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The basic ratio is 1 gal of e85 for every 3 gallons of gas. This will give you a theoretical E28 blend. However the actual concentration of ethanol in e85 will vary across the country (always lower than 85%) so you will be on the safe side as it relates to fuel trims. E30 appears to be right on the limit for my car as fuel trims are running close to max. Each car will vary so the only way to know for sure would be to data log. If you can't or don't want to do that I would go lighter on the blend.
Add me to the list of those giving E85 a try in hopes of getting timing to be a bit higher with the RR Tune. Mixed today around E27 with 93 on my fill-up. Below is my non-E85 mix timing results on just 93 octane from a 2500 rpm to redline WOT pull. Rafi said he looks for peak timing to be in the 22-24 range at 6700 and mine currently shows about 20. I'll do another test later in the week to see if there are any differences.
Add me to the list of those giving E85 a try in hopes of getting timing to be a bit higher with the RR Tune. Mixed today around E27 with 93 on my fill-up. Below is my non-E85 mix timing results on just 93 octane from a 2500 rpm to redline WOT pull. Rafi said he looks for peak timing to be in the 22-24 range at 6700 and mine currently shows about 20. I'll do another test later in the week to see if there are any differences.
I use a Veepeak WiFi OBD2 Diagnostic Scanner which is only$16.99 on amazon in conjunction with a $10 app called Dash Commander for data logging. From the app I then email the data as a csv file to myself and then select the data in the RPM and Timing Column and create the graph. Super easy and I wish I had known about this sooner!
You get a cleaner and true mix when the car is completely empty.
Not understanding your logic?
If you fill up with a 1/4 tank of already blended E30 then your just blending the other 3/4 tank with your E30 blend they mix and that's it? Like I said in a previous post not everyone will get the opportunity to wait until their car is empty before filling up, when your near an E85 gas station and you don't have one close by, it's probably a good idea to fill up while you have the chance right?
You calculate how much remaining you have in the tank, then calculate how much fuel you'll need to put in and do you blend based on that amount it's not difficult. Your percentage% may vary the first couple times by about 3% max but then you'll get better at estimating how much to put in and it'll be seamless. I do it about once a week sometimes every 4 days depending on how much I drive and I can nail it down to within 1%, no need to wait until it's empty.
Why do you need to wait until you're completely empty? Why not just put 3 gallons of e85 in whenever?
Say you originally put 3 gals in and top off the tank with gas. You now have E23 blend (3 gals e85, 13.9 gals gas). To keep it simple, let's say you drive it down to 1/2 tank... there's still 1.5 gallons of E85 left in the tank. You add 3 gals and fill the rest up with gas. Now you have 4.5 gals E85 in your full tank. Your blend just went to E30 (4.5 E85, 12.5 gas). Repeat that process again and you have 6.25 E85 and 10.65 gas = E38. Hope you can see this is a very bad idea.
The key is always topping off with the correct blend that matches what you have in the tank (or gets you to whatever your target is). An easy way to think of it is for every 1 gal of E85 you add, you should also add 3gals of gasoline - this is E29 blend. If you want to go lower here are some other simple blends:
1gal E85 + 4gal Gas = E25
1gal E85 + 5gal Gas = E23
1gal E85 + 6gal Gas = E21
When you guys mix which are putting in first? Or does it matter??
I put e85 first then gas in order to slush it around for a good mix. Think of it as making a drink, alcohol first then the juice/soda. I also shake the car side to side leaving the gas station and do short quick stops to shake the tank. I don't know if it makes a difference, but it's fun lol.
Say you originally put 3 gals in and top off the tank with gas. You now have E23 blend (3 gals e85, 13.9 gals gas). To keep it simple, let's say you drive it down to 1/2 tank... there's still 1.5 gallons of E85 left in the tank. You add 3 gals and fill the rest up with gas. Now you have 4.5 gals E85 in your full tank. Your blend just went to E30 (4.5 E85, 12.5 gas). Repeat that process again and you have 6.25 E85 and 10.65 gas = E38. Hope you can see this is a very bad idea.
The key is always topping off with the correct blend that matches what you have in the tank (or gets you to whatever your target is). An easy way to think of it is for every 1 gal of E85 you add, you should also add 3gals of gasoline - this is E29 blend. If you want to go lower here are some other simple blends:
1gal E85 + 4gal Gas = E25
1gal E85 + 5gal Gas = E23
1gal E85 + 6gal Gas = E21
yes, that makes sense. I should've clarified that I was asking about the first fill up. If I am trying to blend for the first time, I don't see why you would need to go to empty if it's going to mix in anyway.
Say you originally put 3 gals in and top off the tank with gas. You now have E23 blend (3 gals e85, 13.9 gals gas). To keep it simple, let's say you drive it down to 1/2 tank... there's still 1.5 gallons of E85 left in the tank. You add 3 gals and fill the rest up with gas. Now you have 4.5 gals E85 in your full tank. Your blend just went to E30 (4.5 E85, 12.5 gas). Repeat that process again and you have 6.25 E85 and 10.65 gas = E38. Hope you can see this is a very bad idea.
The key is always topping off with the correct blend that matches what you have in the tank (or gets you to whatever your target is). An easy way to think of it is for every 1 gal of E85 you add, you should also add 3gals of gasoline - this is E29 blend. If you want to go lower here are some other simple blends:
1gal E85 + 4gal Gas = E25
1gal E85 + 5gal Gas = E23
1gal E85 + 6gal Gas = E21
...? Whatever you have left to fill up, divide by 4, and that's the e85 you throw in.
Did this have to be explained? lol
I use a Veepeak WiFi OBD2 Diagnostic Scanner which is only$16.99 on amazon in conjunction with a $10 app called Dash Commander for data logging. From the app I then email the data as a csv file to myself and then select the data in the RPM and Timing Column and create the graph. Super easy and I wish I had known about this sooner!
Cool, I am using an obd2 adapter and torque pro. I've only looked at the timing numbers and they look to be correct based on your graph. I will have to graph mine on the next log I do. I thought maybe you were using techstream or something.
11-08-16, 06:54 PM
