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(non-Ebay) Electric Turbocharger (Supercharger?)

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Sorry I've been away guys! Work has got me pretty busy! That and for some reason.. I'm not getting emails on new posts for this thread..

You may be going for a little overkill here.

While that motor will provide the power at 7000 RPM engine speed, it will definitely have to be throttled back at anything less than around 6000 RPM. You may hit 50 psi at low engine RPM if the compressor wheel doesn't choke first. You'll have to do this with programing as there is no wastegate to control boost. You'll need an RPM sensor, not just a TPS.
Hmm.. you're right. It adds complexity but for something this powerful.. It's definitely needed. On top of that; I can create software that will give people control of how much Approximate PSI they want the electrical motor to generate at a given RPM. taping in to the RPM wire shouldn't be that hard right? If I remember correctly; It pulsates to give the rpm.

At 45 lb/min, you're right on the 60% compressor efficiency line. Allowing for the heat of compression:
45 lb/min @ 2:1 PR @ 60% eff = 50.16 HP
35 lb/min @ 1.75:1 PR @ 60% eff = 30.8 HP
1.75 PR = 12 psi
25.5 KW X .9 eff / 746 =30.76 HP

The motor RPM will probably drop until the motor HP equals the required HP.

This has me thinking.. would the 35lb/min be different closer to the TB than further away? I'm trying to justify the 35 lb/min. On top of that.. How do multiple turbo's work as far as CFM work? wouldn't compressing already compressed air create more heat? would having a natural 14b turbo and an electric 20g turbo produce combined amounts of CFM? there has to be a gotcha when involving multiple turbo's correct? I'm leaning towards a positive gotcha, but I've been wrong before :)

I'm going to have to think of a cooling solution for the air coming out of the electric turbo.. thinking about this though; the air isn't passing through an exhaust... hmmm.... Sounds to me that cooling the air coming out is the best way of maintaining efficiency/higher cfm.

I can't see a 9mm wide belt being able to transmit 30 HP. Belts, in general, do not like high RPM.

what would you recommend? Should we stick with the gears? or go with the belt system and give it a try. I'm actually in the process of printing out the belt drive transmission system:

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Electric motors are not rated in amp/hrs, batteries are. That motor will be pulling 300 amps constantly...but you're right, the batteries will last 1 minute @ 60C discharge rate. At a max 15C recharge rate, it will take 4 hours to recharge. Not very practical.

Jim

agreed; I think at this point; the limitation is batteries. we could increase the amp hours by grabbing another set of batteries but then that would be subject those willing to pay to play. I wish there were better batteries :(

Ok don't shred me on this one is hypothetical and I'll research it later on but what about just using 4 or 5 agm batteries, hooked up in series for amp boosting, then use a high powered voltage amp? In that book I have they used 5 lead acid batteries in the trunk to power a electric supercharger and a Peltier junction intercooler, which the junction also required significant power.

Will be looking in to a DIY Peltier junction intercooler.. Sounds like something that could help; specially if the e-turbo is mounted close to the manifold.

Li-pos are more efficient and lighter and can discharge enough but they are expensive so AGM might be something to at least consider, but I think I've heard about that too somewhere.

yes. But to add to this which is why I'm not a big LiPo guy; they are also fairly dangerous if not charged right or punctured. This would make me afraid to wreck my car.

Exactly, cost being the issue as it seems like the motor will cost a good amount on its own. And each person can upgrade to any type they want. One more thing is maybe you should consider how you'll package the charger and intercooler, piping, room for cooling ducts, and lubrication supply demands. A 20g is designed to work on pressurized oil, this can help dampen harmonic vibrations. Not sure if a self contained system would work right, but maybe that was just for the gears. One good thing is the heavy turbine wheel won't be slowing the spool down anymore, and that's probably gonna help the required horsepower to drive just the compressor wheel, right? Or is that already taken into account?

Keep in mind that when I say a 20G, I'm talking about a 20G compressor and wheel; I'm creating my own CHRA from scratch which will support the belt driven system.

