gas, which one is bestw Options

[rodriguez046]

Whats the best fuel to use on our cars?

[Special_Edy]

87 Octane. You will get the highest performance from 87 and its the cheapest so double win

[ILoveMySilly97]

87 Octane. You will get the highest performance from 87 and its the cheapest so double win

Really? I noticed my car ran better at 91 octane? I'm not really sure though because I use to run 89 until I gave my car a full tune up and started using 91 from Chevron only.

[richee3]

Placebo effect. Octane resists knock, it doesn't make your car run better. More octane per gallon = less gas per gallon.

[Special_Edy]

In short octane is the fuels resistance to burning. Higher octane requires more energy to combust, so its less likely to predetonate. The higher the octane rating the less joules of energy the fuel contains. Diesel fuel for example is 30 something octane off the top of my head yet contains TWICE the energy per gallon as 87 unleaded. Thats why diesels are so efficient.

The flip side of this is that higher octane fuel allows you to increase the compression ratio and ignition timing advance; both of which increase the efficiency and power output of the engine. The compression is fixed so unless you plan on rebuilding your engine this aspect doesnt do you much good. The spark timing will automatically advance itself on EFI engines like ours to try to make use of the higher octane, but the benefits are negligible compared to the increased price per gallon and our low compression ratio.

Remember that sign that says "gas may contain up to 10% ethanol"? Well ethanol is something like 120 octane. So how do you think they make 93/91 octane gas? They add ethanol.
There are usually two unleaded tanks in the ground and maybe a third tank for diesel buried under the gas station. So mid grade gas, 89 octane, is simply a mix of the regular and premium gas from those two tanks underground.


As for chevron, I like chevron. Shell is the only fuel I put into my vehicles but I will use chevron if I have to and BP in a pinch. I dont use RaceTrack, QuickTrip or any other bargain gas because from personal experience it makes my carbureted vehicles run like crap. The EFI may not run any different on the cheap gas but its clear to me that there is something superior about Shell and Chevron

[Xander_X]

Agreed ... the higher octane can be harsh especially with the ethanol in it now. I ended up having to replace 2 injectors in my 91 Legacy Sport once they started adding ethanol (old/worn injectors didn't like it). Unless you have 10:1 CR or higher I wouldn't recommend anything other than 87. There is also a controversy whether it's better to run 87 or 91 with forced induction. I'm not even going to touch that.

[kormysh8]

Ethanol reduces energy content in your gaz. avoid using it if you can. I drive a lot of highway. I did some experiments, and the husky 87 gas with 10% ethanol doesn't even come close to the "may contain up to 5% ethanol" shell 89 mileage wise, because said energy loss from the added ethanol. Ethanol is also in the OH group. these are considered "dry" liquids. IMO you would be risking damage to seals and pumps as these aren't really true liquids. well yea they are obviously. just sayin. but yea, NO ETHANOL!! also I run shell.

[TannerEsser]

In short octane is the fuels resistance to burning. Higher octane requires more energy to combust, so its less likely to predetonate. The higher the octane rating the less joules of energy the fuel contains. Diesel fuel for example is 30 something octane off the top of my head yet contains TWICE the energy per gallon as 87 unleaded. Thats why diesels are so efficient.

The flip side of this is that higher octane fuel allows you to increase the compression ratio and ignition timing advance; both of which increase the efficiency and power output of the engine. The compression is fixed so unless you plan on rebuilding your engine this aspect doesnt do you much good. The spark timing will automatically advance itself on EFI engines like ours to try to make use of the higher octane, but the benefits are negligible compared to the increased price per gallon and our low compression ratio.

Remember that sign that says "gas may contain up to 10% ethanol"? Well ethanol is something like 120 octane. So how do you think they make 93/91 octane gas? They add ethanol.
There are usually two unleaded tanks in the ground and maybe a third tank for diesel buried under the gas station. So mid grade gas, 89 octane, is simply a mix of the regular and premium gas from those two tanks underground.


As for chevron, I like chevron. Shell is the only fuel I put into my vehicles but I will use chevron if I have to and BP in a pinch. I dont use RaceTrack, QuickTrip or any other bargain gas because from personal experience it makes my carbureted vehicles run like crap. The EFI may not run any different on the cheap gas but its clear to me that there is something superior about Shell and Chevron

In short? hahaha real short. This is short-> you need to use 87 octane. unless your car is turboed. it will cause gunk buildup if you use a higher octane on an engine meant to take 87 octane

Ethanol reduces energy content in your gaz. avoid using it if you can. I drive a lot of highway. I did some experiments, and the husky 87 gas with 10% ethanol doesn't even come close to the "may contain up to 5% ethanol" shell 89 mileage wise, because said energy loss from the added ethanol. Ethanol is also in the OH group. these are considered "dry" liquids. IMO you would be risking damage to seals and pumps as these aren't really true liquids. well yea they are obviously. just sayin. but yea, NO ETHANOL!! also I run shell.

gas in liquid form doesnt burn its the fumes that burn... just sayin.

