# E85, Octane & Other Fuel Stuff



## Williamttrs (Mar 29, 2013)

In stock form can our cars run on E85 or some blend of E85 and gasoline? If so, are the advantages to doing this?

Does it make sense to consider modding any components to enable the car to run on E85?

Since E85 has a very high octane rating, why isn't it used or discussed more often? Am I missing something?


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## smack_ttrs (Mar 24, 2013)

Williamttrs said:


> In stock form can our cars run on E85 or some blend of E85 and gasoline? If so, are the advantages to doing this?
> 
> Does it make sense to consider modding any components to enable the car to run on E85?
> 
> Since E85 has a very high octane rating, why isn't it used or discussed more often? Am I missing something?


not all fuel lines/filters are e85 safe. the elevated ethanol content can break down these components if they are not made to handle it. 
e85 is a blend. 85% ethanol/15% gasoline. i believe most gasoline(possible all at this point) has some ethanol content to it although much less than the 85% so manufacturers may already be "ethanol proofing" newer vehicles. 

e85 tunes similar to c16(about 116 octane) at least in evos so the benefit is you can be much more aggressive with your tune thereby making more power.

the downsides are fuel usage which is around 25% more than gasoline. also availability can be pretty limited depending on your area. 

storage can be tricky as well(in case you were thinking about keeping a 55gal drum in the garage) since it's fairly hygroscopic which can change the ethanol ratio out from under you. we've also seen stations locally that have had issue keeping a proper ratio. this is the last thing you need when tuning closer to the extreme since it takes much less deviation from optimal for knock/damage to occur.

theoretically if the lines/filters were ethanol safe then you would need a higher pressure fuel pump and possible injectors. don't know how direct injectors do since they already run at such high pressures. you would also want a fuel sensor and display to show you the current fuel ratio the car is seeing. zeitronix has a good setup.

one other problem is that the stock turbo is already running out of steam and the car is running out of fuel on a stage 2 tune so you would probably want to go to a bigger turbo to see any real benefits.

my .02


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## Williamttrs (Mar 29, 2013)

smack_ttrs said:


> not all fuel lines/filters are e85 safe. the elevated ethanol content can break down these components if they are not made to handle it.
> e85 is a blend. 85% ethanol/15% gasoline. i believe most gasoline(possible all at this point) has some ethanol content to it although much less than the 85% so manufacturers may already be "ethanol proofing" newer vehicles.
> 
> e85 tunes similar to c16(about 116 octane) at least in evos so the benefit is you can be much more aggressive with your tune thereby making more power.
> ...


Thank you for the 411. I have been reading about this topic on other forums. Models with larger followings and more years under their belt seem to have quite a lot to say about this subject. I think it is an interesting idea down the road, probably if I were to keep the TTRS and make it a weekend car.


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## jibbed (Dec 3, 2011)

Hi William,

I had asked this question a year or so ago on the VAGOC forum. I also contacted LOBA about their fuel pump and suitability for e85.

They had said that nobody in the world is doing e85 on these cars, more to the point - I don't think anyone is doing e85 on DFI cars. 

I've got the capability to tune my own car (I bought the pro tuning software/hardware), but I can't see any specific injector scaling multiplier in the map (like there is in the evo/wrx ECU's).

I've been tempted to do a 50/50 mix (93ron/e85) to bring it to an E40-E45 level fuel. I figured there should be enough leeway in the fuel system and might bump up the RON rating to 97-98ish, and allow me to add a few more degrees of timing into the engine.

4-5 degrees extra timing even at the same boost level should be worth an extra 20-30hp.

Would love some of the other tuners to chime in on this though!

Oh - and BTW - Was making 450-ish awhp on my evo with e85 (also self tuned).

Cheers,
matt


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## primetime21 (Feb 14, 2013)

I would stick with unleaded race fuels for the car until someone specifically creates a solution for E85... Looks like there are some stations in Houston that sell GT260 at the pump... See link below... 

http://www.racegas.com/fuelfinder

Personally, I run GT260 and/or Shell URT advanced full time in my 2010 S4 and it nets me about .25-.3 in the 1/4 mile and 2-3mph in trap speed... I don't daily the S4 nor the TT-RS so I will be going to 100% race fuel in the TT-RS once it's broken in and tuned... Shell URT is the best unleaded fuel IMO and actually compares well to leaded C16 in performance, however it can't be bought at the pump and it's expensive... I get a good price at about $11 a gallon but GT260 can be bought at the pump by me at 3 stations for $6.59 to $6.89 so about $2.50-$3.00 more than 93...


