Don Terrill’s Speed-Talk

Not even close.

joe 90 wrote:Not even close.

Curious about your explanation. And don't forget the air vs O2 tip

joe 90 wrote:

David Redszus wrote:Since the OP was with regard to O2, I'd like to pose a question.

We know that stoich means a perfect a/f ratio where all the air is combusted with all available fuel.
But a stoich a/f ratio does not produce best power; we need to go slightly richer than stoich.

Why does that work?
If we have already consumed all available air, the additional fuel does not have any air available to burn.
How can it then make more power.

It's because there's 3 different main chemical reactions happening each of which liberates different amounts of energy.
By providing an excess of fuel, you get more of the first and less of the third.

C + 1/2 o2= CO.......most energy.
CO + 1/2 o2 = CO2
H2 + 1/2 O2 = H2O.....least energy

With a lambda of 0.85 you have emissions of H2 and CO due to incomplete combustion but you shouldn't have soot.
If you go richer, you'll have soot too.

More C0 and less C02 releases more heat ?

I have noticed the AFR reading lean out with added timming,,,,is the timming affecting the efficiency ????

Firedome8 wrote:I have noticed the AFR reading lean out with added timing,,,,is the timing affecting the efficiency ????

Eeyup.

I always through to "consume all the air" you need to be a bit rich of stoic due to it being a non homogenous mixture

digger wrote:I always through to "consume all the air" you need to be a bit rich of stoic due to it being a non homogenous mixture

You're heading into deep water there.

Firedome8 wrote: More C0 and less C02 releases more heat ?

Yes.

The Radius Kid wrote:

Firedome8 wrote:I have noticed the AFR reading lean out with added timing,,,,is the timing affecting the efficiency ????

Eeyup.

Hm, depends on how that added effiëncy is arrived at. I have observed that same thing. What I see at the same time is that my mafs are flowing less air, which contradicts higher effiency due to better breathing.
My reasoning here is that due to more ignition timing, the pressures in the cylinder are higher when the exhaust stroke starts, so they get out better with the charge going down the exhaust creating more of a suction effect and better cleaning out the cylinder of residual exhaust fumes which dilute the incoming mixture less.
As always the problem is how much is a good thing and when does it become negative.

Belgian1979 wrote:

The Radius Kid wrote:

Firedome8 wrote:I have noticed the AFR reading lean out with added timing,,,,is the timing affecting the efficiency ????

Eeyup.

Hm, depends on how that added effiëncy is arrived at. I have observed that same thing. What I see at the same time is that my mafs are flowing less air, which contradicts higher effiency due to better breathing.
My reasoning here is that due to more ignition timing, the pressures in the cylinder are higher when the exhaust stroke starts, so they get out better with the charge going down the exhaust creating more of a suction effect and better cleaning out the cylinder of residual exhaust fumes which dilute the incoming mixture less.
As always the problem is how much is a good thing and when does it become negative.

Which efficiency are you referring to? Breathing or combustion?

Firedome8 wrote:I have noticed the AFR reading lean out with added timming,,,,is the timming affecting the efficiency ????

Change in EGT from change in timing changes the displayed AFR on the WB.


They're NOT very acccurate.

So how accurate are they ?

joe 90 wrote:

Firedome8 wrote:I have noticed the AFR reading lean out with added timming,,,,is the timming affecting the efficiency ????

Change in EGT from change in timing changes the displayed AFR on the WB.


They're NOT very acccurate.

I`d be a lot more concerned with it´s accuracy, if it didn`t....

The Radius Kid wrote:

Belgian1979 wrote:

The Radius Kid wrote:
Eeyup.

Hm, depends on how that added effiëncy is arrived at. I have observed that same thing. What I see at the same time is that my mafs are flowing less air, which contradicts higher effiency due to better breathing.
My reasoning here is that due to more ignition timing, the pressures in the cylinder are higher when the exhaust stroke starts, so they get out better with the charge going down the exhaust creating more of a suction effect and better cleaning out the cylinder of residual exhaust fumes which dilute the incoming mixture less.
As always the problem is how much is a good thing and when does it become negative.

Which efficiency are you referring to? Breathing or combustion?

breathing