Lead acid batteries may not be the best solution. You would need 7 batteries wired in series to reach 85 volts.

The amp/hour ratings of almost all auto batteries are rated at a 20 hour discharge rate. The higher the discharge rate, the lower the amp/hour rate becomes. This is known as Peukert's Law.
http://all-about-lead-acid-batterie...amentals/peukerts-law-and-exponent-explained/

Most auto batteries are rated between 80 and 100 amp/hours. At a 300 amp discharge rate, you would drain those 7 batteries in minutes.

k = Peukerts exponent
k = 1.3 - 1.6 for lead acid
k = 1.2 - 1.3 for AGM
k = 1.09 for lithium ion

At 300 amps discharge rate:
100 amp/hour battery = 5.86 minutes @ 1.3k
100 amp/hour battery = 3.89 minutes @ 1.4k

My Advance Auto "Silver" battery is rated at 85 amp/hours.
85 amp/hours = 4.7 minutes @ 1.3k
85 amp/hours = 3.1 minutes @ 1.4k

An Odyssey PC680 battery is rated at 16 amp/hours.
16 amp/hours = 32.44 seconds @ 1.3k

With the batteries wired in series, the voltage goes up but the amp/hour rating remains the same.

The batteries must be wired in parallel to charge them off the stock alternator. The stock alternator is rated at 75 amps. This 75 amps divided between 7 batteries will take approx. 10 hours to recharge the batteries.

Jim

Awesome Math is awesome. I guess it's fair to say that batteries are the biggest hindrance to electrical components. Either go with a weaker motor which won't give power or go with less time on a more powerful motor... Also; I did research on multiple motors and I came up with them not being able to work nicely together. Essentially; each motor would be on their own ESC and have their own timing. At most, a 20% increase in wattage was recorded for two of the same 5kw motors (spoke to the company about this). Something in the timing with the motors eventually ends up with one motor dragging the other one at certain points of a burst.

I think hat is a tad to long. So Lithium Ion or polymer or maybe Lithium Iron phosphate?

I'll look in to those; I'm hoping price isn't a problem honestly. I think I'm okay with the electrical motor being $600. I wouldn't be able to justify batteries for that price unless I know this thing will be a beast.

I've been doing some thinking and I think we need to reflect about the goals and purpose of the e-charger.

The way I envision this project is to provide boost at the lower end of the spectrum until a larger turbo can pick up the slack (if the larger turbo is there. If it's not; I expect PSI to drop off as the RPM's increase). The e-charger should provide boost between 1k - 4.5k on the RPM band and shouldn't be expected to sustain boost at above those RPMS.

So in essence; I think we've (and by we've I mean I) gradually changed our vision for this E-charger to provide maximum boost throughout the powerband and completely forgot that this is supposed to act like a supercharger/nitrous shot combination hybrid thing where it only provides incredible amounts of power below half of the available power band for a larger turbo to pick up.

Is this true? and if so; would any of the calculations (CFM/HP) change considering that our goal is not max boost till redline? Does this change the scope of the project and what motors/batteries be required for the project?

I was reading over some notes and realized that my goals/purpose for this project changed LOL So I wanted to know if I've just been out of the loop for a while or do we need to rethink and make changes to some of the stuff we've decided. To make things simple; this is what I've jotted down as far as equipment is concerned:

- Belt driven system for more reliability and maintainability

- 25.5KW motor for HP needed to maintain boost at certain CFM's

- Batteries powerful enough to work with 25.5KW motor @ 300A drain.

-20G compressor cover

-20G compressor wheel 6 blade billet

- ESC powerful enough to power 25.5KW motor

This is what I have on my list as far as hardware. Is this overkill as far as meeting the original goal of providing large amounts of boost in the lower end of the power band?

On a side note; This doesn't mean I will avoid thinking about direct drive applications, full power band e-chargers, cvt e-charger, and E-Assist solutions. I just would love to finish the original goal first :)
 
Neither did i, hence the question :)

Although there are some extrusion printers that infuse plastic with a carbon fiber thread and manufacturer claims that prints are as strong as aluminum.
 
