Fuel Quality

[Duck Vader]

Let's discuss fuel quality.

I am going to be updating the tune in my truck from a custom one set to run on 87 to a custom one set to run on 92 to see if there are any noticeable changes, especially in MPG. With my new job I will be driving close to 400-500 miles a week and with the difference between 87-92 prices if I can get another 1.5 mpg average it will be worth it. If not I can always switch back.

That said, the guy who is writing my custom tune warned me to only use high quality fuel, especially with the higher octane tune.

Make sure you are using GOOD 92 octane gas, it makes a difference... mobil, exxon, sunoco, amoco, bp, chevron are best brands to use, with mobil and exxon being the best... ----- NEVER use Shell, walmart/sams club/bj's, mom-n-pop, or no-name brands, as it's crap gas/additives that tends to cause a lot of knock retard and less performance/mpg...

Thoughts on that?

I usually use Fred Meyer (Kroger) for my 87 since I get a discount (usually about 15-50 cents off a gallon). However I can also use Costco which is a lot cheaper than other places as well and not much more than Freds with my discount.

Reading online it seems Costco has some high quality gas?

Only other places local are 76, Chevron, and Shell for the most part. I never use Shell as it is always way more expensive. Will use Chevron if too low on gas to get to Freds or Costco on occasion.

So thoughts on using Costco?

And what do you think about what he said?

[DCIV]

Interesting question...I just figured all gas station were filled by basically the same huge tank that had different transporters and stuff. So are different places better quality of gas? Or do we just think they do because better ads or lighting?


Coop

[Duck Vader]

Gas is gas. It is the additives at each location that is different. Those additives is what makes some fuel "better" than others.

Apparently Costco gets their gas without additives and adds them on site with their own proprietary blend, hence why they can get it cheaper.

Other places get it with it blended at the refinery.

It also depends on how long the gas sits in their tanks. Costco and high volume places go through gas a lot so less chance of sitting and contamination.

Or at least that is what I have read.

[aaronatstate]

In the Focus RS community, Shell is also frowned upon, for the same reasons. Though I have never seen any actual data, just all anecdotal evidence to it. I don't use Shell regardless as it is usually more expensive as well.

All of those other ones he listed are all Top Tier rated so they should be similar. Costco is also Top Tier rated as well. Though Shell is also Top Tier rated, but like I said above the RS community doesn't like it either. Also as a note most Top Tier gasoline is only the premium grade.

I fill up at Kum & Go around here, and while it's not listed as a Top Tier station, the gas seems to work perfectly fine in my RS (only 91 octane available in Arkansas anyway). I also get E85 from there for my Stealth. Kum & Go's site states (or used to anyway) that while they are not Top Tier certified, they use the same additives as Top Tier gas, they just didn't want to pay for the Top Tier rating.

[Duck Vader]

Quick calculations show if I pay for gas at Costco vs Chevron for 92 I would save about $40 a month. If I can get 1.5-2 more mpg out of the truck I will break even on 87 vs 92.

Trying to figure out if saving $40-50 a month is worth the risk of Costco?

[DCIV]

I’ve never cared where I get fuel. Interesting.


Coop

[aaronatstate]

[quote=""Duck Vader""]Quick calculations show if I pay for gas at Costco vs Chevron for 92 I would save about $40 a month. If I can get 1.5-2 more mpg out of the truck I will break even on 87 vs 92.

Trying to figure out if saving $40-50 a month is worth the risk of Costco?[/quote]

I don't think you'll get any more MPG out of it by using different stations or different grades. Your engine is still going to need a specific amount of fuel for the conditions, and gasoline has a specific energy density. That energy density does not change between retailers or octane ratings.

[Duck Vader]

[quote=""aaronatstate""]I don't think you'll get any more MPG out of it by using different stations or different grades. Your engine is still going to need a specific amount of fuel for the conditions, and gasoline has a specific energy density. That energy density does not change between retailers or octane ratings.[/quote]

Running a custom tune that requires 92 vs 87. Most of it is anecdotal but I have seen people claim up to 8-10% better mpg, sometimes more, which at the high end would get me the added mpg that makes the switch worth it. That and the increased performance might be noticeable.

If not, I can switch it back. But since I am getting the tune for only $25 I figured it would be worth a try to see how it does.

[vr4]

I only run Costco.

[DCIV]

I would think you would get the most % of gas mileage out of some really good designed tires.


Coop

[Duck Vader]

[quote=""vr4""]I only run Costco.[/quote]

I am going to stop running Freds and only run Chevron or Costco. Just trying to figure out if will cause knock retard like I am warned about.

[Duck Vader]

[quote=""DCIV""]I would think you would get the most % of gas mileage out of some really good designed tires.


Coop[/quote]

Already put good tires on and between the tune, tires, etc I get about 15 mpg average right now with the last few tanks filled at Freds.

But like I said, if no noticeable difference I can swap back.

