Hello, has anybody used e85 in their w12 and does it increase bhp?

 

Looks like no one is jumping on this.

Your question takes a whole bunch of qualifiers before it can be answered with any amount of value.

The first question is: What year W12, and are you talking Bentley or any other W12?

The first simple answer without any qualifiers is - no, it doesn't increase BHP.

 

I tried it in my 2016 Speed. Its a known fact that E85 definitely increases horsepower. It can lower intake temperatures by as much as 80 degrees F. It also contain oxygen. E85 varies from 55% alcohol to 83% so a tester is helpful for comparisons. I'd estimate it was good for a solid 50 horsepower on a full throttle redline shifting pass.

 

That's funny, because it will do absolutely nothing if a tune intervention isn't done. A 2016 has a flex fuel sensor but that is only to adjust fueling for the stoichiometric difference between gasoline which is 14.7:1 and E85 (if it is actually 85%) at 9.733:1. Without a flex fuel sensor adjusting fueling, just adding E85 to an empty tank will produce a P0171 and a P0174 check engine light in about 25 miles (or maybe even less). This is why I asked the ages Q BC before 2012, Bentley didn't come with a flex fuel sensor, but it is possible to add an aftermarket one with a controller.

To get more performance which is hp and possibly torque, you need the change timing to take advantage of the octane rating of E85 which is about 108, compared to the octane rating of gasoline in the US, typically being 91, maybe 93. And this is not on the RON scale so the OP wouldn't recognize this octane scale, maybe.

The dowwnside to E85 (as a steady diet) is BC of the much lower Stoich in the high 9s you'll burn a whole lot more of it than gasoline, to get the same distance.

 

E85 requires 30% more fuel, so for you all to just go dump in e85 might not be the brightest of ideas unless the vehicle comes setup for flex fuel capabilities.

 

Here are the factory specs:

The first Bentley capable of running on both petrol (gasoline) and biofuel (E85 ethanol), its 6.0 litre W12 engineis rated at 630 PS (463 kW; 621 bhp) at 6,000 rpm and 800 N⋅m (590 lbf⋅ft) at 1,700–5,600 rpm – using either fuel.

There are no separate HP/TQ ratings given by Bentley for E85 fuel in a 2016. I know how butt dynos work and I can sympathize with you.

 

Here's a Dyno session. The results were, Octane didn't matter Timing didn't matter once determined (it was 29 bdc for this test with all fuels)

 

You're proving over and over you just don't understand octane and how it's used, and you're not quoting above numbers from your Bentley.

 

With NO increase in HP because of the E85 which was the OPs original question.

I've tuned modern EMSs since 2009. I've setup flex fuel kits on non flex EMSs. I've converted NA engines to FI and tuned those.

E85 has "potential". To a tuner it is a dream race fuel, BUT, and I can't seem to get that through the head of the earlier poster who is grabbing useless charts off the internet, without timing, E85 is just another fuel in the tank and produces a similar power output as premium fuel with the exception of a lot more volume needed for the same output.

Advancing the timing to take advantage of the 108 octane that E85 is, and yes, I'll produce more HP. But 91 octane gasoline simply cannot perform at the same advance timing as 108 octane fuel can. 91 octane fuel would rock the engine silly with spontaneous combustion at the timing advance of E85.

So, if the OP is still interested and is out there, without a tune, you will not see any more HP by running E85 in your 2011 Bentley.

 

I am not going to address the first part of your response. This would get too lengthy to do so.

Without needing to actually intervene in the Bentley's ECU, start by looking at what is available from reliable sources.

The first proof point that Bentley only took advantage of half the opportunity of E85 is in their own performance specs. They list only one spec for both fuels which I posted above, and here:

The first Bentley capable of running on both petrol (gasoline) and biofuel (E85 ethanol), its 6.0 litre W12 engineis rated at 630 PS (463 kW; 621 bhp) at 6,000 rpm and 800 N⋅m (590 lbf⋅ft) at 1,700–5,600 rpm – using either fuel.

The second proof point is the aftermarket performance industry. If Bentley actually utilized E85 to its full potential in what would be a fully switchable flex fuel system and an additional timing table, if they decided to hide the extra HP/TQ produced by simply pulling up to a fueling station and filling the tank with E85, then surely the aftermarket performance side would be full of road tests, performance runs comparing both sides (this is what you asked me in the first part of your reply), dyno results, etc. Let's see if anyone can produce even one such report, or study using a stock factory Bentley continental GT that does not have an aftermarket tune intervention.

So, without the need to personally dyno a Bentley or intervene in the EMS to expose what the factory did, It becomes obvious by deduction.

OBDII by all manufacturers systems follow the same elementary conventions that have always been true about internal combustion engines - Air, Fuel, Ignition.
SAE set up a structure within OBD that all manufacturers must use so that there is some consistency in how these systems are serviced and maintained. Each manufacturer builds their EMS within that structure and does have leeway to create and use their own proprietary addons.

In its simplest definition, OBD divides Air, Fuel, Ignition into two categories:

Fueling (which combines air)
and
Ignition

On the fueling side - The specified fuel (any fuel) has a stoichiometric value which determines how much air must be mixed with fuel to attain a complete consumption of the fuel and maximize that fuel's BTU output. E85 has a very different stoichiometric value than gasoline. The first challenge in a dual fuel setup is designing a "switchable" air mass. That is accomplished using a flex fuel sensor. The sensor can estimate the percentage of alcohol present then can adjust FUEL (not air BC air is a calculated constant at any moment) based on the mixture (blend of gasoline at 14.7 stoich, and E85 at 9,8 stoich. The modification needed in the EMS is to fuel trims. Fueling needs to adapt to the two extreme stoichiometric values and switch more rapidly than traditional fuel trims do with a single fuel type. Also, the base switching capability increased and the lean/rich limits expanded.

