100 Octane In The AV?

Blueruck · Sep 26, 2002

I found a couple of stations in the Denver area that sell 100 Octane - I was wondering if anyone has tried this in their AV or if there is a good reason not to put this high of Octane in my 5.3L.

Butch · Sep 26, 2002

You'll lose Power blueruck..., the stock engine doesn't have enough compression to require the Higher Octane..., and even with the Hypertec, or Superchips tuning the Timing curves are not that aggressive to need Octane that High.... Higher Octane Fuel burns more Slowly..., thats how it prevents Detonation.... You really only want to run the maximum Octane Fuel that You need to prevent Detonation..., anymore is just a waste.., and will actually Loose You Power......

Blueruck · Sep 26, 2002

Thanks Butch - glad I didn't waste my $'s

Murf · Nov 24, 2002

Dont waste ur money #1 -#2 you can scew ur cat convter so watch out .Low compression engines do not need this fuel89 octane is plenty

NJAV · Nov 25, 2002

Murf said:
Dont waste ur money #1 -#2 you can scew ur cat convter so watch out .Low compression engines do not need this fuel89 octane is plenty

Cats...who's running cat's...straight pipe baby........no for real way to much umphh..... :B:

spweebles · Nov 25, 2002

The 5.3 is supposed to take 87 octane. My 00 Silverado has the 5.3 and it runs like garbage

when I use 87 octane(Excessive pinging). I only run super unleaded now. Anyone run anything over 87 (Regular Unleaded) in their AV?

I was wondering on both engines since my Silverado has the 5.3 and my AV is going to have the 8.1

nh_mark · Nov 26, 2002

I have always run 87 octane in my Av and I don't have any pinging. Prior to my Av I also had a '00 Silverado with the 5.3 and I ran 87 octane in that too and I never had any pinging. Knocking but that's a different story

Now prior to that I always ran Super unleaded (92) in all of my truckes and I swore by it. My wife bought a '99 Blazer and we started running Super in it, after about the third tank of gas it started runnning like crap and the check engine light came on. We brought it in and they said that it was the gas. These engines are designed to work with 87 octane and you should not run 92 octane in them. I said, well it will start pinging and he said if it does then that means there is something else wrong. I of course thought this was B.S. but I started using 87 octance and have not had any problems since then.

-Mark

txyank1 · Nov 26, 2002

I used the prescribed 87 octane in my '99 4.8 and it pinged worse than my '01 5.3 does with it. The 5.3 pings just a little under hard acceleration. I put an occassional tank of "+" in when the prices are down. Like now! ($1.149)

steelheadchaser · Nov 26, 2002

I just heard on the news last night that gas prices are down nationwide. Except Washington state. We are still averaging $1.33 /gl for 87 octane.

jstrickl · Nov 26, 2002

As discussed in a few threads in the past, you should never exceed the manufactures recommendation for octane. Your engine was built and tuned for 87 octane. Doing so can adversely affect the engine's performance and longevity. Possibly voiding your warranty as well for damage incurred through knocking/pinging caused by incorrect fuel type.

The only exception to this is when your engine has been tuned for the different octane gas through a programmer or equivalent means.

Jamie's .02

ShapeShifter · Nov 26, 2002

txyank1 said:
Like now! ($1.149)

What?

My first thought was that you added an extra "1" after the decimal point! Prices are down here also, but... My last fillup was $1.569, that's down from a high of 1.598 a month ago. :6:

-- SS

NJAV · Nov 26, 2002

Gas prices are starting to come down gradually around here....thank goodness....I was dropping about $31 a week at the pump...for the mid-grade stuff....going to switch back down to regular and see if I feel a difference in the way the truck runs and idles... :B:

Jake · Nov 26, 2002

I now run 87 octane and have had no problems. My question is this: if it is so bad to run anything over 87 and may void the warranty, why does the manual say a "minimum of 87 octane"? That leads me to believe that it is OK to run a higher octane.

steelheadchaser · Nov 26, 2002

You will get no benefit using a higher octane than needed. Higher octane fuel will not cause knocking or pinging. Do a search using a keyword of octane, fuel or gas. Much has already been written on this.

txyank1 · Nov 26, 2002

ShapeShifter said:
What?

My first thought was that you added an extra "1" after the decimal point! Prices are down here also, but... My last fillup was $1.569, that's down from a high of 1.598 a month ago.

-- SS

Yup....that's a Tigermart I pass every day. The one in my neighborhood where I usually fill up is $1.169.

ShapeShifter · Nov 26, 2002

txyank1 said:
Yup....that's a Tigermart I pass every day. The one in my neighborhood where I usually fill up is $1.169.