[Duck Vader]

Also curious if running higher octane with a supporting tune does for reliability/longevity.

If I get same MPG and switch from Freds to Chevron and from 87-92 I am looking at about $75-100 more a month in gas. Not sure if worth it.

[aaronatstate]

[quote=""Duck Vader""]Running a custom tune that requires 92 vs 87. Most of it is anecdotal but I have seen people claim up to 8-10% better mpg, sometimes more, which at the high end would get me the added mpg that makes the switch worth it. That and the increased performance might be noticeable.

If not, I can switch it back. But since I am getting the tune for only $25 I figured it would be worth a try to see how it does.[/quote]

Running 92 vs 87 alone will not get you any additional mpg. Octane rating is the fuels ability to resist knock, that's it. This is all done with additives to the gasoline.

The energy density of gasoline is the same regardless of octane rating. For gasoline with 10% ethanol in it, the energy density is 33.2 MJ/L. For gasoline with no ethanol it is 34.2 MJ/L.

So if there is any MPGs to be gained it is probably from running fuel without ethanol in it. It is more common for premium gas to not have ethanol in it. This is likely where they are seeing the MPG bump, but it's not going to be 8-10%.

[quote=""Duck Vader""]Also curious if running higher octane with a supporting tune does for reliability/longevity.

If I get same MPG and switch from Freds to Chevron and from 87-92 I am looking at about $75-100 more a month in gas. Not sure if worth it.[/quote]

Does absolutely nothing. If it's tuned for 92, it's going to have more timing etc. to take advantage of the higher resistance to knock. Assuming everything is good, and there is 0 knock on either tune, there will be absolutely no difference for the reliability. That being said, running more power than stock will always reduce your reliability/longevity to a point (could be minimal, could be almost instant failure).

[Duck Vader]

[quote=""aaronatstate""]Running 92 vs 87 alone will not get you any additional mpg. Octane rating is the fuels ability to resist knock, that's it. This is all done with additives to the gasoline.

The energy density of gasoline is the same regardless of octane rating. For gasoline with 10% ethanol in it, the energy density is 33.2 MJ/L. For gasoline with no ethanol it is 34.2 MJ/L.

So if there is any MPGs to be gained it is probably from running fuel without ethanol in it. It is more common for premium gas to not have ethanol in it. This is likely where they are seeing the MPG bump, but it's not going to be 8-10%.



Does absolutely nothing. If it's tuned for 92, it's going to have more timing etc. to take advantage of the higher resistance to knock. Assuming everything is good, and there is 0 knock on either tune, there will be absolutely no difference for the reliability. That being said, running more power than stock will always reduce your reliability/longevity to a point (could be minimal, could be almost instant failure).[/quote]

Interesting.

Thinking back I think I got better MPG with Chevron vs Freds in the Jeep as well. Might be worth the switch to Chevron for a bit until I stop driving as far even if I don't keep the 92 tune.

But for the $25 for the tune I am going to experiment for a bit.

Now back to the original questions as well.

Thoughts on fuel quality even if labeled "top tier" among different brands?

[aaronatstate]

[quote=""Duck Vader""]Running a custom tune that requires 92 vs 87. Most of it is anecdotal but I have seen people claim up to 8-10% better mpg, sometimes more, which at the high end would get me the added mpg that makes the switch worth it. That and the increased performance might be noticeable.

If not, I can switch it back. But since I am getting the tune for only $25 I figured it would be worth a try to see how it does.[/quote]

I've never had issues with any of the major brands (I used to use Shell in my Stealth back in the day). When I pulled the intake off the RS to put the catch can it, it had some carbon build up on the valves, but that's more related to the direct injection mostly. Still it was pretty darn clean as is. When I pulled my stealth apart last time, the heads were more or less spotless running E85 from Kum and Go (which is not Top Tier rated).

[alienviking]

[quote=""aaronatstate""]I fill up at Kum & Go[/quote]

That's what she said.

All I have to bring to this discussion..

[Chris GTO TT]

[quote=""alienviking""]That's what she said.

All I have to bring to this discussion..[/quote]

i have the same thoughts when i hear that brand.



Its funny my tuner doesn't like Chevron because they use too much additives because their thing is how well their gas cleans. I typically only use Costco, for cost and because I know its 'fresh'

[mjannusch]

Not sure how you can tune for reliability and gas mileage at the same time.

For one, the O2 sensor is going to trim out any fuel changes in the tune anyways, unless you force it to burn leaner (which burns hotter, and increases chances for detonation). Timing - just adding advance isn't necessarily the right answer. You can have too much advance and still not encounter knock and it'll reduce your fuel economy and put more stress on the rods and bearings.

Personally, I'd just leave it alone if you want reliability. I've never seen more reliability come out of a "tune" - quite the opposite in most cases.

[Duck Vader]

Not really looking for reliability out of the tune. Just curious to see how it performs compared to my 87 tune and terms of cleaner and better performance.

I'm just more curious about fuel quality at different places.