Mid grade vs low grade

amfr · June 22, 2016

I hope this is the right thread. So I was shopping at Sam's today and I filled up with low grade because Sam's is over priced where I was at and I have noticed a severe decrease in power. Anyone else feel this when they fill up?

sent from Florida beech

Jihans01 · June 23, 2016

I've noticed a big difference between 87 and 89 and no real difference between 89 and 91 so I stick to mid-grade 89 when I fill up.

SouthernSilveradoGuy85 · June 23, 2016

I filled up with 87 and maybe at the beginning of the year I decided to switch to 89 and have been filling up with 89 ever since. I honestly can't tell a difference, but I figured the compression ratio being so high that 89 makes more sense. Any HP gain is just from the ECM adjusting the timing and I don't think it's enough to really notice so I'm thinking it's that placebo effect, but then again maybe not.

Donstar · June 23, 2016

I run 89 but believe 87 works fine. There is a lot of discussion on this forum about the merits of both grades and, if for no other reason, I simply feel better putting a little extra in the tank!

emeryz28 · June 23, 2016

in my 6.2 I usually run 91 Octane. I have one a tank of 89 and could not tell the difference, with that said I could not tell the few times I ran 93. I have never run lower than 89 and never plan to. I am sure you won't see any other effects from the 87 other than lack of power and fuel mileage

TxTruckMan · June 23, 2016

I hope this is the right thread. So I was shopping at Sam's today and I filled up with low grade because Sam's is over priced where I was at and I have noticed a severe decrease in power. Anyone else feel this when they fill up?

sent from Florida beech

Which engine? In a 6.2L there will be a big difference. In the 5.3L or 4.6L you shouldn't notice a difference.

Does Sam's sell top tier gas? I wouldn't use them if not.

amfr · June 23, 2016

Which engine? In a 6.2L there will be a big difference. In the 5.3L or 4.6L you shouldn't notice a difference.

Does Sam's sell top tier gas? I wouldn't use them if not.

5.3 and they do have top tier I might just have to try that

sent from Florida beech

amfr · June 23, 2016

If it makes any difference I do have an intake and exhaust. Always ran mid grade. I pulled off the battery when I installed them and it ran.....smoother.....not as much hesitation and rough idle

sent from Florida beech

TxTruckMan · June 23, 2016

5.3 and they do have top tier I might just have to try that

sent from Florida beech

I looked it up. Costco sells top tier gas, Sam's does not. I wouldn't use it. You don't know what kind of quality you're getting.

http://www.toptiergas.com/retailers/

HondaHawkGT · June 24, 2016

I used to have the same power loss on 87 octane. VERY noticeable on 90+ degree days when the AC was on and climbing hills. The engine would bog down, my foot to the floorboard, just trying to maintain speed. Once it started to feel like a dog it wouldn't go away until I parked it for a few hours. Also had terrible fuel economy to go with it. It's been verified by multiple credible sources that the new engine has a fair amount of knock on regular 87.

amfr · June 25, 2016

I looked it up. Costco sells top tier gas, Sam's does not. I wouldn't use it. You don't know what kind of quality you're getting.

http://www.toptiergas.com/retailers/

O that haha yeah. I was just getting it cause it was there. I generally only buy fuel from bp and shell

sent from Florida beech