Originally Posted by cwylie

Has anyone ever tuned a VQ for E35 with a Utec. I have 600cc injectors coming and it should be plenty of fuel for my 350-370whp. Any advantage of going to E85?

Originally Posted by str8dum1

i thought the seals in our fuel system werent designed for e85?

Originally Posted by thom000001

You very much need a complete aftermarket fuel system....no rubber lines what-so ever....and even a speacial braided line with the proper tubing in it for the e85 (has to do with the alcohol content i believe)

tom

Originally Posted by txshldm

I believe E85 burns like 35% faster then regular pump gas. You may need bigger injectors to run E85. I have no experience with E85, however i know the supra guys LOVE it.

Originally Posted by folgrz

yeah apparently all the B5 s4 guys EAT this stuff

Originally Posted by pimpsmurf

Finally, my small city has received, like mana from heaven, a new gas station which is going to carry both VP110 race gasoline, and E85. Before now, without a hookup, you could only get E85 by purchasing 50+ gallons at a time. Not a big deal, but with the initial core charge for the barrel, I never took the plunge.

Now that it is more easily available, I have decided to jump on the bandwagon and write an article for our good members so that we may all learn of the great things E85 can offer, and the problems that must be overcome to make full use of this fun fun fuel.

Unfortunately, I myself have little knowledge of platforms other than the Sentra Spec-V. Much of this information is generic, however you should research your platform to make sure you are being safe.

To keep myself, and this article sane, I will outline and chapter the information:
1) Information Overload - RON MON and the 6 Funny Fuels
2) Serious Dangers of Ethanol - What you need to know to keep your engine, and car, from blowing the **** up
3) Myths and non-problems
4) Math is Power
5) Dynamic Compression Ratio and you, making the most out of octane
6) DIY E40 - Calculations for the feint of math


1) Information Overload - RON MON and the 6 Funny Fuels


For my reader's easy reference, here you can see the AFR and lambda of e85 and gasoline (pure). I have calculated E40 and added it to the list as well since it will come up later anyway.


Understanding Octane... What a subject. I could spend hours writing on octane levels and how different blends of fuel you find from place to place, and even station to station, are dramatically different. I will skip most of it, because some of you already understand octane, and the rest wouldn't read a 20 page thesis anyway, so to the short and sweet.

There are two measurements used to measure octane in fuel. There is a ROM method, and a MON method. You may have noticed the R+M/2 formula on all the octane stickers here in the USA. This is simply, the average of the two octane measurements. The "R" in the formula is RON or Research Octane Number. This is the octane number of the fuel under idle or low throttle. It is only useful in low throttle. The M is MON, or Motor Octane Number. It is a test using higher temperatures, and higher rpms, which simulates higher loads. If you calculate your required octane to be 100 (per say) then you will gain NOTHING from 115 octane fuel. You should of course run a small octane buffer. Racing gas typically has an octane in the 100 to 115 MON, which is the only rating important for WOT. While that 93 octane at the pump might have 93 R+M/2, it most certainly does NOT have 93 MON. MON is always much lower than RON, in just about any fuel. Most race fuels advertise their MON number because that is the important part, and why they cost so much. In 93 Octane fuel, the MON is typically 88-89, and the RON is typically 96-97. Lower grades of fuel may find a greater spread.

So as a wise man once said, "I told you that story to tell you this one."

The MON of pure ethanol is around 102. It's RON is a huge 129! This is where the flex fuel vehicles fail. To realize the potential of ethanol in a normal type car, the timing must be increased greatly when ethanol is being used. The higher timing allows for lower throttle (less air) to be used to maintain a cruising speed. They don't max out the potential of the fuel. Notice that ethanol's MON is much higher than premium gas' 88?

Also notice that Methanol is only 103 MON. Injecting a little bit of methanol will help a good bit with bringing up your total octane rating, but lets consider a reasonable level of methanol injection.

Lets assume you are using 50/50 meth and water, and 500CC/second of fuel per injector (which is roughly 640cc injectors@80% duty cycle)

This is about what I would find in a 400hp fuel system on my car at 5600rpms.
A 6GPH jet makes:
11.17:1 AFR @ lambda .8
Roughly 91 MON (R+M/2 would be higher)

A 3GPH jet makes:
11.4728 AFR @ lambda .8
Roughly 90.5 MON (R+M/2 would be higher)

Do you notice how little the octane goes up when you double the amount of meth injection? This has the negative effect of inaccurate dosing for the cylinders (unless you are running direct port) and unless you have tuned a progressive injection system, heavily fluctuating AFRs, much lower in lower RPMs.

