Octane?

[Sierra and Jimmy]

Hi all, newbie here.  Long time guest, 1st time poster.  I have a question about octane gasoline, and which grade I should be using.  I currnetly use 87, but the truck pings.  It's not bad, usually when I decrease the accelerator it stops.  Usually happens at higher RPM's in lower gears, 1st to 3rd.  My service girl says ""to keep it at 87.  You're not doing any damage to the engine.  You will do more damage over the long haul by moving up to 91 or 92.  Once in a while it is ok to fill up with a premium grade, but go back to 87.""

 

Just want to know what u all think.  I have run 92 - 93 Sunoco Ultra  in the past and get NO PINGING!  Resposiveness seems to be better, and the engine really sucks it down!  

 

Thanks for the forum, and thanks for having me.

Pete

[TxDoc]

Welcome to the forum.  Very good folks here. Not a lot of bickering and dissention, as on other sites. Good, friendly jabs, though.

 

Here are some threads I brought up with a search:

 

http://www.gm-trucks.com/cgi-bin....=octane

 

http://www.gm-trucks.com/cgi-bin....=octane

 

that should get you started

[Shaners]

My dealer always said the same thing...  stick to what octane your engine was designed for.  He said in some cases the higher octane can give your computer fits!!!  Is it true?  I don't know, but I run 87 octane...

 

BTW, thanks for coming out of the closet and joining in the fun!!!

[Black02Silverado]

I also run 87. So far no problems for me. As for the pinging if it was ok to happen then there would be no need for a knock sensor, right? The higher the octane the slower the ignition point of the fuel, thus no pinging. IMO I don't see what runing higher ocatne would hurt other than your wallet.

[99silveradoz71]

*Phil Donahue Voice* "Are you there caller?"  JK...the "long time reader first time poster thing" sounded like a radio/tv program caller.  Welcome aboard.

[Stepside Z]

I tried 89 in mine for a while and I didn't notice any difference. Stick with 87 octane.

[Sierra and Jimmy]

Thanks all.  Tex, that was some good reading, very informative.  Thanks again.  After reading all the posts, as well as my owners manual, and putting trust in my service writer, I'll stick to 87.  I did that acceleration test from that one reading and pretty much passed it with flying colors.  Really, the only time I hear pinging is at low rpm/gear acceleration.  Owners manual said that is fine/normal.

 

Appreciate the help.

 

Pete

 

PS  As a matter of fact, Bill, thats exactly where I got that slogan, from a local sports talk show on the radio.  I was wondering if anyone was going to pick up on it.

[Shaners]

I don't know if the dealer will still do it, but there is an update for the computer on your truck to help eliminate some of the surging/lugging issues.  I had it done on my '00 Silverado.

 

It seems as though the torque converter locks up very early (35 mph).  This was done for EPA reasons.  They can reprogram it to lock up later which will really help drivavbillity issues.  The only other way to get around it is to drive in "3" instead of "OD" unless you are going to be running the "super slab".

[CapnDean]

Had a severe ping problem with a 99 Dodge Ram:  Learned a great deal about ping in the process.

 

I agree with the others on this site:  Use what your truck calls for (87).  The only time you should go up to premium is if you are towing a heavy load and you have to have that extra to stop the ping.

 

A light ping during gradual acceleration in high gear?  No worrys.  A constant ping without regard to gear, speed or load condition....you got a problem.

 

Been there...done that....got me a GMC instead of a Dodge...Gawd I shoulda never strayed!

 

CapnDean

[Markeaux]

I had been running 91 in my LM7 since delivered new for 2yrs, with absolutely no problems - maybe I did that because I traded in a 98 Z28 LS1 that I always ran with 91, yeah I know they are different engines with different compression and other characteristics but I always got pinging in the LS1 when using <91 so did not want to risk it ....  

 

Anyway, that said, I did recently test the LM7 with 89 and it pinged during acceleration/shifts (and yes I gave the computer time to settle down) - no matter how much the svc advisors, etc, say that is normal I'm not going to accept it, so I now use 89 (and never hear any pinging).

[mikel]

I've kept track of every fillup on my trucks, and I get about 10% better mileage with 91-3 than I do with 87 octane. I also have more power and the ability to pull hillls without downshifting with the higher octane.

 

I believe the engine knocks a little with lower octane, and the computer pulls back the timing so you don't hear it - but it is there! With higher octane, no pinging, more advance, more power, better mileage.

 

For me, the cost of the higher octane is about the same as the savings from better mileage. So, I pay at the pump and accept the increased power without complaining.

[fennsz]

says 87 in the book, and that's what I run.

[TxDoc]

There is no more latent chemical energy in 93 octane than in 87 octane.  What do you think the extra power might be attributed to?  Possibly a more continuous/even burning flamefront?

[BDBWTE]

Your motor doesn't have enough compression to require anything but 87 octane.  If you had 11:1 I would be like yeah 91-93 is required.  Stick with 87 octane.

[siskiyou]

I've tried 87, 89 and 91 octane. I found that I received about half of the price difference in extra gas mileage with the 91. I usually run 89 to save a little and I never get pinging during normal driving. When I tow I always run 91. I can go up the hills faster with no pinging. If I understand how the computer works is when it senses pinging it retards the timing, so you lose some power and mileage, you then press the accelerator down further which causes more pinging and the computer retards it further etc. etc..... As for me I run the octane where I don't get any pinging.