HOWTO: Build an Electric Supercharger
(Do Electric Superchargers Work?)
Written by Wild Weasel
Who Should Read This?
Firstly, if you're hear to read about the testing I've just done, go here for the results!
If you're considering building your own electric boost system or have seen one available
for sale somewhere and are considering purchasing it, this page is for you.
An electric supercharger is generally a waste of money and can potentially cause
some very expensive problems if you try to use one. Take the time to read this whole
page and I'm sure you'll learn quite a bit about why I'm saying this and how to
avoid being scammed.
First I'll explain the theory behind boosting an engine and the basis of this modification.
This is an extremely simplified guide but we're not here to discuss the intimate
details of boost. You'll get the idea and that's what's important.
An internal combustion engine makes power by burning a mixture of air and fuel.
For a street driven car, the fuel is usually gasoline and the air comes from the
When you have the right combination of air and fuel (called a stoich mixture) it
will burn efficiently and produce a minimum of waste. This mixture will consume
almost all of the fuel and oxygen in the mixture.
If you want to make more power, you have to efficiently burn more fuel and there's
a few different ways to do this. The first and most obvious way is to simply use
a bigger engine. If you've got 6 or 8 cylinders to work with, you can obviously
burn more fuel than you can with a typical 4-cylinder engine.
Alternately, if you can cram more air into your engine, you can burn more fuel.
The more air you get in there, the more fuel you'll need to maintain a stoich mixture
and burn efficiently. The more fuel you burn efficiently, the more power you'll
make. This is the basis for boosting an engine.
The term "boost" refers to forcing more air into the engine than it would otherwise
pump in on its own and there are two main ways of doing this.
Types of Boost
The two main methods of boosting an engine involve using a turbo or a supercharger
(also referred to as a blower).
A turbo is an air compressor that's driven by the exhaust gases. It is placed in
the path of the exhaust, whose force is used to spin the compressor and force air
into the intake.
A supercharger is similar but is driven by the engines belts rather than by the
exhaust gases. There are two main types of superchargers. The roots type and the
centrifugal type. The roots type generally mounts right over (or replaces) an engine's
intake manifold and works by forcing the air directly into it while the centrifugal
type looks very much like a belt-driven turbo.
Both of these systems work by forcing more air into the engine which allows it to
efficiently burn more fuel and make more power.
So now we ultimately come to the discussion on the idea of an electric supercharger.
First I want to note that this article doesn't apply to the few electrically driven
compressors that have been specifically engineered for the purpose of providing
short-term boost over a quarter mile. The Thomas Knight products are an example.
Those kits are similar to a turbo or centrifugal blower driven by a high-amperage
electric motor and require heavy duty wiring and entire banks of batteries to drive
them. They do not hook up to the stock 12v vehicle electrical system and are not
meant for street-driven vehicles as they are only capable of producing boost for
very short periods and require a long time to recharge. These kits cost thousands
of dollars and if you're considering purchasing one, I'm going to assume that the
scope of this article is elementary in comparison to the knowledge you must already
So then, back to the topic of electrical superchargers. Understanding that forcing
more air into the engine will make more power, it stands to reason that if we can
place an electric fan in the intake path that will force air into it, we can make
The problem with this idea is that most people who think of it really have no idea
how much air gets pumped by the engine during its normal operation. The engine acts
as a big air pump and is capable of moving huge volumes of air all on its own. With
that in mind, any electric fan that you place in the path of the intake is only
going to act as an obstacle to efficient airflow and not provide any level of boost
whatsoever. In order to provide boost, the fan has to be able to force more air
through the intake than is already being sucked and that's simply not going to happen
with some off-the-shelf computer fan or bilge exhaust blower or whatever else you've
found or had marketed to you.
