Open Source Electric Supercharger

[Grantmac]

TPS vs. RPM would likely work really well once you got it tuned. Very simple and robust, MAP will ultimately be controlled by the throttle plate and all you need to do is ensure the SC is supplying more air then the throttle can flow but not so much that it's wasting energy.
I guess thats why I was thinking TPS vs. post-blower pressure would make a decent table as well, but that would require another sensor.

No lets figure out how to charge a 48v battery with a 50% duty cycle so we can downsize the wiring and battery. Personally I'm thinking LiFePO4 just because of how rugged they are, I've run one as a starting battery on a motorcycle for several years.

-Grant

[neutron256]

Originally Posted by Grantmac

TPS vs. RPM would likely work really well once you got it tuned. Very simple and robust, MAP will ultimately be controlled by the throttle plate and all you need to do is ensure the SC is supplying more air then the throttle can flow but not so much that it's wasting energy.
I guess thats why I was thinking TPS vs. post-blower pressure would make a decent table as well, but that would require another sensor.

No lets figure out how to charge a 48v battery with a 50% duty cycle so we can downsize the wiring and battery. Personally I'm thinking LiFePO4 just because of how rugged they are, I've run one as a starting battery on a motorcycle for several years.

-Grant

The Unichip would also let me do a 3D map with TPS, RPM, and MAP but I'm not sure it's worth the trouble.

The problem with LiFePo4 for this application is that it can't supply the current needed for this sort of application. We're probably looking at 150 Amps and LiFePo4 is limited to about 40 Amps until you start getting really big and really expensive.

[NYCsubaruBRZ]

Originally Posted by neutron256

Come on now, lets not have that kind of talk on this thread.

Some times it's not stupid, it's just a lack of experience. I mostly just want people to know this isn't a DIY, if you're going to attempt building your own electric supercharger, or even just install Phantom's kit you need to understand what your doing, and the risks if something goes wrong.

Who among us hasn't overestimated our abilities/knowledge and gotten bit because of it at some point?

true true.................. but if your careless shit like that happens

[rusty959]

full disclosure: I am a computer guy. Im not going to claim to be good at doing much analysis on physical things. But, after doing some research, for this electronic supercharger idea to really take off, we have to find a way to get the compressor speeds up higher than motors in direct drive are capable of doing. That means a transmission. In the RC world, the first gear off the motor is usually a small metal pinion gear going to a form of plastic gear. These are reliable to very high speeds and require no lubrication. Say we reversed this. have two or three motors with a "large plastic gear" meeting a smaller metal gear on the compressor shaft. Multiple motors would help with shaft alignment and loading on bearings. I'm sure we can find gears that are strong enough. Now 100k rpm may be rough on some bearings, but im sure there are some RC bearings that could take it for awhile. The motor mounting wouldnt be too dificult and flanged and thrust bearings are available. Even if bearings and gears wore out, they are cheap and could be made easy to replace.

In my preliminary looking, this should be feasable. Are there any reasons others have found that would keep it from working?

[neutron256]

Originally Posted by rusty959

full disclosure: I am a computer guy. Im not going to claim to be good at doing much analysis on physical things. But, after doing some research, for this electronic supercharger idea to really take off, we have to find a way to get the compressor speeds up higher than motors in direct drive are capable of doing. That means a transmission. In the RC world, the first gear off the motor is usually a small metal pinion gear going to a form of plastic gear. These are reliable to very high speeds and require no lubrication. Say we reversed this. have two or three motors with a "large plastic gear" meeting a smaller metal gear on the compressor shaft. Multiple motors would help with shaft alignment and loading on bearings. I'm sure we can find gears that are strong enough. Now 100k rpm may be rough on some bearings, but im sure there are some RC bearings that could take it for awhile. The motor mounting wouldnt be too dificult and flanged and thrust bearings are available. Even if bearings and gears wore out, they are cheap and could be made easy to replace.

In my preliminary looking, this should be feasable. Are there any reasons others have found that would keep it from working?

I think this all depends on what your goal is. 4psi is actually more then it sounds like when you aren't getting the parasitic additional load you would from a convetional turbo, or supercharger.

If your goal is to drive a stronger motor and get a higher PSI there is a simple solution that doesn't involve custom building your own transmission for it. A centrifugal supercharger already has a transmission built to do exactly what you want, just connect an appropriately sized electric motor to it. The problem is it will probably run you amount $2K for a new one. Add on the other parts, and you quickly get up to the price of just installing a regular super charger.

Not to put down the idea, obviously I've already put some thought into it myself. It's just to me it sort of destroys the simplicity of the system, and drives the cost way up.

[rusty959]

Originally Posted by neutron256

I think this all depends on what your goal is. 4psi is actually more then it sounds like when you aren't getting the parasitic additional load you would from a convetional turbo, or supercharger.

If your goal is to drive a stronger motor and get a higher PSI there is a simple solution that doesn't involve custom building your own transmission for it. A centrifugal supercharger already has a transmission built to do exactly what you want, just connect an appropriately sized electric motor to it. The problem is it will probably run you amount $2K for a new one. Add on the other parts, and you quickly get up to the price of just installing a regular super charger.

