[jmciver]

Originally Posted by like2short

This is the AAA report on Top tier gas,

https://www.aaa.com/AAA/common/AAR/f...ull-Report.pdf

yes the detergents help prevent deposit formation. The good news is these detergents also seem to work if non top tier was used and deposits have formed. The bad news for direct injection engines is that these detergents don't help intake valve deposits because only air and fuel go thru the valve. Fuel goes directly into the cylinder head.

Use the octane recommend by your mfg and use top tier gas.

Nice read ....

Fortunately, BMW has improved the PCV systems in their current GDI engine line-up such that carbon buildup is significantly reduced (compared to the heavy carbon buildup on older GDI engines like the N54). This post has a picture of the intake valves of an S55 engine in a M4 with ~60k miles: https://f80.bimmerpost.com/forums/sh...40&postcount=8

However, my OCD takes it a bit further and I use the CRC GDI system cleaner on my F80 M3 prior to every oil change:

https://f80.bimmerpost.com/forums/sh....php?t=1640183

[like2short]

Originally Posted by jmciver

Nice read ....

Fortunately, BMW has improved the PCV systems in their current GDI engine line-up such that carbon buildup is significantly reduced (compared to the heavy carbon buildup on older GDI engines like the N54). This post has a picture of the intake valves of an S55 engine in a M4 with ~60k miles: https://f80.bimmerpost.com/forums/sh...38;postcount=8

However, my OCD takes it a bit further and I use the CRC GDI system cleaner on my F80 M3 prior to every oil change:

https://f80.bimmerpost.com/forums/showthread.php?t=1640183

Oh that system cleaner stuff... I've used berrymans before. All those products make some killer smoke!

[1268]

MPG and fuel cost should never cross ur mind in a vehicle of this price range.....

[iconoclast]

Originally Posted by jmciver

Fortunately, BMW has improved the PCV systems in their current GDI engine line-up such that carbon buildup is significantly reduced (compared to the heavy carbon buildup on older GDI engines like the N54). This post has a picture of the intake valves of an S55 engine in a M4 with ~60k miles: https://f80.bimmerpost.com/forums/sh...40&postcount=8

Oh man, don't even get me started on Carbon Build-Up on DI/GDI/FSI motors. I had my initiation into the club with B7 RS4 along with every DI motor after it and have had an uphill battle with this BS ever since. On that car 6-8k miles you needed to a carbon cleaning or your 420hp RS4 was putting down 225whp. Granted a lot has changed with the motors in fourteen years but it is still an issue unless there is a supplemental injector with a wash cycle implemented into the motor (Multi-Port Direct Injection).

[like2short]

Originally Posted by iconoclast

Oh man, don't even get me started on Carbon Build-Up on DI/GDI/FSI motors. I had my initiation into the club with B7 RS4 along with every DI motor after it and have had an uphill battle with this BS ever since. On that car 6-8k miles you needed to a carbon cleaning or your 420hp RS4 was putting down 225whp. Granted a lot has changed with the motors in fourteen years but it is still an issue unless there is a supplemental injector with a wash cycle implemented into the motor (Multi-Port Direct Injection).

Yeah some of the newer engines have port AND direct injectors. Like Ford F-150 eco boost. I think Toyota has some engines like this too, but don't quote me on that.

[iconoclast]

Yes, they do. They were the first to have the issue and the first with a solution. Audi blamed it on the customer, then on poor quality fuel/oil in the US then redesigned their motors to mitigate carbon build-up.

[Wild Blue]

Revisiting this thread. Our X7's recommend 91 octane minimum. Highest octane in Alaska is 90. Am considering whether to regularly add octane boosters. Wondering if others have recommendations, including brands.

[mitch57]

Originally Posted by Wild Blue

Revisiting this thread. Our X7's recommend 91 octane minimum. Highest octane in Alaska is 90. Am considering whether to regularly add octane boosters. Wondering if others have recommendations, including brands.

I've been using this for years. https://www.bgprod.com/catalog/gasol...ystem-cleaner/.

