dmp

...the way the starter works and operates has nothing to do w/ the electric SC pipe-dream.

How is the fan going to operate to flow the right amount of air for the engine's speed? Will you have a 'dimmer' switch in the car to slow the fan down, at less than WOT?

There isn't a viable Electric SC out there which can flow enough CFM to pressurize an intake manifold. Just doesn't happen.

I know of a guy who had a screw from an ERam electric SC come off - and his engine injested it. Toasted a motor. ERam said "the thing wasn't built for your car, that's why" and refused to help him fix it.

There are many more educated people than I who could probably show the flow charts of even a small turbo charger, and show you the tiniest of turbos WAY out-flows the best of the Electric SCs.

MazdaManiac

iTrader: (3)

Is the search button broken?
There isn't a single new idea here - it has all been thoroughly explained in detail elswhere on this forum.

Bottom line - there is no free lunch. Power in is always bigger than power out, that is just the nature of our physical world.
If you want to flow more air into the motor than it will take by itself, you need to push it with a greater than equivalent amount of energy.

Just do the math and check in later.

G8rboy

When I was a teenager I contemplated rigging my dad's gas powered leaf blower into the air cleaner of my '78 Celica... at the time I figured that would have been as good a turbocharger : ). He never gave me the go ahead to try...

TheColonel

This is, before it brakes, could maybe add a few hp on a low reving old civic engine, but not on the RX-8.

StewC625

Guys, the thing to remember here is that all FYI devices use a COMPRESSOR, not a fan. A compressor is exactly that - it takes the air and COMPRESSES it - forces more air into a given volume. The effort and force required to do that are very real.

Think of it this way: Try blowing up a condom like a balloon. Condoms are tremendously stretchy and as little as .3 PSI of air (you can reasonably generate about 1 psi from your lungs (over atmospheric pressure, which is what PSI is ...) will inflate it.

Now take that same condom and hold it up in front of an electric fan. Does it inflate? No. Try stretching it over an exhaust fan like that bathroom duct fan. Still won't inflate.

No way that it's going to provide any sort of FI benefit OVER it's inherent restrictiveness in the intake path.

IcemanVKO

Okay, lets debunk a couple of "Theories" being thrown around here.

1. An electric motor couldn't produce enough force to compress air into your intake.
A. I already debunked this once, by stating that your starter, which turns your entire motor over until it ignites, runs off of your 12v battery alone.
B. Yes maybe a FAN from Walmart wouldn't be strong anough to provide the power needed, but any increase in flow at all would provide better performance, although probably not noticable until it reaches a certain level.
C. If Car companies are looking in to it, then it IS theoretically possible.
D. If you were to take a standard belt driven Super Charger, and hook it up to an electric motor of sufficient strength, and then run this electric motor off of your battery, then you would essentially have a very expensive Electric Supercharger.
E. There are some very powerful electric motors out there.

2. You wouldn't gain back enough power to overtake the power lost powering the electric engine.
A. Current Super Chargers steal power from the engine just like your AC does, and they tend to provide more power than they take away.
B. Turbo chargers steal power from exhaust, and although this is a more effecient power source, because it is to some degree already wasted energy, it does have a negative impact on power, that is less than its overall positive impact.
C. The Alternator has extra power, that is not used, if you could harness 150-300 watts of this and use it for compression or air flow, that would be great!

3. An electric supercharger couldn't detect the speed of the engine and change its power level to match.
A. Check out the latest Aftermarket stereo's. They detect engine speed and increase volume based on it. Its actually really simple, since the alternator creates a frequency on the DC power, that can be detected and reacted to. (Definately not a DIY job however)


That being said however, if noone is willing to give me a positive review of having this installed on their car, I'm not going to Guineypig it.

ScottishRX

OK so it's only my first post but I really am sick of this sort of crap getting posted. Why doesn't everyone grow up, get on with life and actually buy an eight?

IcemanVKO

OOOOO KKKKKKKK

Nice first Post!

So what types of things do you expect to see on here? If we can't discuss these things then what exactly should we do all sit around and say WOW RX8 is GR8

MazdaManiac

iTrader: (3)

Once again - power out follows power in.
In a typical supercharger system, it takes 15 to 25 horsepower to provide a 50% increase in flow over N/A. 25 HP is over 18kW. That is 1500 amps.
Most importantly, the type of "fan" that is being suggested provides no compression or resistance to reversion. As soon as it is faced with any pressure, it stops flowing.

Uh, yeah. 300 watts.

You wouldn't need to modulate it at all. Just vent.


