Tuning for E85 Vs 91

[Crossover Auto]

Arghx7 quoted me on it in another post, but I'll repost it here.

My concern is the long term use of E85 with this car because the use of E85 does and can gunk up the high pressure pump and injectors, along with the port side injection components. This is bad because the high pressure pump operates on very tight tolerances. You don't want the HPFP (high pressure fuel pump) seizing up.

[EN2_Squirrel]

if i went with an e85 tune can igo back and forth between e85 and 91? i am in cali so e85 is rare. and does e85 and 91 mix?

[Visconti]

No one can be 100% sure of the long term effects of E85 on the BRZ/FRS/e85.

So far so good, on top of that Subaru has a very good warranty so if anything did go wrong - they would cover it.

As for the tune side of things - When running pump gas and wanting to switch to e85 you'll want to run the tank very low, then fill up on e85.

I'm currently working on a flex fuel kit for these cars.

I should have a few kits out in the wild for testing in the next few weeks

With the flex fuel kit you won't have to switch maps, the ecu will automatically adjust for ethanol content.

-John

[wparsons]

Originally Posted by Concept-Three-LED's

Premium out here is over $4.00 at the moment. Do you lose MPG using E85 instead of 91?

Yep, you do lose mpg.

Originally Posted by serialk11r

Yea, E85 will make 5-10% more power than gasoline all else equal, typically. For example, Formula SAE allows you to use either 100 octane gasoline with a 20mm restrictor or E85 with a 19mm restrictor, because E85 gives more power per unit air.

More power per unit of air, but less power per unit of fuel. Stoich for E85 is richer than gasoline so you get power at the cost of mileage.

[benlaz88]

This is a noob question. So if i am right, i could fuel up with E85 with no tune correct?

[Brick]

Originally Posted by benlaz88

This is a noob question. So if i am right, i could fuel up with E85 with no tune correct?

You could try but it wouldn't work out well. Read the rest of the thread please. I have a theory based upon a different wideband sensor but this isn't the place nor am I sure it's right so I'm not even gonna bother.
So has anyone looked into what the fuel lines for this car are made out of? E85 likes to eat AL and rubber lines.
Also this should be in the tuning section: @WingsofWar

[Toyarzee]

most switches to E85 require an upgraded fuel pump, injectors, and fuel lines (I almost wanted to say fuel rail as well ). I'm actually quite amazed that just dumping a different fuel in the tank that burns at a different temperature and rate with a simple flash tune is sufficient to keep these cars running, power gains or not.