Stock Tune Ethanol Limit

[BlackandBlue]

I was wondering if anyone has logged a stock tune above the stock E15 limit.

I have a gas station near me that sells 93 straight gas and e85 on the same pump. I generally get 12.5 of real 93 and 2.5 gallons of e85. That should net me 94.5 octane or that ratio. I notice nothing at the top end but this seems to help with tip-in power in hot weather.

How much E is safe on the stock tune. I have no way to log this and will get a tune at some point but completely worry free is really nice.

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[FreedomPenguin]

Sounds like playing with fire, doesn't really seem like a good thing to do.

 

[Notheryote]

Yeaaaaa... no. Get an e85 tune.

 

[BlackandBlue]

Ok I get it. You wouldn’t do it.

Anyone have any actual data?

 

[ChromaticGrey]

Its says up to e15. Probably a safety margin on that tbh. Not something id recommend pushing the limit on.

Getting 1.5 more octane points. Dont think it's worth it. And i have to imagine the boost you feel is in your head.

Run E85 with a tune. Or stick with the 93. Even flex tune.

I don't have data, i just genuinely don't think the power gain is there.

I would be interested in that log though, if its out there.

 

[BigBlue]

How about an answer:


Based on a 16 gallon tank, you can add 1.1 gallons of E85 to the tank and fill the rest up with 93 octane to get to 93.8 octane ish net, should be fine/safe.

Without knowing the exact amount of gas remaining at this blend level, you would need to refill a consistent blend of the two to always have the same blend, meaning you cant fill the tank really without goofing the blend. For this example, you could run it down to 1/4 tank and then add the following each time to keep the blend even:

As others have noted, you wont get the true power out of the E85 since the stock timing caps at like 24 but with a proper E85 tune, you will get 30-31 out of it which is the majority of the power. The above fueling setup though shouldnt hurt for a bit of knock prevention though via octane boost about 1 point, but I wouldnt expect drastic differences.


Here is the link to the calculator fyi:

http://www.georgebelton.com/E85Calculator.php

 

[BlackandBlue]

How about an answer:


Based on a 16 gallon tank, you can add 1.1 gallons of E85 to the tank and fill the rest up with 93 octane to get to 93.8 octane ish net, should be fine/safe.

Without knowing the exact amount of gas remaining at this blend level, you would need to refill a consistent blend of the two to always have the same blend, meaning you cant fill the tank really without goofing the blend. For this example, you could run it down to 1/4 tank and then add the following each time to keep the blend even:

As others have noted, you wont get the true power out of the E85 since the stock timing caps at like 24 but with a proper E85 tune, you will get 30-31 out of it which is the majority of the power. The above fueling setup though shouldnt hurt for a bit of knock prevention though via octane boost about 1 point, but I wouldnt expect drastic differences.


Here is the link to the calculator fyi:

http://www.georgebelton.com/E85Calculator.php

I am running pure 93 so using 12.5 pure and 2.5 e85 I get 95 octane 14.2% ethanol. Not that it matter stock tables being what they are. I really am just looking for better tip in our super hot and humid weather.

I will most likely go an e85 tune at some point in the future but not having to worry about any sounds the motor makes is great. The piece of mind is very comforting knowing everything is COMPLETELY covered.

 

[BigBlue]

I am running pure 93 so using 12.5 pure and 2.5 e85 I get 95 octane 14.2% ethanol. Not that it matter stock tables being what they are. I really am just looking for better tip in our super hot and humid weather.

I will most likely go an e85 tune at some point in the future but not having to worry about any sounds the motor makes is great. The piece of mind is very comforting knowing everything is COMPLETELY covered.

Using pure 93, your calculations are correct, but note that the stock tune is anticipating 93 octane on 10% ethanol. It can adjust either way but would be best to at least check your trims and such if you can borrow a tuner to make sure all is healthy. AFR stoichiometric ratios of pure 93 vs 93 (10% ethanol) are different, 14.7:1 for pure 93, 14.13:1 for 93 with 10% E fyi. Good luck!

 

[BlackandBlue]

You are right. I should prob just pick up an ngauge and be done with it. I can tune later.

 

[Bluemustang]

This is not something I would play with just for a bit of tip-in response on a hot day. Just get an E85R tune from Lund and a 93 tune or flex tune. The E85 tune you are SURE to notice, plus you have the benefit of knowing your car is tuned for it.

 

[BigBlue]

This is not something I would play with just for a bit of tip-in response on a hot day. Just get an E85R tune from Lund and a 93 tune or flex tune. The E85 tune you are SURE to notice, plus you have the benefit of knowing your car is tuned for it.

I do agree here, a proper E85R tune from Lund with straight E85 will be what you're looking for. No knock despite 100+ temps outside and 30-31 degrees of timing, a beautiful thing.

 

[BlackandBlue]

I few questions I have about an E85 tune.

I assume most people don’t test their E every fill up. What happeneds if a batch of E85 at your normal station is all the sudden E55. Do you just watch your knock gauge after every fill up? Would it just be down on power and run rich? Does the E85 Lund tune have the ability to pull enough timing to protect the motor?

 

[Notheryote]

I few questions I have about an E85 tune.

I assume most people don’t test their E every fill up. What happeneds if a batch of E85 at your normal station is all the sudden E55. Do you just watch your knock gauge after every fill up? Would it just be down on power and run rich? Does the E85 Lund tune have the ability to pull enough timing to protect the motor?

Ehhh it's kind of complicated. There's no real good way to know unless you test. Fuel trims would be off more than likely if it was noticeably off from the percentage (85%) the the tune was designed for as the stoich value would be different. E85 is extremely knock resistant, so knockr would be hard to interpret as when there's some alcohol in the mix from what I understand it kind of just doesn't knock until it goes boom.

Obviously regular gas with 10% ethanol has low enough ethanol that it knocks pretty regular, but as the concentration goes up closer to 50% I would expect it to be hard to try and catch before bad things happen. So, the best way is to consistently test your station. The one I use for example uses a specific brand of high quality e85 and consistently tests around 90% ethanol between myself occasionally testing. I'm comfortable enough filling up without too much worry, but from what I've read about other people's experiences in their localities, it can sometimes vary a lot. Especially during the winter months.

I would try and find a good station and test it for a few fill ups over a period of time and then if it is good try and just use that station instead of random ones with unknown quality. Also, best to still periodically test to make sure they don't switch to a winter blend or get a bad batch.

 

[Zelek]

I few questions I have about an E85 tune.

I assume most people don’t test their E every fill up. What happeneds if a batch of E85 at your normal station is all the sudden E55. Do you just watch your knock gauge after every fill up? Would it just be down on power and run rich? Does the E85 Lund tune have the ability to pull enough timing to protect the motor?

This is why I use a Flex tune in many situations. Granted it's made for switching between fuels and mixing. The E85R tune is good to 70% alch I believe. Anything lower, then you'll want to use a flex tune. They have some safety measures built in like that to the tune to compensate for pump variations. It's good to find a good E85 station that is consistent.

 

[OneFordGT]

I few questions I have about an E85 tune.

I assume most people don’t test their E every fill up. What happeneds if a batch of E85 at your normal station is all the sudden E55. Do you just watch your knock gauge after every fill up? Would it just be down on power and run rich? Does the E85 Lund tune have the ability to pull enough timing to protect the motor?

You can drop some cash on a Bluetooth Ethanol sensor like I have. I keep my tuner in the trunk in case I ever receive a bad batch and need to flash the flex tune in place of the E85R tune. So far I have not but it's not my daily driver either. E85R tune is amazing in hot weather vs. 93 tune.

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