Lets see if I can cause some trouble...

[IMINHELL]

I want a civalised debate and you have to provide either some real world experience or a crediable web site to back your claims.

First try to answer some questions:

1. what is the benifit of tuning a cars AFR to a rich limit at WOT (if any)?
(don't need a source yet)

My answer to 1 is this: there is no benifit. all your doing is wasting gasoline, lowering your fuel mileage and spending more of your hard earned money. you gain zero power from over fueling your engine.

Now whats your answer. (Alot of reading material will follow, be warned)


John

[focinite]

well at wide open a natural richning(slight though it may be) will ocur. i like to keep it just a touch over stoich, the power you give is the motor you save. lean is never a good thing, LEANING the mix is how you get power, but lean means burnt heads and pot holed pistons. now when spraying if you go to rich it will get into the rings and blow yer piston top off. i dont know how to answer correctly its a hard one to get.. i like to error on the safe side buti know a leaner mix at the top end makes more power. to rich and you do more than waste fuel, it will start to wash the piston out. so its one of those deals, run it how ya wanna run it.

[sc0tty8]

Richer afr also acts to prevent detonation/pinging due to the air charge being too hot such as in a boosted car.

Running lean generally=hotter burn=burnt rings n shit.

Whats the next q?

[IMINHELL]

Ok. Well the self ignition temerature of gasoline (on average) is 575*F. So it is not the initial air charge temp one must worry about so much. It is the temp rise from compression. Higher compression mean a faster temp rise.

Lean burns do make more power and save more fuel. The down side is they also burn hotter. So why do mfg. and tunners always plan for a rich mixture. Why don't they build with better alloys that resist temp more? or make a better cooling system that can take the heat gain of the head away in milli seconds?

See this is part of my whole bitch about the auto industry. All they ever do is compromise. I have yet to see any "innovation" from Ford, Chevy, Dodge, ect.

John

[IMINHELL]

Some reading material:

Auto ignition Temprature chart

Gasoline Problems

Combustion Variations

Citgo Unleaded Fuel MSDS

Exhaust Emissions

The Combustion Research Group

Detonation and Pre-Ignition

All About Knock

The Gasoline FAQ

What Is Stoichiometry

Metling Point of Various Metals

Shock Temprature of Iron

Shape Memory Alloys


(I love reading stuff like this )


John

[98gsxltd]

i really like where this thread is going, and it doesnt have all the bs posts like some other sites!

[sc0tty8]

i really like where this thread is going, and it doesnt have all the bs posts like some other sites!

Kinda why John left FJ. I hardly go there anymore myself.

And john, they always run a touch rich for "safety", to ensure reliability, especially the oem's, why do you think that so many mail order tuners claim that their tune will increase performance. I know the lincoln ls v8 comes out of the box tuned farly agressive, enought that most mail order tunes for them do them more harm then good.

And John, for someone on dialup you sure do a lot of crusing on the net lol...