I didn't realize you where making your own chra, quite an undertaking but cool. It just seems to me that machining a cover for the turbine housing, using the v clamp to attach it might be easier and cheaper, even just for r&d. From what I've read there's a few things that had to be engineered. Mainly for the bearings, they spun so hasty it whips the oil aerating it requiring special handling to keep it from pulling up like sludge against shaft oil seals, shock absorbing oil hydrodynamic film for damaging harmonics, oil whirl etc. Just a heads up, I know everyone is knowledgeable in here. Also you mentioned not needing an intercooler because they're is no turbine well, it will help heat transfer, but there's also this thing called adiabatic efficiency. If you compress air it gets hotter, period, now some of the most efficient compressor wheels around 80% thermal efficiency. That's the % numbers you see on comp maps, let's you know how much less than the theoretical minimum adiabatic heating of 100% . Quick example , if you boost a engine 1 atmosphere (14.7 @ 70° &sea level) using a compressor with 80% efficient on with 70°f inlet air the temp will rise not to 185°f but 185 divided by .80 which is 231°f! Now that's not to say you'll NEED an after cooler, but depending on other factors ( meth inj, fuel enrichment cooling, e-85's cooling effect, etc.) It may not be needed if the comp is kept in its sweet spot, or if you use something like the Peltier ( nano cooler or cool chips are some ) you can make a bypass for it when the e turbo isn't in use. That's how the Perkins blizzard booster worked, said it worked quite well.
 
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I've been doing some thinking and I think we need to reflect about the goals and purpose of the e-charger.

The way I envision this project is to provide boost at the lower end of the spectrum until a larger turbo can pick up the slack (if the larger turbo is there. If it's not; I expect PSI to drop off as the RPM's increase). The e-charger should provide boost between 1k - 4.5k on the RPM band and shouldn't be expected to sustain boost at above those RPMS.

So in essence; I think we've (and by we've I mean I) gradually changed our vision for this E-charger to provide maximum boost throughout the powerband and completely forgot that this is supposed to act like a supercharger/nitrous shot combination hybrid thing where it only provides incredible amounts of power below half of the available power band for a larger turbo to pick up.

Is this true? and if so; would any of the calculations (CFM/HP) change considering that our goal is not max boost till redline? Does this change the scope of the project and what motors/batteries be required for the project?

I was reading over some notes and realized that my goals/purpose for this project changed LOL So I wanted to know if I've just been out of the loop for a while or do we need to rethink and make changes to some of the stuff we've decided. To make things simple; this is what I've jotted down as far as equipment is concerned:

- Belt driven system for more reliability and maintainability

- 25.5KW motor for HP needed to maintain boost at certain CFM's

- Batteries powerful enough to work with 25.5KW motor @ 300A drain.

-20G compressor cover

-20G compressor wheel 6 blade billet

- ESC powerful enough to power 25.5KW motor

This is what I have on my list as far as hardware. Is this overkill as far as meeting the original goal of providing large amounts of boost in the lower end of the power band?

Yes, you've got to make up your mind about what you want to do. You'll never get anything built if you change your mind every week.

If you just want to add power in the low RPM range, that 25.5KW motor is overkill for a 2 liter engine but it may be fine for a large displacement V8.

Going to a smaller motor will help a lot with the battery problem and batteries are a big problem. A smaller motor will also help with your "transmission".

IMHO, the best application for this set-up would be to spool up a rather large turbo (not a 14b) to launch an automatic tranny car off the line. People are spending $1000+ on nitrous kits and custom torque converters to do this. A 14b will usually provide enough low speed torque to stall the torque converter but anything larger (even a 16G) will require nitrous and/or a restalled converter.

Using your E-charger as a compound set-up with a large turbo would only require around a 6500 to 7500 watt motor to accomplish this. Leopard makes a 7600 watt motor (but 300 amps) that runs on 24 volts. This would save a lot on batteries if you were using lead acid. They also make a 6500 watt motor (180 amps @ 36 volts), currently on sale for $120 at Atomik RC.

