R56 Regular or Premium Gas?
4th Gear
Joined: Nov 2006
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I keep reading this and it's a fiction of the past! Cars now (at least good ones like the Mini) have knock sensors that are used to control timing advance. This is done by detecting the onset of pre-ignition before it becomes a problem. To make the car work pretty much everywhere, they put a decently agressive tune in the car and let the knock sensor handle the safety. This means that you can usually get benefits in performance for at least a couple of octane higher than is reccomended.
The notion that "extra octane is a waste" is true only if
1) you put in much, much higher octane than is reccomended with a knock sensor governed car.
2) you have an older car or one that doesn't have knock sensor based timing retard.
The roots of the this dogma is that cars USED to be equipped from the factory with a fixed timing, and no knock detection. So you put in crappy gas you got pinging. You put in good gas you didn't. Any octane past what was needed to stop the pinging was "extra" and wasted.
Now, not all cars have knock sensor governed timing, but all will. This is because the engine efficiency goes up with timing advance. Using knock governed timing control will allow for the most efficient burn of whatever gas is being used, and this ups overall gas mileage and lowers emmissions.
Sorry if I seem a bit rough here. But about every 20 minutes or so (very exagurated) a new thread pops up, or an old one comes back to life, that repeats the notions of the past as principles of operation for a car that is way more advanced than the machines that created the dogma. So then I have to choose to post again, or let the errors perpetuate again.
Matt
The notion that "extra octane is a waste" is true only if
1) you put in much, much higher octane than is reccomended with a knock sensor governed car.
2) you have an older car or one that doesn't have knock sensor based timing retard.
The roots of the this dogma is that cars USED to be equipped from the factory with a fixed timing, and no knock detection. So you put in crappy gas you got pinging. You put in good gas you didn't. Any octane past what was needed to stop the pinging was "extra" and wasted.
Now, not all cars have knock sensor governed timing, but all will. This is because the engine efficiency goes up with timing advance. Using knock governed timing control will allow for the most efficient burn of whatever gas is being used, and this ups overall gas mileage and lowers emmissions.
Sorry if I seem a bit rough here. But about every 20 minutes or so (very exagurated) a new thread pops up, or an old one comes back to life, that repeats the notions of the past as principles of operation for a car that is way more advanced than the machines that created the dogma. So then I have to choose to post again, or let the errors perpetuate again.
Matt
E85 is higher octane...
Matt
4th Gear
Joined: Nov 2003
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From: Los Angeles, CA
As much as people claim that Regular can be lower gas milage, and you will get performance hinder and hickups and such in your engine, i really dont believe this at all. I think its just one of those theories thats inbeded into our heads.
Having said that, sense my Prelude, I myself use nothing but premium. Its kind of one of those "why not" things. In my daily, pos car, i put regular but anything else and its premium
Having said that, sense my Prelude, I myself use nothing but premium. Its kind of one of those "why not" things. In my daily, pos car, i put regular but anything else and its premium
But it's so easy...
As much as people claim that Regular can be lower gas milage, and you will get performance hinder and hickups and such in your engine, i really dont believe this at all. I think its just one of those theories thats inbeded into our heads.
Having said that, sense my Prelude, I myself use nothing but premium. Its kind of one of those "why not" things. In my daily, pos car, i put regular but anything else and its premium
Having said that, sense my Prelude, I myself use nothing but premium. Its kind of one of those "why not" things. In my daily, pos car, i put regular but anything else and its premium
People forget that these are really a mixture of an airpump and your fireplace. They aren't black magic, and can be tested with results compared to theory.
Matt
4th Gear
Joined: Nov 2003
Posts: 469
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From: Los Angeles, CA
to actually log data and see for real. Cars don't run on philosophy, they run on gas. Performance numbers can be measured. I found 7 HP just from upping the octane in my gas. I also logged data showing WOT timing retard at pretty much all RPMs over 2500. I didn't measure mileage differences, but I'd guess they were on the order of 15% improvement based on tank range.
People forget that these are really a mixture of an airpump and your fireplace. They aren't black magic, and can be tested with results compared to theory.
Matt
People forget that these are really a mixture of an airpump and your fireplace. They aren't black magic, and can be tested with results compared to theory.
Matt
Also others saying
low octane fuel gives your engine the chance to knock
So again, having said all this, i always put premium myself
6th Gear
Joined: Sep 2005
Posts: 1,188
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From: Chico, CA
I add 10% E-85 to my premium to up the octane and help the guys selling E-85 be successful. We are in a transition phase to bio-fuels and the politics are very complicated but I have decided it is a good thing. This raises my octane. I haven't seen a decrease in gas mileage or performance. I think if it were tested while pushing the engine the gas mileage would go down and the performance would go up. Althought the energy density of E-85 is down, an engine can built for it can have higher compression and hence develop more power (and significantly lower fuel economy) using E-85.