I bought a brand new 1989 Toyota Camry back in the day. After about 6K miles I started getting a lot of hesitation when accelerating. The Toyota service tech put this in my tank and it cleaned the valve seats up and no more hesitation. He told me Toyota uses it for their vehicles because it works so well. He called it a "Liquid Tune Up". I've been using it ever since in all my vehicles.

[Resjudicata]

Originally Posted by Wild Blue

Revisiting this thread. Our X7's recommend 91 octane minimum. Highest octane in Alaska is 90. Am considering whether to regularly add octane boosters. Wondering if others have recommendations, including brands.

Lots of track guys use Boostane Professional. The street legal road version is Premium.
I've used professional in other cars, and I'd try using Premium in my bmw; I haven't used anything besides pump gas in mine because we get 93. But Premium will bump it to 100.

https://boostane.com/product/boostan...-16-oz-bottle/

[Resjudicata]

Alternatively you can import drums, but I think some boosters is cheaper.

https://petroleumservicecompany.com/...ab-description

you might also find higher gas at a track; if you live near one.

https://www.alaskacartransport.com/n...cks-of-alaska/

[jmciver]

Originally Posted by Wild Blue

Revisiting this thread. Our X7's recommend 91 octane minimum. Highest octane in Alaska is 90. Am considering whether to regularly add octane boosters. Wondering if others have recommendations, including brands.

I wouldn't worry too much about it. Despite what the recommendation from BMW states, the cars they sell in the US are required to be compatible with the gas available in all 50 states. That includes the apparent 90 "craptane" available in AK. The ECU in the car will adjust the necessary engine parameters (fuel, timing, etc) all the way down to 87 octane for safe engine operation if necessary. The catch is, your X7 will not run at its "potential" as you are not putting in the higher octane fuel. You may not even notice a difference in engine performance with the 90 octane unless you are really driving hard on a regular basis.

What is even more important than octane boosters, IMHO, is using branded or Top Tier gas. These brands have more than the minimum requirements of additives/detergents that not only burn cleaner, but also help to keep your engine internals clean - thus maintaining maximum engine performance. If you run crappy no-name gas for an extended period of time, then run a fuel system cleaner, you should actually feel the regained engine performance. So just don't put the crappy gas in your X7 and you should be fine.

[dmanb2b]

WB...I wouldn't use an octane booster on a regular basis as it leaves significant deposits behind on your plugs and the combustion chambers. You can log your engine parameters and see if you are getting any timing corrections running 90 octane. If you are, so good old e85, up to an e30 mix is the best and widely used to boost octane.

e10 mix is normal 93 pump gas in the northeast, as an example.

[Wild Blue]

I'm giving this a shot. Here's what the fuel door says on the M50i:





Alaska has max of 90 Octane at the pump. So I may be able to get away with using it during the colder winter months without any ignition retardation. During the warmer summer months, sure, the ECU will retard the ignition as needed to protect the engine.

But I don't want to have the car have to protect itself from pre-ignition damage. This is a $100k+ car. I'd rather have it run exactly the way it should be.





So I got some Boostane, and I'm going to try this out this summer. Boostane has an app, which works so-so. Using 4oz of their Boostane Premium (1/4 of a 16oz bottle) for each fill-up of the X7's 20 gallon tank, I should get a final result of about 92.5 Octane.

Cost-wise, each 4oz tank fill will cost about $4.50, which is reasonable.





Boostane cans and pails don't come with ways to measure out portions. So I picked up a little measuring flask to hold it, and measure out each pour. Designed for taking a drink with you, but works pretty good for this application too.

Biggest issue was initially opening the Boostane can. It has a little red plug in the top. Taking that out, the can's pretty full, and just the smallest splash, puts that fuel smell on your hand that sticks around almost as much as fish.





Pours pretty well straight into the tank.

Of course, the big question is if there's any noticeable performance difference. Not going to give any additional performance, but at least restore any performance that was robbed from ignition retardation. Not sure yet if I'll be able to tell any difference. It'll be subtle.

