(non-Ebay) Electric Turbocharger (Supercharger?)

[Chumpaumpalumpa]

would the larger compressor wheel compress more air at 110k RPM's than a 14b?

Yes, more surface area=more air. Look at a submarine propeller vs normal boat, MUCH slower but MUCH more volume. More airflow at a specific PSI.

 

[teknicalissue]

https://www.google.com/patents/US4724817?dq=gary cook turbo&hl=en&sa=X&ei=9TP_VOatBIqxogTv5YC4BA&ved=0CB0Q6AEwAA Look at the images of what Gary did, its similar to your original design. There is a couple diagrams of stuff that could be helpful. Also, this is not simply an off the line solution, but a lag solution at low rpm. Meaning overtaking will be better as well or any situation where you need instant boost.

Yep I giggled a little when I first saw Gary's plan and how my pan looked. If I do a direct drive application however; I'll be skipping this step.

Yes, more surface area=more air. Look at a submarine propeller vs normal boat, MUCH slower but MUCH more volume. More airflow at a specific PSI.

This is excellent to hear! I wonder what compressor wheel/housing I should make the prime candidate for this project? are we thinking 16G? 20G?

 

[Chumpaumpalumpa]

Yup just keep in mind that boost is not what makes power, it's airflow. A 20G size or a 50 trim would be great (320-440 WHP aka the most common power goal region for DSMers), however the amount of power it would take to power it would mean a massive or several motors. Maybe 3 or 4 of that one you found and a small transmission. The key here is high torque for little to no lag. That is why the assist idea is supreme in higher power applications. With that being said, you make this work and you have a real business case for it.

 

[91-GS]

Just had an idea:
If you install a toothless ratchet mechanism in the system it will allow electric motor to spool the turbo, yet when engine's exhaust will spool it faster (as engine's RPM increase) the ratchet will disengage allowing the turbo to spin freely without being slowed down by the electric motor and possibly part of the gear box.

While this will complicate the system it will also permit using smaller motor since said motor will only need to work part of the time instead of producing continuous boost throughout engine's RPM range.

 

[teknicalissue]

Yup just keep in mind that boost is not what makes power, it's airflow. A 20G size or a 50 trim would be great (320-440 WHP aka the most common power goal region for DSMers), however the amount of power it would take to power it would mean a massive or several motors. Maybe 3 or 4 of that one you found and a small transmission. The key here is high torque for little to no lag. That is why the assist idea is supreme in higher power applications. With that being said, you make this work and you have a real business case for it.

<IGNORE>
I tried to make a 20G compressor map work but couldn't find the proper points that gave good CFM and Pressure. I did find a point in the large 16G compressor map. See below: <IGNORE>

EDIT: I went back and remapped the 20G points and was also pleased with the results:

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Looking at the above (butchered) compressor map:

And apply @jim95redgsx formula:

12kw = 16.09 hp

Pressure Ratio = (11.76 + 14.7) / 14.7

Pressure Ratio = 1.8

at 375ish cfm, 1.8 PR and 95,000 RPM I would get about 11.76PSI looking at the compressor map


(375 cfm X 11.76psi )/ 229 X .77 = 14.82 HP required.

The 16G makes more boost at a lower CFM while the 20G makes marginably less boost with more CFM or 25.8 lb/min

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Looking at the above (butchered) compressor map:

And apply @jim95redgsx formula:

12kw = 16.09 hp

Pressure Ratio = (12 + 14.7) / 14.7

Pressure Ratio = 1.81

at 325ish cfm, 1.81 PR and 98,000 RPM I would get about 12PSI looking at the compressor map


(325 cfm X 12psi )/ 229 X .77 = 13.11 HP required.

That is 3HP less than our max so we aren't over powering the motor and complete max. This means that a large 16G would get a bang of 12 PSI at 325 CFM or 22 lb/min if we multiply the CFM by 0.069.

I did the same thing with a 14b and was a bit disappointing with the result:

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12kw = 16.09 hp

Pressure Ratio = (9.99 + 14.7) / 14.7

Pressure Ratio = 1.67

at 325ish cfm, 1.67 PR and 112,000 RPM I would get about 9.99 PSI looking at the compressor map


325 cfm X 9.99psi / 229 X .68 = 9.6 HP required.