Not only this, but methanol is more corrosive to metals, especially Aluminum. You will notice your intake will become very green with corrosion and even your turbo will discolor to a chalky white from methanol injection. It would take many years for this to ever really effect anything, but with methanol injection you are injecting WAY MORE methanol/water (aka, acid) mix than you do ethanol if you are tuning for e85. Not to mention the fact that the ethanol is WATER FREE (no acid) unless you become contaminated, which you are going to take steps to avoid. With meth injection, and my rather rowdy driving habits, I find my oil completely nasty after only 1500 miles. This is both because of the meth breaking down the lubricants, and because you inject so very much of it when attempting to use it for high octane levels. With the much lower CC/min of e85, you will have greatly reduced blow-by contamination and get back to a normal oil change interval.

I am currently running 8.7GPH of 70% meth / 30% water. E85 has 100 octane, more than my large shot of Methanol injection (92MON). Not to mention the fact that more than 50/50 mixtures of Methanol are flamable. An overheating pump can explode with that ratio, and if it has a safety-cut off, will cause you to go very lean, possibly destroying your engine. E85 is a much safer solution to the exact same problem. Too much water will contaminate the oil as well as can cause issues with shorting/wetting the the spark plug.

This is why you hear various numbers for octane levels for ethanol. There are actually many different tests for octane from RON, MON, R+M/2, AKI, etc, etc. We are dealing only with MON in this discussion because it is what is important for high load operation.

Notice that E85 is 100 octane! This is fantastic. Many race fuels with 100 octane cost much much more. The downside is fuel system taxation, which we will get into later, however in the end, ethanol always comes out ahead. Even E40 has a much improved MON and as you saw above, has a much higher stoichiometric AFR meaning less fuel is required, but more on that later.

Originally Posted by pimpsmurf

2) Serious Dangers of Ethanol - What you need to know to keep your engine, and car, from blowing the **** up

If you prepare your car for Ethanol, it is highly important that you do everything needed to keep water OUT. Things you can do to keep water out:

1) Don't go below 1/4 tank. You want to be certain there are plenty of vapors in the tank to prevent air from coming in when you open the cap to fill up.
2) Don't leave your cap off for longer than needed to pump. This means that you shouldn't be setting the pump to fill and going inside for a donut fatty. Fill the tank and cap it immediately.
3) Add some water remover to the tank periodically. Use methanol (Heat) not isopropyl (IsoHeat) because it is mucho better at it's job although it technically forms a very mild acid, cars built in the 90's are not at risk of damage.
4) Use quality gas stations. Some bad stations will add a little water into their gasoline (and especially diesel) tanks because they are cheap sons of bitches. Pay the extra money and go to a good station like a corporate Shell/BP station.

Water contamination damage doesn't typically happen overnight. It happens from repeated, very small exposures, so stay on top of these things to keep everything in check.

Electricity! Pure Ethanol isn't electrically conductive, and neither is gasoline. HOWEVER, there is nothing pure in this world, or so we think. There are by-products from Ethanol production which make the fuel MORE conductive. This conductivity adds to the corrosive nature of the fuel, and can cause electrical terminals to rust, eventually arcing inside of a fuel cell. I hope I don't have to tell you that you can blow your **** up if you don't take proper measures. I wouldn't even mention this problem because our stock fuel system has the electrical terminals coated in a clear insulator. However, when installing an aftermarket fuel pump, running 12-14awg wires directly to the pump is a must! Not only does it provide better power and less vdroop than the stock wires, it can increase flow. After soldering the new wires to the connector, you MUST use a connector coating. I will research and post the coating to be used. This will keep the electrical stuff from rusting and eventually causing bad bad problems.

The first fill up:
Many people recommend completely draining the tank before moving to ethanol. This is a pain in the *** and completely unneeded. All you need to do is add a bottle of Heat (99+% methanol) in the tank before you fill your last tank of regular gas. It will absorb any water left and flush it out with your last tank of gas. Then you are GOGO for higher blends of ethanol.

Many people also recommend changing the fuel filter after a few tanks of E85. Actually, since our congress mandated E10 gasoline, all gasoline containers have been shedding gunk. From the pipelines, to the trucks, to the tanks at your gas station, and even your car's tank: all of the tanks have been sheding sludge buildup from mixtures of gasoline. This isn't to say you shouldn't periodically replace the filter, just that even on E10, you should do it.

