4wd
$50 site donor 2026
Nothing in this thread does - all opinions and tossing the word “detergent” like it’s an actual measure - compared to the additive packages that R&D teams develop from many chemicals …
Is Shell Premium Considered Best Cleaning Gasoline?
- Thread starter ChrisD46
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Patman
Staff member
There is a Costco 2.5 miles away from my house and there is one that is about a half a mile away from my girlfriend’s house. And both of them aren’t bad for lineups, I actually visited each of them today (in each of my cars) and pulled right up to a pump with no wait both times.Maybe we need a how far is Costco thread - betting lots of folks are not that close? 45 miles for me - pumps = Zoo …
4wd
$50 site donor 2026
They are just plain undersized for SW Houston and on the wrong end of the parking lot. If I lived there - would be easier to get there early before the crowds …
At one time Buc-ee’s would sell name brands and that was a dream - but I don’t know much about their own gas now …
Not TT ?
My dog's better than your dog.( You have to be of a certain age)
When I go to Shell stations or any station for that matter I usually get the middle grade presumably is a mixture of 87 and 93 (91) so I assume it has a hefty dose of detergents in it
At my local Costco, the best time to get fuel is after the warehouse closes…gas stays open for 90 mins after the warehouse closes 7 days a week.
I'd also lay odds that Exxon/Mobil has more of their SS+ detergent in their premium gas. Same thing with Costco
Now Chevron on the other hand is known to use the same amount of Techron across regular/mid/supreme
If oil companies used the same add pack quantity across octanes then all of their marketing of their top octane/premium grade would fall apart because there wouldn't be any cleaning advantage.
Thou it's not gonna be about gas itself but the greatest effect I personally saw was when using Redline SI-1 in gas compared to Regane and even Super Concentrated Techron that I used to buy in US. With Redline it felt that engine ran smoother, was more responsive and there was a substantial gas mileage improvement within first 60 miles of driving. I ran a tank of gas only after that and effects were gone, then just an experiment I ran a tank with SI-1 again and effects came right back. Whether it was cleaning effects or something on top of that but Redline is sure on top of my list now.
Patman
Staff member
Costco already says that they use the same level of detergents in their 87 octane as they do in their premium
LSJR just released a video where testing was done by the Southwest Research Institute (SWRI) on several brands of fuels, mainly focused on Top Tier and their premium blends. Check out ~1:14:30 for scar wear results. The video is very long, but he and Chip did a deep dive into gasoline and additives.
4wd
$50 site donor 2026
As I stated earlier - “Synergy” was developed by ExxonMobil Research Engineering - not just a decal …
Makes me want to try a run or 2 of premium Mobil gas in my wifes car to see what happens.
Highly unlikely. From a regulatory perspective in the USA aftermarket fuel additives cannot have a negative impact on emissions. IOW they can't cause injector fouling which ends up increasing emissions.
Top Tier is not an additive. It is a cleanliness standard, IIRC measured by deposits on intake valves. Different additive formulations are used across brands and get TT certification when their fuel meets the TT standards.
I've been preaching Shell premium for my use case, but these results have me thinking about switching for an OCI to see what happens to carbon deposits as seen in the oil filter after several thousand miles of Exxon/Mobil.
Remember, these tests were run by SWRI. Sam's Club (Murphy's) regular was used as the non-TT, regular, comparison fuel.
I went to a Costco yesterday and I witnessed an ocean of waiting vehicles.
I must figure out when their lulls are.
COOL STORY:
On St. Rt. 17 South in Paramus, NJ was a shopping center from the '50's featuring a very large Quonset styled variety store and a large grocery store bookending about 5 other shops.
It's all dated and all coming down. Costco was said to be interested.
HOWEVER, they wanted a privately owned gas station, a BP station which occupies the SE corner of the entire tract, as in, "We don't open new Costcos without gas stations".
The deal was said to have been killed.
Then I heard Costco is indeed building and simply won't be buying the gas station.
It'll be interesting to see how the gas station "plays in the warmth of Costco's aura".
In nearby Teterboro, the Costco price per gallon isn't anything to write home about.
Is this irrelevant being that brands are moving to TT+?
I have been looking but have not seen a single top tier plus sticker on any pump in my area. Will TT+ become the standard or just one of 2 standards that will be out there at the same time?
TT+ is an additional standard for intake valve cleanliness, and IIRC, measurements of exhaust gas at the tailpipe. Except for some brands or independent stations choosing to be part of the program, I suspect the bigger players, e.g. Shell, Exxon/Mobil, Chevron, etc. already meet the TT+ standards.
I found some reports yesterday that the additives used by Shell prioritize cleaning and staying clean, while Exxon/Mobil prioritizes wear protection. That would explain the results shown above.
Based on Shell's prioritizing. cleaning, and my Pilot has a GDI engine prone to carbon deposits, I'm probably going to stick with Shell, as it's proven itself to work in my engine and how I drive.
Costco as moved to TT+. The website suggests that there will eventually be only one standard. TT+ is focused on GDI and with 75% of the fleet GDI there's no reason to have two standards.
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