Are Shell/Exxon better than other Top Tier gasolines?

[JohnnyG]

Read the pump more closely. Its UP TO 10%. It can be less than 10%

I don't care what the pump sticker says. If it's cheaper than gas, guess how much it's getting?
Refiners don't give away octane. All blends (at the terminal) are using the maximum amount of ethanol permitted to make up for the reduced octane of the base gas.

 

[JohnnyG]

Hugher octane fuel emits less heat when ignited, hence - burns cooler.

Nope. BTU content is the same.

 

[JohnnyG]

That would surprise me. I don't think engine management systems are that sophisticated. My wife's kia rio pinged so bad on 87 octane it set off a knock sensor. The engine didn't adjust to that and it was bad enough to trigger a cel. Had to switch to premium until we paid $180 for a software update.

Sound more like a KIA problem to me.

 

[colloyd00]

I’m curious as to how Top Tier Plus will differ from Top Tier….

 

[fantastic]

In my experience, each brand only uses it's own additive supplier. The same additive is used in all grades of gas as well as any blends.
The only thing that varies, is that premium usually contains more of it (but not much more).

That could very well be the case & "better additives" could also be equated to simply "more additives" in their higher tiered fuel. Thanks!

 

[shortyb]

I’m curious as to how Top Tier Plus will differ from Top Tier….

Higher amount of detergents over standard Top Tier. More than likely a response to the need for additional cleaning in GDI engines.

 

[JohnnyG]

I’m curious as to how Top Tier Plus will differ from Top Tier….

+
As in more marketing.

 

[shortyb]

+
As in more marketing.

Bingo.

Meeting Top Tier standards for fuel marketers is voluntary. But, as demonstrated here in this thread, there are folks that will pay for the additional additives to meet TT. So it makes sense for the fuel companies to comply with it for increased sales/profits. Now with TT+, there will be even more detergent additive so it will be easy to market to those willing to pay for it (lots of them). They are betting so much so, that all Top Tier fuel will migrate to Top Tier Plus within a 2 year window once implemented (if not already).

 

[BHopkins]

I'm not all that familiar with Exxon, as they don't have a big presence in the Northern Utah/Western Wyoming/Southern Idaho area. But from my experience, I would say Chevron is the best of Top Tier, followed closely by Shell.

A friend that I used to work with loves to tinker with cars, and had a fair amount of experience with tearing down engines. He often told others about one of his sons tearing down an engine from his Honda Civic, and being amazed at how clean the engine was inside. His son swore that it was because he only used Chevron fuel, nothing else.

 

[PontiacHO]

Read the pump more closely. Its UP TO 10%. It can be less than 10%

North Carolina must be different…
NC State Statute

119‑27.2. Labels for dispensing pumps and devices offering ethanol‑blended gasoline
for retail sale.
(a) The Gasoline and Oil Inspection Board shall adopt rules to require labels for all
dispensing pumps and other dispensing devices that offer ethanol‑blended gasoline for retail
sale in North Carolina. The Board shall require the use of labels to indicate that the gasoline
offered for retail sale contains either of the following:
(1) Ten percent (10%) or less ethanol by volume.
(2) Greater than ten percent (10%) ethanol by volume.
(b) Rules adopted pursuant to subsection (a) of this section may include information as
to the ethanol content of blended gasoline that is more specific than the information required by
subsection (a) of this section. (2011‑25, s. 1.

 

[mojoe]

I'm not all that familiar with Exxon, as they don't have a big presence in the Northern Utah/Western Wyoming/Southern Idaho area. But from my experience, I would say Chevron is the best of Top Tier, followed closely by Shell.

A friend that I used to work with loves to tinker with cars, and had a fair amount of experience with tearing down engines. He often told others about one of his sons tearing down an engine from his Honda Civic, and being amazed at how clean the engine was inside. His son swore that it was because he only used Chevron fuel, nothing else.

Using Top Tier gas has proven to have superior cleaning properties compared to non-Top Tier gas, so yes, using nothing but Chevron, which may (or may not) have a better additives packages than other Top Tier gasses, likely was responsible for the clean state of that Honda engine.

 

[k1xv]

"Ten percent (10%) or less ethanol by volume."

means the same as

"Up to 10% ethanol"

 

[3GTL300k]

Higher amount of detergents over standard Top Tier. More than likely a response to the need for additional cleaning in GDI engines.

I’m curious as to how Top Tier Plus will differ from Top Tier….

I posted a link in this post in the Top Tier + thread the explained the new standard. It went into detail on the new tests added;

3

Post in thread 'Coming soon... TOP TIER+ fuels'

Jul 29, 2025

I found this with more info about the changes


https://www.aftonchemical.com/resou...-for-gasoline-direct-injection-(gdi)-engines/

• 3GTL300k

• 
• 

 

[Burt]

I know that but it appears their proprietary additives work better than some. Gasoline is gasoline but additives make the difference.

Are you agreeing with his posting that additives can cause an immediate, measurable increase in fuel efficiency not related to octane? If so please explain how so.

 

[Burt]

I know that but it appears their proprietary additives work better than some. Gasoline is gasoline but additives make the difference.

Are you agreeing with the poster that additives could cause an immediate and regular 1.5 increase in mpg without increasing the octane? If so please explain how that’s possible,

 

[walterjay]

A while back I had read that Exxon adds friction modifiers into the mix.

Other than that I can't say.

Are you agreeing with the poster that additives could cause an immediate and regular 1.5 increase in mpg without increasing the octane? If so please explain how that’s possible,

 

[walterjay]

Maybe Exxon uses MMO.

 

[fdcg27]

A while back I had read that Exxon adds friction modifiers into the mix.

Other than that I can't say.

Hard to see how friction modifiers in the fuel would do anything at all other than reducing the friction of the bills in you wallet.

 

[BMWTurboDzl]

I know there are similar threads on here, but don't see the info I'm looking for. I understand that they all are basically the same gasoline, but each has it's own unique, proprietary additive packages. I also understand that the Top Tier designation simply means that the gas contains a minimum level of detergent additives that have proven to have effective cleaning properties. I further understand that Shell and Exxon are Top Tier fuels. Given all of that, my question is, is there any reason to think that Shell or Exxon regular 87 octane is better, or has a better additive package than say regular 87 gas from QT, Costco, Citgo, and other Top Tier fuels?

I'm not aware of any relevant testing which reaches any conclusion

 

[walterjay]

Hard to see how friction modifiers in the fuel would do anything at all other than reducing the friction of the bills in you wallet.

A lot of aircraft owners swear by MMO. They say the friction reducing effect gives them more miles per tankfull. I have seen it posted on this forum by an engineer who owns and builds aircraft.