Originally Posted by Aqid

I guess I'm not grasping the difference yet. So with what you're saying, having an E70 blend, how many gallons of that would I need to add to E0 91 pump gas to go over octane 93?

http://www.e90post.com/forums/showpo...7&postcount=57

[GripAndRip]

Originally Posted by Aqid

So the end result would be a 37.25% ethanol blend. The thing that bothers me, is what kind of gas do they mix e85 with? I assume 87.

E85 is close to 100 octane, pretty sure. And you can use an online calculator but if you wish to do the calc yourself or want to calculate it considering the fuel already in the tank, use the picture/calc I posted on page 3.

[BKBMW335I]

Originally Posted by 805beemer

I agree if you have 93 octane. But if your running a flash tune and only have 91 and want to run the agressive maps then blending 40% e85 is a great way to bump up your octane. Ive been doing that since stage 2+ came out, only downside is my mpg has gone down. Can't wait till cobb has an e85 map. Then we can really see what the stock fuel system is capable of.

This +1!!

[BKBMW335I]

Originally Posted by robc1976

I know there are lot of gas threads..wich is better and so on....my question is this......is Conoco gas any good?...they have E85 and 93 and it would be much easier to put 10 gals of 93 and then 4 gals of E85 at the same pump instead of putting the E85 in a container...going to shell and filling up 93 then putting in the E85 from the container. I use shell because I heard it is best.

This is what I do at Conoco.

[jts1981]

From a quick glance at this thread it looks like no one is testing the ethanol content or is using an eca. People are just assuming all "e85" is the same when in reality every pump is different, and then you add in seasonal changes.

[LOWFLYER777]

Here in California, if you fill up with Propel E85, they guarantee it to be at least 100 octane and up to as much as 105 as there are no winter or summer blends here; I spoke directly on the phone with them. As far as what the other 15% is in that E85 blend, I'm not sure and I'll have to call back and find out; never thought of that...

I'm still confused, especially with that math assignment back on page 3 on how to consistently get an E30 blend after the first fill up. I'm wanting to run the Cobb E30 map in my 07 E92 (FBO), but don't wanna punish my LPFP. Got brand new turbos and HPFP (ty BMW).

I also find it interesting that people keep doing the 10/4 thing...I don't know about the sedans, but the E92 coupes have a 16.1 gallon tank that includes 2.1 in reserve according to the owners manual. So is everyone just not accounting for the reserve and filling up when the warning light comes on and assuming that they have 2 gal left and basing their ratio off that? What about the ratio in those 2 remaining gallons? I'm terrible at math btw...

[GripAndRip]

Originally Posted by LOWFLYER777

Here in California, if you fill up with Propel E85, they guarantee it to be at least 100 octane and up to as much as 105 as there are no winter or summer blends here; I spoke directly on the phone with them. As far as what the other 15% is in that E85 blend, I'm not sure and I'll have to call back and find out; never thought of that...

I'm still confused, especially with that math assignment back on page 3 on how to consistently get an E30 blend after the first fill up. I'm wanting to run the Cobb E30 map in my 07 E92 (FBO), but don't wanna punish my LPFP. Got brand new turbos and HPFP (ty BMW).

I also find it interesting that people keep doing the 10/4 thing...I don't know about the sedans, but the E92 coupes have a 16.1 gallon tank that includes 2.1 in reserve according to the owners manual. So is everyone just not accounting for the reserve and filling up when the warning light comes on and assuming that they have 2 gal left and basing their ratio off that? What about the ratio in those 2 remaining gallons? I'm terrible at math btw...

I usually wait till I'm actually close to empty. As for the second fill up and so on, you can account for it.

And my hand calc on page 3 (picture of my notebook) accounts for all 16 gallons

[LOWFLYER777]

Originally Posted by GripAndRip

I usually wait till I'm actually close to empty. As for the second fill up and so on, you can account for it.

And my hand calc on page 3 (picture of my notebook) accounts for all 16 gallons

Ty, I really appreciate that.

