KDXRIDER.NET

One more time...all together now!!

From:
http://www.contactmagazine.com/Issue54/ ... asics.html

Confusion and a lot of questions exist as to detonation and pre-ignition. Sometimes you hear mistaken terms like "pre-detonation". Detonation is one phenomenon that is abnormal combustion. Pre-ignition is another phenomenon that is abnormal combustion. The two, as we will talk about, are somewhat related but are two distinctly different phenomenon and can induce distinctly different failure modes.

I could be wrong about my point of view...but I'm not.

See how this works? Bet'cha wish I'd stayed in my hole, 'eh?

**edit**
A btw, by the way:

'Incidentally, the knocking or pinging sound is not the result of "two flame fronts meeting" as is often stated.'

I've heard this a thousand times if I've heard it a hundred. OK..so I've heard it a couple dozen times. The old 'flame fronts colliding' is bogus. It was bogus last time you heard it. It will be bogus the NEXT time you hear it.

Cheers!

**edit agin**

That link is great! More/better information explained more clearly than I've seen. READ IT!!

It is a good article but they need to throw some pics in there.... I about fell asleep a couple of times!

I took power mechanics in High School but they never taught this stuff.

There are alot of points made in the article that supports alot of my theories.... especially the one about lower octane fuel has more energy than high octain fuel! So... nah,nah, na, nah, nah!

It doesn't say that in those words because I don't use the same words but it is in there!

quote:

"Now our engine was initially designed for premium fuel and was calibrated for 20 degrees of spark advance. Suppose we put regular fuel in the engine and it spark knocks at 20 degrees? We back off the timing down to 10 degrees to get the detonation to stop. It doesn't detonate any more, but with 10 degrees of spark retard, the engine is not optimized anymore. The engine now suffers about a 5-6 percent loss in torque output. That's an unacceptable situation. To optimize for regular fuel engine designers will lower the compression ratio to allow an increase in the spark advance to MBT. The result, typically, is only a 1-2 percent torque loss by lowering the compression. This is a better trade-off. Engine test data determines how much compression an engine can have and run at the optimum spark advance."

You might be asking yourself... Where does it say that?

Well... by lowering the compression and running lower octane fuel.... you can get acceptable performance from low octane fuel.

Purdy interesting....

Love the article CC!

Heavens to Mergatroid....

It says no such thing!!

It does NOT say lower octane fuel has more energy per volume that does a higher octane fuel per same volume. (you said that)

BTW...I'm not saying that is not true..I'm saying the article does not SAY that. Kerosene has considerably more energy per volume than does gasoline..but its octane rating is WAY lower.

It SAYS that an engine OPTIMIZED for premium fuel will NOT run well on REGULAR (lower octane) fuel.

BUT..you can indeed OPTIMIZE for regular fuel and you will get MORE power from an OPTIMIZED FOR REGULAR engine running regular than you will an OPTIMIZED FOR PREMIUM engine running regular.

Nowhere is there a comparison between an OPTIMIZED FOR PREMIUM engine running premium and an OPTIMIZED FOR REGULAR engine running regular.

In each and separate case, the engine is tuned to MBT.

Compression makes power..that's why people do it. It all has to fit together, though. You won't find the same compression ratios in a supercharged diesel that you will in a supercharged gasoline engine, because the two are completely different animals.

You don't build an engine and go looking for a fuel to run it with. A sensible builder will KNOW HIS FUEL to START WITH and build his engine accordingly...to fit...to match.

Obviously you DID go to sleep a couple of times at least!

So...neener neener neener

I accept all apologies for the term 'pre-detonation' ever being written aloud on this board!!

canyncarvr wrote: You don't build an engine and go looking for a fuel to run it with. A sensible builder will KNOW HIS FUEL to START WITH and build his engine accordingly...to fit...to match.

This is very true. The IMSA Ferrari team engine guy named Mr. Ferrari actually designed the 333SP engine according to the specs (actual chemical make-up blend) of the racing fuel used in the IMSA WSC series.