Go ahead, rub it in. Both you and NJAV.

It typically costs me $42 to $44 to fill up, and I have to fill up just about every week, so I figure it's close to $40 per week on gas.

And that's for regular. At those prices, I really don't want to put in anything more expensive.

Now, don't get me wrong, I'm not complaining about the gas mileage. If I wanted high MPG, I would've never bought this truck. Rather, what I'm complaining about how much more it costs me than you other guys.

Dang New York State and Erie County taxes!

-- SS

tpseabird · Nov 26, 2002

I would think that all the exhaust mods would have more of an adverse effect than octane level; however, I now recall my brother's Tahoe having a check engine light issue, which the Chevy shop said was gas related.

These engines sure are funny! They like exhaust changes but not gas changes?

TP

steelheadchaser · Nov 26, 2002

tpseabird said:
These engines sure are funny! They like exhaust changes but not gas changes?

TP

What lean-out there is from a more open exhaust system is made up for by the computer. Higher octane gas is a little harder to ignite.

NJAV · Nov 27, 2002

ShapeShifter said:
Go ahead, rub it in. Both you and NJAV.

It typically costs me $42 to $44 to fill up, and I have to fill up just about every week, so I figure it's close to $40 per week on gas.

And that's for regular. At those prices, I really don't want to put in anything more expensive.

Now, don't get me wrong, I'm not complaining about the gas mileage. If I wanted high MPG, I would've never bought this truck. Rather, what I'm complaining about how much more it costs me than you other guys.

Dang New York State and Erie County taxes!

-- SS

Hey shape...don't sweat it man....one day gasoline is going to be free for all Av owners and then none of us will ever have to worry about paying another dime...

Ps..I also come from a state where things always tend to cost more....I feel your pain...

docanderson · Apr 20, 2003

I have always been a believer in a little bit more than minimum required as far as octane is concerned. A dealer told me to stop running 92 in my av because it was not tuned for it. The very next fillup was with 87. It drives fine until the engine is under a load (passing or uphill, etc.), then it knocks like crazy. I will stay with my 92 or 93.

pktwatch · Apr 20, 2003

How many miles did you run it with the higher octane? These engines get carboned up real easy and if you ran high octane in it for a whle I bet it needs de-carboned. The dealer can do this for you. The way I hear they pull the plugs and put a cleaner in the plug holes and let it soak then pump it out?

Wiki · Apr 20, 2003

If your AV knocks using 87 octane after switching from 92 octane, then your onboard computer may need to be reset. Help me out on this one 11H. I think your computer has jacked up your timming to try to deal with the 92 octane, and when you switch back, it is knocking a bit.

I may be stupid here, but if you dissconnect your battery, your Computer will reset to stock and your pinging may go away with 87 octane.

Can you confirm this 11H

Wiki

txyank1 · Apr 20, 2003

docanderson said:
I have always been a believer in a little bit more than minimum required as far as octane is concerned. ?A dealer told me to stop running 92 in my av because it was not tuned for it. ?The very next fillup was with 87. ?It drives fine until the engine is under a load (passing or uphill, etc.), then it knocks like crazy. ?I will stay with my 92 or 93.

I have yet to experience any knocking in the Av. Admittedly I do drive it a little easier than I did my pickups. Friday coming home from work was the first time I've kicked it into passing gear...slowpoke in left lane...and no pinging. On 87 only

spweebles · Apr 20, 2003

I was told by a GM service dude that engines that are in 2002 and 2003 vehicles are tuned better than engines in vehicles just a couple of years older. My Cookie Monster '03 AV 2500 has the 8.1 liter and it is fine with the 87 octane. My 00 Silverado 1500 has the 5.3 liter and I can't run anything less than super unleaded. Nasty pinging.

I'm trying to figure out the best oil to use in my AV. I know the GM spec says 5w30. To me that is just brown water. It's like the thinnest stuff there is.

Blueruck · Apr 20, 2003

docanderson said:
I have always been a believer in a little bit more than minimum required as far as octane is concerned. ?A dealer told me to stop running 92 in my av because it was not tuned for it. ?The very next fillup was with 87. ?It drives fine until the engine is under a load (passing or uphill, etc.), then it knocks like crazy. ?I will stay with my 92 or 93.

Doc I am surprised you are pinging - I am not sure where you live - but in CO I drive up some very very steep highways running 87 and have never had my AV ping - I bet 1/2 of my 38K miles are running up and down mtn roads and it has never pinged when passing or going up hill.

I think you should talk to the dealer about fixing your AV