badinfluence

I am taking a leap here and designed a open source hardware guide for how to supercharge your Series II with a REAL electric supercharger. No Leaf Blowers, or R/C Turbofans here.
I am going to start with some MATH

In order to make 5PSI of Boost, per liter, at 6,000 RPM, 3.25HP is required on the spinning motor driving a root type supercharger assembly.

1HP = 746 Watts of Power at 100% EFF.

A rotary engine for this formula will be 2.3x the size of the reported displacement or 3.0 Liters.

The kit I am having designed is a total of 20HP on the motor or roughly 15KW.

20HP would equal 10-15PSI on a Rotary at 6,000RPM

So the cost of this part I am having sourced is 2,600 dollars and that isn't cheap. That does not include the batteries to drive the motor, the motor controller, and the custom logic boards I am going to have to make to boost it.

Because all this is expensive and costly, I am building it without a engine for now, and will get a wrecked and salvaged RX8 to test it out on a Dyno and track.

So here are the major parts required

Air Filter
Piping
ESC Device
Insulated Piping with MAF sensor housing
Auxiliary Fuel Device (5th port, 6th port, 7th port or Methanol Injection)

Boost Computer Calculator
Fueling Computer
Health Sensors

Batteries for driving ESC
Motor Drive Controller (PWM)
Charging Mechanism (Inverter switched over to DC for charging)

External MAP Sensor
AFR Wideband
Stock MAF Voltage Tap
Stock TB Voltage Tap
ECT Sensor
Oil Pressure Sensor
Oil Temp Sensor
IAT (MAF)

Tuning Software or External ECU

This is not going to be an easy thing to do, and it would prob just be cheaper to buy a Series 1 and turbocharge/Supercharge it, or just a FD, but it is a puzzle I want to test out.

So the cost is looking like about 3,000-4,000 dollars for the whole thing including the batteries, parts, & tuning costs.

I will be getting the part together for some documentation shortly with some pictures.

The Major benefit is absolutely no parasitic draw from the drivetrain while firing and no backpressure issues from a Turbocharger. The only draw will be a Aftermarket Alternator with an increase of output via FREQ controller.

Going to be some fun so stay tuned.



Got the alternative fueling for the Methanol Injection Sorted out.

Devil's Own 300PSI pump with 3/8NPT fittings instead of 1/4 PTC
Devil's Own 6 Gallon Race tank or 2.25 Gallon Race Tank
Devil's Own DO03 Nozzle (3 GPH)
Devil's Own Progressive Voltage Controller and/or DVC-30 Controller


The tubing and fittings will be all Stainless Steel, via CO2 Tubing from a Fountain Soda Machine, and Swagelock Stainless Steel fittings.


Methanol Tank(7/8 Inch hole) to 1/4 OD Compression
?????

To covert the Devil's Own pump from 3/8NPT to 1/4 Compression (QTY 2)
SS-400-1-6

For the Inline Methanol Injection Filter 3/8NPT to 1/4 OD Compression (QTY 2)
SS-400-1-6

Inline Checkvalve 1/4OD Compression to 1/4OD Compression
SS-4C-TR-10

Nozzle Adapter 1/4OD Compression to 1/8 NPT Female
SS-400-7-2

With all of that sorted the system will be 100% sealed with a very little chance of leaking since the tubing can withstand methanol and fuel at 1800PSI because of the thick sidewalls. That will provide the alternative cooling & Fueling system. Additional Fuel injectors will more than likely be needed in the long run, but this should get things cooling so the compressor doesn't increase the air temps. The methanol mixture will be injected pre-compressor without an intercooler to supercool the intake air.

It is important that EVERYTHING be stainless steel because of the hardness of the tubing. The Stainless Tubing will not stay in a PTC fitting even with Stainless steel grabbers. Compression is the only safe way I can find. I also ran a similar system on my Mazdaspeed 3 and it worked excellent.

There are 2 things I want to add if I can figure them out. A Flow Sensor & Pressure sensor to feed back to a Sub ECU I am designing.

The way the formula was explained to me is such.

