The octane number we refer to as "87,89,92" are actual precentages. Simply put, a percentage of how much Octane is in the fuel. Exp: 87 gas is 87% octane and 13% heptane.

What these numbers mean is the higher the number, the higher the octane concentration, the higher the compression ratio(octane can handle compression better than Heptane), or its ability to be compressed before "self" detenation(due to the pressure).

Knocking occurs when you have early detenation during the compression stage due to low octane gas in a "high octane engine". So 87 is not really worse than 89 or 92, but gas station "A" may have higher quality fuel than station "B".

Unless my memory isnt working today thats a simple explination. Feel free to correct me if I am innacurate.

Pretty accurate JMROD.

To add to it, the a higher octane fuel NEEDS more pressure/heat to burn clean. So if your engine is NOT running well with higher octane in it...it probably doesn't need it.

If you're 1983 Honda doesn't run well with 87 so you have to put higher octane in it, it's not because the higher fuel is better, it's because something in your engine is broken and needs to be tuned.

You're generalizing and making a bad assumption. I just had a relative complain about the same thing in her '07 CRV. She was using 87 and started experiencing starting problems. The vehicle was under warranty, she took it back and the technicians couldn't figure out what was wrong with it. Their computer was saying that no problems had been recorded. They did however offer advice about the fuel... imagine that.

Hey look, it's not that big of a deal. If you want to put that crap in your engine-- go ahead.

True, I was being slightly sarcastic....but only slightly.

If I went to Honda with my brand new CRV, and the manual rates it at 87 Octane, and they tell me they can't fix the problem my ECU is having keeping the engine running, so I have to pay an extra 10-20 cents to the gallon per tank of gas...I'd be raising hell, especially this day and age!

This is pretty accurate... a very detailed description is here:

<http://en.wikipedia.org/wiki/Octane_rating>

The only difference I would add to your description is that the Octane rating you read on the pump is an equivalence-to-measured-percentage rating. I.E. the 92 Octane gas you are buying has the equivalent knock-performance of a fuel composed of 92% ISO-OCTANE and 8% HEPTANE.

Also, the US publishes an average octane number, comprised of the RON and MON ratings... but you can read more about this after the link.

Anyway, I know that in my MINI Cooper S (Supercharged Inline 4) I lose about 40hp using 87 vs. 94 Octane fuel (on a chassis dyno). And it runs like sh!t... but conversely it doesn't like to start when its cold on high octane fuel (ECU is a sh!tty design, and can't compensate at startup... damn british electronics! :-) ) I'd rather a rough cold-idle over the loss of performance! It's had 94 since they day it was delivered!

~LSx

I'm not trying to pick on you Eisenhower, You just made a few points that ...well, didn't seem that sharp to me...(get it;) points; and sharp...get it;) :laugh:) Not really that was a joke...:iono: Really, I just wanted some clarification on some of your posts...

What kind of cars do you have that they all need 92 or higher?

That's really good! i didn't realize they re-sold that well. Especially the Trans Am's; after 6 years they still sell that high! :clap:

I never knew that Toyotas' Nissans or Honda's required high-grade gasoline to start Well...

And fuel with Additives CAN be good, but put too much crap in, and it's not all that good anymore. The cleaners can do more harm then good in some cars. I don't know which specifically, I just know that happens.



And as for the question that started this really moot argument. If a manufacturer "suggests", or "reccomends", a high-grade fuel, you'd probably be alright using a lower grade. It may rob some power, but not enough to be noticed. NOT ALWAYS, THOUGH. If the manuf. "requires" a certain fuel-grade. You'd be asking for trouble putting any lower-grade fuel in there.

My '79 reccomends 91 octane. But it'll run fine on 87, no knocking, pinging, or even any detectable power-loss.

Ha! You know, in all fairness I had a Lumina that I ran on nothing but 87, why? 'cause it was cheap. I think most people use 87 because it's the cheapest. I had no problems at all. I drove it all over the city, to work- whatever.
Later, I bought a '95 Acura Legend (nice car) that absolutely refused to start on anything less than 10 cranks and 20 minutes of sitting using 87. A mechanic actually recommended I start using better gas, so I tried it. Suddenly, I stopped have issues with the starting and life was good again. BUT, it could be the quality of gas at a particular gas station, as was mentioned.

Now, I'm def. not an advocate of using pricier grades of petroleum. All I can tell you is what I experienced. But then again, who really cares? I'd rather talk about the LS2-LS3:burnrubber:

Works for me! :D

I know that this has been discussed in great detail before, but, what is the difference in the L76 and the LS3. Everyone is making it sound like the L76 engine is not the one I want in my new Camaro. I want the new Camaro as bad as anyone, but do not want to trade it in after only one year to get the bigger/better engine. I am looking for thee 400+ HP engine that everone has been talking about. DAMN GM, give us a bone to chew, we need information.

