Gas... Octane ?

**iPublicEnemy47** · 06-05-2009, 11:05 PM

Ok Im sure this question has been proably asked more then once...

What Grade Gasoline do you put in your truck?....

Is it also bad if I used 91 octane then switch back to 87 octane because of the cost of fuel

**ricodog77** · 06-06-2009, 12:33 AM

I run 91 when I'm towing my trailer and then switch back to 87 when I'm not going to be towing for a while. I do change the tune with my programmer depending if I'm towing or not. Haven't had or heard of a problem with that yet.

The only problem you would have is if you tune your truck to run 91 and put 87 in it, it's probably going to knock a lot when you get on the pedal. Hope that helps.

**iPublicEnemy47** · 06-06-2009, 01:38 AM

ok thanks...

so mine isnt tuned so 87 would be fine?

**jerrynino** · 06-06-2009, 02:20 AM

it should be fine as long as you dont jump from one to another every fill up... or at least thats what ive heard... i ran 91 one week then the gas went up a good chunk so i went right back down to 87 lol... and im still running that 87

**Jimmiee** · 06-06-2009, 01:08 PM

Originally Posted by iPublicEnemy47

Ok Im sure this question has been proably asked more then once...

What Grade Gasoline do you put in your truck?....

Is it also bad if I used 91 octane then switch back to 87 octane because of the cost of fuel

It's OK to switch but I would run a few tanks of 91 and then see if you gain any fuel milegae. If you don't see a gain then why waste your money? If your engine is designed to run on 87 then 91 may just be a waste of money.
Another thing to keep in mind as mentioned before is if you are running a programmer than don't use the 87 if you are programmed for 91. Your knock sensor will hear the ping long before you do and will do it's best to eliminate the knock. It does this by retarding your timing which will make your truck loose power even more.
And be careful out there. There are many stations selling 85 which is bad for most engines.

**Crakums_GT** · 06-06-2009, 01:28 PM

Just for my little input i did try to see about getting more mpg with 92 but it didn't work. I now run 87 all the time because it wasn't worth the money for no gain.

-Greg