Carburetor tuning

[Kern Dog]

Well, some of THAT is above my head....
My AEM gauge reads in the mid 14s at cruise with 10% ethanol so I'm running a tad lean but it richens up FAST with light throttle.
When I have reduced jet size, I lose power and the numbers don't change much, if at all. Is that an issue with the accelerator pump shot being too strong?

 

[INTMD8]

If your wideband is on a gasoline scale so 1.0 lambda equals 14.68 on the gauge, you are not running lean at mid 14's.

Doesn't matter if you have zero percent ethanol or 10%. If 1.0 lambda equals 14.68 then mid 14's is stoich no matter what fuel is in the tank.

Only way mid 14's would be lean is if the gauge was -calibrated- to E10, 1.0 lambda = 14.1

 

[Kern Dog]

My only understanding of "lambda" is the fraternity in "Revenge of the Nerds".

 

[INTMD8]

Some calibrate in lambda so you don't have to think about the stoichiometric value of the fuel.

If you set your wideband to read in lambda, 1.0 is stoichiometric

A wideband set to gasoline scale will report stoichiometric as 14.68

So if you are running E10 or any amount of alcohol it will still show 14.68 on the gauge when stoich

If you change the calibration of your gauge to report 1.0 lambda as 14.1 air fuel to match the E10 in your tank and go drive your car, it will now show 14.1 instead of 14.68.

You changed nothing but what the gauge displays so the car isn't running lean, it's just not set to the stoich value of your fuel.

 

[Kern Dog]

But what I wrote was funny. Where is your sense of humor?

 

[INTMD8]

Guess you need to try harder

 

[Geoff 2]

Kern,
Go back to what you were doing/method in post #21. It works for you.
Too much importance is placed an A/F ratios that can be far from optimum for a number of reasons: faulty sensors, faulty meter, how that particular carb meters fuel, et.

Acc pump action is fleeting, fuel is gone in an instant.

 

[Some Car Guy]

That guy at FBO is a proponent of manifold vacuum. I'm not so sure about it. I'd need more convincing before accepting it for my own stuff.
What about having vacuum advance at cruise to get a more complete burn? I'd lose that by switching to manifold vacuum, wouldn't I ?
Or....
Would manifold vacuum still work at light cruise?
I agree that it does want to speed up as I crank in more initial timing.

It will be the same vacuum at any point the throttle uncovers the slot. Manifold just doesn’t have the delay feature that ported does.

 

[SlinktRR]

I use ported for the simple reason that my manifold vac port is dedicated to n96 action. PV works well at cruise with my current Holley clone, same as it did for my edelbrocks. Too much heated discussion over air tubes on a carb.