Spec-v-specific note: The stock fuel canister has a paper filter built into the fuel pump holder. This is NOT serviceable. Even though I only have 24k miles (at the time) and never ran more than E10, my filter was amazingly dirty. It was absolutely filthy, and I could see particles of junk in the bottom of my tank. Also, Ethanol will over time destroy a paper filter, so adding a high pressure, metal screen, inline filter to your fuel system is a must, and changing it periodically is a fantastic idea. I will research and post up a part number to use when I am done with this article.

3) Myths and non-problems

Ethanol is corrosive: It's about as corrosive as gasoline, unless it separates. It takes 4 tablespoons of water per gallon to cause separation, and a little bit of CHEAP methanol in your tank will seek out and destroy the water before that can happen.

Ethanol reduces horsepower: Wrong. That is only true when a moron takes a completely unprepared, non flex-fuel vehicle and fills up with E85.

E85 only gives a 5% power increase: Wrongy Wrong. For a N/A engine, this is true, but in a F/I application, gains of over 15% have been seen.

Ethanol gives 30-40% less mileage: wrong again. a turbocharged car in daily driving will hit 90% of the fuel mileage of gasoline (E10). N/A engines will likely see a 15-20% drop in milage. Only, of course, if the car has been propperly tuned for E85. Of course mileage isn't our goal.

Ethanol has lower energy per unit: not really, because it is oxygenated. It has oxygen in it, which burns along with the air. The Net Energy Value is actually much higher.

I am purposely leaving the political stuff out of my article. For most performance enthusiasts, the subsidies and environmental impact are of little to no importance.

Originally Posted by pimpsmurf

4) Math is Power

Sort of a mantra here at TwoFiveTuning.

Ethanol isn't magic. It doesn't magically increase your power. Meaning, simply increasing your injector size and swapping over to E85 is going to do NOTHING for you. I can't emphasize this enough. You do not get power gains from Ethanol, but rather through the other changes it allows you to make. You can either add timing, raise the boost level, or a combination of the two. It can actually allow you pull your lambda back if you are already skirting the knock level. I'll explain:

Let's say you run 10psi on our beloved QR25DE, and are forced to a 11.3:1 (.769 lambda) AFR on gasoline (no methanol injection). This AFR is far outside of the 12.5:1 ideal rich AFR for gasoline. Without getting to deep into it, you are losing power because you aren't allowing the carbons to burn all the way, using up all the oxygen far too quickly and wasting fuel. When you change over to E40, you will find that the ideal rich lambda drops from .85 to .8! This is good! It means you can run more rich with E40 and still get peak power. The increased octane from e40 also allows you to go more lambda lean to get back to .8 lambda (9.9:1 AFR) without detonation. This will result in a power increase, which is not to mention the increased thermal capacity and increased volume of fuel. Many alcohol powered vehicles will find their coolant temps DROP at the end of a 1/4 mile run. A high hp engine may actually lose 20+ degrees! The cooler the combustion chamber stays, the less likely you are to have problems with preignition and detonation. This is a very good thing for those of us pushing more than 2hp/CI (300bhp in a 2.5L.)

In order to use E85, unless your current fuel system is entirely overpowered, one must increase fuel potential. Either through Larger injectors, increased fuel pressure, or by magic. I'm going to focus on the first two options:

Lets say you are running 499CC injectors and maxing out at 90% duty cycle under 60psi of fuel pressure at 10psi of boost. This is my current setup. You want to run E85, and have already consulted the handy dandy fuel system calculators http://twofivetuning.com/smf/fuel-sy...m-calculators/

With 60psi of base fuel pressure on a 1:1 fuel pressure regulator and a walbro 255-HP pump, you will find that you wouldn't max out the pump until far after 30psi of boost. Now, lets go to E85. We are going to drop in some larger injectors to cover the increase in fuel needed. We have to assume a summer blend (85% ethanol) so we can be sure to handle it. Winter blends will require retuning, but it is easy to test for. To find the injector size to replace your current injectors, multiply currect injector size by 1.4. 500cc injectors become 700cc injectors, and so on. Increasing fuel pressure is harder to do. Lets say we were running 499cc injectors and 43.5psi. Increasing the fuel pressure only would require 85 PSI (holy ****) to accomplish. Not only is this bad for the injectors, but it taxes the pump, and at this base fuel pressure, you max out the pump at only 3psi of boost. This is a bad thing.