6000RPM is the peak flow rate of a ICE where it is moving the max amount of air. The becomes the max reference point of what you need at the top end. Anything lower than that 6,000 pressure will increase because optimal flow is not being achieved. That is exactly why I picked what I did because I only want to use the pressure to force more air in at lower RPMs, not higher ones. The device is only supposed to be a short buster for rapid acceleration. The size of the unit is that of an Eaton M90 supercharger. The flow rates aren't quite known because they vary based on the type of motor used since the pulley input is no longer a constant size. (Diameter) I am trying to archive a boost in toque, not really a boost in HP. One gives you the other in ways, so that is one way to look at it.

All the pressure numbers come from open flow, not below 6,000. Below 6,000 it will flow less so pressure will increase because of a bottleneck. I understand the Renesis isn't the same thing as the ICE the formula was designed for, but I am not trying to use it to widen my power curve, simple increase the torque at lower end by adding a pushing force on the flow rate.

The motor specs allow it to run from 24v to 96v. I never plan on hitting 100% Duty Cycle on the PWM driver so I was going to start with a Gold Cart controller and if I needed to reduce the amperange or gain something I would increase the voltage of the controller. 96v controllers are harder to find than an Ezgo golf cart controller so it was just part of the stepping stones of getting it to work.

Because of the cost of these device, I want to try it on more than just the RX8. If I pick something like a supercharger I have to keep rebuying expensive parts like the charger or the housing. If it do it with electricity it is much more movable. I have 2 types of cars lined up to try it on to see how it effects each car. It isn't just focused on the RX8.

I understand I am wasting time, but like I said, I want to get a chance to understand these kind of problems and how to best solve them. One of the reasons I left pages of data out of the post is because I didn't expect anyone to understand, and asking for a reasonable debate based on facts I figured was impossible. Kudos for at least trying understand instead of saying "it won't work"



So here is the issues with the voltage:

15,000 Watts = 20HP Electric Motor @100% DC
15,000 Watts / 48 volts = 312.5 amps @100% DC
15,000 Watts / 96 Volts = 156.25 amps @100% DC

The 48v golf cart controllers have a max amperage where the controller will either stop sending amperage if it is a good one, or go pop because the load is to high. (If it is a cheap one) So when I am testing with a 48v controller I doubt I will be able to high 200/312.5 amps so 63% DC max of 100% available, if even. Also this is all at 100% EFF which won't happen either. There is just to many open variables to solves for the missing ones without trying to find them. Examples are how efficient the motor is, how efficient the compressor is, how much flow the modified housing can do, etc. It is easier just to get the assembly made and go from there.

@100%DC is irrelevant for what I am trying to do with the project. It isn't going to be switch operated to where it is on or off 0% or 100%. The engine won't need 100% of the power at all times, so I am created a control curve device to see how much to "need" in between. My guess is the power band I want, 2,000-5,000 it won't exceed 66%, so it will be more efficient than at 100%. I am seeking a level of control not available with a bleed based system because I don't want to bleed energy, I want to maximize the use. This is a core difference, but it eliminates parts and makes the system easier to control because a computer is determining the control of the boost.

Organizing this all in plain text is a disaster. When I wrote it all out, it took up 19 pages of graph paper and that was just the trying to "guess" at the flow rate of the parent supercharger the housing was made from. It was just a cluster ****. I started to put it into Onenote and then figured out I cant really export that to something that works with Forum.

Still moving forward on this one.

Ok so I identified that the compressor I have is from a Thunderbird SuperCoupe. It is a great little compressor. The side has in inlet so I finalized how and where I want to mount it.

I hit a very serious problem I wasn't expecting.....My Compression went UP. Yes that is right UP. When I got the car it was at 7.0:1 and now it is pushing 8.0:1. I am obviously taking to good care of it, so I may need to run out the clock on the motor before putting this on a Series II RX8. I am going to try it out in a RX7 Series 1 or a small B16 motor then try it in the 8. Eventually the compression will dip to the point where I need a new engine, and at that point I will go ahead and throw it on. For now I am still mocking it up on my car.

Basically here is the plan.

Buy an AEM.Mazdaspeed Intake and study the exhaust Flow
When ready remove the filter element from the filter and use the MAF pipe for the Supercharger Build.
Adapt the Exhaust flange from the supercoupe to bolt to the AEM MAF Pipe.
Create a custom flange for the charge pipe that draws ram air from the front of the car like the AEM and RB kits.
Create a passive flow system for the supercharger drive.
Buy & program the motor controller.
Switch over setup to super capacitors instead of batteries.

