Tuning Info

[MN C5]

How about adding a feature that would allow us to cut and paste images ect.. into the user notes tab or description tab?

I would like to be able to see certain things associated with the various tables when I'm working on them.

Nice info thanks for taking the time.

[Gelf VXR]

Stoich for gasline is published as being 14.68 which is ~14.7.

I assume EfiLive use 14.63 because thats what the PCM uses in closed loop?


I did a search and 14.63, 14.67 and 14.68 are all there, which is it? I couldn't find a scientific based result..

[joecar]

EFILive uses the value of B3601.

[Gelf VXR]

EFILive uses the value of B3601.

E40 doesn't have that calibration, what I mean is that the PCM programming uses the value 14.63 as stoich?

[joecar]

Oh, it doesn't...? In that case I don't know what is used.

[Xtnct00WS6]

I assume EfiLive use 14.63 because thats what the PCM uses in closed loop?


I did a search and 14.63, 14.67 and 14.68 are all there, which is it? I couldn't find a scientific based result..

Through the research I've done, it seems as though the stoichiometric air-fuel ratio for pure gasoline is 14.7:1. The stoichiometric air-fuel ratio for gasoline with 10% Ethanol is 14.63:1.

Can someone confirm that?!

[swingtan]

In the E38 PCM, stoichiometric fuel ratio is set in B3671 which is a table representing AFR vs Ethanol %. If your car is set up for "Flex Fuel" then this table is used to alter the Stoichiometric figure depending on the amount of ethanol in the fuel. If your car is not set up for "Flex Fuel", then I believe only the 0% Ethanol setting is used which in stock form is set to 14.68:1.

Some figures from the table are as follows.....
Ethanol AFR
00.0% 14.68
06.2% 14.32
12.5% 13.97
18.7% 13.61

and skipping to the end....

100% 9.00 ( which is the correct figure for 100% Ethanol )

Given that the B3671 graph is a straight line between 100% petrol and 100% Ethanol, we can probably assume it's correct.

So the stoichiometric ratio for 10% Ethanol is more like 14.09:1. I run 10% ethanol all the time and my car does not have the "Flex Fuel" option, so it's always using the 0% setting for stoichiometric.

[427]

Thanks heaps-

very helpful-

Nick--

[Chevy366]

Great post , good reference .
Have been playing around with this stuff for a few months (10% Ethanol) I used 14.13 for 10% Ethanol in my LS1 PCM . Does make some difference in performance .
I arrived at 14.13 from a more detailed fuel stoich chart .

[odd boy]

Gents,

I tried toluene as an octane booster. It improved the performance and made the car run faster, even when it is hot!!!!!!!!!!