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## Williamttrs (Mar 29, 2013)

primetime21 said:


> I would stick with unleaded race fuels for the car until someone specifically creates a solution for E85... Looks like there are some stations in Houston that sell GT260 at the pump... See link below...
> 
> http://www.racegas.com/fuelfinder
> 
> Personally, I run GT260 and/or Shell URT advanced full time in my 2010 S4 and it nets me about .25-.3 in the 1/4 mile and 2-3mph in trap speed... I don't daily the S4 nor the TT-RS so I will be going to 100% race fuel in the TT-RS once it's broken in and tuned... Shell URT is the best unleaded fuel IMO and actually compares well to leaded C16 in performance, however it can't be bought at the pump and it's expensive... I get a good price at about $11 a gallon but GT260 can be bought at the pump by me at 3 stations for $6.59 to $6.89 so about $2.50-$3.00 more than 93...


Thanks for the link. There is a shop about 10 miles from my house with GT260. I will be sure to stop by soon.


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## jibbed (Dec 3, 2011)

So just bumping this thread...

I'm going to be trying an E30 blend of fuel which, from all estimations, should run fine using the existing fuel system.

Am going to tweak the tune to match, so I'll come back with a view on the performance benefits of doing so when complete. Should take a couple of weeks I'd say.

Apparently E30 is the equivalent ethanol rating of 97RON We get 94RON fuel here. Am hoping there's another 15-20hp. I'll be v.happy with 450hp.

Cheers,
matt


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## rlab (Nov 5, 2012)

jibbed said:


> I don't think anyone is doing e85 on DFI cars.


That is not true.


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## smack_ttrs (Mar 24, 2013)

rlab said:


> That is not true.


hey bryan, have you had a chance to see if anything(lines/filters) needs to be replaced or is everything ethanol safe?


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## jibbed (Dec 3, 2011)

Would it be more true if I said Audi DFI cars?


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## rlab (Nov 5, 2012)

jibbed said:


> Would it be more true if I said Audi DFI cars?


No, TFSI is a TFSI.


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## jibbed (Dec 3, 2011)

Interesting! So what's the verdict? Assuming you stuck with the standard fuel system, so were limited to e30-ish fuel?



rlab said:


> No, TFSI is a TFSI.


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## Dan.S (Jan 3, 2012)

Bump for answers, I'm itching to quench the desire for E85!!!!!!


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## tdi-bart (Feb 10, 2011)

spicy german fuel ethanol free


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## Dan.S (Jan 3, 2012)

BlA bla bla!!!!!! * _ * 

I ran good euro fuel while I was in Italy. This swill 91 in Arizona is pathetic.

I want more power than 91 oct, in 110*f temps, and retarded timing pulling alows.


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## [email protected] (Dec 14, 2012)

jibbed said:


> I don't think anyone is doing e85 on DFI cars.



We are. It's not release quality yet, but we've got E85 tunes for several cars.


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## Dan.S (Jan 3, 2012)

[email protected] said:


> We are. It's not release quality yet, but we've got E85 tunes for several cars.


Is there required hardware swaps?


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## OldKenzo (Aug 14, 2012)

tdi-bart said:


> spicy german fuel ethanol free


You are too cruel! We Californians get nothing but 91 piss.


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## Optimus812 (May 5, 2012)

I'd also be really interested in E85 tune for the TTRS. I'm currently mixing in 100 oct unleaded to bump up the octane from this crappy 91 in Cali... Problem is 100 oct is like $8 a gallon while E85 is like $3.50. The fun part of running E85 is dealing with the various ethanol levels from the different stations and during seasonal changes. Could be E70 one day E85 the other which affects the tune. I assume other than making sure lines and fittings are E85 friendly, some type of E85 fuel content analyser would also be needed??


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## [email protected] (Dec 14, 2012)

Optimus812 said:


> I'd also be really interested in E85 tune for the TTRS. I'm currently mixing in 100 oct unleaded to bump up the octane from this crappy 91 in Cali... Problem is 100 oct is like $8 a gallon while E85 is like $3.50. The fun part of running E85 is dealing with the various ethanol levels from the different stations and during seasonal changes. Could be E70 one day E85 the other which affects the tune. I assume other than making sure lines and fittings are E85 friendly, some type of E85 fuel content analyser would also be needed??


