Hey people, I was wondering - do I really need to use 91 gas in my engine? Will it cause damage to use 87 ?? I drive a 2010 mini hardtop and recently had an engine malfunction light come on - after a time period of a louder than usual engine rumble. It turns out the light was for emissions and was re set but the noise is still very much there - could this be due to the gas type? I was told maybe to start using dry gas? if thats what its called.. any advice/recommendations would be great thanks

 

READ the owners manual it says PREMIUM ONLY for a reason ...
Running regular can hinder performance , cause check engine lights and long tem damage the headfs/valves of the car ...
Is it REALY worth the risk for $2/$3 a fill up ?

 

whoa w the tude buddy. I know what the manual says - I was asking if thats truly the case. I never said it was worth the price difference either. Nice manners and thanks for the info

 

So you're thinking the manual is maybe wrong?? If it's truly the case?? If you're high enough you might get by with 89, but I'd expect grief at below 100000 feet or so...

 

I questioned this very issue back when I own an Acura TL... I waited till my first service came due and I arrived there 0700 sharp so as to make my way to the back where the mechanics work. LOng story short, I asked for the most senior mechanic present and this is what I was SHOWN. Three engines, heads removed, both indicating serious hard crusty-like blackish residue similar to rust or worse, all because these drivers wanted to save an average of $15 to $20 bucks a month on their gas bill.

Bottom line, the tech advised if I stay with quality brand fuel, 91 octane, the engine will last and last.

I never looked back, never questioned as the evidence was there to see. People with far more advanced knowledge and education know the who what when where and why such products must operate. Then there is extensive product testing. I'd like to think Mini Cooper's undergo similar product development and testing.

Hopefully those of you within these forums can guide me in my future purchase.

 

It would be a HUGE advantage for Mini if you could use regular. They have no incentive whatsoever to increase the operating cost of their cars when some buyers will tip a purchasing decision in favor of a car which will run on regular...your effective mpg drops by two or 3 due to the fuel upgrade. When they tell you 91 you can be sure it's because they HAVE to tell you 91.
I'm sure that Minis use knock sensors and ECU programming which trades off running like crap for damage prevention if you have to run a tank of regular...

 

MissTani,
First may I politely respond to your question…
My wife’s had an ’05 Convertible S for over a year now and she uses mid-grade. She says she feels the performance loss with 87. We bought an expensive car and I expect expensive maintenance/operating costs. I guess it’s just part of the deal but try the ’87 and if it works for you, run it. See below for further details…
Now the RANT!

Quote:

Originally Posted by MissTani

whoa w the tude buddy.

I can’t believe someone with a “tude” like bad venge is a “Super Moderator!” We’re all supposed to be here helping each other and sharing in the camaraderie of MINI! He has one point about performance loss with low octane fuel though, but here it is – if you use the cheap gas and feel no performance loss – use it! If your check engine light comes on, get the diagnostic read and see if it pertains to gas quality. O2 sensors are often the cause of check engine lights and that could be due to gas quality.
Another point, it would be highly unlikely that one tank of gas would cause the engine rumble you mentioned. What these guys are talking about cheap gas damaging heads etc would be very long term – unless you got some terrible gas with lots of water or debris in it – even then, that’s why there’s a fuel filter in the system!
Let me address the “evidence” Garbinator states in his response about the senior MINI mechanic showing him dismantled engines. (no offence intended Garbinator, I just don't know what you were shown and if it specifically pertains to fuel quality) I am a mechanic and am curious what hard crusty-blackis residue you were being shown. You said the heads were removed. Was this stuff inside the cylinder bore or just around the block? I’ve had lots of engines apart and what you are describing sounds to me like the junk that builds up when inadequate oil changes are performed, and not the result of low octane fuel. This junk that I’m talking about is some of the most impressively foul stuff I’ve encountered and could sway any driver to do anything to prevent it from building up in their own engine. Use good quality synthetic oil and this shouldn’t happen. The accumulation of this junk in your engine is hard on everything but the gradual wear on the engine will not result in a noticeable loss in performance, which may be the case with the original fuel octane rating issue.
In any case – happy motoring to you all!

 

The tude is for a reason ...

my best friend is a mini service manager , and trust me I've seen what running regular and mid-grade gas does to the mini heads/ I've seen minis with under 15k miles with valves having so much deposits that they will not even seal. Mini will not warrant these issues. Bills run in excess of $2000/$4000 for the repairs and I have covered this in many other posts.

Mini states that you should run premium gas for many reasons , most are due to keeping the proper temperature in the combustion chamber to burn off the residue on the valves ect. Also the motor is tuned to run on the premium. Running regular and mid grade the motor will De tune itself for the sub par gas. Most motors will get detonation running these fuels and the knock sensor will retard the timing to quell the detonation. This causes lose of performance and gas mileage. I was stuck using midgrade when the local station had a premium tank issue , I ran three tanks and lost 3/5 mpg and a marked loss in performance. The performance loss is much more evidenced on the S models due to the S/C OR Turbos but the loss id there on regular coopers as well.

We had a member of my mini club running midgrade on a standard cooper 25k miles later he was having back fire issues brought in to the dealer and had the motor torn down and sure enough heads were shot...Given an estimate of $3200 he was going to try to sell the car as is. We found a used head and replaced it for $1500 and three guys labor.

Bottom line is you can pay the extra $2 per tank and run trouble free We have one member with 350K miles on an S / I have 85K on mine and 35K on my wifes

Or you can cheap out and gamble that the motor will hold up and not loose a head or valve ...But when it doesn't I don't want to see the post about how mini sucks cause they won't cover my car in warranty cause I used the wrong fuel

 

JeepinDavis,

Naaah! My point was meant only as an "Opinion" not so much as fact because I am not an expert. The other detail I wished to point out... I was not describing a mini per se, I was speaking about a high performance running engine my 2005 Acura TL had in it as it required Premium fuel only. The poster just above this response best describes what I was shown then, but yes, one engine I recall had over 50,000 miles, even so? When a person bothers to purchase such a high performing vehicle, then fails to adhere to the numerous warnings whether safety related or maintenance and performance, all to save a few bucks a month (.10 cents a gallon) difference, oh well?

But I'd say take what I said as in the spirit of the topic. Not the letter.


<<<

 

If your mini is a 2007 or newer and has the direct injection, you muusst use 91 octance or higher with top tier gasoline. (older cars tend to get away with it sometimes but why short yourself??)not using 91 octane or higher using that will result in misfires and premature carbon build up in theintake ports and intake valves.