What is E85?
E85 is a fuel that is starting to be sold more and more at stations across the country. While it has been around for quite some time, it is just now starting to take hold in the US. In some country’s, E85 is a more popular gas than regular gasoline. E85 is a fuel that is made of 85 % ethanol, and 15% gasoline. One thing to note though is that most gas stations can carry variants on this fuel from E70 all the way to E90. It should be noted that E70 and E90 are made up of just what the name says…..70% Ethanol for E70 and 90% Ethanol for E90 with the other percentage made up in gasoline. To know what your current station is pumping you use an ethanol tester or sensor like those found below:

What makes E85 Special?
At first one would think that using E85 would make little sense being that the BTU rating of ethanol (also called Ethyl Alcohol) is less than that of gasoline, meaning it has less British Thermal Units (energy) per molecule, but that is not true. Each fuel has its own BTU rating just like Natural Gas, and even though Ethanol based fuels have a lower BTU rating than gasoline, they require you to inject such a large quantity to reach stoichiometric combustion that the actual amount of molecules in the combustion chamber is greater so the total number of BTU’s is greater also. On avg you can expect to gain around 5% more efficiency on a high ethanol based fuel. Other low BTU fuels would be like those on natural gas. Engines that have received CNG Conversions would be a great example.

SO IF I RUN E85 WILL I MAKE 5% MORE POWER?
This brings up the idea that just like adding high octane race gas to a stock motor on stock timing, you will see little to no gains, the same is true with running E85 with no tune. In fact, you can actually lose power not to mention it takes 20%-30% more E85 to reach stoich so I would doubt the car would idle much less run on E85 without a change to the cars ECU to tune for it. E85, like race gas, is for those of us who are pushing cylinder pressures to the limit. What “potentially” makes it better than race gas is the price.

Uses for E85
Because of the alcohol/gasoline mixture, E85 has a rough estimate octane rating of between 105-113 octane depending on the mixture. Also the alcohol in E85 has a HUGE cooling property associated with it as well. E85 has a lot of the cooling properties that you also find with Water Meth Injection. (www.enginebasics.com/methinjection) It is great at lowering intake temperatures, lowering engine block and head temperatures, and basically doing everything that can help suppress detonation. So with E85 being SO amazing, why don’t we all convert over and start using it?

Cons for use
Because of the fact that E85 has a BTU rating of around 30% less than that of gasoline, it also has a stoic burn that requires 30% more fuel than Gasoline. Because of this most should understand that to convert over to E85 takes more than just putting it in your gas tank. You need to be able to flow 30% more fuel than what you are flowing now. Then again you are converting to E85 so you can make more power, so you are most likely going to require even more fuel than just the 30%. To get to the point, you need to double the capacity of your fuel set-up on all accounts. This means, fuel pump, fuel rail, fuel lines, fuel regulator, fuel injectors……and so goes the list. In summary if you are looking to push the envelope of your motor, but don’t want to pay the 5 to 8 dollars a gallon for race gas, E85 is your fuel.

Fuel System Filtration by Paul Yaw @ Injector Dynamics

Just like an oil filter protects your engine from harmful particles of ‘trash’ that will cause damage to engine
components, your fuel filter protects your injectors.

We have seen a lot of injectors come back for inspection with a deviation in flow that is the result of
improper filtration. I don’t think anyone intends to build a fuel system that’s not right, it’s just not
understood in full by many. We want to change that!

Fuel filters are rated in microns. A micron is a unit of measurement, equivalent to .000039 inches. (39
Millionths of an inch.) The symbol for micron is µ, though you don’t see it too often in fuel filter ads.

To put this into perspective, a human hair is about 100 microns in diameter. Anything less than about 30-40 microns
can no longer be seen with the naked eye. A ’10 micron’ filter will block contaminants larger than 10
microns, and let those smaller than 10 microns pass.

Here’s Bosch’s take on fuel injector filtration.

“Resistance to Fuel Contamination – Quality of the Medium. Dirt particles and contaminants in fuel
represent a potential danger to the fuel injectors. They are to be avoided in order to preserve the correct
function of the injectors. The dirt content in the fuel system must therefore be minimized via a suitable
filter. Recommended filter quality: nominal rating 5µ, minimum 82% capture efficiency according to ISO/TR
19438; dirt particles >35µ are not permissible. The basket filter in the injector serves only to catch
residual particles. Nonconformance of the recommended filter quality can cause damage to and failure of
the components”

So Bosch recommends a 5µ filter and says anything over 35µ can cause injector damage. Think about that,
things you can’t see with your naked eye are big enough to cause damage to a fuel injector. Not only is there
the concern of the contamination clogging the internal filter enough to cause a reduction in flow, but the
contamination that makes its way into the injector scores the bore, affecting critical tolerances.