While there is wiggle room for 6.4 more hp... I can't find a decent point on the map to hit that 16hp. Even if I did.. I'm sure the compromise is either in the CFM or the pressure.

Based on this, it looks like the 20G is the best turbo for this direct drive electric motor!

Thoughts? Perhaps you guys have more ideas on what other turbo's will work for just one of these motors. I will look in to a multiple motor solution once I figure out the proper application for a single motor.

EDIT: with the 12KW motor; My goal will now be to generate 10PSI @ 112k RPM. The final product will surely be a 20G or something of that caliber due to the greater airflow.

 

[Chumpaumpalumpa]

Just had an idea:
If you install a toothless ratchet mechanism in the system it will allow electric motor to spool the turbo, yet when engine's exhaust will spool it faster (as engine's RPM increase) the ratchet will disengage allowing the turbo to spin freely without being slowed down by the electric motor and possibly part of the gear box.

While this will complicate the system it will also permit using smaller motor since said motor will only need to work part of the time instead of producing continuous boost throughout engine's RPM range.

Better than the clutch solution.

 

[teknicalissue]

Just had an idea:
If you install a toothless ratchet mechanism in the system it will allow electric motor to spool the turbo, yet when engine's exhaust will spool it faster (as engine's RPM increase) the ratchet will disengage allowing the turbo to spin freely without being slowed down by the electric motor and possibly part of the gear box.

While this will complicate the system it will also permit using smaller motor since said motor will only need to work part of the time instead of producing continuous boost throughout engine's RPM range.

definitely something to look forward to. This is in assumption that the gear box still exists correct? Either that or I would need to implement this on a motor for a direct drive application.

 

[91-GS]

That's correct. In case of a direct drive it will be a component sitting in line between motor and blower. In case of gear box it can be implemented into one of the gears.

 

[Chumpaumpalumpa]

That's correct. In case of a direct drive it will be a component sitting in line between motor and blower. In case of gear box it can be implemented into one of the gears.

So the approach is changing now? @teknicalissue Are you going e-assist turbo or electric supercharger?

 

[jim95redgsx]

I haven't had much time to look at compressor maps lately. That 20G map does look much better for your lower RPM, direct drive set-up. The lower the RPM, the larger the compressor wheel needed. The larger compressor wheel, the more HP needed to drive it. That 20G wheel looks almost ideal for that 100,000 RPM motor, direct drive, but you would need a smaller wheel for your geared set-up.

Mitsu rates their compressor maps at:
14.50 = inlet pressure
298*K (76.73*F) = inlet temperature
Air under these conditions weighs 0.07292 lbs/cu ft.
This will change your PR and lbs/min calculations somewhat.

You are neglecting the motor efficiency in your calculations.
12KW / 746 =
16.09 HP @ 100% eff
14.48 HP @ 90% eff
13.67 HP @ 85% eff
12.86 HP @ 80% eff
The efficiency of that motor is unknown.

Using the chart in that link that I posted above (that includes temperature and air compression effects):
25 lb/min = 13.2 HP @ 100% compressor eff
and a 1.75 PR
25 lb/min = 17.1 HP @ 77% compressor eff
20 lb/min = 10.9 HP @ 100% compressor eff
20 lb/min = 13.5 HP @ 77% compressor eff

!.75 PR = 10.7 psi boost
25 lb/min = 342 CFM
20 lb/min = 274 CFM

While you probably will not reach your desired goals you will be close and it still fits the 20G map nicely.

Jim

 

[Chumpaumpalumpa]

definitely something to look forward to. This is in assumption that the gear box still exists correct? Either that or I would need to implement this on a motor for a direct drive application.

Ask Gary about his beer can motor, It was supposed to be 27 hp and around 100,000RPM and the size of a beer can.

 

[Chumpaumpalumpa]

http://www.rcgroups.com/forums/showthread.php?t=1898445&page=3
Same sort of idea, decent read.
Proof of concept: http://www.phantomsuperchargers.com/dyno-results.html
They're also going direct drive: http://www.phantomsuperchargers.com/fts-tq25024v.html

Shoot an e-mail to H. Lehner and see if he can provide a motor with your desired specs. [email protected]

HOLY CRAP: http://www.rcgroups.com/forums/showthread.php?t=1898445&page=5

 

[teknicalissue]

So the approach is changing now? @teknicalissue Are you going e-assist turbo or electric supercharger?