Now that you realize how futile the idea of an electric supercharger is, consider
the dangers. If you place something in the intake path between your air filter and
the engine and that thing isn't made to be there, you now run the risk of having
it break and send unfiltered pieces into your engine, potentially causing catastrophic
failure. I would hope this is more than enough to discourage experimentation in
As a general rule, if something seems too good to be true it generally is. Modifying
a car to add power isn't a cheap endeavour and most of these sorts of shortcuts
will only end up burning you in the end.
Interestingly, the company from whom I got that image above even has a small disclaimer
on their site with a list of cars that showed no gain from their units. The list
included GM's 2.4L engine in both the Grand Am and Cavalier Z24. I suspect it likely
includes all cars from ripped-off customers who bothered to get the system dyno
I've had some questions posted about this that I'd like to address. First off, on
the topic of whether one of these things will actually be a hindrance to the airflow,
I did some calculations to determine the maximum airflow of a 2.4L engine. If you're
interested in this, the thread can be found
here. Please let me know if you find the link to be broken.
Secondly, someone just recently mentioned in my guestbook that these fans can be
found rated to move upwards of 1000 cfm. I just wanted to note that those ratings
are referring to the amount of air moved in an unrestricted environment, for which
they've been designed. If you install one of those in your boat to bring outside
air into the cabin, it may very well move 1000 cfm. If, however, you place it in
a restricted path such as your engine intake where there simply isn't room to move
that air without building up pressure, it will not build up that pressure that you
want. While it may be capable of moving this much air past it, it is not capable
of forcing that air to compress into the smaller space.
Tuesday, Apr. 8, 2008:
There's been some questions lately about a company called Thorton making wild claims
about their electric blowers.
The Thorton site is http://www.electricsupercharger.net/
Looking at their site, there are all sorts of warning signs that should send you
Firstly, you'll note that they get their power from the car's 12V battery. There's
no way they're making the boost they say they are with the battery as its power
Secondly, they're offering an "EPROM Performance Chip" with it, which is a load
of hogwash. That's an entirely different scam and I have a
page here devoted to explaining it. That's the first big warning that they're
pulling your leg.
Next, you'll notice that their "100% satisfaction guarantee" requires that you return
everything to them within 2 weeks. If they were really standing behind it, they
wouldn't need that quick a turnaround. This doesn't give enough time to even install
it and book a dyno test.
Now take a look at their fabricated dyno sheet. If you know how to read a dyno sheet
then it'll be good for a laugh. In case they change it on their site, here it is.
If you don't know how to read a dyno sheet, then take my word for it that this is
not only BS, but actually a completely impossible to attain dyno graph for any car.
Finally, take a look at their forum and note all the BS talk on it. I tried to sign
up to ask some questions and every single forum there requires administrative rights
to post in it. It's a fake forum filled with fake entries.
The bottom line is that it appears to be just another electric fan in a metal casing
and, especially after reading this, you'd be stupid to waste your money on it.
Note that the people at NE Performance Inc were the exact same scammers as the Thorton
folks. As I type this, the two share the same hosting company and both list the
exact same phone number (1-253-882-6900) as their contact number.
Note that I removed the link to NE Performance Inc as it appears they gave up on
it and it is currently just a spam link site.
On Thursday, Feb. 24, 2006, a Mr. Ed. Walker left a note in the guestbook saying
it is about the cfm, and not the psi. as long as your giving the vehicles motor
more air than it can naturally draw in(cfm). read the definition of the supercharger
in the dictionary. and our dyno results. www.streetfreakzperformance.com
I won't address all the spelling and grammatical errors. I'll leave that up to the
reader to make their own conclusions about. As for looking up the Dictionary Definition of a Supercharger... Well the reader
can do it themselves and find that my reference above is quite accurate and that
nothing about an electric blower fits it. An electric blower doesn't force air and
doesn't compress it.
