mark kibort

Oh, I understand. Its just that it doesnt pencil out that the boat vent fans could do anything at all. In fact, their full air flow, is far below the requirements of the 928 engine, so it should provide restriction.
however, Ive been to dynos and see stranger things! the only way to know for sure is repeated dyno tests year after year.

MK

mark kibort

actually, they do, and the pressure when not needed is bled off (like when the throttle closes after a WOT run. tubos run off exhaust mass flow, meaning, when you are wide open throttle, you have more mass feeding the turo, it spins faster, creates more pressure and gives more gains, creates more mass, and feeds it somemore! close the throttle, and the high pressure has to go somewhere, and it is vented via blow off valves.

superchargers , belt driven, do run all the time. they have to , as the air has to pass through the supercharger. If it isnt running, the restriction would be too great. The axial flow supercharger (eRAM) has a large enough diameter, so that even if the eRAM didnt come on at WOT, it doesnt provide restriction. why?, it has a 3.5" diameter vs most intakes of 2.7 -3" . flow tested to flow more than a 3' straight pipe, even with a filter on it!

not dumb questions at all. pretty common.

Mk

2V4V

[QUOTE]Originally posted by mark kibort
[B]Greg, before you post things, you should make sure you have a handle on your math and logic. yes, Turbodyne had a electric supecharger,(centrifugal) and it was close to 100amps at 3psi at 100cfm. at the 300cfm range, the pressure was about 1psi. so, in effect, for a 3 liter engine, the eRAM at $300 bucks at 1psi, worked as well as their supercharger at $1500. Anyway, let me clear up some of your confusion below."[B]

--Well, actually they still do. I am not confused at all, my logic holds and my math works according to the laws of physics, but let's not trifle with the facts yet. And Turbodyne had/has a variety of different boosts for different displacements.

[B]"You start talking about how much hp is required to drive an electric motor to run a supercharger 5hp, 15hp, and so on. Remember, this would be the HP required to produce 5 to 6psi at flow rates of 3-400cfm. a rough number for you to hold on here , is about 1hp to drive 1psi at 2-300cfm. so, yes, if you wanted to drive a 5psi 300cfm supercharger, you would need about 5-10hp. (and yes, with all the inefficiencies of the motor, you would need a 10hp motor at least (so over 1000amps) WE ARE NOT TALKING ABOUT THIS." [B]

--Well Mark, I was, and still will. Yes, just for the sake of easy calculation I pretended an electric motor is 100% efficient. Thanks for the acknowledgement that it takes HP to run a supercharger. 1 HP per PSI? That's pretty efficient for a blower, even though most blowers on a dyno will show a higher (up to order of magitude higher) HP need, we can run with that. It proves my amp calcs. And that a supercharger needs power to produce boost.


[B] "Now, lets try and wheel your arogance back in and look at the reality." [B]

--Arrogance? If by that you mean calling an electric fan a 'supercharger' and then my calling you on it, makes me arrogant, well then I guess by that definition I just may be.

[B]"stock 928 air boxes have 1/2" Hg vacuum at red line and at WOT. if you can relieve this alone, you can have that proportional gain. if you can add pressure and match the air flow, you can have a proportional gain."[B]

--I haven't got my mercury stick handy and it's late, so I'll grant some vac at air box. Which side of the filter did you pull from? Just curious.


[B]"The eRAM produces 908cfm in free air and some small pressuer at lower flow rates (ie a 4.7l engine woud require 500cfm at redine)
The net pressure gain by using the eRAM is around 1psi on a 3.2 liter porsche 911 that has a baseline of 200rear wheel hp. with the eRAM, we got around 10hp ,and this was repeated many times on different years and versions of this engine and porsche model.[B]

[B]So, the eRAM is a 700 -750 watt device, drawing between 50-55 amps and producing a net air box change of pressure of around 1psi. (ie 5%) HP gains are in the same range.[B]

[B]Now, you start going off about 10hp, and doing some calculations. were you equating the electrical power consumption to the power gains of the engine? I hope not. 1hp can gain 10hp with the superchargers ability to burn more air and fuel. the 1hp is what is required to make the air density 5% greater, period. the 5 % greater air density , matched with fuel , provides the 5% gains. seen across the board on all sorts of cars."[B]

--Uhh no. I never said anything regarding the draw on electrical being directly related to power output, though of course, eventually it will be. Once the batt drains. We can go back to this later if you want. Not to mention the electric fan motor you are using will melt.