The major Difference between the LS3 and the L76 is power. I'm no expert on the details, but the L76 is 6.0 Liters, and 367+/- hp. The LS3 is 6.2 Liters, and 428 hp.

They both have DoD, or Displacement on Demand. And I think they both have VVT, or variable valve timing. The L76 in by no means a Bad engine. 367 hp in a car is nothing to scorn. I think the biggest worry is why settle for a "weaker" engine when we could have 60 more horses. :iono: Honestly, I would be more than happy with the L76. I would like to have the LS3, but if that doesn't happen (though, I think it will) ...:iono:

I handt' heard about them having VVT...but that excites me.

I know for SURE the L76 has VVT...see that long article I posted...But I haven't heard whether the LS3 has it or not.:iono:

Honestly if camaro doesn't come in LS 3 i won't buy one!

Selfish yes. but why the hell would i spend that much money on something i don't want. when i could buy a 3 year old GTO and have a better FASTER car!

If GM puts anything less than an LS 2 in the camaro they need pissed on. and may mustang win the war!

Sadly i figure the first year will be pretty shitty cars without the best V8 even being available. just like i figure 09 or 10 the G8 will come with the LS 3 in a GXP version.

If they are going to dick me on the engine i'll go to corvette or a GT500. i want a minimum of 400 HP in a car not some half assed engine from a truck.

The L76 is being put into the G8, it's no longer a "truck engine". And I'll say it again...we live in a world right now of lotsa hp, more hp, and even more hp...376hp...IS A LOT OF POWER. Sure, 400 would be nice. but the L76 is nothing to snort at, either.

In any event. I doubt the LS3 won't be in the Car...it makes too much sense to have it in there.

If the ls3 doesn't make it the first year for some reason i'll just wait it out. Eventually it will be an option and it just gives me that much more time to save even more money and buy the best camaro that GM has to offer. So either way it's a win/win for me cause i got all the pateince in the world at this point.

Also i though about this earlier....like with the GTO i'm sure some company will get a hold of one of the camaro's and just go nuts with it like the RA6 GTO. http://www.anthemmotors.com/PontiacGTORA6.html

That's pretty awesome! I'm sure they'll pick up the Camaro and mod it. I mean look at the car! How can you keep your hands off of it? :laugh:

My thoughts EXACTLY!

I know it isn't a "truck" engine but why not just use the LS series engines leave it in the trucks. is it cheaper to build or something? I would probabally be buying a G8 if it came with an LS2 or 3 but 360 HP isn't enough for me in that car, ( my buddy just bought an audi S5. so i'd be beat before i started lol

Using a higher grade fuel than required does not improve performance. Theres no ultra simple "upgrade" like that. 92 doesn't equal "fast" it just deals with the combustion of the gasoline mixture. Using 92 in a car that requires 87 will do absolutely nothing, except maybe eventually cause some carbon build up. Don't confuse 87 with low-grade gasoline.

Absolutely right! But I think what he was getting at (correct me if I'm wrong) was that the cars he owns, at least the foriegn ones, required higher grade gasoline to start immediately. And now that I think of it, I mentioned that my 'Maro runs fine on regular-grade gas (87)...it does...but it takes 20 seconds at least, to start up, it also involves some pumping of the gas pedal (carburator)...

I agree.....however the higher the piston compression ratio the higher octane fuel you ought to use. I know that if I use less than 97 octane in the vette there is alot of pinging going on under the hood. Granted it is not the stock motor under there and the idle may be set a little low. It just runs better on the higher octane stuff. Runs superb on 107.

97...107...:eek: what kind of compression are you running in that thing!?!?

Very true. I just mean to point out to people driving stock Civics, Cobalts, and Ford Rangers that putting 93 in won't make it go faster. I've actually got plans to stroke the 4.0L I6 in my Wrangler out to 4.5L, then bore it .030 over for a grand total of 4.6L. When I was in the shop discussing lift plans, we got to the topic of engines. One guy insisted that the octane is determined by the displacement. I kept trying to tell him that it was based on compression ratio, but eventually I gave up.

The exact compression i don't know. If I had to guess I would say better than 12. In a nut shell (my uncle had this put together balanced and blueprinted so I am not sure of specifics) it is a 350 block, bored out (I assume .40 over), oval track racing cam, aluminium racing heads, solid lifters, hi rise aluminium intake, Holley double pumper coupled to four speed manual transmission and all neatly packaged in the body of a 76 corvette. He said he had it dyno'd and it came in at over 500hp. I had first shot at buying it from him when he could no longer push the clutch pedal in (favorite nephew). Oh and it red lines where the stock tach has no more numbers.

No wonder you need 97 octane with a 12+ compression ratio! :eek: That's one heluva car! You hang on to that!