I was thinking today as I was filling up the tank on my 2001 GMC 2500 with an 8.1L 496, I use 93 octane just to stay on the safe side. My question is this, is 87 octane safe to use on my truck? I find it pointless to keep putting 93 octane if I can get away with 87 and get more for my money.

Use 87 in all of our GMs. 6.0, 5.3 and our V10 in the Excursion. They tow all over the US. Never had a problem.

i have the same truck 2001 8.1 496 with allison trans .never seen anything but 87 . mileage is terrible think i get about 11 mpg pulling a 11.000 lb boat or empty driving to work

Wow and this entire time I've been putting 93 and just throwing money away. Smokin gun your right the truck gets bad gas mileage but it's an awesome truck!!! It has plenty of power and rides aweomse, I absolutely love mine. From now on 87 it is.

I have the same truck too 2001 2500 hd 496 Allison have only ever ran 87, did you see in the manual or something to run 93? Ive never actually checked.

Yes you will be fine, however with lower rated octane you normally get worse gas mileage.

John jr

Mine did not have a manual, seems a lot of people on here have the same truck and I can see why it's a great truck!!

Virtually all modern vehicles can run 87. These vehicles have knock sensors. If you are getting pre-combustion because of lower octane the computer will adjust the timing to compensate. I had a Corvette, owners manual said premium fuel only, I could not tell a difference in power between 92-93 or 87, so I ran 87. No problems.

yes it will run with it but,,,,with 93 octane it burns slower and in return you will bet more mpg,the 87 octane will burn faster and hotter...i use to burn 93 and i went to midgrade..

Octane rate is for the rate at which the fuel is prone to detonation. The higher the rating the less prone to detonation, more of a proper, complete burn. The knock sensors are to pick up just that, when that happens it cuts timing, in turn making a less efficiante burn, can def hurt gas mileage ESP if you are towing something.

John jr