Premium Fuel With 6.2L?

Badass69 · February 5, 2016

The PCM has a low octane spark table to drop down into for those too cheap to run the proper gasoline and make around the same power as the 5.3 they should have bought in the first place. That's why the cheapskates don't hear much.... once its retards enough it just changes tables. Then the adaptives learn all this lax driving and low octane fuel so for that one tank of something higher they run once in a blue moon it doesn't make much difference to them. Don't bother fighting with them... it's a waste of bandwidth lol.

And hey... you can get 3.42 gears and the 8 speed with the 5.3 in higher trimmed models now so there is realistically no reason for the 87 octane only drivers to even bother with the 6.2 option anymore.

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Edited February 5, 2016 by 1994Vmax

ChrisNJ · February 5, 2016

I absolutely notice the difference between 87 and 93 in my '14-6.2. Run 93 all the time.

bigsapper · February 5, 2016

Since you brought up cleaner, that's not necessarily true. The production of E85 actually requires more fuel to produce than it gives, making it an energy negative. Just a little FYI.

Seriously, why don't you go start a dedicated thread about this. You obviously care a great deal about this subject. Edited February 5, 2016 by bigsapper

Tek74 · February 5, 2016

My next one will definitely be a 6.2L and I will definitely run 91 octane. I see no point in buying the bigger badder engine and running a lower octane fuel that diminishes the performance.

I'm guessing that GM did not make a stronger statement on the 91 octane requirement due to variations in altitude. Someone running 87 octane, or better yet, 89 octane, at high altitudes might get away with equal performance to one running 91 octane at sea level.

SouthpawHD · February 5, 2016

Seriously, why don't you go start a dedicated thread about this. You obviously care a great deal about this subject.

I'm not the one making a big deal about, just stating a fact. But thanks for keeping the thread going!

mdrew · February 10, 2016

Hook up a scanner and log knock retard with a tank of 89. You'll switch to 93 if you can get it. I tune my own vehicles, so I'm not talking out my rear end.

There are two spark tables; hi and low. The ECM does not automatically swap between tables. It "learns" spark curves and will bias to either table, depending on KR seen in the map over time. There is also a spark retard function called "burst knock". It is a predictive KR function that will pull spark in large areas of the spark map, based on what the ecm has learned.

Run 93 or the highest octane you can get when SCR is over 11:1. Or buy a Prius.

TxTruckMan · February 10, 2016

LOL! "I paid $3000 for more HP and TQ, but want to cheap out on gas to save a few $$$ which will reduce the HP/TQ that I paid up for."

youn1033 · November 28, 2017

So my question is: what are the problems with running e85 in a 6.2? If premium 91-93 octane is good, is 105 octane e85 not better? Are any 6.2L engines outfitted for flexfuel or can you retrofit one to be for a reasonable cost? E85 is about $1/gal cheaper than Premium

cmysstailights · November 29, 2017

So my question is: what are the problems with running e85 in a 6.2? If premium 91-93 octane is good, is 105 octane e85 not better? Are any 6.2L engines outfitted for flexfuel or can you retrofit one to be for a reasonable cost? E85 is about $1/gal cheaper than Premium

You need a custome tune to account for fuel difference and there is a sensor that you have to add.

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Doug_Scott · November 29, 2017

To the people that run premium fuel because it makes more hp and torque, do you always drive around with your foot to the floor, with the engine at or near redline, and then claim to get better fuel mileage? You cannot get the best economy and power at the same time. They are mutually exclusive. Where I am, the premium fuel has ethanol added to raise the octane. That gives reduced economy in every vehicle I have tried it in, not better.

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KARNUT · November 29, 2017

One of the many wonders in life, why would anyone pay extra for an engine option that requires premium fuel and not use it.

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gmissed · November 29, 2017

1 hour ago, Doug_Scott said:

To the people that run premium fuel because it makes more hp and torque, do you always drive around with your foot to the floor, with the engine at or near redline, and then claim to get better fuel mileage? You cannot get the best economy and power at the same time. They are mutually exclusive. Where I am, the premium fuel has ethanol added to raise the octane. That gives reduced economy in every vehicle I have tried it in, not better.

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I see you're from Ajax, I'm next door to you. Checkout Canadian Tire or Sunoco. It's my understanding their premuim gas is ethanol free.

michigan2500hd · November 30, 2017

Custom tune and additionof fuel sensor. Fixed

How is the e85 tune for power and economy? I have many gas stations around here that sell the e85. I'm considering doing the conversation to my 2015 6.2L.
Still reading up on how to do it.

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scott.moody.9401 · November 30, 2017

So my question is: what are the problems with running e85 in a 6.2? If premium 91-93 octane is good, is 105 octane e85 not better? Are any 6.2L engines outfitted for flexfuel or can you retrofit one to be for a reasonable cost? E85 is about $1/gal cheaper than Premium

No problems that I've heard of.

If folks consider 91-93 octane "premium", what do you consider 105 octane fuel ? (that's E85 in case you didn't know)

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racetrk · November 30, 2017

To the people that run premium fuel because it makes more hp and torque, do you always drive around with your foot to the floor, with the engine at or near redline, and then claim to get better fuel mileage? You cannot get the best economy and power at the same time. They are mutually exclusive. Where I am, the premium fuel has ethanol added to raise the octane. That gives reduced economy in every vehicle I have tried it in, not better.

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Your foot doesn’t need to be to the floor for there to be preignition. Using the recommended octane allows the engine to run as efficiently as possible, which includes taking advantage of more fuel and ignition timing, resulting in better fuel economy.