After doing a lot of testing and research with this gas, and hearing of people's complaints of poor fuel economy, and poor running vehicles I have found a fix.

Because Sunoco Gas has 10% ethanol, the vehicle will actually be running leaner and the 02's will overcompensate for this and add extra fuel resulting in poor milage and drivability issues

Stoich for straight gas is 14.64:1 and gas/10% ethanol mix is 14.13:1. 02 sensor's have the ability to switch around any stoich point. but from the factory, is set to switch at 14.64 We have found that it is possible to switch the stoich point in the pcm to 14.13 and tune for the 10% ethanol mix in sunoco gas. This will allow the 02's to switch around the proper stoich/lambda point.

WOT AFR's will now change in the same way. Remember, AFR is just a math equation based on a lambda value. WOT AFR should be 12.0, or a lambda value of .82 (assuming straight gas). The lambda value of .82 with a 10% ethanol translates into 11.58AFR (14.13*.82=11.58) this will be the optimum AFR for a power adder vehicle.

Wideband airfuel meters come with a transfer function assuming you are running straight pump gas. They detect lambda and preform a calculation displaying an AFR. Because the wideband still has a pump gas transfer function the lambda value of .82 will still display as 12.0. Some wideband's can have their transfer function adjusted accordingly to display the proper AFR values based on stoich/lambda.

Just a bit of tech info for everyone

Sometimes I can write in a fury and I hate reading over my posts. If anything is confusing, i will be happy to clear things up

 

Is this just a canadian thing? I don't seem to have any issue's running sunoco 94 compared with my BP amoco 93. I can't tell the difference.

 

Being in the motor city, you will be effected by the addition of 10% ethanol to your gas. Some states have already started the transition.

 

since 04 1/3 of the nation had E-10...now almost all states are and will be 100% very shortly.

i am not all for it...

 

sunoco 94 works best in my car

 

Yeah, just as I switched to Sunoco 94, they added 10% ethanol and dropped the octane rating to 93 in my area. My fuel mileage did drop very slightly since. I lost about .7mpg. It's not my imagination. I do know ethenol has less fuel mileage potential, compaired to straight gasoline, but you do obtain more power from ethanol.

 

As soon as you go to stage 2 or higher, running this seems to be actually better for your car. If your quite concerned you can try finding some 104/105 and adding it in 1 part for 5 parts 94 and see if that clears up the problem.

- Solo

 

because the higher octane point is less prone to knock, the knock sensor advance and advance rate will be at max. values.

performance wise, this is the best pump gas

 

ya I run 20psi with 21 deg advance at 7000rpm on 94 octane...it does the job lol

 

Yes I agree with what you are saying. I have to pay more for the ethanol blend and put up with worse gas milage. When you look at stociometric though don't you have to consider the addition of MBTE that was formerly used. As you know MBTE is an oxygenate just like ethanol and was originaly used to lean out carburated engines for emisions purposes.

Pierre

 

Another reason that you will have less mileage with the ethanol in the fuel is because ethanol only has about 66% of the energy content as gasoline. Ethanol should however raise the octane of the gasoline. E85 (85% ethanol) has an octane rating of 105.

 

So on my current tunes, would it be better to go for the Sunoco 94, or a BP 93? Mostly I'm concerned about engine life, so which would be safer do you think? Should I go for a retune? Currently I'm tuned for Sunoco 94.

 

cobra ! Long time no speak dude. Hey we are all going to Milan Friday you should come. Also as far as 94 my car runs a little better but I do get **** gas mileage only because when I put 94 in I am usually on my way to a race lol

 

The Stoich point of 90% Gas and 10% Ethanol (that is currently at the pumps or making its way to the pumps) is 14.13. To my understanding there is no methyl tertiary-butyl ether in the gas. MBTE (MTBE) has been discussed as an alternative to ethanol because it is less volatile but has many drawbacks.

I just thought i should post some of this info to shed some light on the topic. a lot of people do complain about milage or drivability

 

higher octane is safer...i only run sunoco 94 in my redline

 

They took MBTE out and added ethanol because of ground water contamination issues. We have had MBTE for years here in the North East. We have not had pure Gasoline in years. You may not have had it in canada though.

Pierre

 

Yah i only run 94 in my SS.

 

Apparently all I can use is 94 as well

 

damn straight that is all u can use

 

I wish I could go tomorrow, but I'm busy. I just put on a nice looking 3.15 billetflow pulley, and will be getting a stage 1 tune shortly. So I will be looking to go to the track soon!

 

hey, 1stbluss, I plan on meeting everyone at the parking lot around 2:45. Also, I have a spare engine mount that I painted arrival blue that I am bringing with me. It really looks sweet. I think I am going to ask about $80 for it.
Mike