[B]"you have Ohms law stated correctly, but thats where your correct analysis ends[B]


[B]Also, voltage and current from the alternator , depend on voltage drop of you battery. with the eRAMs operation at WOT only, in a racing condition (did I tell you we race and use it racing too?) anyway, the eRAM is easily able to be used in a racing environment. at a track like Laguna, you are only full throttle less than 50% of the time. that duty cycle is ok for over an hour of racing use. you even go into wire guage. 12 guage is plenty to carry 50amps for intermittant use. we also have a dual series eRAM that has double the pressure, as would be the principal if you stack axial flow fans." [B]


--I'm well aware of how axial-flow compressors work. There was a guy named Latham that used to sell them for cars. 40 years ago. They produced boost 7-10+ PSI depending on the app.
FWIW, 12 ga. wiring may work in non-continuous duty apps, but running 50-55 amps through it is way in excess of its rated ampacity. Not my 'arrogance', it's just the National Electrial Code (NEC 2002). Article 551 (regards low voltage wiring in cars and RVs) Table 551.10(E)(1) Low Voltage Overcurrent Protection states that "overcurrent protection for a 12 AWG (solid or stranded) is at 20 amps". Not 50-55. Yes, I remember the code for low voltage welding and you can grossly exceed wires rated ampacity for intermittent duty, but I personally feel a little safer with wiring adequate for at least 100% continuous duty. Maybe you don't care, but I wouldn't recommend anything less to anybody.

[B]"before you start questioning what part of the gene pool we come from, you better look in the mirror. As far as I know, Im the only one here actually out there hanging the 928 on the line!"[B]

--Pardon me. Mea culpa. Ad hominen attacks ARE rather tacky, but I have grown weary of companies who sell "xenon lights for $49" and electric "superchargers". I don't think it's being honest. Maybe you do. I don't. And undersizing wiring is just plain dangerous.

-- If you want to classify those lights as Xenon on the technicality they contain some xenon gas, I guess a good lawyer can sell it to a jury. But they aren't true Xenon HIDs. Are they? That's the implication.

-- If you want to call a "fan" a supercharger because it may produce some very marginal (within the error of most dynos, but I'll cede the 10 HP in the interest of fair play and not wanting to waste any more time on it) gains for a VERY short period of time, by producing just a little bit (1 PSI over atmo) of boost a "supercharger" - then I guess YOU can. But it can't produce the boost of a centrifugal/twin-screw/Roots/Latham, nor can it run for long. So to me, and any engineer I've ever talked to, it's a fan. (or an "intake flow optimizer" as my most forgiving friend called it...)

--If you have a system that electrically powered anyone of the above devices (Cent/Roots/Twin) to produce actual boost - like a mechanically powered supercharger, then you would need (more than) the electrical HP that I roughly sketched in my first post to power it. It's just physics. Work in, work out. I have yet to hear that argued.

[B]"Any comments, reply respectfully. Think, then post. But, do you homework first. "[B]


--I did my homework long before that thread was even posted. I never said the "fan" would not add some HP on a non-optimized intake. I just called it what it is, and if your company did too, I wouldn't have bothered to post in the first place.

--But it does not produce "boost" of any sort compared to even the most inefficient Roots, let alone a centrifugal, or twin screw, or Latham (a real axial flow) supercharger. So, I will still call it a fan.