And...the chassis was designed around the specific sanctioned Pirelli tires we used.

I love yankin' yer chain CC!

My reasoning is this... Only losing 1-2 percent torque from a lower compression, lower octane motor means to me that the lower octane fuel has more energy and give very acceptable performance vs. a high compression , high octane motor!

Back in the day, I had a Ford Torino with a low compression 400 with a C-6 that would run like a striped @ss ape on 87 octane. Smoked many so called muscle cars of the day.....

OK... Here's my plan. Run lower octane gas, add 8% Toluene which has the effect of raising the octane rating to anybody's acceptable level.
I just like the way it works.... whatever it is doing.

Toluene is a pure hydrocarbon (C7H8). i.e. it contains only hydrogen and carbon atoms. It belongs to a particular category of hydrocarbons called aromatic hydrocarbons. Complete combustion of toluene yields CO2 and H2O. There are no metallic compounds (lead, magnesium etc), no nitro compounds and no oxygen atoms in toluene. It is made up of exactly the same ingredients as ordinary gasoline. In fact it is one of the main ingredients of gasoline.

Toluene has a RON octane rating of 121 and a MON rating of 107, leading to a (R+M)/2 rating of 114. (R+M)/2 is how ordinary fuels are rated in the US. Note that toluene has a sensitivity rating of 121-107=14. This compares favorably with alcohols which have sensitivities in the 20-30 range. The more sensitive a fuel is the more its performance degrades under load. Toluene's low sensitivity means that it is an excellent fuel for a heavily loaded engine.

Toluene is denser than ordinary gasoline (0.87 g/mL vs. 0.72-0.74) and contains more energy per unit volume. Thus combustion of toluene leads to more energy being liberated and thus more power generated.

There is more energy in lower octane gas however so slight it may be!

great article CC.

uh , let's keep the details straight here....

I believe it is spelled MURGATROYD.

Sheeesh.

Exit...stage left!

I'm a 'right' kind'a guy myself.

Sorry, Mike, for the error!

Inda....give me some facts for the toluene as far as energy. I've only found btus per pound, and my iffy multiplication makes it LESS than pump gasoline, figuring just over 7+lbs per gallon. That's a guess, actually. Certainly it's less than WATER..and that's 8-something.

Yep, toluene is an aromatic hydrocarbon. AND it does work great in my bike..even as low as 5%. I run a mix of toluene and Trick race gas (114 octane), and it does a great job! The folks following me don't care for the smell, much. Tends to give them a headache. Oh well. I'm in front of my own stink, so I don't care!

PULL MY FINGER!!

To tell the truth, I've been using some cherry 'flavored' goo Ski gave me to make 'em happy.

Did you get to (afore you snored) the part that says hemi's are lousy? Obviously, he hasn't been watching the Dodge commercials on the toob! But..it was written in distant history, so...maybe he's just uninformed.

Seriously, the whole dome-topped piston in a hemi head is an excellent explanation of 'stuff'.

But..WE have a flat top in a hemi head...so....we're good!!

Uh..maybe I need some training sensitivity-wise..but what's that term about? It's not related to PRE-sensitivity, is it?

Oh no!

Toluene is denser than ordinary gasoline (0.87 g/mL vs. 0.72-0.74) and contains more energy per unit volume. Thus combustion of toluene leads to more energy being liberated and thus more power generated. This is in contrast to oxygenated octane boosters like ethanol or MTBE which contain less energy per unit volume compared to gasoline. The higher heating value of toluene also means that the exhaust gases contain more kinetic energy, which in turn means that there is more energy to drive turbocharger vanes. In practical terms this is experienced as a faster onset of turbo boost.

How the energy of a given fuel is measured...

http://www.faqs.org/faqs/autos/gasoline-faq/part1/

"I accept all apologies for the term 'pre-detonation' ever being written aloud on this board!!"

Thank you "CC" for that comment, A men to that !

