03tibe85

Hey Guys and Gals,



Just wanted to spread some knowledge on My 03 GK V6 E85 Experiment that's been going

on for about 6 months so far. Its a lot of info so re-read as needed.



THEORY:

With the right size injectors and nothing else done to the V6 engine the OEM ECU

should be perfectly happy running both Winter and Summer blends of E85 all day long. The OEM 03 GK ECU

relies on two pre-cat and two post-cat Narrowband oxygen sensors to determine at what Lambda the cylinder

banks are running at.

I say Lambda because that is more important than what people normally think of as Air Fuel Ratio at this point.

The key point to remember is that a Lambda is determined based on the oxygen content of the exhaust gases

after combustion and that a stoichiometric Gasoline AFR of 14.7:1 is Equal to a Lambda Value of 1 which is also

equal to the Ethanol (E85) value of 9.7:1. So in short 14.7:1 Gas AFR = 1 Lambda = 9.7:1 E85 AFR.

Now why is this important you ask? Because to keep the OEM ECU happy it needs to think its running as close

to its preprogrammed Lambda targets as possible within its allowed automatic fuel trim range.

The key to doing this with E85 is to size the fuel injectors appropriately for the given fuel you plan on running.

In my case that is Ethanol (E85).

You may ask why do I need different injectors to run E85? The short answer is the power content aka energy rating

of E85 is MUCH lower than Gasoline so in order to reach the same required Lambda values (remember 14.7:1 GAS AFR = 1 Lambda = 9.7:1 E85 AFR)

you have to add more E85. The closer you get to true E85 the more fuel you have to add to reach the same Lambda.

On average you need to add between 20-35% more fuel to run the various mixtures of E85. The closer to true E85 the

closer to 35% additional fuel needed. S

So....if you can size the larger injectors to add the extra fuel and stay within the min/max fuel trims programmed into

the OEM ECU then PRESTO! Your running E85 with no need for any sort of extra fuel tuning device.





EQUIPMENT:

-2003 Hyundai Tiburon GT V6 6 Speed with a swapped in 04 Engine that has 150,000 miles on it.

-Damn near perfect compression across the board.

-290cc Blue OE Injectors from a XG350 3.5L engine with low miles

-Stock GK V6 Fuel pump and fuel lines

-Stock Fuel Pressure Regulator

-E85 Ethanol that varies between 85-70% Ethanol and 15-30% Gasoline



TEST Results:

Before starting up the engine I made sure that most of the gasoline in the tank and lines was purged. I did this by using the stock fuel pump to pump out as much gas into containers as possible and then used a shop vac to get the rest out of the tank. This is important as you want to start with as clean a baseline as possible.

I then filled up with the E85 at the pump which in my case was closer to E77 due to the transition from Winter to Summer

blend in Colorado. In the peak of summer we'll get around E82-E85 in the pumps.

The engine fired up on first turn of the key and settled into a nice idle. You'll notice the pitch of the engine change the longer you run E85 because it runs cooler and cleaner than gas. Give the engine a nice low growl!!

Fast Forward 3 or so months and my long term fuel trims are hovering right around the +/- 3% mark with is excellent!

There have been no cold/hot start issues and the stock fuel pump is handling things just fine. There is zero issues showing with the rest of the stock fuel system as well. Ignition Advance Timing is maxed out as the ECU thinks its running at least 91 octane premium. In reality E85 varies between 99-106 octane depending on blend. There's a reason its called race gas at the pump!! Also I have zero CEL codes.

Now I hear some saying "But Dave, what about gas mileage since your using more fuel?"

Well it is true due to the energy rating of E85 you have to use more fuel to play. But since the octane rating is so much higher the OE ECU maxes out the ignition advance allowing the engine to be much more efficient. So while my MPG have dropped its not as much as you might think. Right now I average 25-27MPG on the Highway and 19-21MPG in the city depending on E85 blend and my right foot. LOL. The added bonus to maxed ignition timing is MO POWA!!



FUTURE TESTS:

In order to really optimize performance under E85 you really need to be able to control your fuel and timing. In most cases the OEM programming is set up to utilize the most widely available gasoline octane rating. In the United States that is 91 Premium. Some states do offer 93 but that is few and far between so OE's have to settle for 91. What this means is the ECU will self tune up to a max ignition advance setting as well as a pre-defined lambda target.

To really see the benefits you need to be able to change both max ignition advance and lambda targets in every load range. As of now none of the ECU flashes available have provisions for running E85 so your options are go full standalone or have some way to trick the OEM ECU into running the AFR/Lambda you want.

For now, until I can budget for either a custom ECU flash or a full standalone I plan on utilizing a Perfect Power piggyback ECU that should give me full control of ignition timing and fuel control under wide open throttle. Tuning under close loop will prove trickier.



Further down the line I'm looking into sourcing a Upper and Lower intake manifold from the 2.7L MU engine from the 2007-2011 Santa fe as the manifold has variable length runners to improve efficiency over different load ranges and it should be controllable via my piggyback.

I am also exploring the possibility of using a flex fuel sensor hooked to a homegrown eprom microchip that converts the frequency wave of the sensor into a standard 0-5volt signal that I can then connect to the Air Temp sensor on the piggy back to be able to auto adjust the tune based on Ethanol content.



Feel free to ask any questions you might have.



Dave

ScoupeLS

Do you have headers?



I would like to do this to my GK but right now have a CEL that i don't know what is causing it. I replaced all 4 O2 sensors and I reset the ecu via obd scanner and after i drive it for a day or two the cel comes back and it says my primary O2 sensors are not working.

03tibe85

Nope, running OEM Manifold/cats right now. No mods are done to exhaust system. Hmm...03 GKs in the US typically don't have CEL problems with headers so I'd first make sure your using OE sensors and they are plugged into the right places.. Aftermarket sensors have been known to cause issues. Also if you have a scanner than can monitor as well bring up your O2 sensor stats and see if they are reading correctly.

ScoupeLS

The O2 sensors are NGK brand. i saved the old ones just in case.

Megladon

This is very interesting and unique. I think your on the right path when it comes to efficiency for both power and mpg but of course assuming you dont have a heavy foot all the time. Very interested in a dyno pull to see how much power/torque the GK has improved.

SonataSquat

I have an 03 Hyundai Sonata with the same delta v6 in it. I think the only difference is the ecu. Been wanting to swap to e85 for a while but couldn’t necessarily find anything about it. I know the forum is old but I was wondering if since the original post if you’ve ran into any problems without a tune. Can’t seem to find much on tuning either