6th Gear
Joined: Jan 2007
Posts: 1,479
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From: South Florida.
The R56 owners manual says " NO E85 GASOLINE TO BE USED". Maybe down the road BMW will have a retrofit for this, (fuel pump, seals, etc ).
6th Gear
Joined: Feb 2007
Posts: 15,966
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I think the point he was making is that modern cars automatically adjust for octane, whereas the old cars will choke on lesser octane and just waste higher octane. Does anyone with an older car actually perform a tune-up every time they put different octane gas in the car?
while I dont disagree with that statement that im sure there is "technical" difference. That dosent mean you will see a everyday difference either. For example, im assuming that the 7HP difference was not between 87 and 91 octane and so meaning, does 2-4hp really make a diff if you can even get that same result everytime.
Also others saying , I highly highly doubt that would ever happen. My mom used to put 87 on habbit in her 5 series all the time and never did we see an engine problem. For example, why is it ok for all Accords and Camrys to use 87. Those have some nice and powerful engines and yet their ok, its not like were running this premium high end, sophisticatitly tuned machine. Maybe a tad more argument that the Turbo/SuperCharger units might help (again, I dont see why) but how about just the normal cooper.
So again, having said all this, i always put premium myself
Also others saying , I highly highly doubt that would ever happen. My mom used to put 87 on habbit in her 5 series all the time and never did we see an engine problem. For example, why is it ok for all Accords and Camrys to use 87. Those have some nice and powerful engines and yet their ok, its not like were running this premium high end, sophisticatitly tuned machine. Maybe a tad more argument that the Turbo/SuperCharger units might help (again, I dont see why) but how about just the normal cooper.
So again, having said all this, i always put premium myself
And the Model T used to run on really crappy gas. That has as much to do with the conversation as what your mom used to do.
Matt
6th Gear
Joined: Sep 2005
Posts: 1,188
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From: Chico, CA
I got an email from Saab asking my opinion about an E-85 Saab. In the email they stated it would develop more power and have higher compression. I didn't respond but later became curious and haven't been able to find anything more on the issue from Saab.
3rd Gear
Joined: Aug 2006
Posts: 164
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From: League City, TX
-my 0.02
1st Gear
Joined: Feb 2003
Posts: 27
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I got the 87 octane blues
I tried 87. Itwas disasterous. My mini wound up at the dealer for 8 days with the Check Engine Light going on every time a drove the car for more than 10 minutes. Sometimes it would reset itself and other times I had to go to the dealer for help when the light wouldn't go out. They said the reason was the use of regular and the high content of ethanol (15-20%) in the fuel.
4th Gear
Joined: Dec 2005
Posts: 580
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Premium - AND KEEP IT FULL UP
I can't believe this question gets asked and kicked around so much. You like your Mini? You want to treat it right? You want it to have max performance and a long life? DO WHAT THE FACTORY RECOMMENDS! You wouldn't go 20k miles without an oil change to save a few bucks, would you? It's a performance car, you love it, you spend those extra pennies and put the PREMIUM in it.
Years ago I was doing an oil change for a girlfriend on her nice old VW bug. When I picked up the car, it was on fumes, so I put half a tank in it. After I'd brought it back, she called me and said, "What did you do to my car? Did you tune it up?" Answer: NOPE. Just put PREMIUM IN IT.
You love your Mini, spend those extra few cents a gallon. It's not going to change your life.
And IF you store it in the Winter, put a recommended dose of FUEL STABILIZER in the FULL TANK when you store it. And KEEP THE TANK FULL. Don't let the car sit around with half a tank or less of gas in it anytime. Keeps water condensation out of the tank.
Go ahead, laugh at me. Go ahead.
Years ago I was doing an oil change for a girlfriend on her nice old VW bug. When I picked up the car, it was on fumes, so I put half a tank in it. After I'd brought it back, she called me and said, "What did you do to my car? Did you tune it up?" Answer: NOPE. Just put PREMIUM IN IT.
You love your Mini, spend those extra few cents a gallon. It's not going to change your life.
And IF you store it in the Winter, put a recommended dose of FUEL STABILIZER in the FULL TANK when you store it. And KEEP THE TANK FULL. Don't let the car sit around with half a tank or less of gas in it anytime. Keeps water condensation out of the tank.
Go ahead, laugh at me. Go ahead.
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