Ethanol Has Higher Lower End Torque?

[jeff88]

I posted this article in another thread, but had a question about it not related to that thread. According to this article, ethanol fuel has a higher amount of lower end torque.

But he was surprised to learn of the fuel’s advantages, primarily its higher octane rating, which exceeds 100, and the superior low-end torque it produced in a properly configured engine.

My question is, if this is true, how it is possible. Any ideas?

[YukonCornelius]

You can advance ignition timing farther because of the higher octane, hence more power. Alot of car guys modify fuel systems to run e85 in high horsepower cars. I would create a tune for my Caddy to run e85 but it would max out my fuel injectors.

[jeff88]

Oh, cool that makes total sense, didn't think about that. Thanks! Do you think that if one were to use ethanol (along with any supporting mods) with a VVT engine, one could increase torque to increase city MPG?

I assume by maxing out your injectors you mean the fuel pressure needed? Could you upgrade your fuel pump/injectors to allow for the higher pressure?

[betasniper]

They probably run a higher CR in their racing engines due to the higher octane rating of E85 which would improve torque and efficiency. Problem with flexfuel type cars for ordinary customers is that they can't bump the CR too much due to having to run also be able to run on Regular (or possibly Premium) gas.

Edit: It says that they do run a higher COMPRESSION (They said combustion) Ratio in the racecars and it does mention that the high CRs have to run E30+ exclusively.

[YukonCornelius]

Originally Posted by jeff88

Oh, cool that makes total sense, didn't think about that. Thanks! Do you think that if one were to use ethanol (along with any supporting mods) with a VVT engine, one could increase torque to increase city MPG?

I assume by maxing out your injectors you mean the fuel pressure needed? Could you upgrade your fuel pump/injectors to allow for the higher pressure?

Definitely, but you will never get better fuel economy numbers with E85 over gasoline. But cost per mile is another thing. In the same vehicles you burn 20-25% more fuel using E85. Your Air fuel ratio with gasoline is about 14.7:1 while E85 is more like 10:1. That is why fuel system upgrades are required sometimes to run it. Usually larger injectors will get you by but a upgraded pump could be needed. Alot of variables come into play, mainly how good your stock set up is.

Originally Posted by betasniper

They probably run a higher CR in their racing engines due to the higher octane rating of E85 which would improve torque and efficiency. Problem with flexfuel type cars for ordinary customers is that they can't bump the CR too much due to having to run also be able to run on Regular (or possibly Premium) gas.

Edit: It says that they do run a higher COMPRESSION (They said combustion) Ratio in the racecars and it does mention that the high CRs have to run E30+ exclusively.

My knowledge is with high horsepower street cars making 500-1000 horsepower. In this instance vehicles that benefit the most from E85 are supercharged or turbo charged. These are not high compression engines but have highly volatile combustion. E85 is more detonation resistant so they run higher boost and/or increased timing with E85 vs 93 octane. E85 also has a cooling effect on the intake charge which is helpful for both forced induction and naturally aspirated engines. Because of that cooling benefit the general rule of thumb is that E85 is only worth running in a N/A street car in warm weather.

[Quezacotl]

Yep, when i switched to ethanol, i saw that the timing adjustment fork shifted higher. It starts to cough if you retard as much as with gasoline.
I haven't tested the top performance yet, because i drive with economy
But even with adjusted that it is about equivalent to gasoline, it still feels like it has more power.(note: feels. no actual data)

[cRiPpLe_rOoStEr]

In my mother's Chevrolet Celta with a flexfuel engine, running on E20/E25 in some grades still required 2nd gear, but once I put some ethanol into its tank without her knowing and she could keep the 3rd gear in the same grades.

[ksa8907]

I am playing with ethanol blends and posted in another thread recently, I am seeing this right now in my stock engine, more torque below 2-3k than I have ever had in 8 years with this engine.

[Allch Chcar]

It's well proven that Ethanol makes more torque than pump Gasoline. In a non-VVT, OBDI based engine the effect is negligible, +2% at most from Ethanol's latent heat of evaporation. Adaptive tuning and especially VVT, the difference can be up to +5% more peak torque. It varies with engines, engine tuning, and how much Ethanol is present. The effect is similar to running Premium Gasoline but much more pronounced with Ethanol.
Here's a study on it's effect at low RPM operation.
delphi.com/pdf/techpapers/2010-01-0619.pdf

I don't recommend just running anything past E10 without doing some reading, unless you have a FFV. I know OP doesn't, because OP has a foreign car. Most OBDII engines can run E85 but will need time to adapt without getting a CEL. FFV functionality allows the engine to quickly compensate for a much wider range of fuel composition without generating a CEL. Stock ECU in a non-FFV is limited in how much you can increase fueling without getting a CEL. Regardless of whether you run E85, it will still adapt to safe mixtures to protect the catalytic converter up until the fuel system maxes out. Which usually isn't the problem BTW. People have added turbochargers onto a factory naturally aspirated engine with stock fuel systems for years.


I am not an expert and I tend to be cautious.

[Occasionally6]

I think it's worth asking why only low rpm? What's different at high rpm? Is it related to flame speed or maybe heat transfer and evaporation rates?

EtOH will release a little more heat energy over gasoline in a given engine. You can figure out how much based on the stoichiometry and specific heating values for the fuels and some basic math.

Other variables are the quantity and composition (proportions of CO2 and H2O) of the combustion products into which the heat energy is released. The pressure of the gas mixture - from which the useful work is extracted - is affected by those variables.