Let's look at what he's saying though. Obviously Mr. Walker didn't read the whole
page but I wouldn't expect that from someone trying to bilk people out of their
hard-earned money. He suggests that CFM (Cubic Feet per Minute) is the key here,
rather than PSI (Pounds per Square Inch). He's saying that flow is more important
First of all, I stress again that the CFM rating of those electric blowers is completely
irrelevant in this application and does not reflect how much air the fan will push
into the engine. That number reflects the amount of air the fan can move through
it in an unrestricted environment. An intake tube with an engine powerfully sucking
air through it is hardly an unrestricted environment.
An industrial exhaust fan, 4 feet in diameter and turning at 100 rpm, may be capable
of moving hundreds of thousands of CFM of air but if you were to stick it to your
car and create a funnel leading into your intake, it wouldn't do you the least bit
of good. The same goes for these little blower fans people are hawking as superchargers.
As mentioned above, just because it is capable of moving 1000 (or more) CFM of air
through it in an unrestricted environment does not mean that it is going to force
that much air into the engine. With air already in front of it, the fan blades will
just churn through the existing air causing a restriction in flow while the engine
continues to suck just as much as it was before.
In a boost application, PSI is important. CFM is also important, but only in how
it is applied in conjunction with the pressure. The CFM of the whole system, engine
included, is key but adding an electric blower to the system does NOT increase that
CFM by any significant amount no matter how high the CFM rating of that blower is.
People will tell you CFM is important, like Mr. Walker did, and here I will provide
an example of how that is true with respect to the whole system.
If you take a stock engine and add forced induction via a roots style supercharger,
you will increase your manifold PSI and the engine's CFM of air consumption. By
forcing more air in, you obviously move more air through. Note here that electric
blowers do not force more air in because they do not increase the manifold PSI.
They are not a form of forced induction. Now that you've got your boost (PSI increase),
let's say you go and replace your entire exhaust system with something much better
flowing. The result here is that the air can pass more freely through the engine
so the CFM can increase. This may bring with it a corresponding DECREASE in manifold
pressure (PSI) while providing more power. Your boost gauge will read a lower amount
but your engine will make more power. This is because the supercharger is still
forcing in the same amount of air but the engine is consuming it faster and making
more power. If you had used a turbo, the turbo would simply supply more air to keep
the PSI at the level you'd set. To get your PSI back up with the supercharger, you'd
need a smaller pulley.
Now an unscrupulous salesman might spin these numbers to note that with the higher
CFM you're making more power even though you've got less manifold pressure (PSI).
With that in mind, clearly having an electric blower with a huge CFM rating will
Let's look at that scenario.
If you take that same engine stock, there will be no pressure (PSI) in the manifold.
Air is simply flowing through as fast as the engine can suck it in and blow it out.
With a good intake, this is fairly efficient. Now let's add our high flowing exhaust
system. We still don't have any manifold pressure, but our CFM has increased. We're
making more power because the engine is more efficiently consuming the air it's
sucking through. Now you add an electric supercharger. They tell you that it's got
some monster CFM rating but curiously, the CFM hasn't changed or, perhaps, has dropped
a little. This is because the air can no longer smoothly flow through that section
of your intake. They want you to believe that the fan is helping the air along,
but the truth is that if the intake was free flowing beforehand then all you've
done is put in a restriction. The fan can't compress the air in front of it so it
can't move the CFM that it could with no restriction. In turn, the fan itself provides
restriction to the overall system, bringing down the engine's CFM of air consumption.
For a little bit of amusement for all my fans here, this is taken directly from
Mr. Walker's website.
The E-Turbo from Street Freakz Performance is designed for just that. At full throttle,
your performance turns to 800 cubic feet per minute, equivalent of 185 miles per
hour of wind being shoved down your throttle body. Or get a twin setup, which will
be 370 miles per hour!
Now here's a picture of his ghetto hair-dryer looking contraption.