[mang.vang]

With mhd how much ethanol can I mix to get higher octane before the ecu is unable to compensate for the amount of additional fuel it takes? For example going from 91 to 95.

Originally Posted by mang.vang

With mhd how much ethanol can I mix to get higher octane before the ecu is unable to compensate for the amount of additional fuel it takes? For example going from 91 to 95.

I'd be more interested in LPFP/HPFP capabilities rather than "ECU compensation" in that scenario.

[mang.vang]

Lets assume that the fuel pumps are capable.

[LOWFLYER777]

Originally Posted by FCobra94

I'd be more interested in LPFP/HPFP capabilities rather than "ECU compensation" in that scenario.

I think it's pretty widely accepted judging by the myriad of threads I've combed through that our E9Xs will generally be ok with <6 gallons of E85...to get a solid E30 mix for Cobb or MHD, you shouldn't need more than around 4.5 gallons of it... Again YMMV and depending on the health of your fuel pumps, that'll be the determining factor if can run ethanol or not... The biggest hangup with this seems to be figuring out easily, without some sort of long page of math or a $2xx ethanol sensor, how to continously fill up with an accurate E30 blend...

Originally Posted by LOWFLYER777

The biggest hangup with this seems to be figuring out easily, without some sort of long page of math or a $2xx ethanol sensor, how to continously fill up with an accurate E30 blend...

no, not really...all it takes is a ~$17 testing kit, an online calculator, and a few extra minutes at the pump.

[LOWFLYER777]

Originally Posted by FCobra94

no, not really...all it takes is a ~$17 testing kit, an online calculator, and a few extra minutes at the pump.

In my particular case, here in San Diego, I don't need a tester. I have called our E85 supplier (Propel) which DOES NOT do summer or winter blends because of the generally mild climate here. They DO guarantee at least 100 octane at the pump and up to 105...

So again, where it gets a bit overwhelming for me in my particular situation is that page of math and knowing how much I have left in the tank to even fill that page of math out at the pump...

Can I assume at 1/2 tank I have 8 gallons left or when the low fuel warning comes on at that I have reached the 2.1 gallon reserve?

I have no issue using the George Belton calculator, but after the first fillup, do I run the tank down to 1/2 and just cut my E85 ratio in half and call it good? Or run it down to the low fuel warning and try to calculate from there?

How do I use that calculator if I have 2 gallons left? What E ratio is in my tank at that point if I filled it all the way up initially with an E30 blend? Am I over complicating this??

[GripAndRip]

[QUOTE=LOWFLYER777;21395244]

Originally Posted by FCobra94

The biggest hangup with this seems to be figuring out easily, without some sort of long page of math.

It's three simple calculations. I can do it in my head.

Multiply the gallons of e85 by .85 (use a phone calculator) 4 gallons gives 3.4

Take the number of gallons gasoline and literally move the decimal over. So 11 gallons would be 1.1. Add that to 3.4.

Divide by (11+4)

These are example numbers. Or go to a website on your phone with a calculator for this... as posted by previous members.

Originally Posted by LOWFLYER777

Am I over complicating this??

Yes.

I'm awful at math and even I can understand how this works...

Each hash mark on your gas gauge is 0.8 gallons. After you've figured that out, it doesn't matter whether you have 1 gallon left in the tank or 10 gallons left in the tank, you play with the online calculator until you've figured out the ratio of E85/93 needed to fill the rest of the tank.

[Shane303]

Originally Posted by LOWFLYER777

In my particular case, here in San Diego, I don't need a tester. I have called our E85 supplier (Propel) which DOES NOT do summer or winter blends because of the generally mild climate here. They DO guarantee at least 100 octane at the pump and up to 105...

So again, where it gets a bit overwhelming for me in my particular situation is that page of math and knowing how much I have left in the tank to even fill that page of math out at the pump...

Can I assume at 1/2 tank I have 8 gallons left or when the low fuel warning comes on at that I have reached the 2.1 gallon reserve?

I have no issue using the George Belton calculator, but after the first fillup, do I run the tank down to 1/2 and just cut my E85 ratio in half and call it good? Or run it down to the low fuel warning and try to calculate from there?

