# Level of Octane you put in your ride



## PinkLambo (Dec 30, 2013)

So I finally got the day off to go see the 428i that I've been anticipating and I was a little disappointed but thats just me. Anyways, the salesperson had said I dont need to put 91 in the 428i even though the gas cap says so. He said "... For newer BMW engines not putting 91 is okay." Of course it dirties up the spark plugs and you're sacrificing performance but is it only in older models that putting regular (87) in damaging the engine?

Also, out of curiosity which gas stations do you prefer for your BMW and why? Over here, we have Petro Canada, Shell, Esso, Chevron, then course like Husky, Superstore and the other ones.


----------



## stonex1 (Oct 10, 2012)

91

Only because the manual recommends it.

As for gas stations, I tend to follow the fill ups referred to in this strategy.
Husky and Petro Can since they are close to my routes.


----------



## Kamdog (Apr 15, 2007)

PinkLambo said:


> So I finally got the day off to go see the 428i that I've been anticipating and I was a little disappointed but thats just me. Anyways, the salesperson had said I dont need to put 91 in the 428i even though the gas cap says so. He said "... For newer BMW engines not putting 91 is okay." Of course it dirties up the spark plugs and you're sacrificing performance but is it only in older models that putting regular (87) in damaging the engine?
> 
> Also, out of curiosity which gas stations do you prefer for your BMW and why? Over here, we have Petro Canada, Shell, Esso, Chevron, then course like Husky, Superstore and the other ones.


He is FOS, and just trying to tell you that these cars can be run cheaper.

Use premium. 91 or 93, which ever is available locally. If you own, use top tier. If you lease, use anything. Anything less that 91 will cause your engine to adjust downward to the lower octane.

To run your car at optimum, use the right octane.


----------



## ptabaco (May 23, 2006)

*BMW Recommendation*

I buy my gas at Sam's Club, and the only options are AKI87 and AKI93, and of course I use AKI93, but if I have to refuel at any other station, a tank full of AKI89 will do no harm.
This is what my OM says about fuels


----------



## PinkLambo (Dec 30, 2013)

I've a 2012 x1 that I lease and all my cars are my babies so I give them the best. I'm just wondering, what happens if you give a BMW that clearly says "use 91" something less (eg 87). My dads friend regularly used 87 and the car stopped working which lead to thousands in repairs so Im just curious what happens in newer beemers.


Sent from BimmerApp mobile app


----------



## [email protected] (Nov 25, 2013)

Using a lower octane will not end the world. The engine management software on our BMWs is programmed for 91+. You will get a more complete burn with less carbon deposits. You'll get better performance, and you'll get better fuel economy. Personally, I use premium. My understanding is that it is better to use a higher quality fuel than a higher octane fuel. Bottom line, it's only a couple of dollars more for the good stuff. Burn it.


----------



## Dave 20T (Apr 7, 2013)

The F30 320i in the U.S. specifies on the fuel cap 89 as required, 91 as recommended. The owner's manual specifies the same, except calls it premium.

Washington state seems a bit unusual in having 92 commonly as premium. I wonder why. In California, premium is usually 91. Many parts of the U.S., it's 93.


----------



## PinkLambo (Dec 30, 2013)

I think it might be because different gas companies put slightly different chemicals in their gas while refining it but I'm not 100% sure. Anyone?


Sent from BimmerApp mobile app


----------



## Gluhwein (Aug 21, 2011)

I always wondered....If I put in six gallons of 93 octane and 4 gallons of 89 would it balance out? I only ask because the price difference between regular and premium keeps getting wider and wider.


----------



## PinkLambo (Dec 30, 2013)

Gluhwein said:


> I always wondered....If I put in six gallons of 93 octane and 4 gallons of 89 would it balance out? I only ask because the price difference between regular and premium keeps getting wider and wider.


Well when you fill up your gas tank is never empty so it's really a mixture of both levels of octane. It obviously wouldn't perform as well but like the user said above I don't think anything is going to happen to the engine. Just more deposits left behind and dirtier spark plugs.

Sent from BimmerApp mobile app


----------



## Dave 20T (Apr 7, 2013)

Gluhwein said:


> I always wondered....If I put in six gallons of 93 octane and 4 gallons of 89 would it balance out? I only ask because the price difference between regular and premium keeps getting wider and wider.


