AndrewZPSU

The following has been an experiment regarding E85 in use with the 2008 Corvette LS3.

EDIT: Please see track results, post #26

INTRODUCTION

In this experiment I will be examining three things:

(1) if the car will compensate for E85 without further tuning by simply enabling the flex fuel option

(2) If the stock injectors are big enough to handle E85

(3) How much of a power increase can be pulled out of the car using E85.

First, I will use my custom tune with the addition of enabling a flex fuel option. I will drive the car 40 miles to the E85 station to get fuel trims in line and I will log the trip to see non-e85 power delivered to the transmission by using the “delivered torque” sensor. The car has less than 1/8 of a tank so by the time I make it there, it should be almost completely empty.

Experiment 1 – Flex Fuel Option

I will fill up with E85 without changing the tune at all. I will see if the commanded stoich AFR changes to reflect the use of E85. It should move to somewhere near the vicinity of 9.7, however if it moves at all I consider it a victory. If not then changing the stoich value must be done manually, defeating the “flexfuel” option.

Experiment 2 – Stock Injector Capability

I after making sure the car is in line with the correct fueling, I will do some wide open throttle runs while logging the Injector Duty Cycle. If it stays under 100% the car can run with the stock injectors, if it doesn’t it needs bigger ones.

Experiment 3 – Power Gain

After making sure I can run E85 on the stock injectors I will get the tune inline. Once that is done I will run the car to see the max power gain using the delivered torque sensor. Basically gas tuned vs e85 tuned. This will eliminate the difference between stock and tuned alone to show an actual gain. I will be posting the max power in gas vs the max power with E85 comparison side by side. If the injectors can’t handle it I will show max power up until the injectors stop functioning correctly.



Results

Experiment 1 – Flex Fuel Compatibility - Failed

With the flex fuel option enabled I noticed immediately that the AFR dropped to 14.5 from the 14.67 it usually commands at gas stoich.

Unfortunately when filled up with E85 there was no change, only Long Term and Short Term Fuel trims were affected.

There may be a possibility of using a middle ground stoich value to make the car somewhat a “flex fuel” vehicle.

There might be a sensor that can be hooked up and used and truly make it a flex fuel vehical... I will be looking into this.


Experiment 2 – Stock Injector Capability - Failed

I had only filled up with 13.52 gallons of fuel. This was not a full tank of E85.

Unfortunately when I ran the car on the E85 settings, the car maxed out around 4500 rpms, so it will need bigger injectors to use full E85.

After doing the math I figured I was running around 62% Ethanol. Changed the stoich value to reflect "E62" and the Fuel trims were completely inline. At this level the car would almost reach 100% Injector Duty Cycle with the given PE settings by GM... which were rich as hell. I noticed power falling off as it approached past 5500 rpms. That could be due to injectors maxing out, or not enough spark.


Experiment 3 – Power Gain – Successful

E62 Proved to make power over gasoline during most of the GM WOT settings for alcohol, even without bumping up the spark. There was no knock with E62 at all. Preliminary Results / Comparison below.


(NOTE: TABLE WILL NOT PASTE)
Table shows gains from 1%-5% in low end. Injectors max out and high end suffers.

Getting the E62 WOT dialed in more should prove to be extremely potent. Without tuning for best AFR or best spark, gains shown up to 5.62% in some of the richer areas. Most seem to be 1-2%. This could actually be an increase of 5-20 tq.




After specific tuning…

Unfortunately the weather had changed so my comparison between the GAS power and Tuned E62 became quite useless.

I did notice I was able to run +4 degrees of timing on top of what I had already set. I didn't run it past that yet as I honestly didn't think it'd be able to do 31.5* in mid range, 29* in high end... but it did without any knock. Biggest gains so far were the 29* in the high end, but 30* in mid range.


Conclusion:

Unfortunately the LS3 is still not a flex fuel vehicle. It lacks both the tuning and the injectors. However, there is definately power to be gained by using E85 with the correct tune. Even with 62% Ethanol it was showin a gain.

Owners can be tuned for to use E85 only, or Gas Only. To take advantage of the power gain they must buy bigger injectors.

EDIT: Please see track results, post #26

AORoads

interesting.

adias

Did you do this without changing fuel lines and other bits? How long will your car last now?

AndrewZPSU

Car will be fine. One cycle of E62 will not hurt it one bit. Cars are built to withstand the Ethanol in gasoline currently and are prepared to take E20 or E30 I believe. Pre-98 cars don't fair so well.

glennhl

Fantastic experimentation! Are you planning to replace the injectors with larger units?

LS1LT1

So THIS is what you were doing instead of heading up to Cartek tonight!

Nice findings dude, I'd figured that there was a chance that it could work.

foremaw

Thanks for the info, also from the Owner's Manual:

"E85 (85% ethanol) and other fuels containing
more than 10% ethanol must not be used in vehicles that
were not designed for those fuels."

FortMorganAl

So why does the owner's manual say:Ethanol is NOT gasoline!!! Ethanol has much less energy per gallon. You need about 50% more ethanol to get the same energy as gasoline. Ethanol also doesn't burn very well when cold. You have to raise the engine temperature significantly to get it to fire consistently. Because it doesn't burn very well, it DOES have a high octane rating. For a car that was designed for 10% ethanol max to run on ethanol you would need to increase the size of the fuel pump (and gas tank) by about 50%, increase the thermostat temperature, lengthen the stroke with a new block and crank shaft, decrease the size of the water jacket around the cylinders to allow it to warm up faster,and accept a rough running engine until it does warm up.