Using a 14b as the first turbo in a compound set-up is not a good idea. This will limit you to the CFM rating of the 14b. You'll need a much larger turbo to make decent power. The larger turbo always has to feed the smaller turbo in a compound set-up. The CFM will remain the same but the pressure ratios will multiply.

The E-charger could be turned off after the launch to save battery life. It would only have to be on for a few seconds.

Jim
 
Using a 14b as the first turbo in a compound set-up is not a good idea. This will limit you to the CFM rating of the 14b.

Would it be a good idea to install a flapper (similar to an exhaust cutout where a butterfly valve is opened/closed using an electric moptor) or a large check valve in the intake to counteract that? Basically as larger turbo starts pulling more air that flap opens so air bypasses the small turbo and large one can breath easier. This seems like a logical choice, especially since this small electric turbo will only be used at low RPM right before launch.
 
Yes, you've got to make up your mind about what you want to do. You'll never get anything built if you change your mind every week.

You are 100% correct! I'm officially putting my foot down! it's obvious that battery technology is simply not advanced enough to power a turbo throughout the entire power band.

If you just want to add power in the low RPM range, that 25.5KW motor is overkill for a 2 liter engine but it may be fine for a large displacement V8.

Going to a smaller motor will help a lot with the battery problem and batteries are a big problem. A smaller motor will also help with your "transmission".

IMHO, the best application for this set-up would be to spool up a rather large turbo (not a 14b) to launch an automatic tranny car off the line. People are spending $1000+ on nitrous kits and custom torque converters to do this. A 14b will usually provide enough low speed torque to stall the torque converter but anything larger (even a 16G) will require nitrous and/or a restalled converter.

Using your E-charger as a compound set-up with a large turbo would only require around a 6500 to 7500 watt motor to accomplish this. Leopard makes a 7600 watt motor (but 300 amps) that runs on 24 volts. This would save a lot on batteries if you were using lead acid. They also make a 6500 watt motor (180 amps @ 36 volts), currently on sale for $120 at Atomik RC.

very good news! This actually brings up the a direct drive application back on to the chopping block. The other company was selling me a 7500 watt motor that spins at 115,000 RPM. for $399. Matched up with a 20g; This should do the job correct?

Using a 14b as the first turbo in a compound set-up is not a good idea. This will limit you to the CFM rating of the 14b. You'll need a much larger turbo to make decent power. The larger turbo always has to feed the smaller turbo in a compound set-up. The CFM will remain the same but the pressure ratios will multiply.

Good to know. One thing to keep in mind is that if I could make this affordable; You could buy multiple and install them on your car.. so run 2 e-chargers to feed a large turbo (heck or just run 2 e-chargers). i also agree that the 14b is simply not a good idea; the more RPM's the more strain I put on my system. Going with a larger turbo is ideal for this system. I'm sticking with the 20G for the sake of this experiment. I'm hoping that the 7500 watt motor should be able to handle it tons of low end boost (Like a supercharger).
The E-charger could be turned off after the launch to save battery life. It would only have to be on for a few seconds.

Jim

Agreed. Specially with Lead Acid; It should help with the life of the battery as well

Would it be a good idea to install a flapper (similar to an exhaust cutout where a butterfly valve is opened/closed using an electric moptor) or a large check valve in the intake to counteract that? Basically as larger turbo starts pulling more air that flap opens so air bypasses the small turbo and large one can breath easier. This seems like a logical choice, especially since this small electric turbo will only be used at low RPM right before launch.

hmm.. I'll keep that in mind and see if I could implement something like that.

I think this would rock to launch big turbo auto or even manual cars because no traditional anti-lag means no extra stress of it.

agreed. heck even if this thing were to be put in a 2.0 NA car; you'd still get a nice punch.

What do you guys thing of a button (think nitrous button) to start the smaller turbo? I'm thinking this is a horrible idea as you wouldn't be able to tune for it.. (a friend asked me to ask). With nitrous; you only need a little tuning as the temperature of nitrous prevents detonation correct?

