I was just reading in the wiki today and here is what was stated

"If gasoline is run at its preferred maximum power air/fuel mixture of 12.5:1, it will release approximately 20 MJ (about 19,000 BTU) of energy, where ethanol run at its preferred maximum power mixture of 6.5:1 will liberate approximately 25.7 MJ (24,400 BTU), and methanol at a 4.5:1 AFR liberates about 29.1 MJ (27,650 BTU)."

So why would a leaner mixture make more power??

link http://en.wikipedia.org/wiki/Octane_rating

 

it depends on how rich ur trying to go. the better the mixture is the more efficent it is which inturn will create a better overall burn.


Modified by cartune network at 6:15 PM 10/4/2007

 

well here is another thought, with a finer atomization, it will detonate easier?? make more power with less timing?? need less compression??

 

Go read that **** again, you are 180 degrees off. 4.5 -1 is RICHER than 12.5 -1. Ethonal and methonal burn cooler than gasoline, theirfore less resistant to detonation and can run higher compression ratios. At least do a 9th grade investigation into fuels and 4 cycle engines.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by DonF &raquo;</TD></TR><TR><TD CLASS="quote">Go read that **** again, you are 180 degrees off. 4.5 -1 is RICHER than 12.5 -1. Ethonal and methonal burn cooler than gasoline, theirfore less resistant to detonation and can run higher compression ratios. At least do a 9th grade investigation into fuels and 4 cycle engines. </TD></TR></TABLE>

let me elaborate a bit I guess...why do we try and tune our cars for a 13.2 or so when 12.5:1 is said to make most heat with gasoline?? I am not concerned about ethanol or methanol....I am not building a motor to suite either....

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by DonF &raquo;</TD></TR><TR><TD CLASS="quote"> At least do a 9th grade investigation into fuels and 4 cycle engines. </TD></TR></TABLE>

Ouch. No wonder people are scared to post technical questions on this allmotor section..

 

bump for a response

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by BolivianFuego &raquo;</TD></TR><TR><TD CLASS="quote">

Ouch. No wonder people are scared to post technical questions on this allmotor section.. </TD></TR></TABLE>

Because we have some of the best in the nation at our fingertips

 

I didn't bother reading that link, but I know from past gasoline tests and cobustion theory of "gasoline", that a stoichiatric mixture of 14.7 will have the highest energy output. In this case, energy is in the form of heat. In real world test conditions, this number will be approximately one point richer, around 13.5:1 due to the dynamics of the induction. There is a local Shell refinery that published some SAE papers a while back, and that is what I gathered from the information.

For comparison, methanol has a stoichiatric mixture of 6.5:1 and nitromethane is rougly 2:1.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 92TypeR &raquo;</TD></TR><TR><TD CLASS="quote">I didn't bother reading that link, but I know from past gasoline tests and cobustion theory of "gasoline", that a stoichiatric mixture of 14.7 will have the highest energy output. In this case, energy is in the form of heat. In real world test conditions, this number will be approximately one point richer, around 13.5:1 due to the dynamics of the induction. There is a local Shell refinery that published some SAE papers a while back, and that is what I gathered from the information.

For comparison, methanol has a stoichiatric mixture of 6.5:1 and nitromethane is rougly 2:1.</TD></TR></TABLE>

so per Shell, the Wiki Article is wrong?? What you are saying makes more sense to me but I am just doing some research and came across this....wanted to see the thoughts of some of our premier motor builders....I know I have seen 13.5 make more than 12.5 on the dyno....

 

Sometimes what works in theory does not work exactly as predicted in the real world.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by b19coupe &raquo;</TD></TR><TR><TD CLASS="quote">Sometimes what works in theory does not work exactly as predicted in the real world. </TD></TR></TABLE>

dont say that! you will get flamed by the book worm physicist/mechanical engineers we got here...

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by b19coupe &raquo;</TD></TR><TR><TD CLASS="quote">Sometimes what works in theory does not work exactly as predicted in the real world. </TD></TR></TABLE>

I agree and believe this is the best explanation....I saw this though and had to ask...

I was actually in the hunt for maximum cylinder pressure for a gasoline motor...what should I search for??

