# Anyone using Regular (87) octane?



## YellO5LS2 (Jan 9, 2011)

I have been running premium fuel just because the car wants it. Since gas has gone up again (thank you liberal tree hugging hippies for not drilling for oil 30 years ago) I was curious if 87 will pose any issues. My 94 camaro runs like crap without premium, has a knock sensor but still runs poorly....Anyway, just seeing if anyone was using regular in the LS2 and was satisfied with MPGs and performance.


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## dustyminpin (Jun 19, 2006)

87? EEEEEK! :willy:

In all serious, one of the FEW times I have EVER put 87 octane in my goat was after one of our zillion hurricanes we've had down here on the Bama coast a few years back. ALL the damn gas stations around here were out of gas. You gotta love how people panick and run out and wipe out grocery stores, hardware stores, and gas stations right before these storms come in. The only gas I could get for about 2 weeks was 87. I only had a K&N CAI and Diablosport Predator tuner at the time (maybe had my Borla exhaust but don't think so) so I was 99% stock. 

I took the 93 octane tune out of the car and loaded the factory tune back in it and the car never missed a beat. I didn't see any drop in fuel economy. There may have been power loss but it was marginal. GM says you can use 87 octane but they do not gaurantee the 400hp/400trq rating on the engine. If you're in a pinch, you aren't gonna miss losing 20, 30, 40 hp. 

If another 'cane looks to be coming I'm gonna have to fill up my 6 or more 5 gallon jugs in the shed with premium because the tune I've got now with all the mods won't support 87, or so my tuner told me. I haven't had the ballz or been stupid enough to find out.


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## GTO JUDGE (May 14, 2005)

NO NO NO NO 

If you want to save a few cents here and there.....
Refill at 1/2 tank intervals alternating 89 /91 or 93 octane. 

I did this for the longest while when the difference was 20 cents + a gallon between mid and high octanes. I may end up doing this again since prices are out of hand again.


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## Poncho Dan (Jun 30, 2009)

I fight high gas prices by having a 4 cylinder as a DD...


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## Gotagoat (Jan 6, 2006)

Poncho Dan said:


> I fight high gas prices by having a 4 cylinder as a DD...


Me too.


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## srs7324 (Jul 8, 2010)

Nice update. 
I have a national chain gas station that offers 87, 89, 91, and 93.
Go figure the 93 is a few cents cheaper than the 89 and 91. 
Are they just trying to get rid of it or is that the norm everywhere?

Mixing 1/2 tanks for now on until we decide to drill again.
Maybe awhile.


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## LS2 MN6 (Jul 14, 2010)

Just keep using 93. If you can't afford the extra $2-3 you bought the wrong car.

I never care about the price of gas. I need it, that won't change, so why care about the cost it is out of my control.


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## fergyflyer (Apr 18, 2005)

OP, you are asking a simple math question. 

15,000 miles per year divided by an average mpg of 20 equals 750 gallons per year. 

750 gallons times $4.00 for premium is $3000.00

750 gallons times $3.60 for regular is $2700.00 

The difference is $300. per year. $300 divided by 52 weeks is $5.77 per week. 

For $5.77 per week, less than a buck a day you will lose horsepower and might lose fuel mileage depending on how much timing the computer pulls. If you lose mileage then the above calculations are useless, you might not save any money at all. 

So if having between 5 and 10% less hp is ok with you, and a 380 hp GTO is pretty darn fast, go ahead and use the lower octane fuel. 

If a buck a day doesn't matter that much, keep using premium. 

It's really that simple, less than $1 per day in return for maximum performance.


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## Poncho Dan (Jun 30, 2009)

LS2 MN6 said:


> Just keep using 93. If you can't afford the extra $2-3 you bought the wrong car.
> 
> I never care about the price of gas. I need it, that won't change, so why care about the cost it is out of my control.


:agree

Seriously. It doesn't get good DD mileage for two reasons: 346 (LS1) or 364 (LS2) cubic inches, and it weighs over 3700 pounds. Get a 4 banger that's ~2liters, weighs like 3000lbs, is stick, and call it a day.

For a weekend warrior, IMHO, it gets exceedingly good gas mileage. I haven't gotten worse than 21 combined, and around ~25 on the highway.

If you want cheap fuel, talk to a competent tuner about doing an E85 conversion. There's more than a handfull of people who've done it.


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## tyty (Aug 21, 2010)

you bought the beast now you have to feed the beast.


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## ROBSGTO (Jul 6, 2008)

I always use the 93.


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## GM4life (Mar 18, 2007)

If you want to use 87 use it. Nothing saying you can't use it, it says Premium fuel *Recommended* not *Required*. Do your own experiment and see what you come up with. If you want to sip gas max performance is not important. Some folks have made some good post in this thread.


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## ROBSGTO (Jul 6, 2008)

After I had my headers installed the tuner told me to always use premium gas,but I always did anyways.


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## GM4life (Mar 18, 2007)

Thats a given because you got a tune. In stock form you can use 87. I've used 87 once when I was stock just to see how it would perform, and it didn't run that much different but you can tell it didn't feel right. Didn't do any MPG test because I put 91 as soon as I got to a half tank.


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## YellO5LS2 (Jan 9, 2011)

Ill just stick to premium. I didn't buy the car for fuel economy, I was just curious. I got it because it's bad ass and throws you back in your seat. Never gets old!


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## jpalamar (Jul 22, 2008)

Sell the car, buy a Mustang GT  Stock tune is for 87.

Seriously though, you should be fine but expect a HUGE power drop. On the HHR forum they dyno'd the same car with 93 and then a few tanks later with 87. Similar conditions and there was about 30 HP difference.


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## Poncho Dan (Jun 30, 2009)

GM4life said:


> Thats a given because you got a tune. In stock form you can use 87. I've used 87 once when I was stock just to see how it would perform, and it didn't run that much different but you can tell it didn't feel right. Didn't do any MPG test because I put 91 as soon as I got to a half tank.


The one time I was stuck using 87 in an emergency (I purposely ran her out of gas to test the range feature in the DIC *accurate within 2 miles, I might add*, and only had regular in the can for my lawnmower along in the trunk), I could tell I had to get into the throttle a bit more for the same results... and this was just cruising. The response I was used to was just gone.


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