Aw, why not? Just strap on a CPU fan and a dozen or so car batteries and you are set.
Better yet, get one of these: http://www.boosthead.com/home.php :p

buzzwordenabled

Why would someone who spends nearly $30k on a car install something this poorly engineered is well beyond me.

burnoutking999

THATS ONE OF THE FUNNYEST THINGS IVE SEEN IN A WHILE. its so funny because of the large amount of people who acually represent that that ad in every way. :D

globi

IcemanVKO,

An electric supercharger is not a bad idea per se. If you had enough electric power on hand you could produce more power than with a turbocharger or a mechanical supercharger at the same boost pressure.
As soon as we have more powerful flywheel generators we'll see electric superchargers. An electric supercharger is much more flexible than a mechanical supercharger and has no parasitic loss.

If you're happy with 1 or 2 psi boost then the current battery and alternator might be just powerful enough. But if you're seriously considering it, you have to go with these compressors (as MazdaManiac already mentioned): http://www.boosthead.com/home.php
which still appear to be reasonably priced.

Also this has been discussed before:
https://www.rx8club.com/showthread.p...c+supercharger

rx8wannahave

I understand the "Go search, this has been talked about before"

But don't be so mad that people think it's worth trying out, let us dream people...let us dream...

I know there are always people that tell others, that can't work...your crazy, but if creative and smart people (not saying the nay people are not creative or smart, they are) want to try or want to dream up something special...something new, then let them...this land is bult by dreamers...let us dream...lol

Here is a thought you add:

Some extra batteries
More powerful alternator
Electric sc/turbo thing (with a strong fan/compressor/etc made of metal)
Then, use the spinning wheels as a generator to help out the alternator, and to store engery

Would this help? Would this make it possible? I'm not sure...but I'll dream, dang it...I"ll dream...

LOL

globi

With some extra batteries and a larger alternator you might be able to generate about the same power that the greddy turbo does.
It might be the least expensive way to increase power.

Keep in mind it would only be used at WOT and most people don't drive at WOT for more than a few seconds, so it will work as long as you don't try it on a German Autobahn without speed limit (no alternator will provide enough power to continously drive the supercharger). It's feasible and it's definitely not a silly dream.

http://www.boosthead.com/faq.php

However since the rotary engine is less efficient than a piston engine I don't think this is the ideal engine for a supercharger in general. At least a turbocharger can re-use some of that 'unused' air to drive itself.

BaronVonBigmeat

The main reason why this will not work, even though it may look like it's roughly the same size as a more expensive unit: It can't possibly spin fast enough. Turbos spin at tens of thousands of RPM's. This unit is made of plastic. The heat from the air compression would probably soften it (if not melt it) and the centrifugal force acting on the blades would stretch them like silly putty.

To answer the specifics....yes, an electric supercharger could be done. But this particular one won't cut it because of the cheesy wanna-be compressor.

Point B: This thing would almost certainly be an obstruction to airflow. In other words, any miniscule gain in airflow would be greatly offset by the blockage and turbulence created by the fan.

Point C: I'm not aware of any car companies researching this very heavily....probably because of the manufacturing costs. A turbo or belt-driven S/C needs an expensive pump. An electric S/C needs that too, plus a pretty darn good electric motor, a sizeable battery pack or capacitor, a speed controller for the motor, etc. Pretty soon you've got an alternative which does work...but costs the same (or more), adds significant weight, and only works in short bursts.

A turbo can draw very little power at cruising speeds and allow good mileage, but then spin for as long as you're willing to put your foot down. Hell, adding cylinders is probably a more weight-efficient way to add power than a "real" electric s/c.

Point D: The alternator provides a certain amount of power, and the battery can release power at a certain rate. If MazdaManiac's numbers are right, then the power output of an alternator isn't even in the same ballpark. You can go with more batteries and a bigger alternator, but....why not just "cut out the middleman"? ie,

engine power-->electrical power-->chemical power (battery)-->mechanical power (motor for compressor)

or

engine power-->mechanical power

So yeah, it CAN be done, in fact there is one guy who has a real kit ($2500 IIRC)...but the question is "why"? There are no performance advantages, or mileage advantages, or benefits to driveability or reliability, or even to manufacturing costs.

EDIT: I missed the link to Thomas Knight's product, hmmm. The last time I saw it, I could have sworn that they were like $2500, which is just too close to turbo/supercharger prices.

rx8wannahave

Well, per the link above, if $1250 gives you 6psi...then $3500 for 7psi is a BAD deal compared to the electric system.