Other wise; I can just use the TPS sensor as planned originally and have the turbo kick in at 80% - 100% throttle.

thoughts?
 
I've decided I'm going to try to give the direct drive a shot. Motor can do 10KW under 48V @ 208 amps continuous. Because this is 48V; I found some lead high discharge batteries that are cheap and up for the job here: http://www.batteryspace.com/sealedleadacidbattery12v20ah240whs.aspx

Granted the usage time would still be small; but the batteries would cost me less than half of the LiPo batteries. They are also safer and wont explode :). Cheaper -> safer -> capable = obvious choice.

I've also made a drawing of the motor and what the compressor wheel would look like mounted on the motor shaft:

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I've also found an ESC that will work with 48V and handle 208amps which is located here: http://www.hobbyking.com/hobbyking/store/__25202__Turnigy_dlux_250A_HV_14s_60v_ESC.html

Lowering the power of the motor truly made finding parts for it feasible! On a side note; The motor above is going to run me $499 as It is a custom motor with custom winding, custom shaft, and even a custom casing. A water cooling jacket will be included if I chose to use it... But I think I have an idea of how to cool the motor. which leads me to the next topic.

Now that It looks like I have all of the hardware necessary to make this work (ordered 20G compressor housing and extended 6 blade 20G wheel) I need to start thinking about how to keep the motor cool. This much power will generate heat.

I have two proposals for you guys to rip apart. The first and least complex proposal is water cooling. We all know that part of our stage 0 mods is to rip the coolant lines out of our TB. I could include a water cooling jacket and have people use the existing TB coolant lines to cool the motor. Super easy and utilizes existing coolant lines. The problem with this is that I wouldn't even know where to start if I wanted to sell to other cars. Quite honestly I don't even know how the coolant lines are routed on my WRX LOL. This would work very well with DSM's though.. so Pros = effective and efficient cooling and if the motor is better cooled; I could squeeze more power out of it without issues.

The second proposal is air cooling. I could 3d print a U pipe that would come out of the compressor inlet and make a U turn towards the direction of the motor. I would print a hole for the motor to fit in the U pipe and as the turbo draws in air; It would effectively cool the motor to the temperature that air is being pulled in at. This would work well with other cars as it remains as a stand alone system but it obviously isn't as efficient as the water cooling idea. Pros is that the turbo can work for other cars as a drop and go solution; The cons is that cooling wont be as efficient coolant flowing through the motor. Another con is that if anything broke or there was a failure; there is a possibility of debris being sucked in by the turbo as well..

Pros and Cons... Discuss! I've already sent out to get the motor built so I'm hoping that within the next 2- 3 weeks; I should have a functional working prototype with a neat video for you guys to watch!
 
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I read this somewhere:
"A turbo spins very fast; most peak between 80,000 and 200,000 RPM (using low inertia turbos, 150,000-250,000 RPM) depending on size, weight of the rotating parts, boost pressure developed and compressor design."
 
I read this somewhere:
"A turbo spins very fast; most peak between 80,000 and 200,000 RPM (using low inertia turbos, 150,000-250,000 RPM) depending on size, weight of the rotating parts, boost pressure developed and compressor design."

It all depends on the turbo.. The electrical motor will be powering a 20G which shows will make adequate boost at 115k RPM.

To add to this, I'll have a 13hp motor powering the turbo as well. Just want to clarify that this is not an ebay grade e-turbo POS :)

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Both MCM and Roadkill experimented with leaf blowers. Issue is that leaf blowers are not meant to create much pressure, only volume. While they can make 'some' difference, it will only be noticeable on a small engine and at low RPM.
Reason to go with an electric turbo instead of a 'traditional' charger is it's simplicity. You'll get a single bolt-on unit that won't require much work to install and will act somewhat like NOS, in other words if will give you on-demand boost or help spool a larger existing turbo.