Seems simple enough, so why are so many people misinformed? I hear pretty regularly that people are told
by fuel filter manufacturers that their 10µ filters are not ethanol compatible, so if they’re going to run
ethanol, they need to run a 40µ or bigger stainless element. While this is true, a stainless element is much
better for use with ethanol, the manufacturer has just made a recommendation that will likely cause
injector problems down the road. People don’t like to hear this after the damage, trust me!

The filter before your pump serves mainly to protect the fuel pump. Depending on the pump, usually a 30-
100µ filter is used here. The filter after the pump serves to protect the injectors and as noted, needs to be
much finer. Being that the filter is protecting the injectors, anything after the filer is technically not
filtered. This isn’t a big concern in OEM fuel systems which mostly have hard lines, but when you’re plumbing
your race car with rubber hose, do yourself a favor and put the fuel filter right up by the rail inlet. This will
leave the least amount of unfiltered fuel system and protect your injectors.

A 12µ filter is generally sufficient and they are readily available, with paper elements. If you’re running
ethanol I suggest digging a little and finding a 12µ or similar ethanol compatible element. The 6 and 12 micron
microglass, ethanol compatible fuel filters, have done well in our testing and are recommended.

Also, stay away from small fuel filters, especially those tiny ones with a single round screen disk. Those
shouldn’t even be allowed on the market. The least bit of contamination and they’re clogged enough to be a
major restriction in the system. The more surface area your filter has, the longer the service interval will
be. A pleated filter cut apart and stretched out would probably surprise you with how much surface area of
filtration there is!

THE BASICS

So to start with I naturally consulted Google. Most of the top hits for “torque vs. horsepower” are excellent pieces; they break down the math in a very methodical way, so I won’t repeat that excellent work here. Instead I’ll just summarize the basics that are accepted as fact by everyone:

Horsepower:

James Watt came up with the concept of horsepower — which is a measure of, interestingly enough, power. 1 HP is the equivalent of 33,000 ft/lbfs per minute. The reason for the complex unit is that we’re accounting for three things with this number: the amount of weight involved, the distance it’s being moved, and how long it takes to do it (that last one is important).

Torque:

Torque is nothing more than a measurement of twisting, or rotational, force. The easiest way to think of this is to imagine a long shaft — like a car’s axle — and imagine it’s in a room suspended in mid air. Hanging on the bottom of one end is a rope with a weight attached — a very heavy weight.

Now imagine someone trying to, using their hands, twist the shaft so as to lift the weight. Think of them as essentially trying to act like a wench and reel it up. The amount of force they are able to generate to lift the weight in this manner is the torque that they’re able to produce. One unit for measurement of this is the foot-pound. A foot-pound is the rotational ‘force’ generated by hanging a one-pound weight at the end of a 1-foot wrench.

THE COMMON MISTAKE

The mistake most people make when engaging in this debate is considering horsepower and torque independently. Almost everyone argues as if they are separate, unrelated values. They aren’t.

In fact, there’s not a single machine in existence that measures a car’s horsepower. It’s a man-made number. When a car’s performance is tested, its torque is measured using a dynamometer. The measure of an engine’s performance is torque. Horsepower is an additional number that’s attained by multiplying the torque by the RPMs.

THE PHYSICS OF ACCELERATION

So now for the most important thing on the page. What determines true acceleration for a vehicle isn’t really debatable — it’s force divided by mass. The formula for acceleration is seen below.

f = ma

Which means…

a = f/m

The confusion only comes in determining which force we’re actually talking about.

So we are solving for acceleration and we have a constant mass. We’ve already established that torque is the amount of rotational force being generated at the engine, but we aren’t concerned with the force at the engine. What we’re interested in is the force at the wheels. The force at the wheels is the f in f = ma (actually, it includes the radius of the wheel as well, but we’re simplifying).

But remember, the transmission ultimately gives the force to the wheels, not the engine. And that’s the trick to this whole mess.

GEARING

So that’s where gearing comes in.

Gearing magnifies torque. The torque at the wheels is the torque at the engine combined with the torque magnification given by the transmission through gearing. So the transmission only sees what’s coming off the engine, while the wheels see the resulting force combination of the engine plus the transmission.

That’s what horsepower represents. Horsepower is the combination of the benefits of the engine’s raw abilities combined with RPMs. And RPMs are what allow us to use gearing effectively, which gives us more torque at the wheels.

CONCLUSION

So a technical answer to the question of, “What makes acceleration: torque or horsepower?”, is torque—but torque at the wheels, not at the engine. And since we’re talking about torque at the wheels and not at the engine, the best answer is horsepower, because horsepower encompasses not only the engine’s torque but the total torque that gets delivered to the wheels and therefore provides the f in f = ma.