I just wrote the owner and invited him to this chat but I think maybe in the near future electric systems (if they stay cheaper than the standard stuff) only have one real drawback and that is:

The wait, they run enough for a few runs in the day, of having to recharge the battery would be a pain. So, maybe there is something to do...but the wait time is it's biggest problem.

globi

The throttle is an obstruction already. This is not an argument. And as soon as you fully open the throttle the supercharger is running anyway.

http://waw.wardsauto.com/ar/auto_visteon_eyes_electric/
http://www.visteon.com/products/auto.../vtes_spec.pdf

Unless you live on a Salt lake or something there aren't many places where you can drive full throttle for more than 8 seconds or so. (The car does 0 to 60 mph in 6 seconds.)
I don't believe that adding cylinders is more weight efficient and even if it was, if you add cylinders your fuel consumption will go up no matter what and if you add an electric supercharger the fuel consumption will only go up at full throttle.

Well that's why there are batteries (I guess you forgot that cars sometimes need to drive at constant speed or even decelerate) and that's what the flywheel generator for instance is here for: You hit the brake and it charges the batteries. Otherwise your brakepads would just burn it up. You will basically be using the free brake energy to supercharge the car. Or you use the unused power of the gasoline engine at partial throttle to charge the batteries which is still way more efficient than adding cylinders.
Of course now you say: "A hybrid is more efficient, so why not using a hybrid directly". With an electric supercharger that requires 15HP you might add 60HP or more to your gasoline engine. It's a concept for a fuel efficent sportscar not a concept for maximum fuel efficiency.

Also with an electric supercharger you can use a compressor that is more efficient (like a centrifugal compressor) and benefit from it at low rpms already. Imagine the torque you could produce at 2000rpm.

So there are mileage advantages and there are performance advantages (no other supercharge system will reach as much power with the same boost level).

(I'm not referring to that $80 fan, which I agree is not worth much)

Fanman

From this months Sport Compact Car :

"The ESC 400 (real electric supercharger) is not to be mistaken for those ridiculous "electric superchargers" typically found on eBay like the e-RAM. Typically these are electric leaf blower ducted fans powered by a battery. Thoses deveices do absolutely nothing for power and in fact, every car that we have tried such devices on actually lost power. When calculating the amperage draw from these devices, it's clear they're not capable of providing enough air volumne to increase the density of the inlet charge and are merely restrictions in the intake tract."

bigblockbeater

i came upon this site after researching electric superchargers. http://www.halfbakery.com/idea/bette...20supercharger i think it pretty much explains the reality of such claims

bigblockbeater

my neighbor has an old chevy s-10 which he put an industrial blower on his intake. it does make a noticable difference at low rpms. but when the engine picks up speed and the cfm becomes greater then the blower can produce. the blower actually creates drag, starving the engine.

BaronVonBigmeat

^^^Yeah, that's basically what I meant. For the plastic "supercharger" at least.

The Knight unit does look fairly interesting, and it does look like they've made progress with weight/airflow/air pressure/cost numbers. It might make sense for some cars, especially the smaller ones, as a power adder somewhere in between nitrous and regular FI. For an RX-8 I think I'd just get the Greddy...because the costs would go as follows:

$1300--compressor/motor (does that include the speed controller for the motor?)
$ 300+ (?)--e-manage
Additional "batcaps"--not cheap, at (gulp) $100~$170 each http://www.batcap.net/Indexnew5.htm
$200 or so--Bigger alternator

So you're already up to...$2200, or possibly more. I think I'd just scrape together another $700 for the GReddy personally. In the near future though, they might be much more attractive once the 42V standard is adopted. They need a better name than "electric supercharger" though. I propose the term "Teslacharger". Especially if someone would develop and market the bladeless turbine to go with it, but that's another thread.

bigblockbeater

i found another electric device for forced air induction. http://www.paradox.co.uk/erol.html#7...lockedReferrer

globi

I agree, as I said before I'd probably would go with the Greddy too. It could be something worth a try on a Miata though. Keep in mind the extra batteries can also lower the center of cravity and the compressor can be placed anywhere.

As far as I know now the bladeless tesla compressor would probably reach about the same effiency as a centrifugal compressor. Those 2 compressor concepts are very comparable, however the centrifugal compressor weighs less and has a lower inertia and is commercially available. The advantage of the bladeless compressor is that anyone could build one.

But what I'd really like to see is a axial flow compressor with a high frequency motor placed in the center (efficient, smalll, light and clean).

guitarjunkie28

i wonder how much pressure could be built with a bigass ram air duct...

guitarjunkie28

i wonder if that bathroom fan would work with a 5 hp b&s motor on a go-kart????