Thread: e85 = the shit!

So I was getting bored waiting for my new turbo and I decided to turn up the boost a bit on my current snail in the scooby..

It's a 19t... My stock wastegate solenoid was having issues holding boost to redline so it dropped off to about 15psi, but these plots are a comparison of what that car was making on 91 octane VS e85.. Pre-turbo swap..

e85 is the SHIT.

(This is an interpolation from Airboy's spreadsheet.. These usually read a bit lower than a Dynojet would at the wheels.)

So basically to summarize, on e85 with my current turbo still running a bit rich and not totally dialed in WITH the boost falling off to 15 psi at redline I made 95whp and 124 Ft/lbs of torque more than I could ever make on 91.. Fcuk 91 octane.. NEVER again.

And for reference.. The boost quit falling off after I drove the car to work and the ECU figured out how to deliver the boost I was requesting.. I just didnt have space or time to log another run.. (Plus I smacked into fuel cut for the first time ever.. Need to up those limits a bit.. lol)

Here is my timing and AFR.. The AFR is really rough still.. Have not really dialed it in yet.. Shooting for around 7.8:1

The AFR is corrected for e85 via the LC-1

Timing is basically whatever I want it to be.. Knock doesnt exist, ever.. This timing curve seems to be working pretty good.. No reason to really advance it further.. Most folks dont seem to build any more power advancing much beyond what Im running now..

Here was my boost for shits and grins..

Only 18.2 PSI then it fell of to just over 15 PSI..

I've seen this turbo hold around 20 PSI to redline.. I will make some tweaks to my boost control stuff and log another run..

Not freaking bad for a 19t at around 18 PSI..

I love e85!

Its all in tuning but you have to upgrade your fuel setup because it requires a lot more e85 to move the car.

Expect your MPG to plummet if you car is tuned properly for e85 compared to pump but its the closest thing to race gas you can get for a good price so its worth it.

While everyone talks about the performance, I'd like to point out, that even though it costs almost half as much as 91, it uses almost twice as much fuel, so in the end it's a bit of a wash in terms of cost savings... but it definitely has better cooling characteristics (alcohol burns cooler than gas) and a higher octane rating than anything available at the pump... Obviously it is much cheaper than $7/gallon 105 octane race gas. But don't expect to save a ton of money switching to e85 in your daily driver.

Negative Jon..

Fuel economy supposedly dips around 30%..

In my real world testing so far I was getting just over 30MPG on 91 on the freeway commuting to work..

On e85 I am getting 26 MPG..

Based on my calculations of cost of each fuel and my own personal mileage and fuel economy I am saving about $50.00 per month on fuel.. And I currently have over 100 more horsepowers/torque..

Put that in your internet and smoke it.

And although the antiknock value of e85 is closer to 105 octane gas, thanks to its additional cooling characteristics it has been proven to make just as much power as c16. And Uhm.. Yes.. It fucking rocks..


*edit - although e85 likes to run quite rich for max power, it tolerates some extremely lean conditions. In closed loop no boost conditions (although it is harder to stay out of the boost.. The increase in spool response is very noticeable, any crack of the throttle and my 19t starts spooling) you can acheive a pretty damned good fuel economy as noted above.. And actually EGT's and Cylinder head temps remain much cooler on e85. EGT's are around an average of 200*C cooler on my car and my cylinder head temps run between 5-10*C cooler while cruising to work.

Here is my rough math..

I drive 1800 miles per month (commuting). - this was based on my total mileage put on the car over the last 6 months.

3.30gal-91octane/30mpg = $0.11/mile

2.20gal-e85/26mpg = $0.08/mile


$198/month 91 octane @ 1800 miles/month

$144/month e85 @ 1800 miles/month
----------------------------------
$54/month savings. Roughly.. If I play nice on the throttle ;)

Those were based on what I was paying for the fuels a few weeks ago.. e85 has gone down a bit here.. (I am buying it from a commercial cardlock pump at my office at wholesale price)

Oh and as for cold starts/cold driving.. Before I tweaked my cranking IPW and timing the car was a bit more difficult to startup cold.. BUt once up to temp it ran flawlessly.. Now that I have tweaked my fuel and timing during cold cranking the car starts right up regardless of temp. The most it has ever cranked over is 4 or 5 times to start when ambient temps were down around 35 degrees F. My car runs flawlessly on e85 now.. You can't even tell you are running it.. The only thing I ever notice is sometimes after hard driving the idle dips rich for a couple of revolutions before settling out.. That's more to do with my big fat injectors / deadtime. Did the same thing on 91.. But It's hardly noticeable and the car never stalls.. I'm just anal.

Crap. Forgot. e85 is not equal to ethenol. the 15% gas makes a big difference. Disregard my previous comments.