Do you ever buy non top tier gas when top tier is available?

Interesting that when the EPA does all their testing of new automobiles they only use 87 octane gas. Guess that might be because all new cars are designed to run on 87 octane gas. Why burn midgrade or super in a car designed to run on regular? If your owners manual says to only use super, it is simply part of the marketing myth they are selling you about your car needing to sip Chivas Regal. Nonsense. All the money you save you could take your wife out to dinner once a week...
 
If your owners manual says to only use super, it is simply part of the marketing myth they are selling you about your car needing to sip Chivas Regal. Nonsense. All the money you save you could take your wife out to dinner once a week...
If your owners manual calls for 91 Octane it's typically because the engine has high enough compression to warrant it.
 
Interesting that when the EPA does all their testing of new automobiles they only use 87 octane gas. Guess that might be because all new cars are designed to run on 87 octane gas. Why burn midgrade or super in a car designed to run on regular? If your owners manual says to only use super, it is simply part of the marketing myth they are selling you about your car needing to sip Chivas Regal. Nonsense. All the money you save you could take your wife out to dinner once a week...
Put 87 octane into something like a Hellcat or a Ferrari and you’re in for a very bad time. They wouldn’t spec premium only if it wasn’t necessary.
 
If your owners manual calls for 91 Octane it's typically because the engine has high enough compression to warrant it.

Depends. It's really a combination of compression, timing, and pressure. Forced induction engines may actually have a lower compression ratio but that's more than made up for with boost.
 
Interesting that when the EPA does all their testing of new automobiles they only use 87 octane gas. Guess that might be because all new cars are designed to run on 87 octane gas. Why burn midgrade or super in a car designed to run on regular? If your owners manual says to only use super, it is simply part of the marketing myth they are selling you about your car needing to sip Chivas Regal. Nonsense. All the money you save you could take your wife out to dinner once a week...

Uh no. Most modern engine management uses knock sensors that can back off on timing if needed. That's why it's acceptable to use 87 in an engine designed for 91-93. A flex fuel capable engine can run on E85, which has about an AKI octane of 100-104 and will typically advance the timing a bunch, which is far more efficient. The fuel economy relative to the energy content is higher.
 
Depends. It's really a combination of compression, timing, and pressure. Forced induction engines may actually have a lower compression ratio but that's more than made up for with boost.

I'm thinking of the last few naturally aspirated performance engines I've owned, including my 6.4L which has a 10.9:1 compression and calls for 91. My wife's 5.7L "recommends" 89 and is 10.5:1 in comparison. My S62 also called for 91 and was 11:1.
 
Top Tier only for our cars, the VW owners manual even says to use it. If I were in a situation where I had only two options, one being a run down station that looks VERY low volume and the other being brand new and high volume, I may go to the newer location. That scenario hasn't actually played out so again, only TT for our cars.
 
I'm thinking of the last few naturally aspirated performance engines I've owned, including my 6.4L which has a 10.9:1 compression and calls for 91. My wife's 5.7L "recommends" 89 and is 10.5:1 in comparison. My S62 also called for 91 and was 11:1.

I've noticed higher compression ratios over the years, even with a turbo. Not quite how they handle it other than with a lot of electronic engine management. My 1995 Integra GS-R had a "high" compression ratio of 10.0:1 and they recommended premium. There's a lot that can be done with a knock sensor and electronic ignition. However, my GS-R still used a distributor with a rotor and points. I never did it myself, but I heard that the timing could be adjusted by rotating the distributor. I think there was some sort of vacuum that could retard timing depending on the knock sensor.
 
This particular conundrum comes up when I take long trips. All of the major truck stops (Petro, Loves, etc) are non-top-tier but have excellent placement along the interstate and well maintained facilities. But there are also independently owned Shell and Mobil stations along the interstate (in more irregular locations or distances between stations) that may have Top Tier gas but have sketchy buildings, dirty bathrooms, questionable CC processor terminals at the pumps, etc..

There are a few Petro stations that have Shell gas, though, but they are not common.
 
Around town, I will always use top tier. I currently frequent the closest BP station because it has 93 octane. On road trips (as Reddy45 mentioned), truck stops are easiest to stop at and usually have the best prices. If there is a top tier station at that same exit and it's not too much more, I'll use it.
 
I've noticed higher compression ratios over the years, even with a turbo. Not quite how they handle it other than with a lot of electronic engine management. My 1995 Integra GS-R had a "high" compression ratio of 10.0:1 and they recommended premium. There's a lot that can be done with a knock sensor and electronic ignition. However, my GS-R still used a distributor with a rotor and points. I never did it myself, but I heard that the timing could be adjusted by rotating the distributor. I think there was some sort of vacuum that could retard timing depending on the knock sensor.

Back in my Fox Mustang days you could bump the timing a solid 4 or 5 degrees if you ran 91, which added a bit of throttle response and made more power. That was a 9:1 engine (4" bore) and of course had no knock sensor.

I expect if I mapped the 5.7L on 87 vs 89 I'd see a fair bit more timing retard given the bore size and compression ratio. Not sure how the 6.4L would respond, but I assume a lot of retard given the even larger bore, higher compression and fact the ECM is anticipating 91, lol.
 
Back in my Fox Mustang days you could bump the timing a solid 4 or 5 degrees if you ran 91, which added a bit of throttle response and made more power. That was a 9:1 engine (4" bore) and of course had no knock sensor.

Couldn't you also destroy the engine in short order if you weren't careful? I thought one of the old tricks was that E10 was usually made with whatever octane non-ethanol fuel, but then the ethanol bumped it about 2 octane numbers. I think they called it "octane giveaway". But these days none of that is happening.
 
Couldn't you also destroy the engine in short order if you weren't careful? I thought one of the old tricks was that E10 was usually made with whatever octane non-ethanol fuel, but then the ethanol bumped it about 2 octane numbers. I think they called it "octane giveaway". But these days none of that is happening.
Naw, they were pretty durable. Now, do that with boost, and yes, there was a risk of blowing something up. If you ran 87 with the timing advanced it would typically just rattle (ping) which definitely wasn't good, but I don't recall anyone ever having a failure from it.
 
Interesting that when the EPA does all their testing of new automobiles they only use 87 octane gas. Guess that might be because all new cars are designed to run on 87 octane gas. Why burn midgrade or super in a car designed to run on regular? If your owners manual says to only use super, it is simply part of the marketing myth they are selling you about your car needing to sip Chivas Regal. Nonsense. All the money you save you could take your wife out to dinner once a week...

Are you sure about that?
 
I fuel up at Costco about 80% of the time, and Mobil the remaining 20% depending on my drive schedule. Costco is on the way home from work, while a Mobil station is about a mile from my home.
 
We run gas from our local Kroger 95% of the time...never had an issue or below par fuel mileage using it. The Kroger stores around here all get Trafigura...a non TT, unmarketed gasoline that meets the federal requirements.
 
We run gas from our local Kroger 95% of the time...never had an issue or below par fuel mileage using it. The Kroger stores around here all get Trafigura...a non TT, unmarketed gasoline that meets the federal requirements.

I looked up what Trafigura is. Just a Singapore based commodity trading company with pipeline operations in the US. So they're just trading and delivering fuel bought on the commodity market. Which describes nearly all base fuel sold in the United States.
 
Only time I buy TT is if it's cheaper than non TT. Been using the cheapest gas available for 45 years. Only problem I ever had with any gas was a tank of Citgo about 20 years ago with water in it.
 
Back
Top