[gtimes]

So after reading a lot of posts I'm still not exactly sure what the definition of e40 is most people are using. According to the calculator I use 7 gallons of e85 + 8 gallons of pure 93 (not e10) makes for 98.7 octane with 39.7% ethanol (e40). Now obviously that is closer to 50/50 with e85/gas. I keep reading several places saying 6 gallons is the max and is e40. If recalculated with 6 gallons of e85 and 9 gallons of e10 it comes out to e40 as well. I'm not sure this is what most people are referring to or if e40 is being referred to 40% e85 and not actually 40% ethanol content. I'm not smart enough to do the math to calculate that and figure this out. Hoping I can try 7 gallons of e85 and 8 gallons of pure 93 and log and maybe get lucky and daily on map7. From what I've read it's unlikely without the lpfp upgrade but it seems some have been able to do this safely.

[135Pats]

Few thoughts.

1. Don't run Map7 on "luck". Log diligently and make sure things are set up appropriately.
2. E40 = 40% eth. Not 40% E85. Same would be true for any mixture people are discussing. Always aim to overfill provided you can supply the fuel, it's better to have a bit too much ethanol than to find yourself short on octane.
3. E40 is right on the ragged edge of what the factory fuel can move. Again, just log diligently

You'll be fine

[gtimes]

Don't know why people say 6 gallons is the max and e40 then. I log almost every day it's too easy and fun not too. Well I guess I'll try the 7 to 8 gallons next, thanks.

[135Pats]

Originally Posted by gtimes

Don't know why people say 6 gallons is the max and e40 then. I log almost every day it's too easy and fun not too. Well I guess I'll try the 7 to 8 gallons next, thanks.

Because they're wrong.

E40 = 40% ethanol

[JETmn]

Originally Posted by gtimes

Don't know why people say 6 gallons is the max and e40 then. I log almost every day it's too easy and fun not too. Well I guess I'll try the 7 to 8 gallons next, thanks.

Because gas in most states is E10. Therefore your calculation that showed 6 gal of E85 + 9 gal of E10 = E40 is correct. E35 to E45 seems to be the max the stock system can handle depending on how good of shape your fuel system is in. That is on a stock turbo.

[hetzle]

Do we have a 15 gal tank? I always thought it was 16.

[Jsoboti]

Originally Posted by hetzle

Do we have a 15 gal tank? I always thought it was 16.

16

[mike@x-ph.com]

As mentioned above e40 is 40% ethanol not 40% e85
In order to always get the mixtures right i put 13 gallons at a time.
I aim for ~E65
so i put 10 gallons of E85 and 3 gallons of 91
E85 has 85% ethanol so 10 *.85 = 8.5
91 has 10% ehtanol so 3 * .1 = .3
so total ehtanol is 8.8 .
Divide that by total number of gallons ( 13 in this case)
8.8 / 13 = .67 ; so i got E67

Keep in mind that in the winter E85 has around 70% ethanol vs 85% so you probably should add extra e85.

[gtimes]

Thanks for the replies. We got the option for e10 or pure gas here in Oklahoma at alot of stations. It's actually common here for stations to put a sign out saying 100% pure gas but 93 is very hard to come by and expensive but always 100% gas from what I've seen as well. Luckily I live a couple miles from a specialty gas station that just opened with 93 and e85. I even called them and they mix their e85 in house and guarantee the octane and ethanol content. Would be nice to know how many people are running map 7 on the stock lpfp safely. Being just under 99 octane with so much e85 I think there is a good chance I'll be one of them although I can't complain about map 5! Also thinking about trying octane booster but I really don't want to do that all the time..