New to mini. Is it necessary to use 91 octane?

 

In a base car, its not needed - BUT in hotter weather it may help you get a little *a little* more power.

 

Your engine control unit will adjust the ignition advance to compensate for the fuel you are burning. So, yes you can put regular in your car, you might notice less power compared to premium fuel.

Dave

 

That's what I was thinking but as quirky as these cars are I wanted to make sure.
Thanks for the replies.

 

Higher Octane = slower burn - less detonation ( Spark Knock )


Higher compression motor - turbo or supercharged needed. Just my 2 cents

 

Also, higher octane can translate into a little better mileage, mid grade would be just fine for the Justa.
To prevent O sensor failure be sure to pump only from 'Top Tier' suppliers (the voice of a bad experience speaking).
http://www.toptiergas.com/retailers.html

 

Top Tier gas is critical, imho. Maybe your state doesn't have a problem with bad gas, but we do here - you have to be careful where you fill up. Also, I live in a very hot climate so most of the year my Justa gets premium which stops the knocking under load with A/C on.

 

what does your gas cap sticker say? Should be 91 for pre LCI cars and 89 for the LCI.

 

It's not required, but it's advised. Typically when you pop your gas tank it will say the type of gas you should put into the vehicle. Always follow those instructions. Turbo charged cars absolutely require 91 octane.

-Luccia

 

Top Tier gas is only marketing. Costco gas has always had "top tier' additives and only recently Costco paid to be on the Top Tier list. I've seen people here bad mouth Costco gas because it wasn't "Top Tier", when it had everything Top Tier has except the Top Tier endorsement.

Top Tier means nothing.

Dave

 

Agreed, top tier does not mean if your station is not listed they have bad gas and it is true they pay for the endorsement. It usually means that they don't document the franchise operations buying operations or don't want to pay for the endorsement if they are not on the list. Still, being on the list does offer a measure of confidence in their product to me at least.

There are some really nasty places to get gas in Arizona, buyer beware. PEMEX is just a few miles away and AZ is frequently the dumping ground for old gas out of California during their seasonal change over. Maricopa county has the worst fuel during that time, but out in the boonies (erg: the RES) you don't know what you are getting either.

To OP's point, 91 helps in hot hot weather on a Justa, and in Turbo models in general but mid grade is probably just fine all the rest of the time without a turbo.

 

My 2004 R50 is much happier on 93 than on 87-89. You can tell the difference. For the couple dollars a tank difference it is a no brainer from my standpoint.

Al

 

Hmm, here's a thought about Costco in OUR area that might change your mind. I spoke with an engineer from BP Petro at a party, and while we were on the subject of gasoline[ hey, how often does THAT come up with someone qualified at a party..] He cautioned me about buying gas from the Costco stores in our area. Why, you might ask, well, apparently the storage tanks that Costco was getting its gas from need to be cleaned from time to time according to him to get rid of build up /crud that would be bad for any engine. But, since Costco was only leasing the tanks from BP, they felt it was BP's responsibilty and not theirs. Naturally, BP felt it was Costo's since they are the leasing party.
The tanks haven't been cleaned in a long time.......
he described the material as sort of a corrosive amount of crud that's in the storage tanks.....

 

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. Welcome to the Forum.
Try a grade or octane rating that works best for you in those cold temps and stick with it. If 89 octane works better than Premium when it's that cold, you probably want what gets your Mini running and not leaving you stranded...
Gasoline Volatility matters for cold engine starts to be sure, but with temps that cold, Battery strength and Oil Viscosity also really matter too.

 

..

 

Just run the Premium that you're used to running, and no worries then.

 

Use premium , unless you are in a area that does not have it ( yes some area in the middle of the country or outside the US dont have it ) , then use regular and octane booster.

 

My 2010 Justa said 91 required on the inside of the fuel door and 91 recommended with 89 and 87 ok in the owner's manual. I asked MINIUSA why the difference. The short answer: EPA.

 

I have an 02 - 04 R50 04 5 speed (does that mean getrag?)

For 2 years I ran low octane from Quick Trip exclusively (there’s so many of them), and never noticed a difference when I switched, but I’ll use 91 until all my parts are back to new then get back to you on difference.

Now that I typed it out, I think maybe I heard less ticking in the morning with premium??

 

Midland Transmission for 2002-2004 5 speed manual. One of the few you can get the internal parts for.

 

My MINI uses so little fuel that the higher price for premium is not an issue.

 

Have to point out the owners manual should list a minimum octane listed. You should *never* run an octane lower than that.

Yeah, while the engine controller can vary ignition timing retard timing to avoid detonation there may be a limit to how much retard it can dial in if the octane grade is too low and detonation persists. Also, dialing back timing is not without some cost. While detonation is avoided fuel economy can suck. And the engine may not feel as responsive, accelerate as smoothly/strongly.

Another consideration is exhaust gas temperatures are elevated and every component that is exposed to exhaust gas runs hotter. Exhaust valves even in a N/A engine run pretty darn hot and in a turbo charged engine can run hotter still, to a dull red heat. The turbo turbine wheel which is spun by exhaust gas also runs extremely hot. For the exhaust valves and turbine wheel the last thing they need is even more heat.

Really if say 91 is called for you should run 91 octane gasoline to get the most out of the engine. After all you paid for the higher performance. Might as well get the benefit of that.

 

real quick. I ran lower octane because I didn’t read the inside of the cap. I didn’t realize what I have in this car until the last six months.

I do not suggest running anything outside what your manual says to run. Cris fix has an awesome video explaining why.