Thread: E85 vs Intercooled pump gas

can u run e85 on 44s or would i need 60s

60s would be the best option

E85 is great for forced induction if that is what you are asking.

If you are looking for which fuel has more "power"...its regular gasoline. Gasoline has more btu per unit than E85/ethanol.

Originally Posted by LeadfootCJ7

E85 is great for forced induction if that is what you are asking.

If you are looking for which fuel has more "power"...its regular gasoline. Gasoline has more btu per unit than E85/ethanol.

Just a heads up someone is about to tear apart the last part of your statement there..^^^^^


The quick version as I understand it is that Gasoline is run at 14.7 parts air to 1 part gasoline. E85 is run at around 12:1 to burn best (stochiometric) since you have a higher fuel to air ratio you get more power. That's why drag cars run nitro-methane. It runs at 3:1 I beleive.

Also e85 burns cooler which is better for your engine. BTU's have nothing to do with power as far as I know. All BTU's is is a measure of heat output. More would actually be worse.

In mentioning a "sweet spot" between ignition timing vs. boost... I personally found with my setup that running nearly stock timing tables and just adding boost was the best approach. I have been able to make more power just by leaving the stock timing table alone and adding boost vs. increasing timing at a lower boost setting. The second of the two still resulted in KR where as stock timing and added boost resulted in knock free power!

Originally Posted by indygrandprix

Just a heads up someone is about to tear apart the last part of your statement there..^^^^^


The quick version as I understand it is that Gasoline is run at 14.7 parts air to 1 part gasoline. E85 is run at around 12:1 to burn best (stochiometric) since you have a higher fuel to air ratio you get more power. That's why drag cars run nitro-methane. It runs at 3:1 I beleive.

Also e85 burns cooler which is better for your engine. BTU's have nothing to do with power as far as I know. All BTU's is is a measure of heat output. More would actually be worse.

You are talking about changing other factors. I am talking strictly the product. I deal with refineries, analysis of products, etc for a living. Ethanol has less btu than gasoline (RUG) period. Can you modify things to make it work better in certain applications sure. But apples to apples it has less btu. That's why regular N/A cars that can run both get significantly worse mileage running e85 than straight gasoline. That's why people finally learned it costs more to run e85 in flex fuel cars even though the fuel is cheaper and fewer stations are offering e85.

After running e85 since christmas . I can say its a worthwhile fuel if you can tweak your timing where it needs to be. But e85 no doubt sucks on the highway for mileage. City driving however is barley a hit and at 2.99 a gallon compared to 3.70 for premium.

Originally Posted by darkhorizon

They have a bunch of tuning solutions but the tuning shops market it as "super hard to tune and really corrosive" so they sell fuel line replacement kits injector seals and flex fuel sensors.

Are those flex fuel sensors something worth investing in for these 3800s, and would they even be compatible with our ECUs?

I am guessing even with the flex fuel sensor, our stoich targets can't be changed on the fly like that without an ECU reflash??

Originally Posted by darkhorizon

I could probably design a flex fuel sensor that works, but its not worth it.

GM cars that are flex fuel dont even use a flex sensor, they just use the o2 sensor.

Gm cars used both, the majority use a external physical flex fuel sensor with a alcohol %table to adjust the stoich.

Gm tried using a virtual flex fuel algorithm for a couple years but went back to a physical sensor.

Keep in mind with that the car needs to have a voltage input based off of stomach that changes the master stomach table for the car to run correct.

I find it easier just to reflash the car between summer/winter blend