86 octane top tier or 87 octane not top tier?

[Japanese]

Gasoline leaves deposits as it flows through the engine, especially on intake valves & injectors in port injected & carbureted engines, injectors on direct injected engines, combustion chambers in all engines as it burns.

Gasoline leave some minor deposits (oil leaves much more) after it burns out, not before. Engines get deposits primarily because they burn oil, it's not the gasoline. That is easily observed in 2-stroke engines. They have some deposits always on the crown of the piston and exhaust port, but never on the intake port and below the piston. Gasoline leave minor deposits only if stays too long in a container, gas tank, carburetor, etc. and degrades and evaporates - thats means at least a couple of years.

As far as I know is the opposite - in port injection gasoline cleans your intake valves and doesn't leave any deposits, including in carburetors. Only direct injection engines get deposits on their intake valves. That is why some modern DI engines like the Subaru/Toyota FA20 with D-4S direct injection has both combustion chamber injectors and port injectors. One of the purposes is the port injectors to keep the intake valves clean.

In short:
If your car has DI engine regardless of the gasoline you use (top or low tier) your intake valves will accumulate deposits over time because there is no gasoline going though them.
If your car has port injected engine (like most of the engines from the last 40 years) any gasoline (top or low tier) will keep your intake valves equally clean because the gasoline goes through them daily and clean them.

 

[garageman402]

If your car has DI engine regardless of the gasoline you use (top or low tier) your intake valves will accumulate deposits over time because there is no gasoline going though them.
If your car has port injected engine (like most of the engines from the last 40 years) any gasoline (top or low tier) will keep your intake valves equally clean because the gasoline goes through them daily and clean them.

I had a 73 Pontiac 400 that only got the cheapest gas, & when I took the intake off, the crud piled on the intake valves was molded in the shape of the runner, so, no, straight gasoline does not clean intake valves.

Injectors get clogged too, in DI engines this could lead to gas being directed toward the cylinder wall instead of at the piston dome.

 

[garageman402]

What does top tier gas mean? How is defined? What gas stations are considered top tier?

https://stationfinder.toptiergas.com/

https://www.toptiergas.com/about-top-tier/

 

[Japanese]

https://stationfinder.toptiergas.com/

https://www.toptiergas.com/about-top-tier/

Interesting, I typed a few zip codes in my area and I couldn't find BP under the Brands dropdown. Does that mean that BP are not top tier gas stations?

 

[3GTL300k]

Interesting, I typed a few zip codes in my area and I couldn't find BP under the Brands dropdown. Does that mean that BP are not top tier gas stations?

This is what BP claims. They claim to still meet the standard but apparently they didn't want to pay Top Tier to be certified by them anymore:

Does bp's gasoline meet TOP TIER™ detergent gasoline standards?
All grades of bp and Amoco gasoline with Invigorate® exceed TOP TIER™ detergent requirements and provide enhanced benefits to our consumers, such as cleaning your engine,9 that TOP TIER™ fuels do not.

https://www.bp.com/en_us/united-sta...ne-meet-top-tier-detergent-gasoline-standards

 

[kschachn]

This is what BP claims. They claim to still meet the standard but apparently they didn't want to pay Top Tier to be certified by them anymore:

Does bp's gasoline meet TOP TIER™ detergent gasoline standards?
All grades of bp and Amoco gasoline with Invigorate® exceed TOP TIER™ detergent requirements and provide enhanced benefits to our consumers, such as cleaning your engine,9 that TOP TIER™ fuels do not.

https://www.bp.com/en_us/united-sta...ne-meet-top-tier-detergent-gasoline-standards

They didn't say anything about not wanting to pay for Top Tier, they said their additive package is better.

 

[3GTL300k]

They didn't say anything about not wanting to pay for Top Tier, they said their additive package is better.

Yeah good point. I should have separated that comment. They have their statement, and people on here have speculated that they left Top Tier bc of the fee. Others think maybe they lowered the standard as well but I think the statement they made gives credence to the theory that they don't think it's worth the fee.

 

[y_p_w]

Top Tier doesn't make detergents. One pays to use their signage and subject to possible audit of fuel purchases to ensure one is selling Top Tier's minimum quantity of the detergent you are using.

Top Tier specifies a minimum quantity for every EPA approved detergent. It varies with each detergent.

There is no reason a gas station operator can not use Top Tier quantity without paying Top Tier, just can't say "Top Tier".

There is no assurance the base gasoline is any better, other than Top Tier requires a minimum of 8% motor grade ethanol. If it is "ethanol free" then it can not be sold as Top Tier.

The whole point of Top Tier is to convince you that small brands of gasoline are as good as Shell and Texaco/Chevron. And to line the pockets of Top Tier's owners.

That's not quite it for ethanol requirements. The 8% minimum ethanol requirement is for the fuel used during the testing protocol. The reference to 8% is in 4.3.1.2 (Base Fuel) but that's under 4.3 (Deposit Control Initial Performance Standard). I'm cutting it off where the ethanol is mentioned.

https://www.toptiergas.com/wp-conte...asoline_Performance_Standard_revF_2019-12.pdf
4.3 Deposit Control Initial Performance Standard. All performance testing and fuel composition analysis shall be
conducted by an Independent Laboratory. Initial deposit control performance shall be demonstrated using the tests
shown below.
4.3.1 Intake Valve Keep Clean Initial Performance Standard
4.3.1.1 Test Method. Intake valve deposit (IVD) keep clean performance shall be demonstrated using ASTM D
6201, Standard Test Method for Dynamometer Evaluation of Unleaded Spark-Ignition Engine Fuel for Intake Valve
Deposit Formation. Tests demonstrating base fuel minimum deposit level (4.3.1.2) and additive performance
(4.3.1.3) shall be conducted using the same engine block and cylinder head. All results shall be derived from
operationally valid tests in accordance with the test validation criteria of ASTM D 6201. IVD results shall be reported
for individual valves and as an average of all valves.
4.3.1.2 Base Fuel. The base fuel shall conform to ASTM D 4814 and shall contain commercial fuel grade ethanol
conforming to ASTM D 4806. All gasoline blend stocks used to formulate the base fuel shall be representative of
normal territory refinery operations and shall be derived from conversion units downstream of distillation. Butanes
and pentanes are allowed for vapor pressure adjustment. The use of chemical streams is prohibited. The base fuel
shall have the following specific properties after the addition of ethanol:
1. Contain enough denatured ethanol such that the ethanol content is no less than 8.0 and no more than 10.0
volume percent as measured by ASTM D 4815 or D 5845.

 

[garageman402]

So what cleaning level do these 3 mentioned ASTM tests produce? Are they the minimum EPA level, or the automakers Top Tier level, or the new Top Tier Plus level?