Hitting Rev Limiter WOT Shifting

[Iconic_Supra]

An Ethanol mix tune, be it E30, 40, or E50, will obviously have more ethanol mixed into the fuel which will allow for more knock resistance, which means the Tuner can add more timing and more boost.

So in theory I should be able to run E30 on my pump gas tune without any issues, but I just wouldn't get the added power from the additional boost and timing. Just more knock resistance from the cooler temps. That's what I don't understand is why there could be something in my OTS tune that can't handle E30 because this company has recommended that E30 is on the edge of their OTS capabilities and told me to stick with E10 max. Does that seem right?

The solution to me seems to get a custom flex fuel tune but I'm not quite ready for that yet. And spending more money doesn't seem like a solution when there is a problem somewhere that needs fixed with my current setup

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[Sereph102889]

So in theory I should be able to run E30 on my pump gas tune without any issues, but I just wouldn't get the added power from the additional boost and timing. Just more knock resistance from the cooler temps. That's what I don't understand is why there could be something in my OTS tune that can't handle E30 because this company has recommended that E30 is on the edge of their OTS capabilities and told me to stick with E10 max. Does that seem right?

The solution to me seems to get a custom flex fuel tune but I'm not quite ready for that yet. And spending more money doesn't seem like a solution when there is a problem somewhere that needs fixed with my current setup

Not necessarily. Since Ethanol flows faster the more potent the mix, it's possible that your 93 tune is having issues because it's set for 93 octane, which in general is only 10% Ethanol, but since you're currently at an E30 mixture, the car is burning through the fuel faster than it would standard 93 and your current tune isn't calibrated to do so. Your tune isn't a Flex Fuel tune so it can't "flex" up or down depending on the octane/ethanol mixture. It's set to work with only 93 octane which flows less volume per minute than an ethanol mixture would, so in theory you could be flowing to much fuel for the tune calibration.

 

[suicidaleggroll]

So in theory I should be able to run E30 on my pump gas tune without any issues, but I just wouldn't get the added power from the additional boost and timing.

No

Ethanol burns at a different air/fuel ratio than gasoline. The stoichiometric ratio for gas is 14.7:1, that's 14.7 parts air to 1 part fuel. The stoich for ethanol is 9.0:1, which means you need about 50% more fuel per gram of air when running ethanol versus gasoline. The ECU does not know this, it will think you're running normal gas and will inject the amount it thinks is correct based on a 14.7:1 stoich, if you're actually running ethanol then this will cause the engine to run way too lean, which can lead to detonation and damage.

The ECU is able to detect a small error and adjust automatically, which is why E10 is fine, but you don't want to push it.

 

[Iconic_Supra]

Not necessarily. Since Ethanol flows faster the more potent the mix, it's possible that your 93 tune is having issues because it's set for 93 octane, which in general is only 10% Ethanol, but since you're currently at an E30 mixture, the car is burning through the fuel faster than it would standard 93 and your current tune isn't calibrated to do so. Your tune isn't a Flex Fuel tune so it can't "flex" up or down depending on the octane/ethanol mixture. It's set to work with only 93 octane which flows less volume per minute than an ethanol mixture would, so in theory you could be flowing to much fuel for the tune calibration.

No

Ethanol burns at a different air/fuel ratio than gasoline. The stoichiometric ratio for gas is 14.7:1, that's 14.7 parts air to 1 part fuel. The stoich for ethanol is 9.0:1, which means you need about 50% more fuel per gram of air when running ethanol versus gasoline. The ECU does not know this, it will think you're running normal gas and will inject the amount it thinks is correct based on a 14.7:1 stoich, if you're actually running ethanol then this will cause the engine to run way too lean, which can lead to detonation and damage.

The ECU is able to detect a small error and adjust automatically, which is why E10 is fine, but you don't want to push it.

Thank you gentlemen. This is the cause of the issue I am having without a doubt, accidently filling E30 with my OTS pump gas tune. I was slowly starting to grasp this. I thought the computer could compensate for the additional fuel but since I obviously do not have a flex fuel sensor the computer is greatly limited on how it can adapt to E content. And because Kansas law does not require pumps to list E content I assumed I was fine. I will be more careful when filling in the future.

 

[black_sedan]

Thank you gentlemen. This is the cause of the issue I am having without a doubt, accidently filling E30 with my OTS pump gas tune. I was slowly starting to grasp this. I thought the computer could compensate for the additional fuel but since I obviously do not have a flex fuel sensor the computer is greatly limited on how it can adapt to E content. And because Kansas law does not require pumps to list E content I assumed I was fine. I will be more careful when filling in the future.

yeah e30 on a 93 tune would absolutely cause problems. The fueling demands of 30% ethanol is completely different and the ecu going into limp mode as a safety.

That being said… spend a little extra money for an additional e30 tune and there is a significant jump in power. You can ask the tuner to load map switching if you want to switch back and forth or just upgrade to flex fuel and not have to worry about it

 

[AHP]

E30 - E40 is perfectly fine on most stock turbo setups, stock tune. Log and monitor "Trims" which is reported 0-50 with 25 being effectively 0. Less than 25 fuel is being pulled to hit target and greater than 25 the fuel is being added. Ethanol will effectively lean out the mixture and the DME will compensate (>25 up to 50) to hit target, until it can't.

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