--I never said a bad thing about your race driving, so it's funny you should bring it up. Nice PR ploy, we'll call it "evens" for my ad hominem. Though I find the condescending tone more than a bit ironic. I have no personal ill will, but I feel it necessary to call car parts what they are. If you have an update on how my math doesn't work (other than I deliberately underestimated electrical draws for the sake of a quick calculation), let me know.

Greg

John.

Perhaps it is time for more Lag-Algebra?

Dennis Wilson

Did somebody pull the E-Ram thread from the Porschelist archives? Actually this thread brings back a lot of memories that I wouldn't want to see repeated.

Dennis

tresamore

Jeez, I'm beginning to feel a little akward for bringing this up. I had no idea it had a past history.

928Quest

People seem to think nothing about dropping $300 plus on headers or x-overs, free flow mufflers, cold air intakes etc. Most of these devices make similar small changes in HP, 5-15 hp if your lucky, especially so on a 928 that was designed well from the start. If you look at the electric blower as fitting into this catagory it would seem to be a deal

I remember not to long ago reading about someone wanting to put GT cams in an S4, tons of cash for not much flash.

I rarely see flames this bad when the thread is on for wanting to change headers or mufflers etc. Sure the E-chargers is not a "real" supercharger but its not $5000 either. Seems to me to be alot better than dropping $50 on a k&N or $$$on chips.

So...Mark, ever try a pair of these, one on each side of the intake?

mark kibort

Thank you . Exactly!!

Hey, ive done it all, and spent all the money and time for every bolt on mod imaginable. some work better than others, but the ones Ive done all have worked. I wouldnt remove ANY of the mods that added hp, as thats part of the racing game!!

10hp for $300 was certainly on par with any of the mods i did.

MK

mark kibort

Greg,

if the semantic debate is about whether or not the eRAM is an electric supercharger, then you can take the fact that it is, to face value. Does it raise the pressure of the intake? yes. Is this supercharging? Yes, it is, albeit, only 1psi of a net change, or 5%. To your point, we advertise the eRAM as a " 1psi electric supercharger" as to not mislead anyone. claims are made very clear and are guranteed. Is it less than a roots, centrifugal, or turbo driven centrifugal, absolutely! are we claiming to have anywhere near the pressure gains?? NO. So, I like your classification of the eRAM as an intake flow optimizer, as yes it is this too. However it does add pressure, even to the best flowing intake.

Now, the only reason I started digging into you , was your original closing line referencing to the gene pool we are from. for that, I responded to you to look in the mirror. Had it not been for your closing remark, we probably wouldnt have had this on line discussion. Hey, I understand there are a lot of idiots, selling snake oil, and it pisses me off even more than you, because we have to defend our legitimacy even harder due to the nature of our device, and the general lack of understanding of air flow, and its application in automobile engines.

As far as the guage wire we use in our application, based on sound electrical engineering principals, the wire guage and its fuse, are more than adiquate for 50amps over 30 seconds max, with a 50% duty cycle.
The NEC is set up to set standards to protect consumers. It has to over spec the wire guage vs Current flow, as there are an infinite amount of variables (such as Temp, distance, insualation type, thickness, ect) that all come in to play . NEC2002 sets standards for most all possible applications.

Anyone that has seen the eRAM on the dyno, knows it works and works well for under $300. You mentinon the Turbodyne centrifugal device, again, remember its flow characteristics, 3psi at 100cfm (like used on a 1000cc engine) or its pressure drops to 1psi at 300cfm rivaling the eRAM.
With the eRAM costing $300 and the Turbodyne costing over $1500, the electric supercharger with the best value is the eRAM. (Plus, good luck getting a product from Turbodyne as they have had major company financial, legal problems over the years.)

So, lets keep it light. No insults, and ask any questions you would like

Mark Kibort
eRACING Motorsports
www.electricsupercharger.com



[QUOTE]Originally posted by gbyron
[B]

Dennis Wilson

OK Mark, you have sold me on it. Now if I could just get you to bring it to Hallet next July. Actually, I was hoping the showdown would be arranged for Hallet as it is 40 minutes from home and I would love to see your 928 run.