As for cooling, how hot will the motor get at full power and what is it's safe top temperature? Would almost say that you should go with water cooling and tap into heater hoses for water, but doing so will make this system more complex and somewhat heavier. Installing the motor into the intake to allow incoming air to cool it before it enters the turbo itself will work too, although doing so would require a larger pipe that might end up taking too much space, not to mention the fact that it will heat up incoming air. So the air would require a larger IC to drop it's temperature to 'normal'. Hard to make that final decision without knowing what temps this motor can handle though.
 
I saw one built out of two gas powered leaf blowers. It made a little boost. Not a crazy amount. Not to be pessimistic but why electric? What's wrong with belt or exhaust driven?

On exhaust driven turbo's you get lag. Belt driven turbo's are pricey and don't get you much performance until you are at high RPM's. The benefit of an electric motor is that you get instant speed and instant torque which means you would get instant boost. No more boost building up; It would just be there when you put your foot on the throttle.

Both MCM and Roadkill experimented with leaf blowers. Issue is that leaf blowers are not meant to create much pressure, only volume. While they can make 'some' difference, it will only be noticeable on a small engine and at low RPM.
Reason to go with an electric turbo instead of a 'traditional' charger is it's simplicity. You'll get a single bolt-on unit that won't require much work to install and will act somewhat like NOS, in other words if will give you on-demand boost or help spool a larger existing turbo.
couldn't of have said it better my self :)
As for cooling, how hot will the motor get at full power and what is it's safe top temperature? Would almost say that you should go with water cooling and tap into heater hoses for water, but doing so will make this system more complex and somewhat heavier. Installing the motor into the intake to allow incoming air to cool it before it enters the turbo itself will work too, although doing so would require a larger pipe that might end up taking too much space, not to mention the fact that it will heat up incoming air. So the air would require a larger IC to drop it's temperature to 'normal'. Hard to make that final decision without knowing what temps this motor can handle though.

EDIT: I'll try to get some 3D models of both systems

Very true. I wont know the temps until I do some testing as the motor is not off the shelf and I don't think they'd have that information given the turn around time. I'm sure I can ask them what is the Max safe temp and take it from there. As a side note; Water cooling wont make it too much heavier; The water jacket sleeves are incredibly light weight and are free with the motor if I choose to go with them. It is the same type of jacket you find on RC electrical boat motors. All you would have to do is tap in to pressurized coolant and let the original system do the work :) The reason I do know I need cooling is because the company said that it is highly recommended at this power level. It's 10,000 watts of energy so I could only imagine.

I see where you're going. Makes sense. How about air cooling it with a smaller fan driven off the opposite side of the shaft?

I think It'll require more cooling than that. 10,000 watts is 48 volts at about 208 amps (give or take some decimal points) so it'll definitely get hot. I don't know how hot yet until the motor is fully built (hopefully! I'm sure they'll give me a spec sheet)
 
Those lawn tractor type batteries may not handle 200 amp discharge rates for very long. The Odyssey PC680 recommends 5 second "pulses" when used for starting.

Those batteries will last approx. 1.16 minutes @ 208 amp discharge rate. At a max charge rate of 6 amps, it may take 3.5 hours to recharge them. If you are constantly charging with the alternator, and don't discharge them completely, it may not be so bad.

You say that it's a custom motor with custom windings, shaft and case. What about custom bearings. You will definitely need a thrust bearing. Remember Newton's third law...For every action there's an equal and opposite reaction. If you are pulling 30 lb/min of air into the compressor wheel, there is 30 lbs pressure trying to pull the wheel out of the compressor housing.

Coolant temps around 200*F may be too hot to cool your motor enough.
Neodymium magnets begin to permanently lose their strength at 176*F. There are magnets that will hold up to higher temps though.

Jim
 
Those lawn tractor type batteries may not handle 200 amp discharge rates for very long. The Odyssey PC680 recommends 5 second "pulses" when used for starting.

Those batteries will last approx. 1.16 minutes @ 208 amp discharge rate. At a max charge rate of 6 amps, it may take 3.5 hours to recharge them. If you are constantly charging with the alternator, and don't discharge them completely, it may not be so bad.