However, increasing the base fuel pressure some, can help get you over the hump. Lets say that we were running 499cc injectors and 43.5psi and converting to E85. 700cc injectors for some reason aren't available, but 650's are. We can up the pressure to 51psi and meet the fuel requirements. Also, at this fuel pressure we don't max out the pump until well above 30psi of boost. Great success!


5) Dynamic Compression Ratio and you, making the most out of octane

All of this said, you aren't just trying to convert to E85 to get a bunch of octane for no reason! You want to get some power! If you can't get the gains from adding timing (as is my situation right now), you CAN get gains from adding boost or running a little more lean. This isn't to say you should start tuning 13:1 AFR, but that if you were adding tons of fuel (10.5:1-11:1 AFR) in order to combat preignition and detonation, you can now move up to a more reasonable level.

On E40, you can run as rich as .8 lambda which would show up as 11.76:1 AFR on a AFR gauge/datalogger configured for gasoline. (it is of course, the much more rich, 9.9:1 AFR in actuality.) On E85, you can run as rich as .71 lambda which would show up as 10.44:1 AFR on a gauge configured for gasoline. It is really 7:1 AFR.

More importantly, you won't have to run this rich any longer if you were running extra rich to prevent ignition issues. You will find you can pull more fuel out of the mix and still have no issues because of the reduced detonation. This is one way to make power with E85.

But, we are out to make serious power with E85, not just small gains! We want to increase boost! Well, here is where the math becomes more of a crap shoot.

Running 10psi and maxing out 500cc injectors@45psi and 300whp. You want to up the boost to 15psi, which should put you at 400whp. This is a 33% increase in fuel. So, you need 930cc injectors. WOW O WE WOW. Them sum biggins. Your engine management may not even be able to handle it as it is the equivalent of 660cc injectors on gasoline. Also, you may find yourself in a pickle if you can't get E85 for some reason. If your engine management can't handle 930cc injectors on gasoline, then you will find it will run extremely rich, possibly dangerously rich, and do all sorts of bad things that rich cars do. Now, lets look at the walbro 255-hp again. At 45psi, the walbro 255 can handle 15psi of boost. However, at 50psi, it falls short, maxing out the pump before 10psi of boost. In this situation you have two choices.

You can either run an inline bosch "044" pump (with a 255 in-tank) or dual 255's.

Refer to this:
http://twofivetuning.com/smf/fuel-sy...p-flow-charts/

A Bosch fuel pump between the FPR and 255-hp which is in your tank, will allow the 255 to flow over 80GPH and the "044" is rated to supply over 60GPH at 15psi of boost and 2 bar of base fuel pressure. If you are running 30psi, it still delivers at LEAST 60gph. refer to the link directly above this to see why these numbers are so very conservative. Either way, 930cc injectors are only 59GPH at 43.5 base psi.

Two 255 pumps typically flow 170% more than a single, so two 255-hp's @ 45psi base pressure and 30psi of boost on a 1:1 FPR is rediculously safe. Most tuners recommend putting your fuel pump supply 30% over your fuel needs in case one becomes damaged or otherwise looses efficiency. Either of these solutions is well over that goal if your power goals are under 700hp.


IMPORTANT NOTE:
You have to make a choice, either reconfigure your lambda sensor and relearn everything you know about gasoline AFR, or ignore the lambda sensor and treat the AFR gauge the same way you used to. I will do the latter because I am very lazy.


6) DIY E40 - Calculations for the feint of math

I am going to leave most of the explanations behind. Here is the ratio needed to obtain E40 from E10 and E85. E85 typically has a "winter blend" which is actually E70(ish.) One should use the water titration methods described above to determine actual levels.

With Real E85:
4 gallons of E85 + 6 gallons of E10 makes E40

With E70 "winter blend":
5 gallons of E70 + 5 gallons of E10 makes E40

Blessed with a 11+ gallon tank, this makes mixing relatively easy.

Originally Posted by GSXRJohn

Okay, I'm having a problem understanding this. Stoic for Gas to produce 1 Lambda is a 14.7 AFR. For E85 to make 1 Lambda it needs to be at 9.765 AFR. That's at cruising!?! Max power goes from 12.5 AFR to 6.9!

How is it a myth that it burns almost twice as fast? Seems that is dead on. If your having to run 9.765 to drive to work or to the car wash (no pun) your going through a LOT more fuel.

This is a question, I know dick about E85. Just pointing out the obvious so nobody what what I say and run with it. I'm trying to learn myself.