I'm not pursuing the e-assist turbo yet but I have drawn some crued sketched on how I'd make it work. It would essentially required a custom CHRA that fits a motor and a large gear. The shaft would also have to be custom as it will have a gear for the drive gear to spin. the heat will destroy the motor though... I could implement a water cooling jacket but idk.. I'll pursue this after the first version.

I haven't had much time to look at compressor maps lately. That 20G map does look much better for your lower RPM, direct drive set-up. The lower the RPM, the larger the compressor wheel needed. The larger compressor wheel, the more HP needed to drive it. That 20G wheel looks almost ideal for that 100,000 RPM motor, direct drive, but you would need a smaller wheel for your geared set-up.

I agree! I was surprised when I saw that! I could hit a decent amount of boost on with a decent amount of airflow. I did a little more research and an 11 blade 20g billet wheel will be a killer on this direct drive set up. That will be the end product; a monster E-20g.

Mitsu rates their compressor maps at:
14.50 = inlet pressure
298*K (76.73*F) = inlet temperature
Air under these conditions weighs 0.07292 lbs/cu ft.
This will change your PR and lbs/min calculations somewhat.

Could you recheck my math and add the proper amount of values? A lot of my values I got from doing quick google searches and you seem to be on top of the mathematics on this project

You are neglecting the motor efficiency in your calculations.
12KW / 746 =
16.09 HP @ 100% eff
14.48 HP @ 90% eff
13.67 HP @ 85% eff
12.86 HP @ 80% eff
The efficiency of that motor is unknown.

efficiency is > than 90% on the white papers they sent me. On top of that; I've been offline for a while and forgot to post something that changed. I was able to talk to the company and found out that they can get it to peak at 15KW I posted 12KW as a sure fire number we can get while still having quite a bit of head room.

EDIT: I should also mention that this new motor will max out at 100 kRPM which still is in the best area of the compressor map. Essentially; assume 12 ~ 15KW @ 95,000 RPM.

Using the chart in that link that I posted above (that includes temperature and air compression effects):
25 lb/min = 13.2 HP @ 100% compressor eff
and a 1.75 PR
25 lb/min = 17.1 HP @ 77% compressor eff
20 lb/min = 10.9 HP @ 100% compressor eff
20 lb/min = 13.5 HP @ 77% compressor eff

!.75 PR = 10.7 psi boost
25 lb/min = 342 CFM
20 lb/min = 274 CFM

While you probably will not reach your desired goals you will be close and it still fits the 20G map nicely.

Jim

agreed, See the comments above though. The physical limitations of the motor is 15KW.. I posted 12 to be safe but we can bump it up as needed. Just as long as we don't hit 15KW for extended amounts of time. To give you more insight, the company is building an electric motor for me from scratch so while my modifications are very limited; I'm still somewhat flexible and having them change something to the motor. And yes, this company is charging me $$$ but I'm willing to shell it out for the sake of the project.

Ask Gary about his beer can motor, It was supposed to be 27 hp and around 100,000RPM and the size of a beer can.

Yep! I spoke with Gary about the motor! It's essentially a 20KW motor. Similar to the 25KW motor I pointed out earlier.

http://www.rcgroups.com/forums/showthread.php?t=1898445&page=3
Same sort of idea, decent read.
Proof of concept: http://www.phantomsuperchargers.com/dyno-results.html
They're also going direct drive: http://www.phantomsuperchargers.com/fts-tq25024v.html

Shoot an e-mail to H. Lehner and see if he can provide a motor with your desired specs. [email protected]

HOLY CRAP: http://www.rcgroups.com/forums/showthread.php?t=1898445&page=5

Yep! Someone posted the phantom link way early in the thread if I remember correctly. They build up about 1.3PR of boost. to put it in to perspective; My goal is 1.8 with much more airflow (Thanks to the 20g). To put it in to more perspective; They are running on 24v on two lead acid batteries.(can't find the amperage.. but I can't imagine it's large due to the amp amount on the batteries they require for the turbo); My system will require 48v and will suck a moderate amount of amps. Looking at their products; I can see their turbo's are offering 3000W - 4000W of power. To put it in to perspective; My one motor will be worth 5 of their 3000W turbo's or 3ish of their 4000W turbo's. which is a significant bump if you run @jim95redgsx calculations.

