Tuning for E85

[Marshal]

This is going to be very basic, because it is simple to tune for E85. I have HP Tuners so all I did was change my cylinder gain on the main fuel section from 1 to 1.3. it's not exact science, for example, 1.3 is what you want if you have actual 85% ethanol, but in the winter, the blend goes down to 70% so then you would enter 1.2. you can also use your maf sensor to see what to change the cylinder gain to, for example, if you are running 5% lean then you would richen it up by entering 1.22

 

here is a caveat, only mess with the cylinder gain if you are tuning for E85. if you need to adjust your maf sensor to dial in your car, that is different, and hopefully we can get a how-to going soon.

 

once you change your cylinder gain, it's usually a good idea to do a maf adjustment because it will probably be different.

 

There is also a way to make your car start easier with E85 because some people have cold start issues, but I don't remember how I did it.

 

I've also heard that you can install 42.5 lb injectors and run E85 without tuning because they are 30% bigger than stock. 

 

here are a few things I've learned about E85 over the years: One, ethanol is oxygenated, so it has better duration than unleaded gasoline. Two, ethanol is cleaner than gasoline. Three, it takes about 30% more E85 so expect worse gas mileage. Four, E85 has a propensity to attract water, so if you are like me and store it in your garage, it is best to keep it sealed up in a metal container. Five, E85 has an octane rating of around 105, and it also works well as a chemical intercooler, so you can run a smaller pulley on the supercharger if you have access to a tuner, have bigger injectors and can get E85 somewhat easy. I drove 85 miles to get E85 and store it in a 55 gallon drum. I will buy like 35 gallons at a time and top off my drum. Lastly if you are converting to E85, don't be like me and cheap out on 42 lb injectors because if you are going to run E85, you will max them.

 

I am currently running a 3.0 pulley with an XP cam, mildly ported heads a gen 5, water/methanol injection and E85 with no kr, and 42 lb injectors that are at 90% duty cycle, so almost maxed out. with 60 lb injectors I would have a huge amount of headroom.

[digitaloutsider]

This is going to be very basic, because it is simple to tune for E85. I have HP Tuners so all I did was change my cylinder gain on the main fuel section from 1 to 1.3. it's not exact science, for example, 1.3 is what you want if you have actual 85% ethanol, but in the winter, the blend goes down to 70% so then you would enter 1.2. you can also use your maf sensor to see what to change the cylinder gain to, for example, if you are running 5% lean then you would richen it up by entering 1.22

 

For DHP users, this table is Injector Skew Percent. For a summer E85 blend, I've found that ~133% works well.  For winter, scale it back a little.

 

 

There is also a way to make your car start easier with E85 because some people have cold start issues, but I don't remember how I did it.

 

I've also heard that you can install 42.5 lb injectors and run E85 without tuning because they are 30% bigger than stock. 

 

I'm not sure what the table is in HPTuners, but in DHP it's Crank Fuel vs Coolant Temp. Scale the top of the table (-35 C) to 5 or 10 degrees C 10% higher. I think Frosty's guide had you changing it up to like 20 degrees C, but I don't see that as being necessary.

 

This is why swapping to the 42.5s untuned is doable, but it doesn't solve for cold starts, and you're leaving a lot of power on the table by not ramping up the timing some. I've had great luck starting with the GFS table from an '05 Comp-G and tweaking it from there.

 

Other random things I can think of: On the stock fuel pump with a rewire (highly recommended to do the rewire on stock, mandatory on an aftermarket), I was good down to a 3.2" pulley on a Gen V. Below that I started leaning out on cold nights. I went with the AEM 320lph E85 pump.  I also recommend the Deka 60s for the additional headroom. Also, stay away from eBay injectors. Injectors are the lifeblood of the car, really. And the last thing you want is a shitty injector flaking out at WOT with tons of boost. Spend once, cry once. Get the genuine Dekas.

[redgrandprix]

My brain has been pondering e85 lately, the obvious octane increase is incredibly boost friendly but ive seen some cars gain almost 30whp just from e85 and tune N/A. Had me thinking maybe i could get 400whp from the ls4 with H/C/I and then toss the e85 on top. Just daydreaming for the daily

 

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[Marshal]

my daily is a 2008 GXP as well, have an overkill tune for it, and when I run E85, the difference is almost not noticeable. however, a H/C/I swap would likely net a big horsepower gain. IF you knew you would always be running E85, you could bump the compression and get even more power.

[redgrandprix]

my daily is a 2008 GXP as well, have an overkill tune for it, and when I run E85, the difference is almost not noticeable. however, a H/C/I swap would likely net a big horsepower gain. IF you knew you would always be running E85, you could bump the compression and get even more power.

Im pretty sure mine has a can tune from a diablo handheld or just used a diable to turn the dod off. I dont know about upping compression didnt want to really go full out just want to put a decent size cam like a titan 4 from cam motion with a holley sniper race intake with ls7 maf and tb and then found texas speed and perf sells stage 1 243 polish/port heads for like 900 bucks.

 

 

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[Imp558]

That falls under pretty "full out" build. Most guys leave the rotating assembly alone.

[Marshal]

That falls under pretty "full out" build. Most guys leave the rotating assembly alone.

 

he's talking about an LS4, not a 3800. different types of problems.

[redgrandprix]

That falls under pretty "full out" build. Most guys leave the rotating assembly alone.

Kinda and not, a cam is a pretty significant modification considering the work it takes to do it but in the world of LS its almost like a baby step. Full out would be like what jarek is doing to his turbo se with the forged/billet/big turbo stuff. I will say though with a cam it seems proper supporting mods kinda snowball for a 500 dollar bumpstick

 

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