At 12 volts this motor draws a little shy of 300 amps. I tested it with a 12 volt battery and it immedately started to whine and die out. After I added a 1Farad audio cap it did a bit better. I have a 350Farad supercap set I built to replace a battery in a SCCA car, and tested it with that. With all 6 caps in series it is about 58Farads. I expected it to act like the 2 Farad cap and run for about a half second without a battery, but I was VERY WRONG. It ran at full Speed all the way to 5 volts over 1 minute! That is 400 amps from 58 Farads and it out preformed a 12 volt battery and audio cap! I was very very shocked! So this renewed my faith in using these supercaps, and I learned I dont need the 80 dollar ones to do the job. The only challenge is creating a mounting design to hold them. I will prob need a 3D printer to do so.

badinfluence

Saved for Stage 1 Pictures.

badinfluence

Saved for Stage II Pictures

badinfluence

Added Methanol Injection Information.

jasonrxeight

I dont think 5PSI at the diameter of the intake at WOT is gonna be only 3.25hp. superchargers that puts out 7psi under WOT is gonna be around 70-100hp range to drive them. you are wishful thinking.
the thing I dont understand the whole electric supercharger thing is why driving it with electricity. why not just use say the engine like all the car manufactures been doing? converting energy is a huge waste. why not just drive the supercharger with a pulley, instead of using alternator to convert mechanical energy into electricity, then convert that into chemical energy, then convert it back into electricity, then convert it into mechanical energy?

MEboy

iTrader: (1)

1 hp = 0.746 W

Posted From RX8Club.com Android App

jasonrxeight

746w

9krpmrx8

iTrader: (46)

Total waste of time an effort IMO.

Prophet

If electric superchargers worked in any practical form, they would be using them on race and production cars. You would need a pretty large motor to have enough power to compress the air. You are not just blowing air into the engine. A fan wont cut it. So, big electric motor attached to a supercharger is what you are basically doing. Adding lots of weight over a light little pulley.

9krpmrx8

iTrader: (46)

A lot of people fail to grasp the concept of a fan versus a compressor.

TeamRX8

iTrader: (25)

Why not make it a real challenge and just tie one arm behind your back while your at it ....

Prophet

Another thing I just thought about. Where the hell are you going to find an electric motor that can turn fast enough to run a blower? I know centrifugal superchargers are basically turbo compressors with a pulley in place of the exhaust turbine. Those turn at speeds over 50,000 rpm. Some times a lot more. Not sure on roots style, but I imagine it's up there a ways. The only electric motors I have seen that are that fast are tiny things. Not ones big enough to run a compressor.

badinfluence

That is per liter, which technically the way the Renesis acts it would be more like 7-11HP would be required of the motor. So based on what I have heard, it would be 7 or 10hp for the Renesis at 6k rpm for 5 psi. Displacement for the Renesis isn't straight forward, so it is something to experiment on.

The reason electricity, is load bearing and spooling speed. It is faster than N2O, and can be controlled with a PWM signal instead of unmetered energy controls of a supercharger or turbocharger, aside from load.

Car manufacturers are starting to develop Hybrid Electric superchargers and have been for about 5 years. The issue they have is the dual rail charging systems & how to approve a second voltage standard for the car. Some manufactures are already working on that like GM. People want V8s, so they make V8s. Consumers drive the need for cars to be made a certain way, and if it is cheaper and nothing is stopping them, why would they stop?

badinfluence

Yeah, I wrote one thing on paper then blanked when I transcribed it. I used 750w for all my calculations, not 725.

badinfluence

Exactly what I am proving. The concept only works on little engines, anything bigger than 2 liters isn't worth the "pool" of electricity you need.

Every form of Forced Induction moves energy around. The assumption is that Supercharging and Turbocharging and the best way because no one else does anything else. There is very little to prove this concept could not be done besides Chinese people advertising leaf blowers are turbofans.

You don't do something like this to make power, you do something like this to expand and collect knowledge about how something works. Not everyone is looking to "go fast." If I wanted to do that I would just buy a bottle and be done with it. Can you say you bought an RX8 to go fast? There is always a cheaper way of making power, but I bought my 8 because I wanted a different engine platform.

badinfluence

A Transmission is technically built into a supercharger based on the side of the pully driving it. Because of the EV conversions out there, DC electric motors are everywhere, and cheaper because of it. I am not designing it, just buying it and tinkering with it.

badinfluence

I expect a lot of hate, and so does the guy helping me with the project. He deals with it all day, but the truth is, this is an engineering project for fun, and some for a potential benefit. I am documenting my results, because I want to share my results, negative or positive. If it isn't cost effective or possible, it cost you 15 minutes to read the thread and figure that out. If it is, then you just figured out something new to do that may make power for cheap. If it was already clean and documented, I wouldn't waste my money or time developing and documenting it.