I did catch that.. I wonder if 5 seconds would be enough? The reason I went with these batteries was because they could be recharged a whole lot easier than the LiPo batteries. I wonder how much time it would take the RPMs to hit 4k shifting from 1st to 5th as those would be the time the e-charger would kick in. I also wonder how much rest in between 5 seconds is needed. Worst case scenrio; I buy another 4 piece set and wire them in parallel to have a 48v 40AH battery which should be able to do 10 seconds of discharge in theory. It would weight a ton though.. Man.. battery technology needs to up their game.

alternatively; I could go with even lower voltage for this motor such as 24volts but the amps would be incredibly high for a reasonable ESC. I know you mentioned some batteries in some of the previous posts;could you provide links to some of the batteries that would work better for the application? worst case scenerio is that I go back to LiPo's.

You say that it's a custom motor with custom windings, shaft and case. What about custom bearings. You will definitely need a thrust bearing. Remember Newton's third law...For every action there's an equal and opposite reaction. If you are pulling 30 lb/min of air into the compressor wheel, there is 30 lbs pressure trying to pull the wheel out of the compressor housing.

Coolant temps around 200*F may be too hot to cool your motor enough.
Neodymium magnets begin to permanently lose their strength at 176*F. There are magnets that will hold up to higher temps though.

Jim

I'd have to ask. I explained to the company the application and we got in to a conversation about bearings not too long ago so it is on their minds. I'll send an email out just in case. The good news is that they've made motors for similar turbo related applications (Or so they say) so I'm hopeful. I'll shoot them an email and bring that up to them.

As far as cooling is concerned. You are right correct... If anything I would have to pass the coolant through some type of heatsink that is being cooled by the air passing through. hmm... That might work; but then again; why not just have the motor air cooled in the first place.

Jim ~ what is the maximum CFM we will expect to see at 4.5k on the 20g spinning at 115k and generating 10kw of power? I need to be able to tell them how much pressure they would need to plan for when building the motor.

Edit: maybe I could create a custom alumnimum heatsink that is cooled by two peltier coolers? The heatsink would rap around the motor and definitely keep it cool.
 
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Here is the original air cooled idea:

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Here it is without the massive pipe:

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EDIT: I thought about cooling and I will be using a stand alone PC water cooling system with a peltier cooler attached to chill the water. Essentially; I'll be buying this:

http://www.newegg.com/Product/Product.aspx?Item=N82E16835106219

I'm attaching the cold side of the peltier cooler to the water cooling processor block which will chill the water passing through it. I'm going to then splice (Yes I know this is a closed loop system.. no biggie though) the hose going from the chiller to heatsink and place the motor with a water cooling jacket in between. I am then going to buy the following heatsink:

http://www.newegg.com/Product/Product.aspx?Item=N82E16835103099

To dissipate the heat generated by the peltier cooling.

Because of the price; I will be offering various cooling options. The water cooling option which is this, or an air cooling option which essentially a heat sink wrapped around the motor. I'm going to scrap the U pipe as it's a very bulky design. Water cooling with a peltier cooler chiller + heat sink should do an amazing job at keeping that RC motor cool.

Edit 2: I spoke to the company about the bearings and They are using angular contact bearings capable of 200,000 RPM and can hold a maximum (breaking point max) of 260 lbs of pressure. This means that the bearings should be able to support:

(where X is CFM)
X * 0.069 = 260lbs/min
260/0.069 = 3768.11 CFM

We should be golden in the bearing department :)
 
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Unfortunately. I don't have any links to better batteries. Instead of having two sets of those lawnmower batteries wired in parallel, you would be better off using four 80 - 100 amp/hr auto batteries. There wouldn't be much of a weight penalty compared to eight 14lb batteries. They could be charged at a faster rate too.

I don't think that your cooling system is going to handle the job. A 10,000 watt motor @ 90% efficiency will generate 1000 watts of heat. I'm not sure, but I think those CPU cooling systems are limited to less than 100 watts of heat removal.

