What octane fuel to use?

[kmtalko]

I just hope your not pulling my tail because you want me to wreck my fuel system. Lol

[Fan4Focus]

Yes, do the math and put in the E85 first, then top it off. Don't be concerned if you see a small drop in mileage on the first tank. The computer needs time to adjust for the different O2 level from the ethanol. Be patient and see what you get with the second tank at the same blend. I will definately say my Z-tec likes this blend! I saw better mileage and performance from the first tank with the blend. My son has a ZX3 also with the Z-tec and he is doing this too with the same results.

[kmtalko]

Alright awesome, thanks for the tip.

[zetecDon]

Just a bit of fair warning to you. Be sure to check all information available before you try E85. Not trying to cast any doubt here but most states don't really regulate E85 very well.

[Magus2727]

I always thought that E85 was a less energy dense fuel. It does have a higher octane rating and it does have lower tail pipe emissions. but what benefit would you have? most regular fuels can have up to 10% ethanol anyway (I think recent law passed that made it so if its under 10% they did not need to advertise that it had that % in it...)

So your raising the octane of the fuel in your tank but your also lowering the energy density also. you may see a small drop in MPG. I think most flex fuel vehicles get a way with a slightly higher compression (due to E85 having a higher octane rating) to make up in their power.

I think a report showed that the Escalade vs the E85 and the normal one had a 1-2 MPG difference in its fuel economy. but E85 is sometimes cheaper and has less of a carbon footprint.

[Fan4Focus]

Originally Posted by Magus2727

I always thought that E85 was a less energy dense fuel. It does have a higher octane rating and it does have lower tail pipe emissions. but what benefit would you have? most regular fuels can have up to 10% ethanol anyway (I think recent law passed that made it so if its under 10% they did not need to advertise that it had that % in it...)

So your raising the octane of the fuel in your tank but your also lowering the energy density also. you may see a small drop in MPG. I think most flex fuel vehicles get a way with a slightly higher compression (due to E85 having a higher octane rating) to make up in their power.

I think a report showed that the Escalade vs the E85 and the normal one had a 1-2 MPG difference in its fuel economy. but E85 is sometimes cheaper and has less of a carbon footprint.

It is true that E85 is lower in heat energy. However, in higher compression engines (the Ztec is 9.6:1) you see a slight gain in performance with a blend such as 20%. If you go much over 20% you will start to see a loss. I have found 30% to be the turning point. When the Indy Racing League switched to Ethanol in 2007, they saw better performance on Ethanol by simply running higher compression ratios in their engines. They are running "denatured" ethanol (98% ethanol/2% gasoline). The E85 atomizes faster and therefore provides a cooler fuel/air mixture which actually boosts performance. Racers know that cooler fuel/air mixture provides more power. That's why drag racers use a "cool can" to lower the fuel temp. It is also why we put on cold air induction systems.

I am speaking to non-flex fuel vehicles here. Flex fuel vehicles have a different chip in the computer that allows for a wider fuel/air adjustment.

[1turbofocus]

I will be the bad guy here and say DONT use e85 , the ecu doesnt need time to learn the o2 , the o2 will make changes faster then you can see it needs changing even on e85 this is what gets a lot of people in trouble they dont understand e85 / Tuning and think its a wonder fuel and it isnt

It the most / only unregulated fuel in the US which should say a lot, its never a 103 - 105 octane like people say your lucky if its even 93 when they get through with it and why they dont have to put the octane on the pumps , it has less energy , less MPG and under WOT the ecu has NO WAY to adjust for the fueling unless your in a 2012 or newer Focus and running 100% e85 you need to add 26 - 30 % more fuel which nothing older then a 2012 Focus can do at WOT with any fuels

The IRL did go to "E" fuels but the octanes were strictly regulated and they did have much higher octanes then anything ever sold at the pumps

Yes I have seen gains in TQ with running e85 then he returned 4 days later with e85 from another station and was down on power and had spark knock because the blend wasnt the same as his car was tuned for , most guys are not as lucky as he was and they tow the car home

My opinion till they regulate the octane its JUNK fuel , 95% of all the guys over the years that raved about e85 have stopped using it because of failures

There is a ton of misinformation out there about this fuel , best thing I can say is do a LOT of homework before using it