How do I use that calculator if I have 2 gallons left? What E ratio is in my tank at that point if I filled it all the way up initially with an E30 blend? Am I over complicating this??

If you wish to run ethanol why don't you just get a sensor and ease the pain?

[LOWFLYER777]

Originally Posted by FCobra94

Yes.

I'm awful at math and even I can understand how this works...

Each hash mark on your gas gauge is 0.8 gallons. After you've figured that out, it doesn't matter whether you have 1 gallon left in the tank or 10 gallons left in the tank, you play with the online calculator until you've figured out the ratio of E85/93 needed to fill the rest of the tank.

This is helpful, thank you!!! I've not seen that anywhere else I've looked.

So say you're at the 3rd hash...this means you have 2.4 gallons of gas left in the tank of already blended E30 from your previous fillup...how do you now calculate your blend with just the 2.4 of E30 blend remaining?

I'm sorry if this totally noobish, but those of you humoring me are saints and i really appreciate your time mostly non existent sarcasm.

Originally Posted by Shane303

If you wish to run ethanol why don't you just get a sensor and ease the pain?

I've looked into that...They're not reliable if you have water in the system...Saw a YouTube video where they used the Zeitronix sensor and it can be easily fowled and give you an incorrect reading.

Originally Posted by LOWFLYER777

This is helpful, thank you!!! I've not seen that anywhere else I've looked.

What haven't you seen? Basic math? You have a 16 gallon tank and 20 hash marks...division is hard

Originally Posted by LOWFLYER777

So say you're at the 3rd hash...this means you have 2.4 gallons of gas left in the tank of already blended E30 from your previous fillup...how do you now calculate your blend with just the 2.4 of E30 blend remaining?

How old are you again?

Let's assume you already have E30 in the tank and you're just trying to match that on your next fill up; otherwise we'll be here all day...

If you subtract 2.4 from 16 what do you get?
.
.
.
.
13.6

Use the following calculator and enter in:
http://dbtest.net16.net/ethanol-01.html

[1] - *Amount of ethanol in your 91/93 source* (typically ~10%)
[2] - 30
[3] - *Amount of ethanol in your E85 source* (in my area it ranges from ~E74-~E87, depending on the season)
[4] - *Amount of fuel needed to fill the tank* (in your example, 13.6)

The results should be self explanatory.

Originally Posted by LOWFLYER777

I've looked into that...They're not reliable if you have water in the system...Saw a YouTube video where they used the Zeitronix sensor and it can be easily fowled and give you an incorrect reading.

If you have that much water in your system, you've got more to worry about than being a mathlete...

[LOWFLYER777]

Originally Posted by FCobra94

What haven't you seen? Basic math? You have a 16 gallon tank and 20 hash marks...division is hard


How old are you again?

-36...and I'm still learning what I can where I can...I did not realize that the hashes indicated .8...I can do division but the fuel gauge has never been explained to me that way before. And maybe it shouldn't have had to be, but I honestly didn't know that and again, it's been the most enlightening piece of information I've come across in this search for the perfect blend...

Let's assume you already have E30 in the tank and you're just trying to match that on your next fill up; otherwise we'll be here all day...

If you subtract 2.4 from 16 what do you get?
.
.
.
.
13.6

Use the following calculator and enter in:
http://dbtest.net16.net/ethanol-01.html

[1] - *Amount of ethanol in your 91/93 source* (typically ~10%)
[2] - 30
[3] - *Amount of ethanol in your E85 source* (in my area it ranges from ~E74-~E87, depending on the season)
[4] - *Amount of fuel needed to fill the tank* (in your example, 13.6)

The results should be self explanatory.

-Outfreakinstanding, yes they are. Do you prefer that calculator over the George Belton one or the app in the app stores? I noticed the app I have gave a slightly different amount...I'm talkin tenths.

If you have that much water in your system, you've got more to worry about than being a mathlete...

This is what I saw....

https://www.youtube.com/watch?v=XEPJo1FN32k