Before you go destroying your car you might want to investigate why GM says not to use E85. It isn't because they are just another evil corporation out to do everything they can to destroy the environment. There are actually physical reasons why ethanol is a very poor substitute for gasoline.

AO-08

I'm not so sure. The o-rings in the entire fuel system are not designed to withstand those levels. They will swell and overfill the cavity and fail for sure. Hopefully you ran that out and put in spec gas quickly. Certain materials in the pump must be changed as well.

These changes cost money of course or every car would be good to go from the factory.

ps. Qualifications include being the project engineer for the C6 fuel modules in a previous life.

Vettin08

Engine/fuel system wasn't designed for fuel w/ more than 10% ethanol. Hope this works out for you.

tolnep

engine will run fine on e85.

and you can make tons of power on e85..

But.. to do so you need the capability to flow more fuel and a tune. and where it really pays off is with raised compression or forced induction.. your fuel system needs to have components designed for ethanol. its corrosive. and there can be issues if ethanol absorbs enough water which it is prone to do.

supposedly 1 gallon of pure ethanol has 75 percent the energy of 1 gallon of gas.. i assume e85 has a bit more. nevertheless it will significantly reduce your mpg.

in my opinion, the ability to run a vette on e85 would be a positive thing, since you can make more hp. never understood all the hate about e85... i expect to see this eventually. GM has other flex fuel vehicles. the beauty of flex-fuel of course is that you dont have to run e85 if you choose not to...

Vettin08

Yes, but how do you account for this?


And, as posted above, from the owners manual.....

That's on page 5-6 of the owners manual

'06 Quicksilver Z06

Very interesting work, and I think that if anyone finds a way to swing this, this young man will be the one to do it, having had experience with this in his GTO.

I just hope he doesn't bust something trying to.

So if one were to add bigger injectors, a fairly simple matter, a very simple matter in fact, and adjust the tune, one could run E85 and thus make more power, and significantly more torque with everything else stock?

Very impressive.

HOXXOH

Oh Andrew. Just why did you have to go and do this now? (sigh)

So many people were waiting on the Cartek confirmation of your bone stock status and subsequent reruns.

Now you have just subjected yourself to more scrutiny for any future admission to the performance lists.

While I admire your honest and upfront attitude and your willingness to experiment and share results, your timing just plain sucks.

talon90

Yep, right up until the fuel system melts down from corrosion - but man it was fast while it lasted.

Several components need to be changed to accomodate the higher ethanol content. In the other thread that he started I alluded to this.

Ethanol is a combustable fluid any engine once fed Ethanol will run. It is sustaining that that becomes the issue.

'06 Quicksilver Z06

You are so right.

You are so very right. Both of you guys. This kid's timing just plain sucks.

His early experiments using E85 and Flex fuel, , successes and failures, are well documented in the GTO forums.

He has experimented with this using a GOAT that he just got rid of.

That GOAT was one of the quickest in the GOAT forum. If it wasn't the quickest. Did he screw something up in that GOAT which led him to get rid of it and decided to start over with a "clean slate" using a new LS3 based Corvette? People are going to ask that question.

He, according to his GTO posts, discovered that he needed larger injectors in that GOAT to make things work right with E85 and his posts indicate that he was hunting for larger injectors for use in his GTO in the GTO forum.

He then says that his Vette is "tuned". Says he went back to "stock" and ran a record setting time. Among the things which came into question with regard to that run, is how his car managed to run at 130*. Someone offered up an explanation. http://forums.corvetteforum.com/show...&postcount=396

This kid obviously knows his way around tuning, HPTuners, he definitely knows his $#!+ when it comes to tuning a car and can seemingly make it run off of tap water if he puts his mind to it.

Some of this stuff, you feel like pulling up a chair and learning from him
http://forums.corvetteforum.com/show...&postcount=398
http://forums.corvetteforum.com/show...&postcount=401

Now he posts up the results of experimentation using E85 in his LS3 based Corvette, just a week after his record setting time. Talk about bad timing.

It is a fact that if you can swing it, an LS3 running E85 will make more power on E85 than it will on plain gasoline.

I agree with you wholeheartedly. This kid's timing, like you say, "just plain sucks".

But for what its worth, if his 11.7 came as a result of running E85 in his LS3 based Vette, then that is a contribution, an achievement in and to this forum which far supercedes any results that he could post up onto any fast list.

Andrew, if thats what you did, and I am not saying that it is, but if it is, then you need to let the board know. Because what you would have accomplished, should that be the case, would rank among the top 3 contributions to the C6 Forum. Forget the list.

LS1LT1

I hope you don't mind Andrew but I'm going to link this over to the C6 Tech/Performance section as well because it is tech related and I think some racers over there might find it interesting as well.

dennis50nj

so will this work on my LS2 or is it LS3 only

Maui

I've noticed a power drop since the state mandated 10% ethanol. The car feels like it's pulling anchor. E10 sucks.

dennis50nj

thats true with 10%