What octane fuel ?

[Shortbus]

O.K. '05 Denali 6.0L engine . My salesman said 93 , the owners manual
says 87 ? A carsalesman that lies ? Come on ?


Also , how do I find out the gears in my truck ?
Everything else that i have ever owned said on the window sticker .

thanks
wally

 

[ID_Escalade]

Im not sure what the octane if for sure with the 6.0 but the 5.3 is 87 and for the gear ratio this side should help www.compnine.com/vid.php it should tell the ratio and a lot more, i found the site on the forum and it helped me a lot.

 

[gtbigup01]

87 like the books says. If the sales man tells you 93 then he's smoking crack.

 

[dwmmatt23]

i have always ran 93 in everyone of my cars including the hoe, does it really not make any difference to run the higher octane?

 

[Grocery Getter]

87 unless your tuned gor higher octane. I run 91(no 93 in AZ) but also run 105 Octane E85 as much as I can. There is only one station near me and it's not always open when I need to fill up. I'd run E85 all the time if it was readily available.

 

[Eagle]

87... or 89.

we don't have 87 out here, only 86 and 88, and it runs smoother and shows more power on my expertly calibrated butt dyno when on straight 88 or an 86/88 mix (87) than on straight 86.

 

[gtbigup01]

does it really not make any difference to run the higher octane?

Only difference is about $2.50 less in your wallet. However you'll hear lots of arguements saying that it burns cleaner and less pinging and produces more power.

 

[Shortbus]

Thanks everybody . The 6.0 seems to have alot more ass than the 5.3 . I'll add some 87 and check my own butt dyno!

Related : My brother has an '07 yukon 5.3 . It got a new engine at 45K . Ran E85 exclusive since new . Also used a quart of oil a month since new ?
I thought he just had a lemmon...'till TWO guys at work ( '07 5.3 pickups ) started bitching about the same thing . No smoke....no spots on the driveway ? wtf? The dealership is not talking . Just gladly swaping motors .

You guys heard about this ?
wally

 

[cam3439]

No, I haven't heard about this, but E85 ruins your engine and you get horrible gas mileage with it. As for the octane, I would at least run 89 (if you're rated at 87). I use to run 89 on my '02 5.3L until I got it tuned for 93. With a grade higher than recommended you should be able to prevent any detonation/pre-ignition. This is what EAGLE is experiencing. It's not that much more expensive and will be safer for your engine. Test the different grades and see what your truck runs most efficiently with. And don't use those octane boosters as they ruin your O2 sensors and your cats.

 

[jdpromo33]

93 baby

After Justin (Black Bear) tuned my baby up he recommended I stick with 93 and it runs fine with that