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by DonF &raquo;</TD></TR><TR><TD CLASS="quote">Go read that **** again, you are 180 degrees off. 4.5 -1 is RICHER than 12.5 -1. Ethonal and methonal burn cooler than gasoline, theirfore less resistant to detonation and can run higher compression ratios. At least do a 9th grade investigation into fuels and 4 cycle engines. </TD></TR></TABLE>

use toilet paper, not sandpaper

it depends on what the motor asks for. Put the engine on the dyno and figure out what it likes the most. Some motors like to run a little rich and will get more power that way. Others, such as stock motors or motors with mild compression can/will gain from leaner conditions.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 98vtec &raquo;</TD></TR><TR><TD CLASS="quote">use toilet paper, not sandpaper

it depends on what the motor asks for. Put the engine on the dyno and figure out what it likes the most. Some motors like to run a little rich and will get more power that way. Others, such as stock motors or motors with mild compression can/will gain from leaner conditions.</TD></TR></TABLE>

I agree!! That is what everyone tunes for I would think. What would make certain motors like richer conditions though?? Would it be the flow of the motor??

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by clean rice &raquo;</TD></TR><TR><TD CLASS="quote">

Because we have some of the best in the nation at our fingertips </TD></TR></TABLE>

I dont think that gives reason though to act like a jerk to someone who is willing to learn. Correct them in a better way, show some class.

Reminds me of these SNL skits. LOL
http://www.youtube.com/watch?v=uNEJHpThhH8

 

awesome!!!

you shouldnt try and keep others from learning....that is what a forum like this is for anyhow isnt it??

 

Yeah show some freakin class

"Bolivian Honda-Tech Member #1 Punishing Girls in the A-HoleJust Killing The Competition"

"Residing behind your *******"

LOL.

I think I infected Don with a severe case of "Fuckuitis" Doh.

Technically the benefit of the alcohol is it's cooling/high octane properties so you can benefit from the use of sky high CR.

 

I'm no chemist but this is how I understand it.
Please someone else chime in if they know more

Theory

Fuel + O2 = CO2 + H2O (14.7 AFR)

Actual

Fuel + O2 = CO + O +H2O (Richer Possible)

Because combustion is such a variable & violent process some of the C02 is broken down into CO & 0. The additional Oxygen (oxidizer) released in the products of combustion allows the addition of more fuel hence a richer than 14.7 mixture.
Again this is somewhat simplified, but may answer you question.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Master of the Universe &raquo;</TD></TR><TR><TD CLASS="quote">Yeah show some freakin class

"Bolivian Honda-Tech Member #1 Punishing Girls in the A-HoleJust Killing The Competition"

"Residing behind your *******"

LOL.

I think I infected Don with a severe case of "Fuckuitis" Doh.</TD></TR></TABLE>

Riiiiight Mr. Rocket or shall i say internet god. Thats just a funny little quote, does that take away members from learning on this forum? I dont think so. Just might leave them with a smile on their face, not a frown from being made to feel like a dumb inferior POS. Besides you know deep down inside you want to give me a hug for that quote.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Master of the Universe &raquo;</TD></TR><TR><TD CLASS="quote">Yeah show some freakin class

"Bolivian Honda-Tech Member #1 Punishing Girls in the A-HoleJust Killing The Competition"

"Residing behind your *******"

LOL.

I think I infected Don with a severe case of "Fuckuitis" Doh.

Technically the benefit of the alcohol is it's cooling/high octane properties so you can benefit from the use of sky high CR.</TD></TR></TABLE>

Rocket, add to the thread man!! you are one of the "heavy hitters" Put something useful in the thread for the crowd.... I know you know something about this subject

 

Want some good insight?

Does the CR effectively increase if you put more fuel in da chamber?

DOH!!!!!!

Try to get that knowledge from "journalistic type" gurus.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by BolivianFuego &raquo;</TD></TR><TR><TD CLASS="quote">

Riiiiight Mr. Rocket or shall i say internet god. Thats just a funny little quote, does that take away members from learning on this forum? I dont think so. Just might leave them with a smile on their face, not a frown from being made to feel like a dumb inferior POS. Besides you know deep down inside you want to give me a hug for that quote. </TD></TR></TABLE>

Glad you took it like a man and are not "butt hurt"

I'll put in a good word for you so Don won't kick your ***.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by pomansouth01 &raquo;</TD></TR><TR><TD CLASS="quote">

Rocket, add to the thread man!! you are one of the "heavy hitters" Put something useful in the thread for the crowd.... I know you know something about this subject </TD></TR></TABLE>

he's too afraid that someone will find out the secrets of "his" honda universe.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Master of the Universe &raquo;</TD></TR><TR><TD CLASS="quote">Want some good insight?

Does the CR effectively increase if you put more fuel in da chamber?

DOH!!!!!!

Try to get that knowledge from "journalistic type" gurus.</TD></TR></TABLE>

well more stuff in the same amount of space says it has to be compressed tighter....but doesnt mean it will burn hotter....more on this topic please??