I thought Stoich was just the best ratio for emsions, the most complete burn happens at a leaner ratio, right?

 

Best emissions and complete burn are one and the same

"Stoichiometric or Theoretical Combustion is the ideal combustion process during which a fuel is burned completely. A complete combustion is a process which burns all the carbon (C) to (CO2), all hydrogen (H) to (H2O) and all sulfur (S) to (SO2). If there are unburned components in the exhaust gas such as C, H2, CO the combustion process is uncompleted."

 

OK, Here's another one:

At a given A/F ratio what are factors that contribute to detonation, and how can that detonation be controlled without reducing power dramatically ??

 

leaner than 13:1 seems to raise heat rapidly and heat is a huge part of detonation, not just timing. I can run 4 more degrees of timing in the winter just from iat's being lower. Detonation is controlled primarily through 3 things
1.timing: more efficent heads need less timing and can run higher compression on lower octane our heads are a great example of this. Mean max timing wot NA seems to be around 26 degrees, anything over that drastically increases detonation chances and reduces gains. Where as look at older style heads like those on a 302 ford motor and they are running 30+ wot for max power.
2.Controlling heat: this is done by head material-aluminum is a great example disipates heat fast, coolant flow in our engines is diverted to the heads first before going through the block
3.Fuel:afr issue which everyone knows fuel has a big cooling effect greater than the other cooling factors listed. With a cooler combustion chamber less chance of detonation, more timing
octane rating is huge also for obvious reasons
Meth injection is a great way to control detonation without sacrificing power any type of engine can use it(including diesels) and it addresses 2 or the 3 reasons I look at for detonation.

 

So...A/F ratio as it applies to timing question:
Do you tune for optimal A/F and then increase timing until you get detonation and then back off a little?
On a boosted application from my experience and what I've read, without meth, you can't really get above 20*. In fact my tuner wont go over 18* even though I wasnt seeing any KR. Is that a good method? I was running 11.5 to 11.8 AFR.
Does running a richer AFR allow for more timing (to a point) since the unburned fuel should act as a cooling agent, or no?

 

what if you were to run say 14.7:1 at wot and used water injection to lower temp? water is better as cooling than gas. so then would there be more power to be had?
i just learned alot of crap yesterday about o2 sensors and one thing i learned is that i've been running around with like 11:1 or richer afr for awhile now. and i've been wondering why my truck is a dog lol. so i'm gonna lean it up and go to the dyno saturday.

 

yep your right....before meth/water i was running 11.7 at 18 deg. and now with meth im running same at 26 deg on top with no kr....

 

Yes there would be power to be had if your motor and parts could handle the heat.
it's just too much oxygen burning off. Too hot. To get to that ratio you still only have 1 pound of fuel per 14.7 pounds of air. No matter how ya shake it, meth, water, mix, fuel...it's still 1 LB to 14.7LBs.

On your o2's, you came to this conclusion on stock o2's right? I don't believe you have a WB. That's fine to come to the conclusion of, just be careful as if one thing you are gonna learn, stock o2's are precise at measuring 14.7:1. Not 10:1 to 14:1 or 15:1 to 18:1. They do it obviously, just not precise. Careful careful careful.

 

TTT, this one has been good! Alot of great info inside.

 

So meth alone allowed you to add 8* of timing? All while keeping the safe AFR? Any idea what the power increase was from that? Dyno before and after meth?