Dennis

Rufus Sanders

I have another question. As someone a few posts up asked, can you put two (or more?) in the system and get 2 or more psi pressure increase? The air filter box on the (my) 928 isn't the snuggest fitting unit around. How much extra pressure can it hold w/o leaking it out? - Ruf

Tony

eh...bolt one of these on and call it a day.


http://www.rolls-royce.com/civil/pro...00/default.htm

2V4V

Mark,

Yes, I have a semantic issues. A Roots/Centrifugal/TwinScrew supercharger can run 1-100% output depending on set up. The eram cannot. A R/C/T supercharger can see extended on-duty cycles in the 1-100% output range for extended periods of time. The eram cannot. If pressurizing the intake 1 PSI is the sole requirement for calling it "supercharging" then a "Ram-Air" Pontiac is supercharged - provided, of course, you can get it up to speed. (Yes, I realize that there's no fan involved in a 'ram-air' system.) As far as the nomenclature "intake air optimizer" goes, that was one of my engineering buddies' quotes, he's the politically generous one (if you want it, help yourself, he won't trademark it).

As to airflow engineering, there are many changes to the underhood airflow dynamic that take place when you start a car actually moving, that vary greatly from what happen when it is static - like on a chassis dyno. To that end, I guess I'll do some airflow testing of the 928 intake system in the next couple of weeks. I recently picked up some toys from an airflow lab that are begging me for a new experiment. Yes, they're NIST traceable. I'll post results when I have them.

As far as wire ga. goes, if you feel exceeding a wire's NEC rating is based on "sound electrical engineering" I'm curious as to who gave you that data. Yes, wire's rating does vary by length of run, insulation type, environment, duty-cycle - once again, I believe that a product should have a margin of safety, and no, the number of determinant factors is not infinite. 2 EE's and a Master Electrician (along with the aforementioned NEC) said 12 ga. is too small to have a adequate safety margin even at partial duty, especially when hooked up to a motor (higher draw at start-up and all that). I know that instinctively after 25 years of messing with electronics and cars, but for verification I consulted the 'credentialled' folks. You're right, the NEC is about engineering to more than minimum margin of safety that is not limited to consumer products, or houses. Office buildings, manufacturing plants, swimming pools, radio and TV stations, garages, ad naseum, all have to meet code. But, if you feel safe, whatever.

As to Turbodyne, if you read my first post, you will see that I am well aware of the issues it had/has. But, you seem to keep referencing one particular low flow model that was for a small-displacement engine. Perhaps this is the only one you ever saw, but they did have a spectrum of units, several of which were geared to large gas/diesel engines - putting out more than 3 psi on flow rates for a 5L plus scenario. No, I don't own any of their stock, and could care less about them.

Bottom line, if you think 1 PSI available on 30 sec max duty cycle is an electric 'supercharger' I can't convince you otherwise.

But, $300 for 10 HP that I may, or may not, be able to find everytime I step on the loud pedal? That sounds like a leaf blower under the hood of my car? (Yes, I've seen/heard/driven them before.) That guaranteed produces nothing except at WOT? That's a restriction in my airtube the rest of the time? (And if it isn't being powered to spin at intake speed, then it is, by definition, a restriction.) All that for (at best) less HP than most folks would get with a standard hard part (RRR, RMB, headers, electric fan update, air pump removal, etc.) that can produce performance gains at a variety of throttle inputs? And all of which have a lot longer MTBF? And have about a $300 price tag?(Of course you can spend more. LOTS more.)

Can you please get over the gene pool crack? I even apologized. And I didn't retaliate for the half-dozen odd condescending little remarks floating throughout your earlier posts.