To clarify; I acknowledge turbo's like these are out there but the price per hp is not worth it for me (My own opinion). The goal here is to get tons more power using a similar concept without breaking the bank.

It's very interesting though... They market their 4kw turbos as a 40 shot of nitrous.... ool I wonder how many shots my 12 ~ 15KW motor is worth?

 

[jim95redgsx]

I'm not pursuing the e-assist turbo yet but I have drawn some crued sketched on how I'd make it work. It would essentially required a custom CHRA that fits a motor and a large gear. The shaft would also have to be custom as it will have a gear for the drive gear to spin. the heat will destroy the motor though... I could implement a water cooling jacket but idk.. I'll pursue this after the first version.

By E-assist, I think he was referring to a compound set-up with the E-charger mounted after the intercooler with a relatively large turbocharger.




I agree! I was surprised when I saw that! I could hit a decent amount of boost on with a decent amount of airflow. I did a little more research and an 11 blade 20g billet wheel will be a killer on this direct drive set up. That will be the end product; a monster E-20g.

That 22 blade 20G billet wheel will more HP to drive.





Could you recheck my math and add the proper amount of values? A lot of my values I got from doing quick google searches and you seem to be on top of the mathematics on this project

I already did for the 20G. There's probably no need for the others.



efficiency is > than 90% on the white papers they sent me. On top of that; I've been offline for a while and forgot to post something that changed. I was able to talk to the company and found out that they can get it to peak at 15KW I posted 12KW as a sure fire number we can get while still having quite a bit of head room.

EDIT: I should also mention that this new motor will max out at 100 kRPM which still is in the best area of the compressor map. Essentially; assume 12 ~ 15KW @ 95,000 RPM.

Greater than 90% efficiency should give you over 14.5 HP. You probably shouldn't be pushing the motor to it's absolute limits anyway.



agreed, See the comments above though. The physical limitations of the motor is 15KW.. I posted 12 to be safe but we can bump it up as needed. Just as long as we don't hit 15KW for extended amounts of time. To give you more insight, the company is building an electric motor for me from scratch so while my modifications are very limited; I'm still somewhat flexible and having them change something to the motor. And yes, this company is charging me $$$ but I'm willing to shell it out for the sake of the project.





Yep! I spoke with Gary about the motor! It's essentially a 20KW motor. Similar to the 25KW motor I pointed out earlier.






Yep! Someone posted the phantom link way early in the thread if I remember correctly. They build up about 1.3PR of boost. to put it in to perspective; My goal is 1.8 with much more airflow (Thanks to the 20g). To put it in to more perspective; They are running on 24v on two lead acid batteries.(can't find the amperage.. but I can't imagine it's large due to the amp amount on the batteries they require for the turbo); My system will require 48v and will suck a moderate amount of amps. Looking at their products; I can see their turbo's are offering 3000W - 4000W of power. To put it in to perspective; My one motor will be worth 5 of their 3000W turbo's or 3ish of their 4000W turbo's. which is a significant bump if you run @jim95redgsx calculations.

To clarify; I acknowledge turbo's like these are out there but the price per hp is not worth it for me (My own opinion). The goal here is to get tons more power using a similar concept without breaking the bank.

It's very interesting though... They market their 4kw turbos as a 40 shot of nitrous.... ool I wonder how many shots my 12 ~ 15KW motor is worth?

With a normal turbo system, a rule of thumb is that 1 lb/min is about equal to about 10 HP, but this is on all out race cars. A more normal street car should be closer to 8.5 HP per lb/min.

I notice that Phantom supercharger uses ceramic ball bearings. I wonder how that would work out at 100,000 RPM with a self contained oil supply. All turbochargers (journal bearing and ball bearing) require a pressurized oil supply off the engine. All turbochargers also require a thrust bearing. Ball bearing turbos use an angled ball bearing for this thrust.

Jim

 

[jim95redgsx]

I think I screwed up that post. I tried to split up your quote with my answers but it didn't come out right. You'll have to pick my answers out of your quote.

