Best gas..

[MarcoSolara02]

What's the best type of gas that should be put it a stock solara with 80k miles?

[mig0s]

regular. 87 octane is enough for both the i4 and the v6 engine. I made a lot of researches on this and there's supposedly no benefit of putting more octane than the manufacturer suggested one.

[TheGreenDutch]

Remember that all the additives they put into 87 you get a cleaner burn with 91-93 octane. Cheap gas is what it is. My good friend who has been a mechanic for 30 years always tells to use the premium gas and I've never had a fuel delivery problem with any of my cars. The extra dollar pays for itself in the long run I think. One thing you should never do is fill up when the tanker is filling up the station tanks. All the sediment gets stirred up and goes right into your tank. Also know the gas station too. Some places will do anything to save some money and cheapen the gas rating. Even if that means that they use fillers and stuff in the tanks. Even tho cars are made to run off the 87 I think its beneficial to use a better quality in the long run. In my experience.

[jimmm]

Well, there you have it folks. Will it be door number one or door number two? In an ideal world, I think that following the manufacturer's instructions would be sufficient and this is what I do with my V6 SLE. I tried the higher octane for a while at first but decided that it probably wasn't necessary. I do use Lucas Fuel Treatment periodically however to help improve the lesser octane gas and it seems to improve performance as well. Nonetheless, based on what the second poster said, using higher octane makes a lot of sense too. Bottom line: some say yes, and some say no; I tend to agree.

[1gSE]

If I'm paying this much for gas I'm using the good stuff. 92 it is. The difference is only a few bux for a full tank

[MarcoSolara02]

Lol now i cant make up my mind

[02slera]

higher octane is only really necessary on high compression engines.
the owners manual in my car says its rated for regular gas, BUT for best performance use premium.
that being said, i run mid grade, and only for one reason, my car will sometimes make a knocking sound when i floor it at low rpm's and using a higher octane fuel seems to help it not do that. this is weird i think because my cars powertrain is stock. i dont really know what the knocking is.
to help you make your decision... i have personally seen (im sure others have as well) plenty of cars go over 300,000 miles never having a fuel problem even though they have only used regular gas. and if my car did not make the knocking sound at low rpms with full throttle then i would be using regular gas.
if you supercharge it, or turbocharge it, or raise the compression any other way, then you will be forced to run higher octane gas.

EDIT: if your still not sure... just run mid grade.

[mig0s]

My friend has a twin turbo 300zx and yes he needs high octane gas. On the Solara user's manuel it clearly said 87 or higher, just like many other cars. I've read stories of people having the same car and running different gas for years but after 10 years the cars are in the same condition. Some people even said since the gas will burn slower, there will be a loss in HP especially if your engine is relatively small.

As for my personal experience, I've tried both 87 octane and 91 octane periodically in both my Solara and my old Accord didn't feel the difference at all, except the more expensive 91 octane lasted longer, which is normal.

I don't see why higher octane will be better for your car and 87 octane is definitely not "bad" for the car. Never heard of a car broke cuz of low octane gas lol.

[NightRider]

I've been using 91 octane on this car and my two previous cars. So I am used to paying for the little bit more expensive gas so it doesn't bother me. But I can tell you from experience that I can tell the difference from using "cheapy" gas compared to premium. And my car does run better with it. That's my opinion on higher octane gas.

[mac-phisto]

i run 89 b/c i have problems similar to what 02slera described above. engine noise & lag (esp. on hills, which are all over where i live).

but also, i see a noticeable difference between brands. maybe this is all in my head, but i seem to get better fuel economy & better engine response on sunoco fuel. exxon & citgo seem to be alright, but shell seems to be the absolute worse. whenever i put that junk in my car, it seems to gobble the fuel & my car runs like crap.

[jimmm]

Isn't it wonderful that we live in a country where we have so many options? God Bless America??? What more do we need?

[MarcoSolara02]

Isn't it wonderful that we live in a country where we have so many options? God Bless America??? What more do we need?

LOW gas prices..

[mig0s]

Interesting post found on another forum:

three different posts in the same thread by the same person http://www.civicforums.com/forums/140-h ... m-gas.html

I'm not sure what kind of expert opinion you are looking for. But if you are running 93 octane, you ARE losing power, and you ARE going to build up crap and contaminants in your engine much quicker. They always say 87 or higher, because of the fact that some places may only offer 88 or 89.

You are wasting money, you are losing power, and you are gonna have a fairly gunked up engine by the time you get up there in mileage.

I'll explain this again since you seemed to have missed the technical explinations. The only thing octane rating is, is resistance to detonation and heat. The higher the octane, the more heat required to get the mixture to ignite.