Anyone dumb enough to think that this thing is going to provide hurricane-force
winds to their engine probably deserves to be suckered out of their money. That
fact aside though, the speed that air flows through a fan is entirely dependant
on the rpm of the fan and the amount of restriction to airflow that exists. If you
put 20 fans in a row, the air flowing through them does not accelerate faster and
faster through each fan. The fans later in the line will simply have less load on
them as they won't have to work to move the air. It's already flowing as fast as
they'd be trying to move it. Of course, if you put a powerful vacuum at the end
of this chain, all those fans would just be providing more and more restriction
to the flow.
June 9, 2006
These same clowns showed up on j-body.org and tried to defend their garbage so they
could kick up some more sales to poor souls who don't know any better. Check out
the discussion here and be sure to read all the way to the end:
As I did in that thread, I'll reproduce their "FAQ" here along with the truth to
explain their lies and marketing spin. The questions and answers are taken directly
from their site, without change. The title on the site is "Q & A with Street Freakz
Here you have the original questions, answers, and my addition of the truth.
Question: Why don't they work with my vehicle?
Answer: The computers map sensor will not adapt to the increased cfm
flows that the E-turbo pushes out.
The Truth: Someone actually did tests on those cars and proved our
product is garbage. When people test other cars, they too will be added to the list
of cars not supported. MAP sensors read pressure, not CFM so our explanation doesn't
actually make any sense.
Question: Why not call it the electric supercharger instead of the
Answer: The turbocharger is defined as a centrifugal blower, not the
supercharger, and we use the centrifugal shape.
The Truth: The shape has nothing to do with the name. There are
centrifugal superchargers, most famously from Vortech. The turbo is actually defined
by the fact that the engine's exhaust gases provide the power to turn the compressor.
A supercharger is traditionally belt-driven but other variants of compressors not
driven by the exhaust are also referred to as superchargers. They're actually calling
it a turbo because they think it sounds cooler and will scam more people into buying
Question: What is the difference between your electric turbo and
the bildge pumps?
Answer: This is rather simple to answer, in order make a difference
in the motors hp range, you must be able to give the motor a higher volume of air
than it can normally take in (cfm), this is why a ram-air system will not function
correctly unless your doing speeds of 155+ mph. the largest (bildge pump) or ventilation
fan pushes 250 cfm, so after around 2500rpm's your now creating a (restriction)
in your motors air flow. Our electric turbo pushes 803 cfm per unit, this lasts
through the entire rpm range of your vehicle. Why? Because it pushes more cfm (volume
of air) than the motor naturally draws in.(even at max rpm) but remember, even though
it pushes more cfm than it takes in, a V8 will require 2 units to make a respectable
The Truth: There is no difference. You can get bilge blowers that
flow over 1000 CFM. CFM stands for "cubic feet per minute" and refers to the volume
of air that the fan is capable of flowing through it in an unrestricted environment.
This rating has absolutely no bearing whatsoever on the capabilities of the blower
in a restricted environment such as an engine. In this situation, the blower has
to be able to push the air such that pressure is build (PSI) and these fans are
not capable of such. Don't let their marketing spin confuse you. When it comes to
boosting an engine, it's PSI that is important. Increased CFM for the engine is
a byproduct of having an unrestricted intake and exhaust. It is not something you're
looking for in a boost solution.
Question: What makes your units defy the laws of physics, claimed
Answer: They do not defy the laws of physics because if the theory
doesn't match the facts then the theory must change, because the facts will always
remain. Our facts are the dyno sheets.
The Truth: They don't know anything about physics or theory when
it comes to engines. They forged up some dyno sheets though to make it look like
their product works so you'll buy it. They don't know that it would take over 10
psi of boost pressure with associated fuel mods to accomodate it to give a 60% increase
in power to the 1995 Cavalier they tested. They only know what they made the chart
say it does. Suggesting that basic engine theory and perhaps physics itself should
be changed to support their forged dyno sheets is just plain ludicrous!
Question: If the electric turbo is so great, then why arent the bigger
companies either making or using them?