That's one of the big reasons I said it's not production ready. In it's current form, with the current hardware on the cars, it's quite risky. Yes, ideally an ethanol sensor is required.


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## Williamttrs (Mar 29, 2013)

Sea[email protected] said:


> That's one of the big reasons I said it's not production ready. In it's current form, with the current hardware on the cars, it's quite risky. Yes, ideally an ethanol sensor is required.


 Remind me. e85 is a problem because it is corrosive to standard engine parts? Is that right?


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## jibbed (Dec 3, 2011)

*Sean* - I'm currently running your V1.2 stage 2 map (v2.0 isn't out here in .AU yet )...

With our E85 (other than at one station) it is a constant 85% ethanol - have run numerous cars for years on it.

If you're after a beta tester, I'm itching to start putting ethanol in my car.



[email protected] said:


> That's one of the big reasons I said it's not production ready. In it's current form, with the current hardware on the cars, it's quite risky. Yes, ideally an ethanol sensor is required.


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## [email protected] (Dec 14, 2012)

Williamttrs said:


> Remind me. e85 is a problem because it is corrosive to standard engine parts? Is that right?


Nah... most US gasoline has 10% ethanol, so cars are built to tolerate it. Older cars, ya, they have gaskets that ethanol can dissolve. But, nearly everything now tolerates it.

The bigger problem is that E85 requires about 25% more fuel flow than E10. On cars where the power limitation is fuel flow, E85 isn't practical. Stage 3s for example will require significant upgrades to the fueling system. But, stage 2+ FSI cars have plenty of fueling already. So, they do quite well on E85.

We haven't done the TT-RS on E85 yet.


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## jibbed (Dec 3, 2011)

bump for a beta tester 

FWIW - My car was the original development car for your first APR TTRS tune.


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## Quisp (Mar 18, 2012)

Dan.S said:


> BlA bla bla!!!!!! * _ *
> 
> I ran good euro fuel while I was in Italy. This swill 91 in Arizona is pathetic.
> 
> I want more power than 91 oct, in 110*f temps, and retarded timing pulling alows.


You can get unleaded 100 octane here but it is $7.50 a gallon. Have it in Scottsdale and in chandler by firebird.


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## [email protected] (Dec 14, 2012)

jibbed said:


> bump for a beta tester
> 
> FWIW - My car was the original development car for your first APR TTRS tune.


One thing at a time.. we've got plenty of other TTRS stuff to release before E85. We'll probably do it, but it's going to be a bit.


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## jibbed (Dec 3, 2011)

I shall be watching with a keen interest.

Any word on the ROW V2 updates?


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## [email protected] (Dec 14, 2012)

jibbed said:


> I shall be watching with a keen interest.
> 
> Any word on the ROW V2 updates?


We've got it out for testing. Just waiting to make sure there aren't any issues before we release. We have had one underboost code here in the states, but we're pretty sure it's hardware related.

If everything goes well, it will be out soon for ROW.


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## jibbed (Dec 3, 2011)

Excellent - thanks for the update!



[email protected] said:


> We've got it out for testing. Just waiting to make sure there aren't any issues before we release. We have had one underboost code here in the states, but we're pretty sure it's hardware related.
> 
> If everything goes well, it will be out soon for ROW.


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## psabo (Oct 3, 2008)

OldKenzo said:


> You are too cruel! We Californians get nothing but 91 piss.


yes, it really depresses me... even the east coast gets 93 octane in most areas with many offering no ethanol


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## Dan.S (Jan 3, 2012)

When I get my stg II tune I'm going to be running straight E85 and start testing results... Consequences be damned.


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## jibbed (Dec 3, 2011)

LOL - That's the spirit! 

I'd think there'd be enough leeway in the system (not sure whether there's any adaption in the AFR's to try to get back to a certain level) to get to an E30 or E40 level without too much grief?


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## Dan.S (Jan 3, 2012)

I do not believe there are systems like that in cars.... 

I'm just doing it to find the gains for E85 over our **** 91 Oct. As well as to find how long stock fuel pieces last untill failure lol. If they don't fail, well then everyone can start drinking!