That is ONE side of a two-sided equation and, I know it is all Bentley addressed with the flex fuel option, which BTW, is perfectly acceptable.

The second side is ignition

On the Ignition side - The opportunity exists (within certain calculated physical limits) to take advantage of fuels with different burn rates and this is where the final delivery of maximum BTU outputs of different fuels resides. A fuel's burn rate is measured on a scale known to the novice as octane. The scale works in reverse of intuition, the lower the octane number the faster the burn rate, the higher the octane number the slower the burn rate, (using one of a couple different standard scales).

Before E85 and with only one type of fuel (gasoline) used commercially, there is a significant range of octane to accommodate different design output expectations and different manufacturer's offerings in the market. These fuels are not interchangeable yet, given the public's ignorance and the opportunity to grab a fuel nozzle and put whatever they want in their car, the ignition side of the EMS accommodates this by the use of two complete timing tables, one called the high octane table, the other called the low octane table. When the wrong fuel is used (in one direction) the fuel not only performs poorly but causes physical changes (because physics was violated) detrimental to the health of the engine. This is spontaneous combustion also known as knock. The ECU uses knock from sensors, and an algorithm to start reducing TIMING that takes advantage of higher octane fuels (in the high octane table) when lower octane fuel is mistakenly used. The algorithm uses both a capacity and a timer to make timing adjustments then correct back if the fuel is changed.

Timing tables are huge. They provide a timing value for every possible position of RPM and spark air mass. When knock is present, the ECU changes the timing value of that very cell where it was detected. In the case of adding an entire tank of the wrong lower octane where a higher octane was required, the ECU is constantly (emphasized CONSTANTLY) calculating new timing values. to accommodate, the mistake.

Now comes E85 - it presents the same challenge on the timing tables because E85 has an even level of octane in the other direction and the high octane timing table cannot adjust up in value as no sensors are there to pick up that E85 is burning so much more slowly. However, the opportunity is there if a third timing table existed. This is what Bentley did not do.

With that said, I CAN intervene and rewrite the entire high octane timing table (which is what tuners are doing now). That would accommodate the 108 octane rating of E85 and it would definitely produce more HP and TQ. But, that would cause high octane gasoline to perform poorly now and causing very serious spark knock. At this point, the ECU would need to be back to performing on an algorithm similar to the one sued now for just gasoline, however, the range here is much wider.

What tuners do now in the aftermarket, they rewrite the high octane table with new E85 values then convert the low octane table into a new high octane (gasoline) table. But, this is what Bentley DID NOT do, because now there would be no fallback for the person who might accidentally put low octane fuel in this setup. That would pretty much destroy an engine faster than it could be corrected.

Another option that tuners use is a switchable controller (and a flew fuel sensor, or course) to switch back and forth between tank fillups. Users will add E85 for performance days, then switch back to gasoline on in between days.

Just for graphics sake, here are two tables as a reference only. The first is a high octane timing table, the second low octane. In the case I describe above, the high octane table values would be copy pasted to the low octane table, then the original high octane table would be completely rewritten to accommodate E85, but again, this takes an aware owner.

 

My, my, to be lectured by Dark Green about behavior, of all members on this board.

You have a lot of nerve.

I suspect you're a young smartass who hasn't reached maturity yet. Your knowledge is limited, and when confronted with something you have no clue about or cannot find in IETIS you throw a child's tantrum.

We won't need to communicate any further going forward.

 

You have one massive and common misconception. Octane does not affect the rate of burn, only the resistance to knock.

 

Octane ratings are not indicators of the energy content of fuels. They are only a measure of the fuel's tendency to burn in a controlled manner, rather than exploding in an uncontrolled manner.

[size=8333px]Burn rate.[/size]

 

Saffire - You're trying to do a quick learn about octane by spending 5 minutes googling it. You are accurate that octane is a measurement of its resistance to detonate (knock), but that's the result, the tip of the spear. You have the "what it does" you need the "why and how it does it"

You need to spend more than five minutes because Octane is far deeper than that. Try googling "flame propagation" as it will help you understand more the mechanics of what is going on that results in resistance to knock.

Here I'll help you along a little, but please do the rest.

In engines[edit]

In an internal combustion engine, the flame speed of a fuel is a property which determines its ability to undergo controlled combustion without detonation. Flame speed is used along with adiabatic flame temperature to help determine the engine's efficiency.
"...high flame-speed combustion processes, which closely approximate constant-volume processes, should reflect in high efficiencies.[4]"
The flame speeds are not the actual engine flame speeds, A 12:1 compression ratio gasoline engine at 1500 rpm would have a flame speed of about 16.5 m/s, and a similar hydrogen engine yields 48.3 m/s, but such engine flame speeds are also very dependent on stoichiometry.[5]

Also try googling burn rate
In chemistry, the burn rate (or burning rate) is a measure of the linear combustion rate of a compound or substance such as a candle or a solid propellant. It is measured in length over time, such as millimeters per second or inches per second. Among the variables affecting burn rate are pressure and temperature. Burn rate is an important parameter especially in the area of propellants because it determines the rate at which exhaust gases are generated from the burning propellant, which in turn decides the rate of flow through the nozzle. The thrust generated in the rocket of missile depends on this rate of flow. Thus, knowing the burn rate of a propellant and how it changes under various conditions is of fundamental importance in the successful design of a solid rocket motor.[1] The concept of burn rate is also relevant in case of liquid propellants.[2]

 

Wikipedia all you like. Dynos don't lie
6.2 LS3 10.7:1 compression, fuel & timing optimized for each fuel. Btw 12.6:1 for gasolines 8.4:1 for E85. ALL peak power at 29 bdc.