It almost works out mathematically. [(6 x 93) + (4 x 89)]/10 or [(6 x 4 higher octane)/10 ] + 89 = 91.4 If you were a chemist and tested it, it would be very close to 91.4.

In areas where they sell 87, 89, and 93, 89 is often half way between the 87 and 93 price. If you want it cheaper, you can mix your own gas. 89 from the pump is mixed while in the pump.


----------



## Dave 20T (Apr 7, 2013)

PinkLambo said:


> It obviously wouldn't perform as well but like the user said above I don't think anything is going to happen to the engine. Just more deposits left behind and dirtier spark plugs.
> 
> Sent from BimmerApp mobile app


Sometimes true, sometimes not true.

Chevron and 76 say that the amount of anti-deposit additives is the same in all grades. Shell says they put more in premium.


----------



## Gary J (Dec 18, 2013)

I'm a foodie. So is my car.


----------



## HugH (Apr 26, 2006)

Dave 20T said:


> Sometimes true, sometimes not true.
> 
> Chevron and 76 say that the amount of anti-deposit additives is the same in all grades. Shell says they put more in premium.


Shell had to change their song after EPA asked for proof that their high grade additives were better for the engines.

For many years now, you do not see the advertisement any more at their gas pumps. Only that their additives are the "best" or something like that.

For the last few years, I've mostly used Costco regular on two Lexus, a GS and ES, as well as the present 2013 328i. Very satisfied with their gas and prices.


----------



## 335i Driver (Nov 29, 2006)

Dave 20T said:


> It almost works out mathematically. [(6 x 93) + (4 x 89)]/10 or [(6 x 4 higher octane)/10 ] + 89 = 91.4 If you were a chemist and tested it, it would be very close to 91.4.
> 
> In areas where they sell 87, 89, and 93, 89 is often half way between the 87 and 93 price. If you want it cheaper, you can mix your own gas. 89 from the pump is mixed while in the pump.


It doesn't work that way. Additives increase the octane level at a logarithmic rate, not a proportionate rate. It's not like blending wine. In your scenario you would more likley end up with an octane around 92.4.


----------



## 335i Driver (Nov 29, 2006)

PinkLambo said:


> So I finally got the day off to go see the 428i that I've been anticipating and I was a little disappointed but thats just me. Anyways, the salesperson had said I dont need to put 91 in the 428i even though the gas cap says so. He said "... For newer BMW engines not putting 91 is okay." Of course it dirties up the spark plugs and you're sacrificing performance but is it only in older models that putting regular (87) in damaging the engine?
> 
> Also, out of curiosity which gas stations do you prefer for your BMW and why? Over here, we have Petro Canada, Shell, Esso, Chevron, then course like Husky, Superstore and the other ones.


The only way to know for sure it to put your car on a dyno to see which fuel delivers the best performance. Even though BMW recommends 91, they are always going to be ultra conservative with thier recommendations.

I've seen dyno's for the 335 posted on some of the tuner sights showing the best performance with 93, and that doesn't suprise me for a high performance TT engine. I'm not so sure it would be the same for the na I6. Your 428 could very well run better and get better on 89, but it must be proven on a dyno, not sure BMW has done this or they just print use premium in their manuals and go with it.

I can tell you my Kawasaki manual says use premium yet dynos have shown the highest HP using 87. So you can't assume anything until you put it on a dyno and test both octanes back to back on the same dyno under the same conditions draining the tank between runs.

Also, 87 will not dirty up your spark plugs any more than 93, that's another fallacy.


----------



## need4speed (May 26, 2006)

93 Oct. E0. N4S


----------



## banglenot (Feb 10, 2004)

Premium, usually 93 around here, with whatever has Techron in it.

BIG difference in performance for mine between 87 (the few times I've used it while experimenting) and 93, particularly when it's hot and the ECU is adjusting the timing to compensate for knock/ping.

Also a bottle of techron every six months just 'cause I like to....


----------



## Dave 20T (Apr 7, 2013)

335i Driver said:


> It doesn't work that way. Additives increase the octane level at a logarithmic rate, not a proportionate rate. It's not like blending wine. In your scenario you would more likley end up with an octane around 92.4.


I thought that anti-deposit additives don't increase octane level. If they did, how would it explain Chevron, which says that the Techron level in all octane grades are the same?