If you want the truth, I get itchy just sitting around unless I am in the garage making something. That is just the way I am.


....****, I guess RX8 doesn't add quick posts together like MSF. Sorry about that....

jasonrxeight

It just seems to me you are doing a lot of work for nothing. why use electric motor when you can simply just drive off a pulley. why use electricity when you have mechanical force available. the only reason electric motor is good is in situations when no coupling is allowed meaning it will have to spin up from complete stop such as an electric car cuz you get instant torque from stop. you dont need to stop your supercharger. also there is no such thing as spooling up a supercharger since its driven off a pulley.
its not we are saying you are doing the impossible, and there is no hate going on. its just that you are doing something not necessary when there is good solution already available.
and how did you get the 6000rpm 5psi at 7-10hp calculation? why is there are rpm related to psi? dont you want 7 psi across the whole rpm? are you treating an engine as if its a sealed box? remember, engine sucks air. pressure is BS when there is no flow. my electric power washer makes 1700psi but at only 1/16 square inch area maybe less, when you fan out the water, the pressure drops significantly.
also the equivalent 4 stoke engine to a 13b renesis is a 4 cylinder with 2.6L displacement. if you cant figure that out you probably need to go back to the drawing board.
and have you seen the size and weight of a 70hp or even a 10hp electric motor? its massive. also what kind of voltage are you gonna run the electric motor at?? even at 48V new EV standard, you are pulling 153A with the 10hp electric motor. its over 1000A when using 70hp motor.

badinfluence

Most of these aren't my calculations, the formula was given to me as such. If it is wrong I can't find the right formula to fix it. I was told it was either 2.6 or 3.9, I knew it was not 1.3. The engineers I am talking to stated the 3 rotor faces make it a 3.9 and the other set said one 2 faces contain the compression and ignition stroke so they dont matter. Either way they stay within the 20hp tolerance for the motor so I said screw trying to figure out what side is right.

Prophet

Even if it did work, you still added a couple hundred pounds of battery and electric motor to the car. Maybe more. That's never a good thing. That spoils everything about the car. Just makes the whole thing more pointless. I don't see any reason for doing this at all. Even if it works, the cons far out weight the pros.

jasonrxeight

its twice the displacement. the rotor turns once per eccentric shaft rotation makes one explosion vs 4 stoke with one explosion per two rotation.

here is your problem. open flow is different from induction. the pressure measured inside the intake manifold is the combination of the supercharger pressure minus the engine suction. a normally aspirated engine at wide open has a suction pressure equal to atmosphere pressure meaning it cant suck more than the atmosphere pressure.. so if you have a supercharger that puts out same pressure as the atmosphere pressure, it will be only enough to satisfy the normal operation of the engine. to have any power increase, you will need the supercharger to put out more pressure than the atmosphere pressure which is 14.696 psi. so if you want 5psi in the manifold, you will need a supercharger that will at least put out close to 20psi at open flow.

TeamRX8

iTrader: (25)

Considering that many hybrids use a gas motor to run the electrical generator should tell you something.

I'm still trying to imagine where you can fit a supercharger belted to a big honking motor in the engine bay.

skc

Love your enthusiasm, I will follow with interest....

badinfluence

People are ******* idiots for buying Hybrids. An gasoline car is leagues more eff than any damn hybrid. People are sheep for going along with the idea that they work for the price you pay. If you ran the ICE on something besides gas for your Hybrid it would make sense.

You are describing a Electric car.

Most Hybrids use the Gas generator to turn the transmission same as the engine.




Electric cars use a Gasoline generator to provide power in addition to the batteries. The Gasoline generator never mechanically touches the drive shaft. That isn't a Hybrid, it is an electric car.

badinfluence

The displacement takes guesswork about of it thanks for that.

The answer to his lies in the validity of the formula. I didn't write the formula so I don't know if it included Atmo or not. The was rated on the Dyno as positive pressure, so I can only assume it did. I am going to check on that one.