Real Benefits to 91/93 Octane in a regular LQ4???

Marky Dissod said:

Pessimistically, 1 gal of gas equals 10 stop'n'go miles. Optimistically, as much as 25 highway.
So a 25 gallon tank (never run it bone dry) should cover between 250 and 625 miles.
Price of 91 / 93 in NYC is about 30% higher than the price of 87.
250 * 1.3 = 325 miles ... 625 * 1.3 = 812 miles

If 91 / 93 doesn't improve mileage by enough to offset its additional cost, then save your money.

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This sounds like good advice, if you're willing to ignore post 8.

joe

It has been one hell of a day so I won't be going through tune tables tonight. Had to run 2.5 hours to the kids place at college to remove and replace a frozen caliper on the Silverado, then pads and rotor. Then drive 2.5 hours back. I'm shot. I'll try to get them up tomorrow

homesick said:

This sounds like good advice, if you're willing to ignore post 8.

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Oh, but I am.
1. GM designed spec'd built and tuned every 4.8L and 5.3L specifically for 87 octane; same goes for the LQ4,
and most of GM's other 6.0L V8s.
2. Too many are reticent / averse to having their pcms / ecms & tcms tuned.
They fail to appreciate how easy it is to tune an LQ9 or any other 6.0L or 6.2L to operate safely with 87 -
even without more burst knock or power enrichment.
(No one should operate any engine that recommends 91 using 87, PRIOR to the 87 tuning,
except as gently as possible until 91 or E85 can be used - no towing / hauling / racing / hooning on 87!).
3. Even many tuners understandably hesitate to de-tune an engine from 91 to 87.
It's so much easier to simply lean back on the standard disclaimers and tell 'em to keep using 91.

I keep track of my MPGs for every fill up...at best I saw less than 1 MPG using 93 octane over 87 and 93 is usually about $1.00 more per gallon (best I had found was .85 cents)...

I agree with those that say my 6.0, without a tune will see little benefit in using a higher octane gasoline than recommended by GM which is 87

I appreciate the feedback from everyone and may consider getting a tune, Blackbear or otherwise but for now, 87 Top Tier for me...

Bill

SilverSport said:

I keep track of my MPGs for every fill up...at best I saw less than 1 MPG using 93 octane over 87 and 93 is usually about $1.00 more per gallon (best I had found was .85 cents)...

I agree with those that say my 6.0, without a tune will see little benefit in using a higher octane gasoline than recommended by GM which is 87

I appreciate the feedback from everyone and may consider getting a tune, Blackbear or otherwise but for now, 87 Top Tier for me...

Bill

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I have an LQ4, tuned from Blackbear and usually just run their 87/89 tune. They provide you with both an 87/89 tune and a 91+ tune. So you can swap between the two.

They're finishing up a tune for me now on an LQ9, so I am curious to see if they give me both files for that engine as well, or only a 91+ tune since it is higher compression. But the LQ4, you will get both since the LQ4 could run on 87.

thanks for sharing your experience...

Bill

this may be helpful for anyone wondering as I was...

Bill

Higher octane is to prevent spark knock (also known as pre-ignition). That's it. That is the only benefit. If the vehicle doesn't require or recommend it, it is a waste of money. You will not get more power and you will not get more fuel economy.

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91RS said:

Higher octane is to prevent spark knock (also known as pre-ignition). That's it. That is the only benefit. If the vehicle doesn't require or recommend it, it is a waste of money. You will not get more power and you will not get more fuel economy.

Gasoline explained - octane in depth - U.S. Energy Information Administration (EIA)

An introduction to gasoline octane, why octane is important, and how it is measured.

www.eia.gov

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I'm so glad you worded it fuel economy. Because yes you can get better mpgs. But, if it isn't enough mpgs to offset the higher price of the higher octane, the economy part isn't there.