What did you do to your NNBS GMT900 Tahoe/Yukon Today?

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Wes
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Interesting how your petrol standards differ from Finland. I use only 98 E5, 95 "e10" is the other option but meant for economy cars. contains some more ethanol, max 10%. But there's literally only two options available anywhere. E85 flexfuel is stupidly rare over here so I haven't even bothered (would have to travel 30 miles to fill 'er up) and I highly doubt doing a bit of this a bit of that is a good idea in the long run. Choose one and stick to it and see where it gets ya.

tl;dr We have a ton of jabbering about about massive fuel prices over here, yet I've never seen anything like those octane numbers, different octane measuring standard? Could e95 with 10% octane actually be decent fuel for a v8 flexfuel engine and fuel linings? They market the 98 as "V8" fuel after all.
it's basically just marketing, but the mix is slightly different. not entirely different than a big company owning 10 products on the shelf with different brand names, they just end up with more market share.
normally the price gap on gasoline grades is not a lot so one person might go with the lower grade and still spend 90.00 versus 100.00
lots of competition between "brand" names which often all source the fuel from the same source. with a few exceptions
here locally the fuel is pumped into the local port and sent to a variety of stations with different names, but a big brand like Chevron may come from there refinery 80 miles away.
 

mikez71

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Interesting how your petrol standards differ from Finland.

Could e95 with 10% octane actually be decent fuel for a v8 flexfuel engine and fuel linings? They market the 98 as "V8" fuel after all.

I am guessing that a certain percentage of ethanol doesn't guarantee the same octane rating
(depending what they mix it with?)..

That said, I thought our 5.3's could drink just about anything?
 
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Pandabird

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I am guessing that a certain percentage of ethanol doesn't guarantee the same octane rating
(depending what they mix it with?)..

That said, I thought out 5.3's could drink just about anything?

First fill after buying was indeed E95 and got home without any issues whatsoever, however a workplace buddy got all frothy about it and i've done E98 since. A gallon is like 3.79 litres, the price difference would accumulate to roughly 20-60 cents a gallon after currency conversion (we get a lot of daily price fluctuation). Might be because i'm at 290k miles at this point and the engine could be getting 'brittle' despite its flawless service record.
 

Fless

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Interesting how your petrol standards differ from Finland. I use only 98 E5, 95 "e10" is the other option but meant for economy cars. contains some more ethanol, max 10%. But there's literally only two options available anywhere. E85 flexfuel is stupidly rare over here so I haven't even bothered (would have to travel 30 miles to fill 'er up) and I highly doubt doing a bit of this a bit of that is a good idea in the long run. Choose one and stick to it and see where it gets ya.

tl;dr We have a ton of jabbering about about massive fuel prices over here, yet I've never seen anything like those octane numbers, different octane measuring standard? Could e95 with 10% octane actually be decent fuel for a v8 flexfuel engine and fuel linings? They market the 98 as "V8" fuel after all.

Different ways to state octane:


"There are 2 widely used rating systems used in the world of fuel. Around the world the most common is RON (Research Octane Number), which is found by utilizing a knock engine. Here in the US we use AKI (Anti-Knock Index), while AKI is determined by taking the average of MON (Motor Octane Number) and RON. While the fuels are technically the same, the numbers at the pumps will differ. For example, 93 octane AKI, here in the US, is found by taking 88 octane MON added to 98 octane RON (used around the world) and dividing by 2.
93 AKI = (88+98)/2"
 
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j91z28d1

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it is possible that one fuel will ping in your engine and another won't, most an old school carb thing when they didn't retard timing because of that averaging. some engines
I used to only have 1 E85 option within 5 miles of my house. Recently they built a Sheetz and Casey’s within 3 miles of my house that both have E85.

View attachment 439826

In my ‘13 Escalade when you either run premium 93 or E85 and the price difference is well over $1+ per gallon choosing E85 is an easy choice.


what on earth is 88? is that some e based stuff, or just out of order mix between 87 and 89?
 

j91z28d1

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Interesting how your petrol standards differ from Finland. I use only 98 E5, 95 "e10" is the other option but meant for economy cars. contains some more ethanol, max 10%. But there's literally only two options available anywhere. E85 flexfuel is stupidly rare over here so I haven't even bothered (would have to travel 30 miles to fill 'er up) and I highly doubt doing a bit of this a bit of that is a good idea in the long run. Choose one and stick to it and see where it gets ya.

tl;dr We have a ton of jabbering about about massive fuel prices over here, yet I've never seen anything like those octane numbers, different octane measuring standard? Could e95 with 10% octane actually be decent fuel for a v8 flexfuel engine and fuel linings? They market the 98 as "V8" fuel after all.


honestly the best way to know if one is better than the other would be to look at your timing retard. this can be done with a cheap 30$ (over here) obd2 Bluetooth dongle and a phone app like torque for 5$ or even some free ones that show live data.

I pull mine up and on 87&89 I do see a little retarding of timing at interstate speeds just as you tip in the throttle. can't feel it at all but you can see it on the screen.(I believe the ecm settings are super aggressive about it since everyone is going to be running cheap gas in this hybrid version) usually about 5deg, but I've seen a flash as much as 10deg. to test if it was other engine noises from high mileage, I ran good 93 thru it, the highest we easily have access to and only get 1-2 deg at the same speeds.

funny I towed a car on a trailer 2k miles round trip in cheap 87 when I first got it without ever thinking to check it. it was probably pulling a good amount timing, but I see no side effects from it. next time I'll tow with 93 thou. around town, I still run 87 and let it do it's thing.

sadly I don't have a flex fuel version. I have e85 right around the corner.
 

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