The best, affordable, Peltier coolers (TEC1-12706) seem to be limited to 92 watts max of heat removal. You would need about 11 of them and they draw 168 watts each of electrical energy. Having too small of a heatsink or too small of a Peltier cooler will actually add heat to the coolant.

That sounds like good news with the bearings but I would still worry about the lubrication holding up with heat.

Jim
 
Unfortunately. I don't have any links to better batteries. Instead of having two sets of those lawnmower batteries wired in parallel, you would be better off using four 80 - 100 amp/hr auto batteries. There wouldn't be much of a weight penalty compared to eight 14lb batteries. They could be charged at a faster rate too.
hmm.. Good point. I'll look at that tonight

I don't think that your cooling system is going to handle the job. A 10,000 watt motor @ 90% efficiency will generate 1000 watts of heat. I'm not sure, but I think those CPU cooling systems are limited to less than 100 watts of heat removal.

darn, I was hoping it would do some good. My original idea was to set it up like so:

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My thought process was that I could cut the lines and inset the motor between the peltier heat sink and the fan heat sink.My reasoning was that hot water from the motor would get slightly cooled by the heatsink and then cooled even more by the peltier cooler thus cooling the motor. And I was actually planning to us just one peltier cooler LOL. The question is.. How much cooling power does that heatsink provide? and then the question becomes; Is this better than nothing? 5 different 5 second bursts (switching gears) with about 2-3 seconds of rest (depending on what gear your on) generates X watts in which we would have to cool. My other thought process is that you could leave the car on for about 3 minutes or so which will effectively being the coolant to the coolest point and then have a run at the track. This wouldn't be idea for autox though... Hmm.. any thoughts on cooling?
The best, affordable, Peltier coolers (TEC1-12706) seem to be limited to 92 watts max of heat removal. You would need about 11 of them and they draw 168 watts each of electrical energy. Having too small of a heatsink or too small of a Peltier cooler will actually add heat to the coolant.

That sounds like good news with the bearings but I would still worry about the lubrication holding up with heat.

Jim

I called the bearings company and verified that the lubrication would hold up at that heat level. The only thing they warned about is that at higher speeds; Lubrication may actually interfere with how fast the bearing spins meaning that there could be a very slight loss of RPM. Also, by higher speeds I mean above the recommended rated amount :)

Hmm.. LOL I wonder if we could set up the heatsink somewhere where it gets a lot of air like an intercooler LOL

EDIT: Actually... This could work. I would use the original idea of air cooling but would have the air drawing through the heatsink and not the motor itself. Might even be able to not even use the peltier cooloer at this point. The air being sucked in would definitely cool the motor..

I could create an adapter that holds the heatsink and allows it to attach itself to a 3inch pipe. so:

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EDIT2: yes I know the diagram does not show the motor in the right place.. LOL Just wanted to illustrated the cooling process I had in mind.

Water cooling + Air Cooling..ish.

Thoughts?
 
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Great find Jim! Do you have any suggestions on how many gallons per min I should be looking for? Also; Is this to mount in front of the car? or to let it be cooled by air being pulled in from the turbo? This will help me determine the size of the hose.

EDIT: I found these:

http://www.ebay.com/itm/131409659620 - pump

http://www.ebay.com/itm/121450588380 - heatsink by same company but 14k BTU

Would these work?
 
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The gallon/min flow is hard to estimate. It would depend a lot on your motor cooling jacket and the size of it's inlet and outlet tubes.

That pump and cooler that you linked to above is way overkill.

!,000 watts = 3412 btu/hr

Allowing for any efficiency losses, I would double that btu rating.

This cooler is rated at over 7500 btu/hr and is less than 1/2 the price of the cooler that I originally listed. ($30.89)http://www.transmissioncoolers.us/1401.html

I would stick with the pump that I originally listed. It's inlet and outlet barbs will match the cooler and probably be very close to your motor cooling jacket sizes.

The cooler should be mounted in the front of the car, with good airflow. It should NOT be mounted in the compressor inlet path. This will kill compressor efficiency and is NOT a good idea, especially with a compound set-up.

Jim
 
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