# Thread: e85 and using a gas wideband

1. ## e85 and using a gas wideband

If we are using a gas wideband and e85,

What would the ideal afr be for idle and wot?

Say if we're getting 14.1 afr idle and 12.0 afr WOT, is that close to ideal?

2. E85 has a differnt stoichiometric mixture
E85 = 9.765 as apose to normal pump gas being 14.7
wot with E85 you want your target AFR to be around 6.9

3. Don't you have to set your AFR gauge to run with different parameters. I know my MTX-L can be set to measure different fuel types (inc E85). Or can you use the normal gasoline setting and tune richer?

Originally Posted by westy
E85 has a differnt stoichiometric mixture
E85 = 9.765 as apose to normal pump gas being 14.7
wot with E85 you want your target AFR to be around 6.9

4. Yeah its got 2 settings... hmmm

But stoich is still 14.7 with e85 running on 'gas' setting though isnt it??

5. Yes if you do not change the calculation then you would read for gasoline.

The measurement Lambda is the actual air fuel ratio over the stoichiometric ratio. A Lambda
measurement of “1” equates to the air fuel ratio of 14.7 (for gasoline engines). When Lambda is
less than 1 the engine runs “rich”, i.e., unburned fuel exists in the exhaust stream. If lambda is
greater than 1 the engine runs lean, i.e., free oxygen (02) is present in the exhaust. Depending on
the engine, maximum power is typically delivered when the engine runs slightly rich (for example
at lambda values of 0.8 to 0.9 for most engines). This instrument provides a means to measure
the actual air fuel ratio or lambda in the engine in operation directly from the exhaust. For this a
special wide-band oxygen sensor is used to measure the lambda value derived from the oxygen
content (or lack thereof) of the exhaust gases
Gasoline 14.7
LPG (Propane) 15.5
Methanol 6.4
Ethanol 9.0
CNG 17.2
Diesel 14.6

6. lolzer
yes using gas setttings you can use gas numbers but with the higher octane and cooler charge (than gas) you can run leaner
IMO 12-12.5 wot afr

7. ## +1 by:

8. Originally Posted by beerdart
Yes if you do not change the calculation then you would read for gasoline.

The measurement Lambda is the actual air fuel ratio over the stoichiometric ratio. A Lambda
measurement of “1” equates to the air fuel ratio of 14.7 (for gasoline engines). When Lambda is
less than 1 the engine runs “rich”, i.e., unburned fuel exists in the exhaust stream. If lambda is
greater than 1 the engine runs lean, i.e., free oxygen (02) is present in the exhaust. Depending on
the engine, maximum power is typically delivered when the engine runs slightly rich (for example
at lambda values of 0.8 to 0.9 for most engines). This instrument provides a means to measure
the actual air fuel ratio or lambda in the engine in operation directly from the exhaust. For this a
special wide-band oxygen sensor is used to measure the lambda value derived from the oxygen
content (or lack thereof) of the exhaust gases
Gasoline 14.7
LPG (Propane) 15.5
Methanol 6.4
Ethanol 9.0
CNG 17.2
Diesel 14.6
+1. Just run a/f like gasoline. Fwiw, ill be running wot @ 11.5 in my ski, just as I did on my evo

9. ## Re: e85 and using a gas wideband

Or you can switch the wideband to display lambda so you will have the same number no matter what gas you use.