Jim

 

[teknicalissue]

By E-assist, I think he was referring to a compound set-up with the E-charger mounted after the intercooler with a relatively large turbocharger.

Oh! If that's the case; the turbo can be used in either or scenerio. Either feeding the large turbo or the large turbo feeding the little one. This can be one of the tests we can run to determine what works best for this particular set-up. i'd say the larger one feeding the smaller one will be the most effective as there is less space to fill up with air thus the nitrous effect.

That 22 blade 20G billet wheel will more HP to drive.

do we know how much power? my peak is 15kw so I could safely do 14KW for the amount of time we will be running this for so let's shoot for 16.8 HP (14 KW * .90 eff). Worst case scenario is that I'd go with the 6 blade.

With a normal turbo system, a rule of thumb is that 1 lb/min is about equal to about 10 HP, but this is on all out race cars. A more normal street car should be closer to 8.5 HP per lb/min.

I notice that Phantom supercharger uses ceramic ball bearings. I wonder how that would work out at 100,000 RPM with a self contained oil supply. All turbochargers (journal bearing and ball bearing) require a pressurized oil supply off the engine. All turbochargers also require a thrust bearing. Ball bearing turbos use an angled ball bearing for this thrust.

Jim

The way I read it is that the turbo needs the pressurized oil to cool down the moving parts due to the close proximity to the exhaust. If you remove the heat; you would effectively remove the need to cool the shaft as it wont be getting near as hot as if the other end was touching hot exhaust.

The 100,000 RPM motor is being used else where in other applications as well. I asked about that and they said that they have the proper solutions to make the motor as reliable as possible. If you'd like; I can ask them for more details about how exactly they are making it work.

Thanks for all the help! Do we want to keep on looking at other compressor maps? I'm also curious about the HP required to drive the billet wheels for HP... Good thing I held off on buying 20G equipment

 

[Chumpaumpalumpa]

What if a geared system was used but you utilized belts instead of oil in a transmission.

 

[Chumpaumpalumpa]

The way I read it is that the turbo needs the pressurized oil to cool down the moving parts due to the close proximity to the exhaust. If you remove the heat; you would effectively remove the need to cool the shaft as it wont be getting near as hot as if the other end was touching hot exhaust.

You also need the oil pressure to support the shaft.

 

[teknicalissue]

What if a geared system was used but you utilized belts instead of oil in a transmission.

Possible, But then the question is; why would we want to? I think we said that the direct drive would work the best as there are less points of failure, cheaper, and more efficient.

You also need the oil pressure to support the shaft.

Just like the Phantom superchargers, it would not require any pressurized oil to support the shaft. with a direct drive set-up; the shaft would be at max a 2 inch length shaft which is very small and will be supported by the motor that's being made for this.

 

[Chumpaumpalumpa]

Possible, But then the question is; why would we want to? I think we said that the direct drive would work the best as there are less points of failure, cheaper, and more efficient.



Just like the Phantom superchargers, it would not require any pressurized oil to support the shaft. with a direct drive set-up; the shaft would be at max a 2 inch length shaft which is very small and will be supported by the motor that's being made for this.

Here's the only issue with direct drive and your application. You simply will not get the volume of air you need under pressure to produce any significant amount of power at that low of an RPM. The direct drive would be perfect for an e-assist but I dont think that is what were going for here. Plus, remember that the phantom-chargers are being equipped on vehicles that did not previously have a turbo; having higher compression as well. The fear with this is at $1,000 I could not justify that price for 10 or even 20 HP. My 2 cents here are direct drive if were going e-assist and geared if were going electric supercharger, otherwise no substantial gains will have been made other than proving a concept that we all know works already. That being said, this may work as a nice retrofit for the NT DSMs.

 

[91-GS]

As for "why use oil instead of bearings" the answer is longevity.
With a bearing as RPM increase so does wear due to friction. With oil as RPM increase a shaft begins to push oil under itself and actually float on a thin film of oil, but away from the bushing it's in. Since there is no direct metal-to-metal contact any more there is no wear. Really only reason this set-up would wear out is during starting/stopping (before/after the shaft 'floats') or due to contaminants in the oil.

