Switching between pump 93 and e85

[phecker410]

Hi All,

Wondering if anyone has experience switching between 93 octane pump gas and e85 (preferably on this platform, but interested in information from other cars as well). By switching, I mean mostly running 93, with the occasional e85 fill-up occurring 10-25% of the time. I'm most interested in understanding the long-term risks of such a fueling schedule. The closest e85 is about 45 minutes from me in a direction that I rarely drive. I'd like to realize the performance benefits of e85 on occasion, but I'm sure as hell not driving there for every fuel-up.

I've never run e85 in any vehicle. From what I understand, it allows for more efficient turbo production and also decreases combustion temps. If the combustion temperatures are changing regularly as a result of my fueling changes, can this contribute to accelerated engine wear? My 10th grade understanding of thermodynamics leads me to believe that continual temperature change could be a no-no for aluminum engine components.

Is it a common practice to switch between pump gas and e85? Or is it more of an "all the time or not at all" fuel?

Thanks in advance for any experienced input!

 

[MonkeyMD]

I do it all the time. No negative effects so far at over 100k miles.

 

[daconchslop]

Same here. Mostly switch to 93 if I know I’m going outside of e85 zones.

 

[ZuMBLe]

Hi All,

Wondering if anyone has experience switching between 93 octane pump gas and e85 (preferably on this platform, but interested in information from other cars as well). By switching, I mean mostly running 93, with the occasional e85 fill-up occurring 10-25% of the time. I'm most interested in understanding the long-term risks of such a fueling schedule. The closest e85 is about 45 minutes from me in a direction that I rarely drive. I'd like to realize the performance benefits of e85 on occasion, but I'm sure as hell not driving there for every fuel-up.

I've never run e85 in any vehicle. From what I understand, it allows for more efficient turbo production and also decreases combustion temps. If the combustion temperatures are changing regularly as a result of my fueling changes, can this contribute to accelerated engine wear? My 10th grade understanding of thermodynamics leads me to believe that continual temperature change could be a no-no for aluminum engine components.

Is it a common practice to switch between pump gas and e85? Or is it more of an "all the time or not at all" fuel?

Thanks in advance for any experienced input!

No negative effects. 45 min is kind of far. Keep in mind your fuel consumption will go up as the ethanol content goes up. You may want to consider getting fuel jugs instead of just relying on filling the tank.

 

[phecker410]

Good enough for me, thanks all! I'm already running MPI with a LPFP I should be good to go, right? I just need an e85 map from EQT?

 

[jimlloyd40]

Good enough for me, thanks all! I'm already running MPI with a LPFP I should be good to go, right? I just need an e85 map from EQT?

Yes. Have you ever dynoed your car?

 

[phecker410]

Yes. Have you ever dynoed your car?

Nope. Still on pump gas tune revision 3. I may dyno in a month or two

 

[ZuMBLe]

Good enough for me, thanks all! I'm already running MPI with a LPFP I should be good to go, right? I just need an e85 map from EQT?

You should be good to go... back to the E85 station often... hahaha.

 

[billbadass]

I just got the "Fuel It" ethanol sensor and switch all the time and track it in the fuel it phone app real time. In my opinion, serious full throttle runs for any extended duration should not be done on 91/93 octane in these MQB cars on the stock bottom end, they are too sensitive to elevated combustion/exhaust temps pump gas creates, just my own opinion for a number of reasons, so I take it easy on pump gas and only really ever push the car on ethanol tune. E50 by the way gets you like 95% of the way there on the ethanol benefits and uses less ethanol and a full tank lasts longer, so i just had my car tuned on E50 and I gained like 85whp vs 91 octane on very very mild hybrid is38, and my car also tuned by ed at EQT. transforms the car. I also just keep like 10 cans that are 5 gallons each in my garage of pump E85 and put it in my car at home and mix it that way. nearest ethanol station to me is not that convenient either.

 

[jimlloyd40]

I just got the "Fuel It" ethanol sensor and switch all the time and track it in the fuel it phone app real time. In my opinion, serious full throttle runs for any extended duration should not be done on 91/93 octane in these MQB cars on the stock bottom end, they are too sensitive to elevated combustion/exhaust temps pump gas creates, just my own opinion for a number of reasons, so I take it easy on pump gas and only really ever push the car on ethanol tune. E50 by the way gets you like 95% of the way there on the ethanol benefits and uses less ethanol and a full tank lasts longer, so i just had my car tuned on E50 and I gained like 85whp vs 91 octane on very very mild hybrid is38, and my car also tuned by ed at EQT. transforms the car. I also just keep like 10 cans that are 5 gallons each in my garage of pump E85 and put it in my car at home and mix it that way. nearest ethanol station to me is not that convenient either.

What power level are you at now?

 

[billbadass]

What power level are you at now?

my car made 480whp on Ed's dyno. his dyno reads a little higher than other dynos so maybe my car is making 435whp on a dynojet?

the ethanol tune transforms the car in many other ways than just power increase too, my car even idles a little smoother on ethanol, and the turbo spools way better and motor is just far more responsive at all amounts of throttle.

 

[jimlloyd40]

my car made 480whp on Ed's dyno. his dyno reads a little higher than other dynos so maybe my car is making 435whp on a dynojet?

the ethanol tune transforms the car in many other ways than just power increase too, my car even idles a little smoother on ethanol, and the turbo spools way better and motor is just far more responsive at all amounts of throttle.

Wow Ed's dyno is off that much?

 

[Razgriz337]

This is my pump after roughly 10 months of running E85 (content usually 70-77%). My primary concern was the "gumming" which seems to have accelerated the filter clogging. This pump would do 6+ bar at 80% duty cycle new, and by the time it came out I was down to 5bar at 100% duty cycle.

If you plan on running ethanol full time long term be sure to keep an eye on your low pressure readings. But, I'd also note it's entirely possible this particular filter element clogs faster than the OEM one as it's designed be serviceable.

 

[daconchslop]

This is my pump after roughly 10 months of running E85 (content usually 70-77%). My primary concern was the "gumming" which seems to have accelerated the filter clogging. This pump would do 6+ bar at 80% duty cycle new, and by the time it came out I was down to 5bar at 100% duty cycle.

If you plan on running ethanol full time long term be sure to keep an eye on your low pressure readings. But, I'd also note it's entirely possible this particular filter element clogs faster than the OEM one as it's designed be serviceable.

View attachment 196740

Did you replace just the sock, or was more recommended?

 

[Reggie Enchilada]

If anyone needs help with installing an ethanol content sensor and gauge let me know. I just did it a few weeks back and can give some part suggestions and installation advice.