density and you’ll want midgrade, because midgrade at high elevations is 87 octane while regular is 85-ish) or if you’ve got an old hooptie with a lot of carbon buildup on the valves.
The carbon retains heat and after it gets hot enough can act like a glow plug and cause lower grade gas to predetonate. If you’re driving an old car and it sounds like a popcorn maker under the hood even though you know the timing is adjusted correctly, run higher grade gas until you have time to clean the valves.