There are fancier ways to have 'frictionless' or rather 'contact-less' bearings, but they are too complicated and/or costly for this particular project.

 

[teknicalissue]

Here's the only issue with direct drive and your application. You simply will not get the volume of air you need under pressure to produce any significant amount of power at that low of an RPM. The direct drive would be perfect for an e-assist but I dont think that is what were going for here. Plus, remember that the phantom-chargers are being equipped on vehicles that did not previously have a turbo; having higher compression as well. The fear with this is at $1,000 I could not justify that price for 10 or even 20 HP. My 2 cents here are direct drive if were going e-assist and geared if were going electric supercharger, otherwise no substantial gains will have been made other than proving a concept that we all know works already. That being said, this may work as a nice retrofit for the NT DSMs.

Out of curiosity; Where are you getting those values from? based on the math above; we would make at the very least 20lbs/min and at 8.5 hp per lb we would be seeing a potential of 170hp not 20hp. Again, this is math for a 13hp motor. The motor I will be using will have approximately 18hp which is theoretically good for 25lbs/min or 212.5 hp (I'd pay $1,000 bucks for 200hp any day!). I must have missed something in the math somewhere!

As for "why use oil instead of bearings" the answer is longevity.
With a bearing as RPM increase so does wear due to friction. With oil as RPM increase a shaft begins to push oil under itself and actually float on a thin film of oil, but away from the bushing it's in. Since there is no direct metal-to-metal contact any more there is no wear. Really only reason this set-up would wear out is during starting/stopping (before/after the shaft 'floats') or due to contaminants in the oil.

There are fancier ways to have 'frictionless' or rather 'contact-less' bearings, but they are too complicated and/or costly for this particular project.

I think this is a limitation of an electric motor as well as I wouldn't know where to find an electric motor that has pressurized oil for it's shaft. keep in mind that the electric motor company will create the motor to have the shaft for the compressor wheel already in place. All I would have to do is simply create an adapter plate for the CHRA to insert the electric motor and tighten the compressor wheel nut. If anything; I'd be more worried about the compressor wheel balance! and you are correct that the only metal on metal contact would be inside the electrical motor itself; which will most likely have angular contact bearings. anything outside of the motor will contain no friction

 

[Chumpaumpalumpa]

Out of curiosity; Where are you getting those values from? based on the math above; we would make at the very least 20lbs/min and at 8.5 hp per lb we would be seeing a potential of 170hp not 20hp. Again, this is math for a 13hp motor. The motor I will be using will have approximately 18hp which is theoretically good for 25lbs/min or 212.5 hp (I'd pay $1,000 bucks for 200hp any day!). I must have missed something in the math somewhere!

I meant a 20hp gain and was being conservative. 25lbs/min is only really good for 230HP if you can deliver it at pressure. With that, 200HP is stock and still, even a 40 hp gain from a stock DSM doesnt seem worth that much money. I'm not sure where you are getting a 212HP gain from, especially with that little airflow. If I am in fact missing something, please point it out.

 

[teknicalissue]

I meant a 20hp gain and was being conservative. 25lbs/min is only really good for 230HP if you can deliver it at pressure. With that, 200HP is stock and still, even a 40 hp gain from a stock DSM doesnt seem worth that much money. I'm not sure where you are getting a 212HP gain from, especially with that little airflow. If I am in fact missing something, please point it out.

Ahhh i see what you mean now! You're completely right! For what ever reason I had forgotten that it's not a calculation of gain but a calculation of overall potential...

Hmm... I guess going back to the heated system makes more sense doesn't it!

I'll stop the process with the direct drive motor. Good thing we caught my error early!

 

[Chumpaumpalumpa]

Ahhh i see what you mean now! You're completely right! For what ever reason I had forgotten that it's not a calculation of gain but a calculation of overall potential...

Hmm... I guess going back to the heated system makes more sense doesn't it!

I'll stop the process with the direct drive motor. Good thing we caught my error early!

Yes sir that's why you have people here backing you! What do you mean by heated? At least you found some badass little motors in the process. I think using belt drive would be the best as far as simplicity while using the same motor you were going to for direct drive so you can really get into the compressor efficiency range. Additionally, using a Larger compressor (ie. HX-35 or similar) paired with that motor and you've got a hell of a lot of airflow!!