But I think you are at least partly correct. Mix half 87 octane and half 93 octane and the mix will be slightly higher than 90, but not much. Mix 60% 93 and 40% 87 and mathematically you should get 91.4. I'm not so sure the mix would be 92.4 as you mention, though. I thought it would be around 91.6.


----------



## Dave 20T (Apr 7, 2013)

banglenot said:


> Also a bottle of techron every six months just 'cause I like to....


Overuse of Techron is not recommended. If one does add a bottle, it's better to change the oil after that tank is mostly used up.

I engage in ritualistic behavior by occasionally changing the brand used for several consecutive tankfuls even though there's no evidence that a brand's additives are needed to wash away another brand's additives. Still, I use a few tankfuls of Shell once in a while and a few tankfuls of 76 every few years.


----------



## Sedan Hussein (Aug 22, 2013)

93 oct.


----------



## Leftlane11 (Sep 28, 2013)

335i Driver said:


> It doesn't work that way. Additives increase the octane level at a logarithmic rate, not a proportionate rate. It's not like blending wine. In your scenario you would more likley end up with an octane around 92.4.


If the gas station has pumps for 87, 89, and 91 - the station blends 87 and 91 in the underground tanks to get the 89. You can do the same for yourself.


----------



## 335i Driver (Nov 29, 2006)

Dave 20T said:


> I thought that anti-deposit additives don't increase octane level. If they did, how would it explain Chevron, which says that the Techron level in all octane grades are the same?
> 
> But I think you are at least partly correct. Mix half 87 octane and half 93 octane and the mix will be slightly higher than 90, but not much. Mix 60% 93 and 40% 87 and mathematically you should get 91.4. I'm not so sure the mix would be 92.4 as you mention, though. I thought it would be around 91.6.


Don't confuse octane boosters and anti deposit additives, they are 2 totally different things. Anti deposit adidtives could boost octane, but they don't necessarily do so. Octane boosters like aromatics burn very dirty thus they need anti deposit additives to keep the carbon buildup down.


----------



## AskylitDrive (Oct 29, 2013)

PinkLambo said:


> So I finally got the day off to go see the 428i that I've been anticipating and I was a little disappointed but thats just me. Anyways, the salesperson had said I dont need to put 91 in the 428i even though the gas cap says so. He said "... For newer BMW engines not putting 91 is okay." Of course it dirties up the spark plugs and you're sacrificing performance but is it only in older models that putting regular (87) in damaging the engine?
> 
> Also, out of curiosity which gas stations do you prefer for your BMW and why? Over here, we have Petro Canada, Shell, Esso, Chevron, then course like Husky, Superstore and the other ones.


I put 94 in both my 2012 x1 and x6 at petro canada whenever gas is cheap or fair. When gas prices are high and i need gas, ill go with 91 at shell. Personally i like to use the best of the best regardless. I can definitely feel the difference when i put in 94 compared to 91. I would never put in 89 even if my SA told me i can.

Sent from BimmerApp mobile app


----------



## 328 M Sport (Apr 4, 2013)

PinkLambo said:


> So I finally got the day off to go see the 428i that I've been anticipating and I was a little disappointed but thats just me. Anyways, the salesperson had said I dont need to put 91 in the 428i even though the gas cap says so. He said "... For newer BMW engines not putting 91 is okay." Of course it dirties up the spark plugs and you're sacrificing performance but is it only in older models that putting regular (87) in damaging the engine?
> 
> Also, out of curiosity which gas stations do you prefer for your BMW and why? Over here, we have Petro Canada, Shell, Esso, Chevron, then course like Husky, Superstore and the other ones.


328i M Sport; 91 octane *ETHANOL FREE*. Only because real gas is my personal preference. 
_____________________________________________________________________
2013 EBII 328i XDrive M Sport; M Performance Brake Kit


----------



## milsalespurchas (Jan 26, 2014)

Dave 20T said:


> It almost works out mathematically. [(6 x 93) + (4 x 89)]/10 or [(6 x 4 higher octane)/10 ] + 89 = 91.4 If you were a chemist and tested it, it would be very close to 91.4.
> 
> In areas where they sell 87, 89, and 93, 89 is often half way between the 87 and 93 price. If you want it cheaper, you can mix your own gas. 89 from the pump is mixed while in the pump.


