The gas station I frequent has E85, I was wondering if I could run a gallon or two mixed into a tank of CA 91 octane without issue. I currently have a stage 1 tune and know that an E85 mix will increase the octane rating and slightly decrease temps. I did not know if you need a tune to properly run such a blend, or if it will be fine with a mild blend.

Thanks all.

 

In my opinion, Absolutely. E20-E25 is safe with or without fuel pressure adjustment. Above that you Probably want your tune to adjust fuel pressure to increase flow. On JB4 I plugged green wire in and was able to run pretty heavy mixtures with little effect on trims (green plug increases fuel pressure requested, prior to green plug I ran e25 all the time). On EC tune I’ve been running about 6 gallons e85 to 10 gallons 91 (91 is also E10 here in California) and no issues. I regularly log and no warning signs either. I’ve “heard” of people running into problems above e40 mix.

the m276 in our car is effectively e85 friendly as far as I know. In some of its other applications it’s been used as flex fuel.

issues for c43 is getting enough fuel to the engine as e85 is less energy dense so at higher mixes the pump (and maybe injectors?) can’t keep up.

tldr: yes

 

People definitely do

 

Well documented, E30 is ideal blend...5-5.5gal of E85 per full tank.

40k miles doing this without issue.

 

Awesome. Is this without a tune or JB4 tailored specifically for this fuel blend? Did you notice a power difference or temp difference between this blend and straight pump gas? Thanks!

 

Pre and post-install of JB4 w/BCM and custom map6. It ran just a tad more aggressive pre-JB4, but once I hammered down my map6, I can absolutely notice if I only run 91/93. My quickest times are with 93/E85 blend, but we have very few 93 pumps so it's very inconvenient to run it exclusively.

 

Thank you for your response and insight, very much appreciated. I will be filling up this Friday and will report back.

 

I just filled up with an e30 mix (probably e28-29 given the amount left in the tank). It is approximately 95 f outside so I did not give it the beans driving home. All good cruising and will take out for a canyon drive early tomorrow morning.

 

I put approximately 60 miles on the car with an E30 blend. It drove well and felt strong.

 

So I have a stage 1 tune by Eurocharged. After having it a few months i asked for a bit more out of the mapping. They sent me back another a more aggressive map. I noticed there is a lot more bangs and pops in the downshift in S+ mode which is is unburnt fuel in the exhaust (backfire). Confirmed with my mpg going down. Would it be safe to say that the remap is made to run richer? I was told to also add 2-3 gallons of E85 and have been doing it for a couple of months now with no issues. Do you think it would be safe to run more E85 ? And what would happen if you ran too much? You mentioned the fuel pump and or injectors not keeping up. Would it just stall or what????

 

well I'm sure there's safeguards for not enough fuel, but running lean would be very bad for the motor. I always thought running rich is much safer than running lean.

 

The bangs and pops are likely "cosmetic" and not related to the actual performance side of the tune. And contrary to what you stated, pops and what not during downshifts can actually be related to overly lean conditions, that are so lean they cannot ignite in the cylinders, and instead, the "small" amount of fuel ignites in the exhaust. At least that's my understanding.

The remap would not aim to make your mixture richer. A good tuner, which I would classify the guys at EC as, is aiming for the ideal AFR. Stock C43 is probably close to ideal AFR although it might be slightly off to meet emission standards. As c43PDX stated you actually make more power on a lean mixture, but it also runs hotter and you risk engine damage.

EC told you to mix some E85 in as they've increased boost/timing, so you need more octane

E85 increases octane, but it has less energy, so you need more of it. Your ECU watches several variables closely to ensure your AFR, fuel pressure, trims, etc. is where it wants it. The ECU will generally prevent damage from things such as low octane and not enough fuel. You'll likely get a CEL, either because your mixtures gone too lean or the ECU has noticed fuel pressure has dropped. Your car will go into limp mode where you have drastically reduced power, with the idea being you don't stall out completely in the middle of the highway.

Sudden changes could cause a misfire or perhaps an engine stall. I had several misfires when I changed my jb4 map and didn't let the car adjust cause I'm an idiot. My guess is the car requested the amount of fuel it thought it would need for the amount of boost it thought it would make. My fuel had more E85 in it though and my boost was higher, so brief lean mixture -> hot cylinder -> misfire.

This is just info I've picked up along the way and I could be wrong about some stuff so please correct me

 

so if I’m in California and I am tuned with 93 octane map, i can safely run e25 or e30 at all times by mixing 91 and e85 ??

 

I have been using approximately e30 since my original post above without issue (over a year of which at stage two).

 

if you’re tuned always ask the tuner. From an octane/knock perspective you’re more than safe with a e25/e30 but you never know how your tuner is handling fuel trims. If their tune happens to be maxing out trims already (unlikely) then your engine might struggle to get enough fuel. Your almost certainly good but no harm in asking

 

So over a year and about 50k miles on my C43 tuned by Eurocharged I've been using about 4 gal of E85 and have not had an issue at all. Now as I previously mentioned my tune is a bit more agressive than a cookie cutter tune and I do have BMS intakes as well. Now I did push it at one point and put in 4.5 gal of E85 to see how much I could safely and all was good until I got to the search for gas station low fuel warning and a check engine light came on but ran fine. After adding more gas (91 octane) here in So Cal the check engine light went away. So I max the amount of E85 to 4.3 gal and car runs great.

 

so are u tuned for 91 or 93 octane ? Can you asked to be tuned for 93 and add e85 to raise the octane even tho you only have access to 91 instead of 93. Would this result in faster times ? Also what’s ur current 0-60 and 1/4 mile after adding the 4 gallons of e85

 

I suppose I could have, but where is 93 octane out here in California? E85 would be better for a tune. So I just turned 105,000 mi on my car and have been running 4 and 1/2 gallons of e85 for almost 2 years now and it definitely runs better. Now to go full 85 but have to replace the fuel pumps the injectors are capable of providing enough fuel but the fuel pumps are the weak link. I don't have time for my 0 to 60 or quarter mile times. Are you out here in Southern California?

 

I read that anything over 10% ethanol was harmful to the fuel lines. I know the American Motorcycle Association conducted a big campaign against going to E15 because it would harm fuel lines in motorcycles. This may be true for only older motor vehicles, but you might want to check to make sure all of the fuel system components can handle more than 10% ethanol.

 

It is my understanding that the fuel line issue was with older cars and should not be a problem for the c43.

 

Hey I was just wondering if anyone on here has kept running E85 with their car and if there have been any issues. Thanks!

 

In the almost 3 years since I created this thread, all is good. I have been running an e25 to e30 blend on my stage 2 tune without issue.

 

What do you use 91 or 93 or 94 and how much e85 do you put in because I tried 94 with a little e85 and I was hitting like 3.5 0-60 but if 91 and e 85 mix is better because AMR did give me a e30 map whats the percentages looking like

 

The higher the octane the better. As such, if you have access to 94, use that. I fill up to a half tank on this car - so I generally mix 2 gallons of e85 with 6.3 gallons of 91 to get my desired blend.

 

Spending an extra $10 to fill my $150K vehicle's tank wth 91/93 octane doesn't annoy me, and I don't drive enough to worry about the cleaner exhaust gases that might result from E85.