[dmanb2b]

I would log engine parameters before using this and see if you are getting any engine timing corrections. I know I mentioned this before, but if a little boost of octane is required, a splash of ethanol will go a long way vs. MMT based product which will shorten the life of spark plugs and o2 sensors. Below is a link to a thread of what an exhaust pipe looks like from somone running MMT un catted https://f87.bimmerpost.com/forums/sh...3&postcount=18

[MystroX5]

I can never understand why anyone wants/needs to save $8 a tank and go against the recommended optimal fuel from the manufacturer on a $100k luxury /performance vehicle??? Sunoco 93 or Ultra 94 in everything I own.

Seriously, a Olympic athlete can probably perform on a diet of generic hot dogs for awhile as well but one would think ‘good in =‘s good out”.

[jmciver]

I would also stay away from the octane booster stuff as well, especially for the type of long term usage you are talking about - especially since I believe you intend to keep your X7 for the long haul. AK may not get the best octane gas, but what you do get up there (90 octane) will still run fine in your M50i (especially if you use Top Tier gas). All modern BMWs require a minimum of 89 octane (as written on the label you posted - same for my 40i).

The ECUs in these modern BMW engines are VERY smart and will always optimally run the engine under varying conditions and types of fuels. Adjusting some engine timing and spark a bit to account for the lower octane fuel you have available is not a bad thing and will not hurt the engine, so I would not try to outsmart the ECU with this stuff - especially for just daily driving usage. Besides, how hard are you running your X7 on the road to the point where you could feel a difference anyway?

If you are really concerned, why not talk to your local BMW dealer? Specifically, a knowledgeable SA or even better, a shop foreman. I will speculate there are MANY stock BMWs that run just fine in AK and I am sure most don’t run that stuff regularly. I am sure the dealer will be able to alleviate your concerns AND also confirm the warnings you are getting about extensive use of octane boosters you buy at the local auto parts store.

[iconoclast]

I don't have much confidence in boostane as they cannot even spell desired properly.

[Wild Blue]

All good points.

FWIW, Boostane isn't in gas stations, and is reported not to leave the residue that low-grade octane boosters do. I don't plan on running this long-term. Will try for a couple tanks and see how it goes.

dmanb2b unfortunately (?), I can't find ethanol in Alaska. What would you use to log engine parameters?

[jmciver]

Originally Posted by Wild Blue

All good points.

FWIW, Boostane isn't in gas stations, and is reported not to leave the residue that low-grade octane boosters do. I don't plan on running this long-term. Will try for a couple tanks and see how it goes.

dmanb2b unfortunately (?), I can't find ethanol in Alaska. What would you use to log engine parameters?

BimmerLink allows you to monitor all of the engine parameters (and then some) and log them.

[unfoundnemo]

Originally Posted by 1268

MPG and fuel cost should never cross ur mind in a vehicle of this price range.....

+1, many stations don't have 91 near me, but I've always put 93 in regardless. I happened to notice recently that the delta from regular to premium is substantially different depending on where I stop (sometimes $0.60 more, sometimes over $1.00), but still, it's not worth going out of my way to save a few bucks a fill up. What am I going to save, maybe like $500 a year? Not worth a second thought.

As @Wild_Blue mentions, there are certainly use-cases for octane boosters beyond trying to save money or address a certain circumstance. On a recent trip to Utah, I found 85 for at a pump for the first time ever, and 91 wasn't available in many cases. After some research regarding how people could have a high performance cars in this area, I at least did find and realize that the altitude played a role which is why you will only see 85 in certain areas.

[jsmonet]

the 91 recommendation is in place because markets like mine in CA don't have 93. Remember when the STi first came stateside? It was tuned for 93 and had knocking issues in summer here. I had to throw an accessport tune on it for 91 to get around that--the extra power didn't hurt, though.

It's pretty absurd to fill with lower grade even though your ecu will tune-by-knock down to the fuel grade. It's understandable in WildBlue's market, but that's about it.

[Wild Blue]

Initial impression--may be psychological, but car definitely seems more "alive", or responsive already. Would be very interesting to see empirical data of what's happening.