I bought my 99 Eclipse N/T around 5 months ago.... i been using regular gas from petro canada 4 months now... a month ago i switched to sunoco 89 octane.... jus wondering if i should use 91 or beeing a non turbo it doesnt really matter?

thanks

87!

regular! cheap cheap cheap!

87

Do they still sell leaded Gas??

I use 94 but I have my base timing so far advanced that anything less than ultra 94 makes my engine ping like a deamon. But the car performs much better than stock really wakes up the motor.

your filler neck will not even accomodate a leaded nozzle.

87 at a no name gas station to save the extra penny!

You're not running turbo, so your fuel octane doesn't need to be that high. Turbocharged engines will detonate easier on cheaper gas, so that's why we run 92-94 octane. Gas prices are too expensive to be runnin that on a N/T. 87 all the way!!

alright thx!

87 it is

For your information guys, if you put high octane fuel in an engine that runs on regular 87, your emissions will go up, your car might run like crap, and it is a waste of money. High octane fuel is for high compression engines. You probably are saying "Well, the turbo models compression ratio is way lower, why are you guys using it." My answer to that, how static compression ratio will be the same 7:8:1 or 8:5:1, however, when boost kicks in, the boost compression ratio will go higher than 12 or 13:1. At those compression ratios (None static), you need higher octane fuel to resist detonation, pinging and knock.

Arn't all three the same thing?

Yes. Aviation fuel.

and why is that?

Because Jesse likes to spread information on this board like he has some technical credibility worth listening to.

Well your emmissions and power might get a bit worse. Would it be noticible? I don't have a clue. The higher the octane rating the slower the burn. So if the timing is already tuned in at max ECU advance with 87 octane to acheive the most efficient transfer of energy it won't advance further with 94. So the point of peak pressure will actually fall too late having an effect on the intended efficiency. Slower burn rate also means less burned in the given period of time which I would assume leads to higher emmissions.

Pinging, knock and detonation are all the same.

Rob your a smart ass sometimes. Why should you use low octane fuel for an engine designed to take low octane? Simple, that engine is designed for regular gas. The ECU is programmed to run on 87 octane. So if you put high octane fuel in something that takes regular, your emissions will go up, your fuel economy won't be as great and it is possible that your car won't run properly. And Rob, when have I spread information in this forum? You really need to get your facts straight. If you have nothing positive to say, just DON'T POST!

If you don't believe me? Drive a car that takes 87 octane fuel in the owners manual. Do a emission test and test how much mileage you get per tank when you put 94 octane in it. Than, do another test using regular fuel. Tell me the results.

For once I can say, you're right Jesse.

Jesse, your a tool, plain and simple. If you want me to dig up any of your rediculous posts I will, and have a thread dedicated to your retardedness. Thats where my credibility comment comes from.

Your right, I cant argue that a car with an ECU programed for 87 will run better with 94. But it sure as hell wont fail an e-test as you are so confident about. If it fails, it aint because of the gas in the tank. I wastnt even making an argument. Just stating an opinion unrelated to the topic at hand.

I have lots positive to say, I just dont like you in particular.

Happy now?

Just let it go Jesse... you couldn't troubleshoot your way out of a wet paper bag. Leave the advice for the more senior or experienced people here.

4. Stay on topic, otherwise, start a new thread.


10. Take all personal discussions to either private messaging or email.

Thats for you Rob, read the rules. I don't want to argue with you. Many people hate you to Rob. If you hate me so much go start a thread about me, I dont care. Noah, and what? You are an expert as well? You are judging me because I had a problem trouble shooting a problem that a SHOP couldn't even figure out? Guess what, I did figure it out, so you should just stay out of this as well. Again, if you don't have anything positive to say, don't post. If you have a problem, PM me or e-mail me like what the rules say.

Mike,
Higher octane doesn't burn slower, it actually burns ffaster and that is the advantage of it.

Lower octane burns slowly, higher octane explodes and suddenly ignites.

Really the change is a shift from burning to explosion.


With higher octane it is fast and therefore at the right time, as oppose to a gradual burn as the temperature and pressure increase.


basically if you look at the "burning" graph with respect to time, you could see a peak and, smaller variance and most reactions happen closer to the peak of the "wave" and it is "sharper"

in case of lower octane the burning process is spread over time and the curve would be a bit more flat. As such it is a bit harder to programme a system for.


It would be very naive of me to say that a higher octance would not have ANY side effects in a engine made for 87. Because I can't claim I own the thermodynamic business. It is just that mathmatically it seems that higher octance is better, it just could be that you are not going to gain anything passed a certain point.


Jesse,

There are some rules to technical posts and writing. There are also some defacto rules to an "average" discussion outside the vicinity of a bar. You didn't exhibit a knowledge of those either. Hence I rather admit that "you are right"

I have done my research when it comes to proper gasoline for your car and what are the side effects. I am doing part time classes at centennial college, I am only saying what my profs have taught me. Anyway, Rob you need to stop PMSing and Noah, stop judging me because of one trouble shooting problem.

Anyway Steve Alba, I hope that answers your octane question. Read your manual and see what the factory recommends. There is a reason why the factory gives specific octane fuels for their cars.

Guys (Rob, Jesse, Noah, Dean, Nathan), stick to the topic please.

This is the opposite of what I've always heard, and a quick google search would seem to indicate that it is incorrect. As a general rule, Higher octane fuel burns slower, just like Mike said.

Jeff you are correct. Thats why when you put in low octane fuel in an engine that uses how octane, there usually is a violent or rapid combustion because it burns faster. This causes detonation or pinging.

" fuels with higher octane ratings burn less easily"


I think I should rephrase what I said. The lower octance burns easier which could also be called faster.

however that inhenerently mean that it will take longer from the earlier "knocks" to the end of combustion cycle.


where as higher octane, starts later, so I guess it could be called slower. It is more resitance to the start of the combustion. however the total span of time during which the fuel is consumed is shorter.


That might have been the confusion.

" (Using a fuel with a lower octane rating than necessary can damage the engine and hinder its performance, but using one with a higher rating than needed does not improve performance.) "

http://72.14.207.104/search?q=cache:6slJl1NhOLcJ:scifun.chem.wisc.edu/chemweek/MTBE/MTBE.html+octane+burn+slower+faster&hl=en

I did, and i got 12%+ more mileage from an 89 Octane compared to an 87 octane from my '87 civic.

As well, ive noticed that an 89 octane from Sunoco is a lot better than an 89 octane from Petro Canada in terms of km/ltr. I noticed an average of 20-25 km more mileage i get from Sunoco than from Petro.

87 to 89 isn't a big leap. Joe, put some 94 octane in your car. Do the same test.