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## illbillTS (Apr 11, 2006)

Bumping this thread from the dead to see if anyone has experimented with running ethanol blends on their TTRS. An E85 pump just opened up a few blocks from me so I was looking at trying an E30 blend that URHank talks about here on my stage 2 tune. 

I know it's very common on the B8 S4 side to run 93/E85 mixes (even to run race files), but I couldn't find too many guys trying it with their 2.5T.


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## rtbrjason (Jun 14, 2015)

illbillTS said:


> Bumping this thread from the dead to see if anyone has experimented with running ethanol blends on their TTRS. An E85 pump just opened up a few blocks from me so I was looking at trying an E30 blend that URHank talks about here on my stage 2 tune.
> 
> I know it's very common on the B8 S4 side to run 93/E85 mixes (even to run race files), but I couldn't find too many guys trying it with their 2.5T.


It's not a problem to run it on any modern car with adequate fuel, but you need to be able to tune for it. You'll get some increase in low end torque and power from just E85 alone, but the real magic of it is its knock resistance. You can run a lot more timing and boost before you have knock issues. The tune should account for the fact that E85 requires 25-30% more fuel as well though. You can drive around with your fuel trims pegged at +25% but it's not ideal.

I'd only use it if I had a real DIY tuning solution. I've seen a range of fuel from E70-E90 at our local pumps so even running a vendor tune isn't ideal. In my previous car, I ended up tuning for E80 and let the fuel trims adjust +/- 5% to account for the difference in fuels.


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## illbillTS (Apr 11, 2006)

Yeah at this point I'm not looking to try to get away with a 100 octane file with an E85/93 blend but, like you mention, just as a form of knock prevention/timing retard in these summer days with 3-4 gallons of E85 mixed in. I'll give it a shot next time I fill up and log timing etc to see how the car reacts and stft/ltft. I have the Loba HPFP, so not too worried about the extra fuel flow required. 



rtbrjason said:


> It's not a problem to run it on any modern car with adequate fuel, but you need to be able to tune for it. You'll get some increase in low end torque and power from just E85 alone, but the real magic of it is its knock resistance. You can run a lot more timing and boost before you have knock issues. The tune should account for the fact that E85 requires 25-30% more fuel as well though. You can drive around with your fuel trims pegged at +25% but it's not ideal.
> 
> I'd only use it if I had a real DIY tuning solution. I've seen a range of fuel from E70-E90 at our local pumps so even running a vendor tune isn't ideal. In my previous car, I ended up tuning for E80 and let the fuel trims adjust +/- 5% to account for the difference in fuels.


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## rtbrjason (Jun 14, 2015)

Adding a few gallons to the mix certainly won't be an issue and will definitely raise octane a bit. Fuel trims should fully account for about ~E70 so any mix below should work okay. Check how your Long/short fuel trims look now on the E10 93 and then see how it is with some different mixes.

Assuming a 14 gallon capacity, if you fill 6 gallons of E85 in and then top off with E10 93 (for a total of about 8 or so gallons of E10 93), you'll effectively be running "E42" with an estimated octane of about 96. The 96 assumes that E85 has the equivalent of about 100 octane.

If you reverse it and run 8 gallons of E85, and 6 gallons of E10 93, the mixture will essentially be an "E52" with an effective octane of 97. Fuel trims on this mix would be right around +20% assuming everything else is okay.

Also, if you're going to play with this, you might want an E85 tester. You won't know if what you're pumping is E85 or E70. The numbers above assume E85.


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## illbillTS (Apr 11, 2006)

I ended up testing an E85/93 mix that resulted in an E30 blend (4 gallons of E85 + 10.5 gallons of 93). After the car adapted to the fuel by doing a few WOT pulls, I was seeing much cleaner timing up to redline compared to my straight 93 logs. Timing retardation was zero degrees across all cylinders and my lambda values were essentially identical between 93 and E30, so fueling does not appear to be an issue. Unsurprisingly my LTFT jumped from 4% on 93 to 11% on E30, but well within limits of adaption. 

Seat of the pants, car feels slightly stronger and more importantly it feels more consistent when going WOT. It seems like I'm maxing out the performance of my GIAC Stage 2 93 map, so there's really no need to try anything above E30 right now. If I get ambitious I might test higher ethanol blends to work toward being able to run the 100 octane map, but for now I'm satisfied. Overall :thumbup:


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