Well I am definitely no chemist, but that little math equation up there assumes that the relationship between different octane levels is linear. I highly doubt that is indeed the case, and I think trying to create your own octane level using simple math is nonsense. My 328i is still enroute, but I plan on using BP fuel, as per BMW's recommendation in their owner manual.


----------



## SippinSomethin (Oct 16, 2013)

93


----------



## flavius99 (Nov 18, 2013)

I switched from 89 to 93.


----------



## PinkLambo (Dec 30, 2013)

flavius99 said:


> I switched from 89 to 93.


What have you noticed performance wise? And how do you drive it?

"When I lay rubber down the street
I pray for traction I can keep
But if I start to slip and slide 
Dear god, protect my ride."


----------



## flavius99 (Nov 18, 2013)

PinkLambo said:


> What have you noticed performance wise? And how do you drive it?


If I could only get 91 in more places where I live I'd use that, I think. There was one moment where I thought this feels different with 93 octane now - if there is a real difference it would be hardly noticeable - right?

How I drive? My current average is 18.3 MPG


----------



## chacon777 (Nov 29, 2014)

go big or go home


----------



## Autoputzer (Mar 16, 2014)

Octane varies linearly with mixing. Here's a SUNOCO website: http://www.racegas.com/article/52

They really don't make mid-grade 89 octane gasoline. It's mixed at the pump (form 87 and 91, or 87 and 93 octane) to create 89 octane. I actually "invented" 89 octane back in the 1980's. Back then, there was just two grades sold, and I'd mix them in my parent's Mercury to stop it from pinging.

In the U.S. and Canada, octane is reported as AKI (Anti-Knock Index), which is different that RON (Research Octane Number) used in the EU. Here's the Wikipedia write-up: http://en.wikipedia.org/wiki/Octane_rating

I had a Chevy pick-up that supposedly took 87 AKI, but would ping going up a hill. 91 AKI would completely stop the pinging, and I could tell the difference in how the truck ran (especially going up a hill). Back then, there was a $0.10 difference in prices between 87 AKI, 89 AKI, and 93 AKI. At first I mixed 50% 89 AKI and 50% 93 AKI to achieve 91 AKI. For a 30 gallon fill-up, I saved $1.50. But, then I realize that if I used 33.3% 87 AKI and 66.7% 91 AKI, I got my 91 AKI and saved $2.00 per 30 gallon fill-up. Whoopie! I put in the 87 AKI first to make it mix better. I still mix 33.3% 87 AKI and 66.7% 91 AKI to achieve the required 91 AKI for my BMW, saving about $0.15/gallon at today's price differences. My E46 M3 would occasionally ping when lugging the engine with the specified 91 AKI.

BMW, VW, Toyota, Honda, GM, and Mercedes-Benz collaborated to create the Top Tier gas standard, exceeding the EPA requirements for additives that keep the combustion chambers and injectors clean. Here's the website for that:
http://www.toptiergas.com/index.html#

Ethanol has about 2/3's the energy of gasoline. So, E10 (10% ethanol) has only about 96.7% the energy of gasoline. Ethanol-free gas (used mostly for marine engines) is very expensive, and the energy increase is not worth the extra cost. Marine gasoline might not have all the additives that automotive E10 has, and might contain additives that cold damage the catalytic converters and O2 sensors. Modern cars are designed to withstand E10 without damage in regular use (except for the case of long term storage). E10 will eat the floats in carburetors, though. But, cars in the U.S. haven't had carburetors for decades.

I use marine grade ethanol-free gas in my gasoline powered implements of destruction (lawn mower, edger, trimmer, and blower) because they have carburetors. I buy it in small quantities, so it's all used up within a month. My Honda mower has a fuel shut off valve, so after use, I close the valve and let it run the carburetor dry to prevent damage to the float. Before using a new batch of fuel, I empty the old fuel into one of the implements of destruction and run it completely dry.


----------



## Autoputzer (Mar 16, 2014)

milsalespurchas said:


> Well I am definitely no chemist, but that little math equation up there assumes that the relationship between different octane levels is linear. I highly doubt that is indeed the case, and I think trying to create your own octane level using simple math is nonsense. My 328i is still enroute, but I plan on using BP fuel, as per BMW's recommendation in their owner manual.