Hence the reason cars with higher compression engine or turbos require premium. Cars with turbos, etc, and with higher compression tend to have their mixture get much hotter in the combustion chamber before the ignition spark. Using a lower octane gas in a car that requires premium causes premature detonation (which is bad, duh) since the heat detonates the lower octane gas.

Likewise, if you are using higher octane gas in your civic, the mixture may not get hot enough in your combustion chamber to burn completely through. This leaves excess fuel/air mixture in your combustion chamber during the exhaust stroke, causing a loss of power and buildup of excess contaminants. Stop using 93 octane, because you're losing power and you're pissing money away. This also burns your valves and over time you will burn through them.

As for using high octane gas and nitrous, this is somewhat a paradoxical situation. Nitrous can benefit from using higher octane gas, since the oxidization process induced by nitrous causes the mixture to super heat. again higher octane gas is more resistant to heat, therefore will help prevent detonation when spraying.

however, when you're not spraying, you're back into the category above, where it's causing loss of power and excess waste and contaminants.

As for using 100 octane gas in your car, I'd advise against that in a very cautious sense. The addatives in higher octane gas worsens the effect you're seeing here, even if you're using nitrous. Turbos can use it if they crank up their boost to the point that they'd benefit from it. However, most don't do that unless they've been tuned for it, becuase running high octane gas and high boost without being tuned is a very dangerous combination to gamble with.

If you see some ricer in his n/a civic filling up with 100 octane, point and laugh, because everyone else who actually knows what they are doing, will certainly be laughing along with you.


Oh and I found out the thing with the injectors. The addative that they use to give gas its higher octane can cause premature injector failure, injector misfires, etc, if your injectors were not made for that kind of fuel. This is an extreme case and few and far between, but it can happen, and does happen. I have to go back and look, but the addatives cause buildup on the injectors, leading to the above said failures. However, this is not always the case, so really, it's hardly worth mentioning.

Dear god this is not hearsay. This is SCIENTIFIC FACT! Methanol is completely different than using pump gas. You can't even compare the two.

No, higher octane gas does not burn more cleaner, nor does it burn more completely.

AGAIN. for the last time.

ALL THE OCTANE RATING MEANS IS THAT IT IS MORE RESISTANT TO DETONATION AND HEAT!!!


And as for the person who got better mileage with 89 than 87. Assuming your car isn't FI'd then you did NOT get better mileage just because you used higher octane. There are too many other factors involved to do an experiment like that. The ONLY case where this would be is if your car was detonating for some reason, but you'd get a CEL if something was that majorly wrong.

Also, the whole "well premium gas has more cleaners in it to help your car". wrong. government regulations prevent this. the only difference is the addative used to increase octane rating.

Once again. Higher octane gas is more resistant to heat and detonation. (this also means it takes longer to burn, which is WHY if you DONT have a car set up for premium you'll eventually burn through your valves). If you are going to run premium you have to tune for premium. you would have to advance your timing 2 degrees and retard your exhaust valves in order to allow the mixture to burn through completely before the scavaging of the chamber.

Here... so you know I'm not talking just "hearsay"



this was in a pdf i found at the american petroleum institute. here are some excerpts. i believe this was also hilighted on the service advisor web site.





WHAT IS OCTANE RATING?



Octane, by definition, is the resistance to burn or detonation. The higher the rating, the slower the burn when ignited during the compression burn cycle of the piston. The higher octane allows for better control of burning for high compression engines. So we want to match the correct octane rating of the gasoline to the engine design to ensure complete burning of the gasoline by the engine for maximum fuel economy and clean emissions.



I THOUGHT GASOLINE WITH HIGHER OCTANE REDUCED ENGINE KNOCK?



It did in older engines using carburetors to regulate air/gas mix They cannot as accurately regulate the air/fuel mix going into the engine as a computerized fuel injector. Carburetors need adjustment, as a part of regular maintenance, to keep the air/fuel mix as accurate as possible. So many times, these adjustments were not made regularly causing too much fuel to be mixed with the air. When this happened the gasoline would not burn completely soaking into carbon deposits. This would cause a premature ignition of the gasoline due to the intense heat in the engine cylinder creating "engine knock." When this happened, people would change to the higher octane/slower burning gasoline to resist the premature burn, thus minimizing the knocking problem. And it worked. Good solution.



However, since the middle to late 80’s, engines are designed to use fuel injectors with computers to accurately control the air/fuel mix under all types of temperature and environment concerns. However the accuracy of the fuel injectors and computers is based on using the recommended gasoline for that engine.



