"I'm "ruining" the conversation? You're the one resorting to profanity in contrast to logical argument."

I wasn't using profanity in contrast to logical argument, I was using it in conjunction with logical argument. I could have said "I don't believe you", but since you were being cocky, I figured that BS was a more appropriate way to put it.

"Regardless of your assumptions, you've no idea what I may have tried and experienced."

Well, you obviously haven't ever run Avgas or any other high-octane fuel in a normal engine, because if you had, we wouldn't be having this argument, you would have already agreed with me.

"Further, if you genuinely believe your sweeping generality that ALL engines produce additional power without limit by increasing fuel octane with no adjustments or modifications because of unspecified and undocumented "real world" tests, and vague "logarithmic" (asymtotic?) curves, you're welcome to the notion."

I'm sorry I didn't document my tests and write a 3-page summary and post it on the internet, I didn't realize it was a homework assignment in disguise. I'm also sorry that I assumed you would know what a logrithmic curve looked like, I guess I figured anyone with a high school education would know that. Plot y=log(x) in a graphing calculator for a good illustration.

Basically, if you start at 0 octane, you develop no power, and as the octane rises the power increases rapidly up until 80-90 octane, where the curve begins to flatten out, showing less increase in horsepower for increase in octane, but still an improvement nonetheless. The curve would approach a limit (say 100hp) as the octane increases, but will never reach it, understand now (even though a log(x) curve increases without bound (no limit), the shape of the curve itself is similar)? Constantly getting closer to it's limit, constantly increasing. A more accurate curve for a 100hp limit, if you would like to punch it into a graphing calculator, would be 100-100/((x/20)+1) The more educated people that read my post probably understood it and would agree with it.

 

Motorhead and I have debated this subject before,with little useable results.I totally said the same things that Tree Farmer and Deej had said.I have tried the higher octane thing on my cars/trucks/motorcycles/ATVs before.I have never really noticed a performance differance on ANY motorized engine that did not start out spark knocking.

A few wks ago,my brother John and I were headed about 150 miles from our home town to go quad riding.He drove his full size Dodge PU ,equipped with a 318 engine.This truck has never spark knocked before.John allways used 87 octane fuel.It was loaded with three quads and pulling a trailer.We noticed a bad spark knock with all the extra weight.I had suggested that we stop and pick up a bottle of Octane booster.Guess what?We completely stopped all the spark knock with the booster.The demand and strain on the engine had been increased with the weight of the extra quads/trailor,therefore requireing a higher octane rating to stop the pinging.

My point?I beleive if your engine is not spark knocking,you are wasting you $$ on higher octane fuels.

I realize that Motorhead used his G-tech accelerometer and did indead acheive a higher HP rating on Avgas,however,im wondering,besides just his experience with the increased reading on the Accelerometer,if he could show me any documented instances of the same?

It could be the one thing that changes my beleifs.=====BILL

 

Thanks for sharing the benefits of a high school education with those less fortunate, Motorhead!

If I understand correctly, you've proven beyond the shadow of a doubt, the following:

1. All engines produce more horsepower with increase in octane of fuel burned; the increase is without limit: more octane equals more power output, regardless of any other variables.

2. The exact horsepower correspondence may be calculated by the formula, Horsepower = (C) log(Octane Number), where "C" is a constant peculiar to a particular engine.

Does my understanding comport with your "real" world?

Tree Farmer

 

"1. All engines produce more horsepower with increase in octane of fuel burned; the increase is without limit: more octane equals more power output, regardless of any other variables.

2. The exact horsepower correspondence may be calculated by the formula, Horsepower = (C) log(Octane Number), where "C" is a constant peculiar to a particular engine."

Try to understand what you read before you write the reply.

Point1: I said it would approach a limit, this means there is a limit, an unachievable limit, which it approaches but never reaches. Think of a ruler, cut it in half. Now cut the half in half. Now cut THAT half in half. See what happens? Your ruler is always getting shorter, but never reaches zero length. I'm sorry, that's a little more Calculus related than high-school math, but I thought you would be able to understand the concept.

Point2: I didn't say that was an exact formula, I was generalizing what would happen if you took a horsepower measurment of an engine running on a given octane level.

You need to grow up a little. I think your getting frustrated because you can't think of a good point to dispute me, so you go and take my post out of context and warp it to look like I'm the one who doesn't know what he's talking about.

This is my last post on this topic, people are getting immature and hostile, and I have no more points to make. I've tested it, I've proven it to myself, I could care less whether you want to believe otherwise. If you still believe higher octane yeilds ZERO performance increase, so be it. Just don't preach to other people like you KNOW it doesn't, because you DON'T.