This post has been edited by TannerEsser: May 4, 2012 - 11:01 AM

[Xander_X]

Ethanol reduces energy content in your gaz. avoid using it if you can. I drive a lot of highway. I did some experiments, and the husky 87 gas with 10% ethanol doesn't even come close to the "may contain up to 5% ethanol" shell 89 mileage wise, because said energy loss from the added ethanol. Ethanol is also in the OH group. these are considered "dry" liquids. IMO you would be risking damage to seals and pumps as these aren't really true liquids. well yea they are obviously. just sayin. but yea, NO ETHANOL!! also I run shell.

gas in liquid form doesnt burn its the fumes that burn... just sayin.

This is true but gasoline runs through your engine, up until it is compressed, as a liquid and actually acts, in part, as a lubricant. Ethanol, in its liquid form does not do this. It is not petroleum based and does a number on your seals, and plastic/rubber bits. Thus why my 22 year old injectors didn't like it. But this is neither here nor there as the thread is really just about which gas is best in a 6gc. 87 in a stock/mildly modified engine (or I guess Shell 89 apparently ...idk ... we don't have Shell around here)

This post has been edited by Xander_X: May 4, 2012 - 11:24 AM

[Special_Edy]

Ethenol also burns hotter. It requires more initial energy to combust and yeilds less power. Its 100% about how you have your engine tuned. Spend the extra dollars you would of wasted on premium gas on a decent set of tires, you will be much happier with the results.

Tips-
-Dont fill up when the gas truck is refilling the underground tanks
-Fill up in the morning or on a colder day, gas contracts when it cools and its measured by volume not weight. So you get more gas per gallon when its cooler.
-Always pick a new gas station over an old one. The underground tanks will be cleaner.
-Pay the extra couple cents for the superior brand. Cheaper gas stations are cheaper for a reason

[ILoveMySilly97]

Sooooo..............overall 87 octane is the best then?

[richee3]

For the 5S/7A, yes.

[dudeofchaos]

''7a-fe engine - Unleaded gasoline, Research Octane Number 91 (Octane rating 87) or higher. 5s-fe engine - Unleaded gasoline, Research Ocatane Number 91 (Octane rating 87) or higher. For improved vehicule performance, the use of premium unleaded gasoline with a Research Octane Number of 96 (Octane Rating 91) or higher is recommended.''

Directly from my owner's manual.

I've always used Shell V-Power 91 octane in my St204 and it runs good. I ran on 87 octane when I bought the car for like a few weeks or so and it felt a bit better when I switched to 91. Felt like the throttle responded a bit quicker and was a little more torquier (is that how you say it? lol).

This post has been edited by dudeofchaos: May 4, 2012 - 11:33 PM

[Box]

Shell and Chevron for me.

[ILoveMySilly97]

''7a-fe engine - Unleaded gasoline, Research Octane Number 91 (Octane rating 87) or higher. 5s-fe engine - Unleaded gasoline, Research Ocatane Number 91 (Octane rating 87) or higher. For improved vehicule performance, the use of premium unleaded gasoline with a Research Octane Number of 96 (Octane Rating 91) or higher is recommended.''

Directly from my owner's manual.

I've always used Shell V-Power 91 octane in my St204 and it runs good. I ran on 87 octane when I bought the car for like a few weeks or so and it felt a bit better when I switched to 91. Felt like the throttle responded a bit quicker and was a little more torquier (is that how you say it? lol).

Yea I took out the Owners Manual and read it and that's what it said too. I ran on 89 octance for a month when I bought my car. Then gave it a full tune up and started running 91 and it feels like it had better throttle response and more torque too. I've pumped Chevron only but I think the previous owner ran cheap gas because it wasn't that healthy before the tune up. Lol.

[richee3]

Tune ups tend to do that

I'm kidding. Seriously though, I've run literally thousands of gallons through my Celica, all different octane ratings. The difference in how the car performed was never in octane rating; it was always in brand selection. Good fuels perform better, no questions asked. If the 91 you were buying came from Shell whereas the 87 came from a mom & pop gas station (no offense- I'm all for supporting small businesses) then that's why the car could have felt better. And once again, no offense, but the placebo effect has a lot to do with it. If you think you're doing your car a favor, you feel like it reacts better. Just like when I put the SS-III seats and TRD short shifter in my Celica, both Brigette I felt like the car was a lot faster when it was the exact same car behaving the exact same way. Premium fuel just costs a little more per gallon in a car designed to run on regular.

On the flip side, regular fuel in a car designed to run on premium can and will cause issues. My IS 300 requires premium and I went cheap, trying to save $5 one day, and filled it up with 87. Within a mile of driving, my check engine light came on and the ECU pulled timing until I basically had no power. Same thing with the BEAMS. I was not in a WOT position nor was I putting either car under heavy load, but both engine detected knock under average acceleration, which can and will damage your engine. But an engine designed to run on 87 will have no issues running 87 and will have gains that are a fraction of a percent by running premium.

Here's a good read: http://www.toptiergas.com/index.html

This post has been edited by richee3: May 5, 2012 - 2:09 PM