Andy.F

This interesting little blower went almost unnoticed in a previous thread, looking at the spec it is a bit more than a PC fan !
http://www.electricsupercharger.com

They 'claim' 1.7 psi and 750 cfm for the super e-ram model, at 100 amps power consumption this may be believable ? 1.4KW sounds about right as we use 90kw motors for driving 750cfm compressors at work pumping 100 psi.

Running this in series with a turbo such as my own could see some worthwhile gains.
Turbo's work with pressure ratios ie if my turbo is peaking out at PR 2.7 at 630cfm (approx 440bhp) and the gauge pressure is (2.7 x intake pressure - atmospheric pressure) = 1.7bar
If you increase the inlet pressure to say 1.1 bar absolute (by adding 1.45 psi from the fan) then the gauge pressure becomes 2.7 x 1.1 -1.0) = 1.97bar.
At 1.97 bar my engine will consume 693 cfm of air which equates to 488bhp, a handy increase of 48bhp !

The above assumes negligable loss of density during the 1.45 psi compression and that the turbo will actually flow 10% more air when the inlet pressure/density increases by 10%. I assume turbos are normally flow rated at std atmospheric density ?

Before anyone says you can't get this energy for free, you don't, it comes from the battery for the short duration it's on, then the alternator recharges the battery over a longer period at a lower rate (when off boost)

Anyone care to comment ?

Andy

Pavlo

you will need the extra power when you're lugging around the bigger battery (bigger than a small one) and alternator not to mention the charger itself

you can work out shaft power required to compress fluid at a flow rate, it's easy, I just can't remember it (I could work it in a very complicated and stupid way though).

Paul

Andy.F

Yea, I could do it the long way but can't be bothered !

Even little racing batteries will run 100 amps for 20 seconds ok then the std alternator makes it up at 33amps for 60 seconds for example.

You would only use the fan during 'maximum attack' maneovers bit like NOS but it recharges itself !

john banks

It looks very interesting. I'll help you test it on either or both your or my car

Mr J

It sure sounds nice ...if it would work

Well what are you wating for Andy put one in your or JB's car so we will know if it will work or not


/Jan

Jay m A

iTrader: (2)

I've been toying with an idea which is a kind of motor driven anti-lag that doesn't kill the turbo.

I'm thinking along the lines of using an electric motor to spin the turbo during gear changes only. I.e. take a normal turbo, split it in half, add a chain/belt driven gear to the spindle in the middle, then some how have the inlet and exhaust housings each side. The gear is mounted by a roller bearing, so when in normal operation (turbo on boost) the spindle spins faster than the gear, the only losses being friction in the roller bearing. then, during a gear change the motor drives the turbo, maintaining boost.

Is this feasable?

Just an idea

NENO

Knowing very little about these things, just a suggestion. Would it not be of equal use at getting rid of lag? Could you use the fan to create boost before the turbo has spooled up?

[zip] Flame suit on...

Adam M

Finally a reason for spending so much on an yellow topped optima.

shame my intake pipeowrk is more than three inches .

Andy.F

Go on Adam, it will be about the only thing your car doesn't have
You could run a pair in parallel 1500 CFM. Equal area to 108mm bore pipe.

Jay - The problem with that is getting a high torque motor that will also run at very high rpm. It will need a lot of current at 12-14 volts, even the units referred to will produce only 1.7 psi with 100 amps current.

Neno - It would help a bit I guess. I'm not sure how long you could run it with that sort of current though !

JB - Are you putting up the cash I'll supply the labour/pipework/wiring and 50% of the enthusiasm

Andy

john banks

Fool, cash, parted, power, Subaru. Rearrange into something meaningful

john banks

I can see this quite neatly replacing my MAF sensor

Andy.F

Your TD05/06 should make over 500 bhp on your new 2.3 with this 'pre boost' plus 1 bar from 2500 rpm.....how can you resist ?

john banks

I don't think I can.

john banks

Controversy:

http://www.crxsi.com/resources/classified/ads/7666.htm
http://home.att.net/~t.vago/howto/eram-waste.html
http://gawlowski.com/mr2/mr2_dyno.html

"On a public forum I read a horror story regarding one of the highest selling electric superchargers, the ERAM, where the device flew apart during operation, sending metal fan blades into the engine, destroying a piston among other vital innards with no compensation from the makers of the ERAM."

ChristianR

iTrader: (1)

Andy, the td05/05, sounds good at making 1bar of boost from 2500 - when does it hit 1.8bar to 2bar of boost?

EMS

John,

In your car it will probably "only" destroy the turbo is a blade comes off......

Mark.

Forester_GP

Electric compressor of that power should deliver what its been quoted for BUT NOT in series with a turbo !Once the turbo gets spinning then it will either suck the fans or blow them into the intake, depending on its location. I'm sure that with some crafty* engineering (*David)it could be made to work in a bypass configuration from 0-2500 RPM.

George

john banks

Christian, on my 2.0 it will run 1.5 bar surge free in any gear as early as the turbo will provide it, which in 5th is at about 3200 RPM, 3rd about 3500 RPM. I can run 1.8 bar at 4500 RPM in 3rd gear as it flies through this zone quickly, the issue is using quite sophisticated boost control to hold it back a little later in 4th and 5th (UK gearing), which is the opposite of what usually happens with boost control. With shorter gears it is only an issue in 5th gear. I'll have to see what it's like on the bigger engine, but for a 2.0 running up to 1.5 bar there seems to be no issue.

At nearly 700 CFM I do wonder if the electric supercharger is such a good idea... It doesn't appear to have been tested at such boost levels.

FASTER MIKE!!

john do you realy need any extra power after the 2.3?

Andy.F

Looked at those links John, appears that it can flow 750CFM and produce 1.7 psi........but not at the same time

Oh well, back to plan 'A' with the parallel and series turbos

ChristianR

iTrader: (1)

John, is that how td series turbos work? It seems to be taking forever to spool up from 1bar to 1.8bar of boost(getting 1bar of boost at 2500, and takes over 4500 to get 1.8bar)?

Mr J

I think that's because of the surge problem...me thinks..

john banks

The issue is holding it back from going higher than 1.5 bar until 4500 RPM on a 2.0 because of surge. You could argue that the turbine side is too small in allowing the compressor side to surge, but on the other hand if you are only planning on 1.4 to 1.5 bar like myself for 450 BHP and 400 lbft it should be good and relatively lag free. Despite the issues for an area under the curve contest on a 2.0 I think it does quite well, and appears not to have been beaten yet? Well, no one has published a graph to compete with Andy F's overall, maybe they are out there... Bob?

[Edited by john banks - 5/18/2003 1:25:35 PM]

Leslie

I wonder how much extra power would be lost by the alternator trying to supply as many amps as it can to help the battery to run the electric turbo!

Les

Leslie

Accidental double post

Les

[Edited by Leslie - 5/21/2003 12:52:37 PM]

Pavlo

as mentioned earlier, it would deplete the battery on full power, then when you weren't using it, the alternator would charge the battery.

paul

Leslie

Yes agreed but the alternator will still be trying to charge at its full rate during use of the electric jobber and that will take some engine power to drive it.

Les

[Edited by Leslie - 5/21/2003 12:56:26 PM]