BP only recently changed their formula to meet BMW's gasoline standard (Top Tier Gas). Before that, BP was rot gut gas. BMW recommends BP because BP owns Castrol, and Castrol sponsors a lot of BMW's racing efforts. Gasoline is gasoline. The differences are in the additives, and the additives are mostly made by one company, Lubrizol. Lubrizol is now a Berkshire-Hathaway (Warren Buffet) company.


----------



## Gary J (Dec 18, 2013)

You can watch the same tanker trucks stop a different brand stations.


----------



## Autoputzer (Mar 16, 2014)

Gary J said:


> You can watch the same tanker trucks stop a different brand stations.


Yup. Where I live, you never see a oil company branded tanker truck. It's always a local tanker trucking company. Don't follow a truck from station to station, though. DHS and the FBI will have a tizzy.

Almost all the gas goes into the pipeline/tanker/tank farm distribution system and gets mixed together. The additives (the difference between Top Tier Gas and bottom tier gas) and ethanol are added at the tank farm before getting trucked to the stations.

A lot of people don't use Citgo gas because Citgo is owned by communist Venezuela. Citgo has lost a lot of it's retail business. But, Citgo still produces a lot of gasoline for the wholesale market. So, you likely have some Citgo gasoline in your current tank of gas.


----------



## Autoputzer (Mar 16, 2014)

PinkLambo said:


> So I finally got the day off to go see the 428i that I've been anticipating and I was a little disappointed but thats just me. Anyways, the salesperson had said I dont need to put 91 in the 428i even though the gas cap says so. He said "... For newer BMW engines not putting 91 is okay." Of course it dirties up the spark plugs and you're sacrificing performance but is it only in older models that putting regular (87) in damaging the engine?
> 
> Also, out of curiosity which gas stations do you prefer for your BMW and why? Over here, we have Petro Canada, Shell, Esso, Chevron, then course like Husky, Superstore and the other ones.


Car salesmen will say whatever they need to sell a car. As a general rule, if their lips are moving assume they are lying.

Although it defies logic, people get all bent out of shape about buying a car that uses premium gas or synthetic oil. If you're worried about and $0.30/gallon extra for premium gas, why are you buying a new $50k to $75k car?

I have to admit though, it's amazing how well my wife's Honda runs on 87 AKI.


----------



## need4speed (May 26, 2006)

93 e0


----------



## Rich328 (Jul 22, 2014)

93, tier one Quik Trip


----------



## Nigel720 (Jan 4, 2014)

Normally I use Shell V Power but Huskey's 94 makes a difference and give better fuel mileage. If there is a Huskey near when I need fuel, the old girl gets a treat.


----------



## ZTR (May 31, 2014)

In a performance vehicle, I would be more concerned about too much octane. For example, a stock BMW that is designed to use 91 octane, will actually make less power with 104 octane Sunoco 260 GT Plus Unleaded racing fuel.

Some of the most powerful racing fuels for normal gasoline engines, actually have surprisingly low octane ratings, for example VP's MR12 unleaded racing fuel is 87 octane.


----------



## Autoputzer (Mar 16, 2014)

ZTR said:


> In a performance vehicle, I would be more concerned about too much octane. For example, a stock BMW that is designed to use 91 octane, will actually make less power with 104 octane Sunoco 260 GT Plus Unleaded racing fuel.
> 
> Some of the most powerful racing fuels for normal gasoline engines, actually have surprisingly low octane ratings, for example VP's MR12 unleaded racing fuel is 87 octane.


VP's website said that it's 87 MON (Motor Octane Number). The correlation between MON and Research Octane Number is not perfect. See the Wikipedia web page. But, 87 MON equal can equate to an AKI of up to 94.

Octane and energy or power are two different things. Octane is essentially the resistance to ignition by relatively low temperature sources. You want the fuel burn to be started only by the very hot spark, not from a hot spot on the piston, cylinder head, exhaust valve, etc.


----------



## BMWX7 (Dec 14, 2014)

Ever since i owned X5 have always filled with premium gas at costco. By mixing 1/2 n 1/2 you may save up to $5 is it worth the sacrifice of lowered fuel eco, sooner replacement for plugs or engine flush. Infact when i had a 4runner which always saw 87 i topped 93 occasionally n OH boy i did see how smooth it ran for those tanks. So My theory is I look after her & She looks after me.


----------



## Spartan01 (Aug 24, 2014)

91 or 93. Even my minivan gets premium.


----------



## badreligion702 (Sep 1, 2014)

91 is premium here.


----------

