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Discussion Starter · #1 · (Edited)
I checked with dealer who told me everything except M models use regular and that is what the dealer used when filing up my gas tank.

On the gas lid it says 89 minimum so what is the deal here?
I got the 4 cylinder version of 2017 430i 4 cylinder engine.

Thanks
 

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I use premium... I thought it said somewhere we were supposed to but I would need to look in the manual to see if it specifies.

EDIT: Looked it up in the manual, page 186 of the PDF for the 435 GC. You might want to check in your own manual because I dont know if its different for the 430.

Recommended fuel grade
BMW recommends AKI 91. (this is premium I believe, 91 octane)
Minimum fuel grade
BMW recommends AKI 89. (this is unleaded with 89 octane, or "regular" unleaded instead of premium)
Minimum fuel grade
Do not use any gasoline below the mini***8208;
mum fuel grade as this may impair engine per***8208;
formance.***9664;
If you use gasoline with this minimum AKI Rat***8208;
ing, the engine may produce knocking sounds
when starting at high outside temperatures.

This has no effect on the engine life.
 

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Disregard the dealer and use at least 89 octane, which is mid-grade. In fact, since the salesman said the dealer uses regular, I would add premium so that the octane level in the tank approaches 89.

I found that using premium results in better gas mileage but not enough to recoup the cost. I tested this in 2005. The EPA also has released separate gas mileage figures for the same car using regular and premium and the difference was 1 mpg.

If one is economical, mid-grade is ok but I might use premium in very hot weather when cars need slightly more octane.

I use 92 octane (strange but that is the octane of premium here) but cannot justify it too well.
 

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Not that driving a new BMW means that you're wealthy, but we're not penny pinchers neither. If you were being economical, would've bought pre-owned or even a Honda/Toyota (something w/ minimal running costs). I'm not say you per se, but to all of us, the cost difference on a tankful between premium and regular shouldn't be an issue. $10-15 maybe? My opinion is that it's better using premium fuel from a decent station (top-tier?).
 

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Not that driving a new BMW means that you're wealthy, but we're not penny pinchers neither. If you were being economical, would've bought pre-owned or even a Honda/Toyota (something w/ minimal running costs). I'm not say you per se, but to all of us, the cost difference on a tankful between premium and regular shouldn't be an issue. $10-15 maybe? My opinion is that it's better using premium fuel from a decent station (top-tier?).
More like $5 to $7...
 

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I checked with dealer who told me everything except M models use regular and that is what the dealer used when filing up my gas tank.

On the gas lid it says 89 minimum so what is the deal here?
>SNIFF<

Sir. You now drive a fine BMW; purchase of 'premium' fuel is always a priority.

The very mention of 'regular' gives offense and we, the 1%, must question your motive. What are your intentions?
 

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I checked with dealer who told me everything except M models use regular and that is what the dealer used when filing up my gas tank.

On the gas lid it says 89 minimum so what is the deal here?
I got the 4 cylinder version of 2017 430i 4 cylinder engine.

Thanks
You can always tell when a car salesman is lying; his lips move.

91 is what the car needs to run like it was designed to run. 93 might make it run a little better under heavy load conditions.

If you use less than 91 AKI, you car will de-tune itself when it hears itself pinging. That will affect performance and fuel economy.

If you don't have 91 AKI where you live, you can make your own:

1/3 87 AKI + 2/3 93 AKI = 91 AKI
1/2 89 AKI + 1/2 93 AKI = 91 AKI

The mixture using 87 AKI is usually a little cheaper. Reset the trip odometer and MPG meter when you fill up. Right before the next fill up, divided the miles by the MPG. That will tell you (fairly accurately) how much gas you're going to need. Take that number, divide by three, and pump in that amount of 87 AKI. Then, finish filling the tank with 93 AKI.

Gasoline is recirculated between the high pressure fuel pump and the tank. So, the mixture of different grades of gasoline will blend quickly.

93 AKI is $0.55/gallon more than 87 AKI where I live. I take 17 gallons when I fill my tank. That saves me $3.12/tank. In 12,000 miles of driving (one year for me) at 26 MPG, blending gas saves me about $85.
 

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I checked with dealer who told me everything except M models use regular and that is what the dealer used when filing up my gas tank.

On the gas lid it says 89 minimum so what is the deal here?
I got the 4 cylinder version of 2017 430i 4 cylinder engine.

Thanks
The dealer is an idiot.

Go with the gas lid/manual.
 

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I enjoyed a fabulous trip to Italy several years ago. Since we drove from Rome to Florence to Venice, I got to know the Auto Grills there. Good gnocchi, but I also noticed at the pump there was just diesel and Premium. I also recall Clarkson on TopGear referring to American gas as "jungle juice". My point in all this is Europe doesn't have 87 octane. To sell cars here, some manufacturers will tune their motors to run on 87 octane. BMW isn't one of them.

Here in Texas premium gas is 93 octane, so use it. I have been using a Fuel Rewards card to make back some of the difference, and all summer I have been getting $.10 discount per gallon for filling up with Shell V-Power.
 

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Discussion Starter · #10 ·
I was a bit surprised since my previous car which also was European (not a BMW) ha a 4 cylinder turbo and it required 89 minimum.
Thanks I will go with premium going forward.
 

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I wish I could find 91 octane in these parts. 99% of the stations around here carry 87, 89, & 93. Generally, I fill up at Costco when I can. Their 93 is the same price as most stations' 87.
 