Answer: Well, you must understand, that the electric turbo was never
intended on replacing the higher psi turbo's or superchargers. the electric turbo
was intended on being an economy turbo, with the on demand setup. but it became
much bigger than that. it started getting better results on many vehicles than the
base 4psi supercharger or turbo setups, even the factory option units. for example;
the factory option supercharger for the 95-99 cavalier recieved a 40hp gain and
costed over $2,500. then you have our electric turbo that recieved a 53.8hp gain
for the same vehicles but only costed $460 for the entire kit. this is why the bigger
companies don't use these or care too, it's a direct threat.
The Truth: They don't work and everyone who knows anything about
engines and boost knows that. If a company could produce a solution for even $1000
that did what a $3000 system could do they wouldn't see it as a threat. They'd see
it as an opportunity to make massive profits. The simple fact is that these don't
Question: Explain how yours differs from those axial flow units?
Answer: Well, axial flows were supposed to be designed to act like
a jet engine, but they forget to add the other 5 fans like a jet engine has. There
are alot of faults with the axial flow designs, the biggest being that their all
using toy airplane motors and a plastic 6 bladed fan. and not to mention that the
motor is mounted directly in the center of the air flow path. what do you think
will happen to your motor if that axial flow motor fails? And the restriction that
it causes when it's not in use. our units on the other hand do not pose any of these
problems our faults mentioned, and we have what nobody else does, overheating protection.
Every motor that we manufacture has an internal thermo switch imbedded in the motor,
so if anything happens, it will shut itself down.
The Truth: First of all, an axial flow one is absolutely nothing
at all like a jet engine no matter how many fans you add to them. These people don't
know how boost works and clearly don't know how jet propulsion works either. The
clear answer here is that there is no difference. Their piece of garbage is also
in the intake path and if things break on it, they're still going into your engine.
They chose this design because the shape looks similar to a turbo and people think
turbos are cool.
Question: Why are you using a mild steel fan instead of the plastic
or aluminum like the other units out there?
Answer: Our units spin at 22,000 rpm's, we don't want the fans to
The Truth: This is a good time to mention that turbos spin upwards
of 150,000 rpm to produce around 10 psi and do so while actually compressing air.
These guys are using metal fans instead of plastic simply because that's what sort
of fan comes on the ghetto bilge blower they decided to use.
Question: Why do you need to reboot the vehicles computer when adding
the electric turbo?
Answer: A lot of computers simply have to be tought that the added
air flows are there. Even when dealerships add the optional superchargers to their
vehicles, they have to reboot or reflash the computer system. we give the buyer
the instructions on how to do this, it's very simple and takes about 10 minutes
The Truth: Resetting the ECU and reflashing the ECU are 100% different
things. They talk about them as though the terms are interchangable. Reflashing
means you're actually reprogramming the computer to change the fuel tables and other
parameters. Resetting simply involves cutting power to it for a certain amount of
time so it loses it's saved parameters. To suggest they are the same just shows
the level of misinformation being spread by these people.
Question: Do you have any type of warranties or guarantees?
Answer: Yes to both, We have a 30 day money back guarantee, if you
don't like the product return it in the original packaging, undamaged for full refund.
We also guarantee a minimum 10 horsepower gain over stock with a dyno test proving
under a 10 Hp gain (what we need is a copy of the dyno tests within 90 days) and
we even refund the dyno test itself. Now as for the warranty, the Electric Turbo
includes a warranty card that must be returned, and you get a Limited Lifetime warranty
on the casings. Motor,fan, and wiring harness Limited 1 Year warranty. And a 1 time
replacement for 1 year on the brushes.
The Truth: Most people won't have the time to install and test this
crap within 30 days so they've got nothing to worry about. If someone actually tests
it, they'll just add the car they tested it on to the list of cars it doesn't work
on. Good luck actually getting compensated for the dyno time.