 

Howdy Bill. I think I'm gonna give up on this topic.. people just don't want to listen. Just wanted to point out a couple things in your post before I call it quits.

"I have never really noticed a performance differance on ANY motorized engine that did not start out spark knocking."

Just because you couldn't feel the difference doesn't mean it wasn't there. Like I said, the human body isn't a precision instrument. However if you couldn't TELL the difference, then no, there is no reason for you to spend more on the higher octane gas.

The only point your Dodge pickup story makes is that an engine that is pinging will ping less with higher octane. The story in no way shows that higher octane on a non-pinging engine produces no power gains. Also, you have said that pinging was related to the engine timing and compression ratio, not the load the engine was carrying. Did pulling the load increase the compression ratio or advance the timing? Nope. So what exactly happened there? I'll leave you guys to explain that. I'm outta here.

 

Your last post on the subject, Motorhead?

Awwwwwwwwwww! I shall miss your learned tutelage. And just when I was beginning to grasp the theory of limits, too! A value approaching a limit "logarithmically." Wow!

Hey, that story about the ruler's pretty good! Feller up here at the general store near the farm, 'round the stove, told us 'bout a hound chasing a rabbit, gaining half the distance with each jump; said the dog would NEVER catch his prey.

'Course, us "real world" guys knowed he was foolish--naturally a hound that fast would catch that rabbit!

Now, I'll tell you what I WON'T miss: your self-righteous, judgmental, gratuitious character guidance.

You tell me I need to "grow up," when you use profanity in your posts, presume to lecture me on when I may talk, falsely accuse ME of preaching, or wrongly say I claim to know something I never have.

Lacking substance in your argument, you told me, "You don't know what you're talking about." Is this your idea of mature discussion?

While you instruct me to read your posts carefully, I turn that advice on you. If you do, you will not find I ever claimed to "know" anything. Certainly, I questioned your ideas, making you uncomfortable to the extent you retaliated with profanity. But I never claimed I "knew" anything.

I don't "know" anything. My life is buttressed by a fragile scaffolding of speculative hypotheses. However, I'm reluctant to exchange a single plank in this structure, just because Motorhead said to.

Thanks for sharing your fascinating beliefs.

Tree Farmer

 

DeeJ:
Yeah, you are right about the first part, with my truck getting better performance, and yes, that was probably due to the slight mod's. My question was though, we've got a '91 Suburban, an '86 Toyota Corolla, and my '97 Honda Civic, all of which get about 5 miles per gallon more on premium, than running regular. However, my mom's '93 Old's, and my sisters '92 Pontiac don't see any difference in mileage, so they run regular. That is why I was wondering if both Motorhead and Tree Farmer were both right, that maybe it was possible with differing engines. All of the above mentioned vehicles are all stock, no mods what so ever, which is why I was curious. Thanks for the thoughts though.

Happy trails!

Mike

 

It sounds to me like everybody is on the right track here but there are a few scewed ideas. Octane does not cause fuel to burn slower. It does however; keep fuel from igniting, if that makes any sense. Any fuel, when placed under a great enough amount of pressure, will ignite without the aid of a sparkplug. This is the way that a deisel runs. No spark. The lower octane fuels (87) in a combustion engine with over 9:1 is on the edge of being too low for that engine. The fuel actually ignights prior to the piston being at TDC and before the plug fires. When you lug an engine, you are forcing more fuel and air into the combustion chamber which creates, effectively, a slightly higher compression ratio, therfore causing it to "ping". Higher octanes insure that the fuel doesn't ignite by compression before the plug fires. The reason race cars burn higher octanes is because they have to. If your comp ratio is 12 or 13 to 1 or even higher, and you try to burn 87 or 89, it will rattle like it's got a busted crank.
you guys that are talkin about av gas are compairing apples to oranges.

 

I beleive that the post above me explained why the extra octane was needed in my brothers situation.I cant ever recall stating that pinging could not be related to the load you are carrying.In fact,it has to be.Why else would the pinging stop after adding the Octane booster?

I certainly wont say that your findings are inaccurate either.I sure would like to read some documention on your findings though.So far,everything I read does not support your findings about Octane improving ALL engines HP ratings.Im not an expert,and im willing to learn.If you find any helpful documents verifying your comments on higher octane increasing all engines HP ratings,I'd love to read it.====BILL

 

All this talk about big V8 motors. Are we forgetting that most all quads are single cylinder. Therefore; with 100% power coming only every fourth stroke it can't very well be compared to an 8 cylinder engine. The individual who noticed the jump from 240hp to 255hp, figure out how to hook that neat gadget up to a quad and let us know how it comes out.