Fuel Quality

[mjannusch]

Seems like more of a placebo sort of thing to me. I dunno.

[ChargerX3]

Not sure why this hasnt been asked yet. What compression ratio is your engine? Is it 10:1 or higher? Also is your truck equipped with a fuel grade sensor? If the answer is no then you will likely see no difference over medium grade, or negligible over low grade.

I have a petroleum customer I work with and Shell is on the top of the list as well as the others you mentioned. All of that fuel comes from the same pipeline, or ship. The pipeline gasoline comes in batches miles long. Cheveron, Exon, Conoco, Shell pay extra for first dibs on the sweet stuff which is found in the middle of each batch. Diesel and other petroleum based products come down the same pipeline. Typically they use iirc water to separate them out. Well that water mixes with the start and ends of each batch and obviously lower the grade. That's where your am pm, maverick, golden gate, and other low price fuels get their fuel from. They get it cheaper, but they also still have to do more work to get their fuel back up to par. Some do a better job than others for sure. That's why cheap gas can be a gamble for high performance cars.

[Duck Vader]

9.5:1 - or that is what it should be.

As for sensor - no idea honestly and google isn't much help.

I have been running a custom tune set for 87 using Fred Meyer (Kroger) fuel as my go to for awhile now. Which is not a Top Tier gas. I do notice a slight difference when using Chevron/Costco vs Freds fuel.

If I see/feel no difference then I am out a tank or two of extra money on gas (figure $20 at most) plus the $25 custom tune. It is only $25 because it is just a retune for a different octane. I waste more money on that on other random junk all the time. Already paid more and did all the other stuff when I had the custom 87 one done so it is not just some cheap ass tune in case anyone was wondering. I will be doing data logs and all that as well after I run a tank of the higher octane with the tune.

[Monochrome]

I would question tuning any vehicle to be so close to the ragged edge that finite quality variances in the quality of gas would cause an issue. Especially a vehicle which you need to be reliable.... 20 degree temperature changes in the ambient air make much larger of an impact on the tune than a single point of octane in the fuel.

Gas quality mainly comes down to how much debris is in it and nothing more. This is why you have fuel filters before the pump and before the injectors. You should run the highest quality of gas for this reason only. To prolong the life of your injectors.

[aaronatstate]

[quote=""Duck Vader""]I have been running a custom tune set for 87 using Fred Meyer (Kroger) fuel as my go to for awhile now. Which is not a Top Tier gas. I do notice a slight difference when using Chevron/Costco vs Freds fuel.[/quote]

I highly doubt there is any real difference. In order to test it properly, you'd have to eliminate all the other variables like temperature, humidity, traffic conditions, routes taken, etc. The only way to know for certain would be to eliminate those. I think if you were able to do that, you'd see no difference in mileage or anything else.

Gasoline has the same energy density regardless of brand. It takes a certain amount of energy to produce the horsepower in the engine, that is not going to change.

That being said, go for the premium tune. Should get some more power/tq, so you should be able to feel that difference for sure. My guess is you'll end up getting worse gas mileage because you're gonna drive it more aggressively

[DirtyRyda]

I've never heard that Shell is bad. My knowledge is limited to reading that top tier better, and Shell is top tier though. I usually use that or BP, and try to always use top tier.

[DCIV]

So to be clear, the people here who I trust utmost, have never seen a difference?


Coop

[Duck Vader]

I can't really say. I do know I've seen better mpg and better overall engine feel using top tier, but only top tier I use is chevron or costco

[aaronatstate]

[quote=""DCIV""]So to be clear, the people here who I trust utmost, have never seen a difference?


Coop[/quote]

You should just really follow your tuners advice. For the RS, they say to avoid Shell if possible. They say Shell tends to knock more etc. Maybe Shell is actually making 91/93 octane, where the others are slightly higher (since it is a min rating)? Don't know.

That being said, you should be fine to get gas at most any major retailer (except maybe Wal-mart/Murphy USA). Again, this is for a tuned performance vehicle. Your Tahoe, you'll be fine to run pretty much anything, as all gasoline still has minimum standards it has to meet. The Top Tier stations do have more cleaners and additives in them that will help, but again a lot of the times with the Top Tier, it's only in the premium grade. Also, just because a company isn't Top Tier certified (read, they didn't pay for the rating) doesn't mean their gas isn't as good (i.e. Kum&Go). They can still put the same detergents/additives in, just they don't want to pay for the rating.

[DCIV]

[quote=""aaronatstate""]You should just really follow your tuners advice. For the RS, they say to avoid Shell if possible. They say Shell tends to knock more etc. Maybe Shell is actually making 91/93 octane, where the others are slightly higher (since it is a min rating)? Don't know.

That being said, you should be fine to get gas at most any major retailer (except maybe Wal-mart/Murphy USA). Again, this is for a tuned performance vehicle. Your Tahoe, you'll be fine to run pretty much anything, as all gasoline still has minimum standards it has to meet. The Top Tier stations do have more cleaners and additives in them that will help, but again a lot of the times with the Top Tier, it's only in the premium grade. Also, just because a company isn't Top Tier certified (read, they didn't pay for the rating) doesn't mean their gas isn't as good (i.e. Kum&Go). They can still put the same detergents/additives in, just they don't want to pay for the rating.[/quote]

Not so much the Tahoe as I know those engine are supposed to eat whatever you feed them.

More my escape and vr4. Not that the escape is tuned but with direct injection and not that the vr4 is tuned great but if there are better why not.


Coop

[aaronatstate]

[quote=""DCIV""]More my escape and vr4. Not that the escape is tuned but with direct injection and not that the vr4 is tuned great but if there are better why not.


Coop[/quote]

It doesn't matter for your Escape either. Dirty valves on direct injection are caused by blow by, and not having the fuel injector to clean them off. Basically the only way to prevent that is with a catch can in the PCV system.