This is why I try to give the best results with the current so called gas availably in this every day changing blend of pump gas with all my mods.

Now for all of you that want to play with different fuel combos, I have a good one foy you........??? (stay tune)

I am not an expert or an engineer in this but have 30 years experience of mixing and tuning with different blends of fuel and engine types.

Everyone is looking on the net and quoting others research on this topic?, but I really don't think you even know what they are saying or have practiced it your selves.

Thank you,
Ron

Hence the discussion!

Trying to get this stuff in the open so all the myths and misinterpetations can be dispelled is not a bad thing.

I have only dabbled in fuel since I don't have the time or toys to experiment with. But, I do want know about it and I am not much of a "go find a book guy", so the internet is my best and worst friend.

canyncarvr wrote:PULL MY FINGER!!

OK...

BUT PULL MINE FIRST !!!

I think Ron is about to tell us a secret......

Bradf uses an olive in his!

Hey! I take exception to the 'don't know what they are saying..' The link above made more sense to me about more things than most others I've read. I'd never heard or seen the term 'MBT'. Maybe he made it up? I dunno..but it makes sense. Just 'cuz it makes sense doesn't make it so, I suppose.

I thought the part about the hemi was interesting. It's something I have always wonderered about. Having a domed piston sticking up into a like shaped head never made sense to me.

One thing is pretty much a given. When you get into the chemistry of fuels...indeed I get lost quick! I do know enough not to trust what's 'common knowledge'.

Like...'Race gas. Good!' Uh...no. In the first place there are so many different kinds/types/blends of 'race gas' the term by itself doesn't mean anything.

It was Ron that suggested toluene way back. Now there's a treat!! That stuff is wonderful!! What a blast to ride with a dose of toluene in your fuel!

Now...if I could find a 35 gallon drum for $70..THAT would be a REAL treat!!

Amen

Ron hit the nail on the head with Toluene. The stuff is fantastic even though the hardware store employees look at you like your a drug dealer when you buy it.

Well you are feeding your crack habit...LOL

Curious...are you relating density to energy? You did say 'more dense and...'. That does NOT say more dense=more energy.

Was that your meaning, though?

Note that xylene is more dense than toluene btw.....

http://www.simetric.co.uk/si_liquids.htm

What energy is released when gasoline is burned?

It is important to note that the theoretical energy content of gasoline
when burned in air is only related to the hydrogen and carbon contents.
The energy is released when the hydrogen and carbon are oxidised (burnt),
to form water and carbon dioxide. Octane rating is not fundamentally
related to the energy content, and the actual hydrocarbon and oxygenate
components used in the gasoline will determine both the energy release and
the antiknock rating.

Two important reactions are:-
C + O2 = CO2
H + O2 = H2O

Coincidentally.. that is exactly what is released when Toluene is burnt, nothing more, nothing less.
Of course... this is only what I have read and should in no way be considered fact unless you also know this to be true too!

Ok. Fine...

That didn't answer my question about density.

OK...here's what I was getting to.

First off..and btw, no. Octane is not related to energy content.

Diesel is considerably more dense than pump gas. It has considerably more energy per volume than pump fuel, too.

Toluene is more dense than pump gas. I don't know for sure about the energy per volume with it. I believe it has more than pump gas, but I haven't seen any numbers to 'prove' that..or not.

The kicker of the whole thing? Water. It is more dense than pump gas, diesel, toluene, xylene, JP-1..all that stuff.

I suppose it does have more energy than any of that other stuff..if you can get the hydrogen out easily, but you're not going to get a whole lot of energy trying to burn it in your bike.

That was the point. More dense does not mean more energy (in liquids..used as a fuel run thru a carbonator).

Actually CC... there was talk of a high performance fuel that was going to go into production that was 60% water and 40% Toluene.

Now if that doesn't bunch yer panties... I don't know what will!

The whole density comment was a BTW statement. Not meant to make a blanket statement about any substance.