Downsides of E85
 

There seems to be alot of people (like mlpilot) and others who have been devoted to explaining the very obvious upsides to using E85. What are the potential downsides of E85? My local tuner told me that there are lots of downsides since the mix isn't exactly regulated and he recommends buying race gas instead. It can lead to alot of block problems and possibly rehoning your cylinder. I understand there would have to be alot of datalogging to do every month seeing the fact that they love to switch the mixes around. Tell me what your experiences are with the 3 classes and how often they get changed at the stations. E85 is very abundant in my area that is why I am so interested in switching over. I understand all the upsides to it, but I would like it if anyone shared the clear downsides to it and having a vendor tune to it if you are not able to datalog and retune your car every month. Just want to everyone to chip in or make it clear what exactly are the risks to doing this setup. I am aware on how to datalog for knock on my car but I haven't learned how to properly tune.

I think one of the biggest problems, like you said, is that stations will vary on the mixes. When winter hits the E85 can drop down to E70. If you use E, datalogging on a regular basis is best. I would almost say at each fillup.

Downside is that the alcohol in E85 eats away at rubber parts in the fuel system. The rubber in the fuel system is designed to handle "some" ethanol, but i doubt for 85% mixture. I know people who've run E85 on a daily basis for at least 1 year and no problems to report. However, nobody knows how long the rubber parts in the fuel system will last with E85. Guess we'll find out in a couple of years or so on how the rubber holds up.

Also, since E85 releases a lot of water vapor, your exhaust system might rust out faster compared to regular gasoline.

Here in California, you wouldn't have to worry about the Winter blend, but the consistency of the Classes is a concern. I'm about two weeks away from making the switch and talking with my Tuner, will be shooting for a conservative tune, just for this reason. It's not like all 91oct or 93oct are consistent, you'll find some inconsistencies from station to station or brand to brand. That's what your Knock Sensor if for. I think as long as your not shooting for every pony you can squeeze out of the tune, you should be fine.

I agree with the OP, there are some inherent risks in running E85. I'm willing to take those risks for the dollar savings over running 105 octane race gas - which is not available at the pump anyway.

IMO, the key is to (1) have a safe conservative E85 tune, and (2) have the CEL flash-on-knock mod with parameters set to, say, 5 & 10. If you see occasional knock - figitabotit. If you see consistent knock do some data logging and adjust either your tune or simply your boost.

:mitsu:

Yes like everyone says, do a conservative tune with zero knock. My tuner said I had a very sensitive knock sensor so He tuned my car zero knock at 23.6 psi. I still had a gallon of premium in the tank so it wasn't all E85. Just switching the gas with 1000cc injectors netted me 43 hp. It was conservative so it's safe just in case the weather or mixture changes. Bang for the buck you can't beat it. I recently paid 3.12 a gallon well under the national average. Look at the figures from the AAA (http://www.fuelgaugereport.com/. ) Per BTU you're only paying $4.38 for E85, but premium is going for $4.53. 15 cents less and you get more power. It makes perfect sense to do the switch if you have the availability.

IMO the Rubber corrosion is a myth.. We have been using it for over a year on an rx-7 and now our evo for several months with no issues.. as far as the mix goes its just like running 500hp on pump.. you have to be careful not to get a bad fill up course..

Other than rubber corrision, since it is a cleaning solvent, what other damage is possible??

The rubber corrosion is a myth!! All cars after 1998 were mandated to be able to handle Ethanol in their rubber lines.

Tired of hearing this crap.

-E

No downsides other than you use 30% more of it cruising, and becuase it makes the car more fun probably more than that.

Pros-

Car runs cooler

Engine is more knock resistant

Makes more power over pumpgas

Smells cool

Cons-

Makes the car too much fun

+1.. also, when we tested e-85 in cwills car it made more power than Q16.. Im jealous honestly that he can ride around in a 127mph trap car all day long and step on it whenever he wants w/o worrying about if he is on race gas.. I love it!!!

Only downside I've gotten from this thread is that you must datalog frequently especially when you are getting excess knock on your sensor and best to get a conservative tune that has no knock during any load, yeah?

Isn't one downside that E85 has more cold start problems, especially in very cold weather?

Says the man that lives a couple hours west of the Mohave valley :)

Yes it is, the greater the ethanol content the harder it is to get it to start from what I have been told..

Scorke

LOL, you got me. :D BTW, E85 is reportedly coming to a local filling station for me. I will be all over it when it arrive.