Tom

[Fan4Focus]

Originally Posted by 1turbofocus

I will be the bad guy here and say DONT use e85 , the ecu doesnt need time to learn the o2 , the o2 will make changes faster then you can see it needs changing even on e85 this is what gets a lot of people in trouble they dont understand e85 / Tuning and think its a wonder fuel and it isnt

It the most / only unregulated fuel in the US which should say a lot, its never a 103 - 105 octane like people say your lucky if its even 93 when they get through with it and why they dont have to put the octane on the pumps , it has less energy , less MPG and under WOT the ecu has NO WAY to adjust for the fueling unless your in a 2012 or newer Focus and running 100% e85 you need to add 26 - 30 % more fuel which nothing older then a 2012 Focus can do at WOT with any fuels

The IRL did go to "E" fuels but the octanes were strictly regulated and they did have much higher octanes then anything ever sold at the pumps

Yes I have seen gains in TQ with running e85 then he returned 4 days later with e85 from another station and was down on power and had spark knock because the blend wasnt the same as his car was tuned for , most guys are not as lucky as he was and they tow the car home

My opinion till they regulate the octane its JUNK fuel , 95% of all the guys over the years that raved about e85 have stopped using it because of failures

There is a ton of misinformation out there about this fuel , best thing I can say is do a LOT of homework before using it

Tom

I don't claim to be an expert on this subject but, I will say I have ten years of experience with using a blend of E85 here in Minnesota with no negative effects at all and I DO see a gain in mileage and performance. You can listen to all the negative information out there about ethanol or, you can take it from someone with experience. Just understand, I am not advocating that anyone run full E85 in a non flex fuel vehicle. That WILL create problems with your system. I am only suggesting a 20-30% blend,

You are correct that the ECU makes very quick adjustments to the fuel/air mixture. What happens with the ethanol is that it sees it as a lean mixture due to the higher oxygenating effect of the ethanol. The computer makes big adjustments to compensate for a lean mixture, hence the possible drop initially. Then the ECU makes much smaller adjustments over time to get to a balance. That is why you may initially see a drop but it will stabilize after a tank or two when it sees this as the new normal. The ECU does learn or driving habits and compensates accordingly.

I will drop the subject at this post. I know I am in a small minority of people who have long experience with ethanol.

[zetecDon]

Originally Posted by Fan4Focus

I don't claim to be an expert on this subject but, I will say I have ten years of experience with using a blend of E85 here in Minnesota with no negative effects at all and I DO see a gain in mileage and performance. You can listen to all the negative information out there about ethanol or, you can take it from someone with experience. Just understand, I am not advocating that anyone run full E85 in a non flex fuel vehicle. That WILL create problems with your system. I am only suggesting a 20-30% blend,

You are correct that the ECU makes very quick adjustments to the fuel/air mixture. What happens with the ethanol is that it sees it as a lean mixture due to the higher oxygenating effect of the ethanol. The computer makes big adjustments to compensate for a lean mixture, hence the possible drop initially. Then the ECU makes much smaller adjustments over time to get to a balance. That is why you may initially see a drop but it will stabilize after a tank or two when it sees this as the new normal. The ECU does learn or driving habits and compensates accordingly.

I will drop the subject at this post. I know I am in a small minority of people who have long experience with ethanol.

Tom wasn't trying to cast you out here. He was just merely stating the fact that he has seen performance runs on a dyno when people are using E85. I know a few people who have ran E85 also. They get mixed results varying on where and when they get it. Just because you have some experience on it does not make you an expert on it by any means. As Tom and I have said before, there really is no regulation on E85. That means you can have an octane rating of 102 one day then the next delivery will be down around 82 octane. The only thing I would suggest to someone is to read up and learn as much as you can about E85 before even attempting to use it.

[kmtalko]

Update: I filled up yesterday, not a full tank, but I put in about 6 gallons of 87 and 1 gallon E85. I have driven about 20 miles with this mix so far and ik thats not much but it does some to accelerate a little better, might be the placebo effect but I really wasnt try to think about it while driving. I'll see today how the MPG's go as I have to drive another 25 miles to work. With these mixed reviews I might just stay 87, but I'll have to see how many miles I can gain with E85 and if nothing and even possibly lose mileage, I'll stick to regular.