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I was a bit surprised since my previous car which also was European (not a BMW) ha a 4 cylinder turbo and it required 89 minimum.
Thanks I will go with premium going forward.
Fuel economy, torque, and power are improved by increasing the compression ratio and turbo boost pressure. But, it also increases the minimum octane rating required to prevent detonation. BMW's are premium cars, so they need premium gas to achieve premium performance.
 

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You can always tell when a car salesman is lying; his lips move.

91 is what the car needs to run like it was designed to run. 93 might make it run a little better under heavy load conditions.

If you use less than 91 AKI, you car will de-tune itself when it hears itself pinging. That will affect performance and fuel economy.

If you don't have 91 AKI where you live, you can make your own:

1/3 87 AKI + 2/3 93 AKI = 91 AKI
1/2 89 AKI + 1/2 93 AKI = 91 AKI

The mixture using 87 AKI is usually a little cheaper. Reset the trip odometer and MPG meter when you fill up. Right before the next fill up, divided the miles by the MPG. That will tell you (fairly accurately) how much gas you're going to need. Take that number, divide by three, and pump in that amount of 87 AKI. Then, finish filling the tank with 93 AKI.

Gasoline is recirculated between the high pressure fuel pump and the tank. So, the mixture of different grades of gasoline will blend quickly.

93 AKI is $0.55/gallon more than 87 AKI where I live. I take 17 gallons when I fill my tank. That saves me $3.12/tank. In 12,000 miles of driving (one year for me) at 26 MPG, blending gas saves me about $85.
Excellent writeup! When we owned our '09 328i we ran Sunoco Plus (89 octane), which was fine. But am consistently running Premium 91 octane in the new 340xi. Does it really need it? Maybe not, but for a around $0.07-0.08 per gallon more, I'm willing to pay it to get the most from the engine. I use Sunoco Ultra (93 octane0 in the Porsche, but it would likely run fine with 91. It's just my preference.
 

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I found that using premium results in better gas mileage but not enough to recoup the cost. I tested this in 2005. The EPA also has released separate gas mileage figures for the same car using regular and premium and the difference was 1 mpg.
Yes, this is right. Higher octane gasoline contains slightly less energy, but using higher octane fuel prevents preignition, which means the engine doesn't have to retard the ignition timing to compensate and it runs more efficiently and cleanly.

On a sidenote, here in Colorado the highest octane fuel you can usually get is 91. At high-altitude, that's fine for a normally aspirated car that requires premium because the air is thinner. But in a turbocharged car, the forced induction compensates for the thinner air, so it would be nice to have higher octane fuel available here.
 

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There are always the 2 R's

Recommended or required - If you want to feel better inside yourself then put in premium gas. If you want to save a few bucks, then put the octane level of the minimum gas required in. The engine will work well with both.
 

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You can always tell when a car salesman is lying; his lips move.
The dealer is an idiot.
....we drove from Rome to Florence to Venice....I also noticed at the pump there was just diesel and Premium. I also recall Clarkson on TopGear referring to American gas as "jungle juice". My point in all this is Europe doesn't have 87 octane.
Mine says 91 minimum on the gas cap and in the manual.
Thank your boys, I knew others would chime in.

Real BMW pilots do not buy 'regular.'

 

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You can always tell when a car salesman is lying; his lips move.

91 is what the car needs to run like it was designed to run. 93 might make it run a little better under heavy load conditions.

If you use less than 91 AKI, you car will de-tune itself when it hears itself pinging. That will affect performance and fuel economy.

If you don't have 91 AKI where you live, you can make your own:

1/3 87 AKI + 2/3 93 AKI = 91 AKI
1/2 89 AKI + 1/2 93 AKI = 91 AKI

The mixture using 87 AKI is usually a little cheaper. Reset the trip odometer and MPG meter when you fill up. Right before the next fill up, divided the miles by the MPG. That will tell you (fairly accurately) how much gas you're going to need. Take that number, divide by three, and pump in that amount of 87 AKI. Then, finish filling the tank with 93 AKI.

Gasoline is recirculated between the high pressure fuel pump and the tank. So, the mixture of different grades of gasoline will blend quickly.

93 AKI is $0.55/gallon more than 87 AKI where I live. I take 17 gallons when I fill my tank. That saves me $3.12/tank. In 12,000 miles of driving (one year for me) at 26 MPG, blending gas saves me about $85.
On my 330e the manual says 89 is acceptable but recommends 91. The problem with the solution offered above is that in some parts of the country (e.g. much of the west) premium is 91 octane and one can't get 93 octane. So out here blending doesn't work.
 

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1/3 87 AKI + 2/3 93 AKI = 91 AKI
1/2 89 AKI + 1/2 93 AKI = 91 AKI
I was under the impression that there would be no math on this exam? :dunno:
 

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On my 330e the manual says 89 is acceptable but recommends 91. The problem with the solution offered above is that in some parts of the country (e.g. much of the west) premium is 91 octane and one can't get 93 octane. So out here blending doesn't work.
Our there, blending is not needed either.

It's pre-blended at the tank farm. In most of the country (excluding California and high altitude areas in the Rocky's) they only make 87 AKI and 93 AKI at the refinery. 89 AKI and 91 AKI grades are made by blending the two as they fill up the tanker trucks.
 
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