Lightly,

Greg

mark kibort

Greg, sounds like we are again speaking the same language. Thanks for the applogy about the gene pool crack, over that now too.

Ok, 1st off, I do like your " intake air optimizer" name. (thanks for the offer, we may use it in some way. As far as passive "RAM" in an intake scoop or the dynamic operation of the eRAM. I didnt review my old post, but I thought I mentioned that we did take an stock air box and ran 120mph and got 1/4" of Hg vacuum under full throttle. Then, we sealed the air box, and did it again (sealed with RTV and clamped with better clamps on the air box cover) 1/2" Hg vacuum. then, we added the eRAM. Guess what happened? Yes, not only did we neutralize the vacuum, but we gained some slight pressure. Immeadiately the next day, went to the dyno and saw the 5% gains. (on both the 911 and the 928).

Moral of the story is that the eRAM is a very light supercharger. 5%, no more no less , on engines less than 5 liter.

RAM are is a misnomer. if you go through the calculations (and I have many times) max pressure gained by ram air effects on a very EFFICIENT hood scoop, tall, and out of the boundary layer, is .36psi at 160mph and that drops to .08psi at 80mph!!!!!!! (again, that is with a very efficient hood scoop. our cars are much less effcient as far as intake flow, and so are any hood scoops you see on cameros, mustangs, firebirds, etc)

Last, as far as WOT 1psi operation, dont concern yourself with the restriction possiblity, as there is none anyway (due to the eRAMs diameter, the flow of the eRAM in the "off " mode, is more than a straight through 3' pipe. (measured at SEMA 2001, on a powerflow flow bench) Next, who cares, at part throttle, your throttle plate is makeing the restriction, as thats its job!! (throttle, means " choke" ) think of your throttle, as a variable pressure dropping device. at any time its not at full throttle, it reduces mass flow, buy increasing a pressure drop, and subsequently lowers power output, right down to idle!! I think this is the most missunderstood part of understanding engine air flow.

wire size? again, yes, you unerstand the purpose of those types of regulatory groups. We have done testing on our wiring, and in worst case senareos, the temp never gets beyond safe. Im much more concerned by our connectors to the power relay. those are standard auto connections and they get hot. the resistance of a crimp connection can be far more to worry about than the wire guage. never seen a burned wire, but Ive seen plenty heated connectors. Anyway, with our duty cycle, racing, we never see much more than 7seconds on, and 7-10 seconds off. over an hour race, all components are in great shape! Over 3 years of racing use, no issues. So, our field testing concludes that the connective system is safe.

NOW, you start equating 10hp for RMB mufflers, electric fan conversions, headers , and removing an air pump!!! com'mon. please, again do the math first. air pumps and electric fans vs driven clutch fans are no more than less than 1hp for the air pump. (it is a very free spinning device, with very low inertia as well) The fan may be 1-2 hp, MAX. and we all know about a header job on a 928. 600-1200buck, and 6hours labor for 12hp.
rear muffler bypass, probably the best bang for the $, but still 2-300bucks for 10hp. RRFR's , 2-3hp for optimizing fuel ratios, but also they cost $400 for a S2 and $175 on an S4. Guess what, thats all good, and Ive done it ALL!! and It all adds up!!

Glad we got on the same page, good rant, sorry about the comments that were taken to be condecending. they were not ment to be.

Mark

mark kibort

yes, putting more than one in series doubles the pressure. we have even done 3-4 units and have not got a pressure reading yet, but it is pretty awesome to see in a test. generally, the eRAM really is .5psi and relieves the vacuum in our intake air boxes. so, really, it is a 1psi net change in pressure. 2 eRAMs in series take the pressure to 1.5psi. 3, we guss would be around 2, 4 would be around 2.5psi. (gets expensive real fast)

the 928 is funny, as it has the dual intakes. generally, with the 928, you need one on each side. or you can have marginal gains by just having one and relieving the intake air box restriction . kind of like a portable ram air device, that just neutralizes vacuum.

MK