Most cars are designed to burn regular unleaded fuels with an octane rating of 87. If the vehicle needs a higher octane rating of 89-93, there is documentation in the owner’s manual, as well as possibly under the fuel gauge and by the fuel fill hole. Usually you will see this rating for high performance engines only.



WHAT IF I PREFER TO USE GASOLINE WITH HIGHER OCTANE RATINGS?



You can, but there are no real benefits, other than the gasoline manufacturers making more money off of you. When you use a fuel with a higher octane rating than your vehicle requires, you can send this unburned fuel into the emissions system. It can also collect in the catalytic converter. When you over stress any system, it can malfunction or not do what it was designed to do properly. In the early 90's, an early warning symptom was a rotten egg smell from the tailpipe. Easy fix, go back to using regular 87 octane gasoline. The rude odor usually disappears after several tanks of gasoline.



DOESN'T HIGHER OCTANE GASOLINE HAVE MORE CLEANING ADDITIVES THAT ARE GOOD FOR MY ENGINE?



No. Government regulations require that all gasoline contain basically the same amount of additives to clean the injectors and valves. The only differences are the type to help create the different octane ratings. All gasoline burns at the same rate, it is the additives that create the different octane ratings for the different types of engines.





http://auto.howstuffworks.com/question90.htm



And here's from the federal trade commission.

http://www.ftc.gov/bcp/conline/pubs/autos/octane.htm

[mig0s]

continued:

Cars that do not have higher compression have a lower temperature of the mixture before ignition. (this is basic physics... the more you compress air/matter the hotter it gets) So in a car that does not have higher compression, honda builds the car from the factory with the appropriate timing for the recommended octane.



Higher octane gas burns LONGER since it is more resistant to detonation and heat. So the time it takes to burn through the mixture on 87 octane is LESS than what it takes to burn through a mixture with 93 octane.



if your car is setup for 87 octane (like the civic) the 93 octane will not have completely burned through the mixture by the time your combustion chamber has opened the exhaust valves and is scavanging the mixture. This gives the still burning mixture the not-so-great opportunity to burn through your valves since it now has an out and a re-introduction of oxygen via the open exhaust valves. This is what causes the buildup of crap on your valves and other parts which can lead to damage down the road. Also because the mixture did not finish burning, some of that fuel or unburned mixture can go through your exhaust and then settle in your catalytic converter, causing you to fail emissions and/or damage your cat.



So there are 2 keys to having a car that can run premium effectively without these issues. number 1, higher compression, which causes more heat, allowing the mixture to burn more efficiently and more thoroughly with less leftover contaminants.



number 2, advanced ignition timing and retarded exhaust valve timing, allowing the mixture more time to burn with closed valves.



going from 87 to 89 octane isn't too bad, but going from 87 to 93 can be harmful in the long run and cause a loss of power in the short run. (if your mixture burns all the way through, it gives you more power obviously)



------------



Just for the record, octane rating is this:



pure iso-octanol (the harder to get of the two forms of octanol) is considered to have an octane rating of 100. 87% iso-ocatanol and 13% n-octanol has an octane rating of 87. Every other compound is then measured agianst 100% iso-octanol, for instance methanol, has an octane rating of 104, so it is 104% harder to ignite than iso-octanol.



You see this has little to do with carbon build up. Really it is more like the adative they put in to the fuel, try changing gas stations. But from what I have seen of other peoples pistons on this site, it isn't abnormal. Gearbox had heavy build up after only 20k (i think it was 20K) and he never sprayed or anything (that I know of).



What a company can do is take a low grade fuel, like say 80 octane octanol, and mix 5% methanol (which has an octane rating of 104) and get 87 octane. These addative have are more likely to cause carbon build up. Some of these addative are to raise the octane while other are for the enivroment.



Also keep in mind, methanol is bad, not for your engine but for all the plastic lines and O-rings, Shell uses methanol in their gas.



This is text book stuff, yes I have those text books. I'm a chemical engineer, chemical enginers purpose is to refine oil and work in the petroleum industry.



In the end, just use what gas your manual cars for. Detergents are nice, but your car doesn't require them to run nor will they give noticable power or anything of that nature nor will they clean you engine more (well maybe a little, but you'll never notice the difference).

Just to summerize, don't run premium gas:)

[jimmm]

Thanks, mig0s, for such an EXHAUSTIVE, all-embracing, all-encompassing, all-out, catholic, comprehensive, embracive, encyclopedic, extensive, far-reaching, from A to Z, full, full-blown, full-dress, full-scale, in-depth, intensive, no stone unturned, out-and-out, profound, radical, sweeping, the word, thorough, thoroughgoing, total, whole-hog report. I think I no longer need to concern myself with this subject any longer.