Not to put down the idea, obviously I've already put some thought into it myself. It's just to me it sort of destroys the simplicity of the system, and drives the cost way up.

4psi may be more than it sounds like, but going off the experience we have so far with these types of systems, that 4psi quickly turns to 1 psi near redline. My personal goal is a "solid" amount of boost at redline. Now what solid means is up for debate, but its more than 1psi. I want to be able to have a controller that will keep a consistent boost level across the rpm band. (for which I am starting to write some software)

Yes, a centrifugal supercharger could be a possible solution, but as you say the cost is a real turn off. However atleast you could still have the benifits of controlling how much boost you have where. But, to drive it to a good level, from what I am seeing, multiple motors are probably still going to be needed, which brings us back to a similar issue.

In the end I guess as you say it depends on what your goal is. I'm going to keep an eye on how well your system goes and then consider implementing a simple transmission for myself if I feel it is still needed.

[neutron256]

Originally Posted by rusty959

4psi may be more than it sounds like, but going off the experience we have so far with these types of systems, that 4psi quickly turns to 1 psi near redline. My personal goal is a "solid" amount of boost at redline. Now what solid means is up for debate, but its more than 1psi. I want to be able to have a controller that will keep a consistent boost level across the rpm band. (for which I am starting to write some software)

Yes, a centrifugal supercharger could be a possible solution, but as you say the cost is a real turn off. However atleast you could still have the benifits of controlling how much boost you have where. But, to drive it to a good level, from what I am seeing, multiple motors are probably still going to be needed, which brings us back to a similar issue.

In the end I guess as you say it depends on what your goal is. I'm going to keep an eye on how well your system goes and then consider implementing a simple transmission for myself if I feel it is still needed.

Yeah the fact that boost falls as rpm rise is an interesting characteristic of the electric super charger. Since my goal is more torque at lower RPMs it should actually work just fine for me. If you want consistent boost across the RPMs you'll really just be holding back the supercharger at lower RPMs. Other then feel I'm not sure what the real advantage of that would be.

[Wild Weasel]

Originally Posted by neutron256

Yeah the fact that boost falls as rpm rise is an interesting characteristic of the electric super charger. Since my goal is more torque at lower RPMs it should actually work just fine for me. If you want consistent boost across the RPMs you'll really just be holding back the supercharger at lower RPMs. Other then feel I'm not sure what the real advantage of that would be.

The only advantage to this is to get more boost at higher RPM's while avoiding too much boost at the bottom. If you're not getting too much then you're right... holding it back doesn't really serve any purpose.

I'm curious... I've been keeping up on this thread and a while back there were some cool pictures and stuff... but has anyone actually put anything together and installed it yet?

[rusty959]

the feel is a big part of it for me. I want the feel of consistant boost. Additionally, id love to make a system powerful enough that with the supercharger wide open it wouls be too much boost at low rpms, and id need to control it. We have the technology to do it we just need to apply it. Maybe it will need some more maintenance than it could be for oem, but im fine with that.

A few psi is all well and good and has its place, but I think we can do better.

weasel the other electric supercharger thread has working examples but those are through phantom. to my knowledge no one has made their own yet

[neutron256]

Originally Posted by Wild Weasel

I'm curious... I've been keeping up on this thread and a while back there were some cool pictures and stuff... but has anyone actually put anything together and installed it yet?

I'm probably the closest to actually having a working prototype here. Mostly just need to find time to get to the shop to machine two custom parts I need. I'll eventually be building at least two different prototypes using different sized compressors, and a couple different motors.

In the mean time I'm focused on designing the controller which is proving simpler then I expected using Unichip. That however doesn't make for exciting pics. LOL

[BlueDubbinTDI]

Originally Posted by neutron256

Yeah the fact that boost falls as rpm rise is an interesting characteristic of the electric super charger. Since my goal is more torque at lower RPMs it should actually work just fine for me. If you want consistent boost across the RPMs you'll really just be holding back the supercharger at lower RPMs. Other then feel I'm not sure what the real advantage of that would be.

I think this is actually a pretty cool characteristic. Ide be down for this.

[Urmyson]

Does anyone who is testing the ESC have any mods like headers or unichip? I've been wondering if headers would make a big boost power wise. I'm also thinking about buying a unichip and want to know if it would line up good with the ESC.

Thanks

[neutron256]

Originally Posted by Urmyson

Does anyone who is testing the ESC have any mods like headers or unichip? I've been wondering if headers would make a big boost power wise. I'm also thinking about buying a unichip and want to know if it would line up good with the ESC.

Thanks

Better to ask on The Full throttle electric supercharger thread. No one on this thread has sucessfully built one yet.

http://www.ft86club.com/forums/showthread.php?t=39719

[mid_life_crisis]

@neutron256
What max rpm did your motor of choice end up having? Like many, I'm very curious as to what kind of cfm your creation is going to be capable of moving.