P2 Supercharger Thread
- Thread starter AlexLTDLX
- Start date
SGL12GUNNER
Member
I did not see that before.... thank you
SGL12GUNNER
Member
Really just the housings dimensions. Not sure how I missed that on their website... I should be okay, but if you can get the thickness of the housing and back plate that would be helpful.
SGL12GUNNER
Member
Awesome, thank you sir!
Does anyone one have specs of the standard bearings that ship in these?
I've purchased one and the stock bearings are a bit noisey for my liking. I'll go back to the seller to see what they think but i'll probably replace them anyway. If anyone has recommendations for new bearings that would be great.
Also, reading through the thread there is a lot of good discussion about motor ratings which i'm torn on.
I'm pretty settled on the hobbywing max4 ESC as it looks proven.
I'd like to keep the voltage as high a possible so shooting for 12s
Currently looking at either the hobbywing ezrun 70125 but its only 560kV so i'd have to gear it up about 1.6:1 to get around 40k impeller rpm.
the other option would be the 2028 castle that alex is using or the 1100kV option. this would be less gearing but i don't think the motor has the same output as the 70125.
My thinking is i need motor that can deliver ~15kW and the actual RPM can be sorted by gearing. using 12s as opposed to 8 or 10 makes this a lot easier.
I also like the idea of using the same brand of ESC & motor for compatibilities sake (and i don't have MGM money...)
Is that reasoning sound?
I've purchased one and the stock bearings are a bit noisey for my liking. I'll go back to the seller to see what they think but i'll probably replace them anyway. If anyone has recommendations for new bearings that would be great.
Also, reading through the thread there is a lot of good discussion about motor ratings which i'm torn on.
I'm pretty settled on the hobbywing max4 ESC as it looks proven.
I'd like to keep the voltage as high a possible so shooting for 12s
Currently looking at either the hobbywing ezrun 70125 but its only 560kV so i'd have to gear it up about 1.6:1 to get around 40k impeller rpm.
the other option would be the 2028 castle that alex is using or the 1100kV option. this would be less gearing but i don't think the motor has the same output as the 70125.
My thinking is i need motor that can deliver ~15kW and the actual RPM can be sorted by gearing. using 12s as opposed to 8 or 10 makes this a lot easier.
I also like the idea of using the same brand of ESC & motor for compatibilities sake (and i don't have MGM money...)
Is that reasoning sound?
There's another member on here who checked out the bearings in his unit and they're not great. They're not actually rated for anywhere close to the blower's Max RPM, but for our actual achievable RPMs I think they're going to be okay. Also keep in mind with my MGM LMT setup, even running with a 1" restrictor - which I'm guessing is equivalent to about 500 horsepower or so, I wasn't able to hit 40,000 impeller RPM - you can watch the high-powered sledgehammer test video to see the actual numbers. I would love to see what the hobby wing motor is actually capable of geared up, but don't expect 40k. Power in watts and horsepower are directly relatable. I'd give more details, but I just pulled a 10,000 lb trailer from Alabama to Texas today and I'm literally dictating this into my phone while lying down in the back of the expedition at a truck stop with semis all around me. It's 3:30 a.m. local time. And I had the same tire get two separate punctures the day before (one in SC on the other in GA), on top of driving almost 600 mi I spent the morning getting that fixed. But I did want to get back to you.
I don't think anyone here has tried a NeuMotor (neumotor.com) but they seem to have a good reputation in the RC world. Their model 3020 is rated at 10kW continuous and 20kW peak. Their 3030 is rated for 15kW continuous and 30 kW peak. There are various options for Kv depending on how the motor is wound. With 40V speeds of 20,000-30,000 rpm are attainable. You will also need to consider batteries. LiPo nominal voltage is 3.7V. LiFePO4 3.2V and LTO 2.3V. It seems like most are going with LiFePO4 or LTO because they can be discharged and charged faster then LiPo.
@AlexLTDLX thanks for the response, These bearings are a bit noisey for my liking so i'll replace them anyway and let you know what i find. The 15kW estimate is pretty loose but its based on the turbo shaft power requirement from the borgwarner calculator. I figured if that was the "effort" required to get to ~6PSI at the flow rate it's a good place to start with the supercharger. It will be interesting to verify that actually.
Sounds like a huge trip hope you got some decent rest and made it safely. Junk on the road is so frustrating, I hit a piece of rebar not long ago that cost me one of the tyres i hadn't planned on replacing.
@88fiero I took a look at the neumotor and they are the in the same ballpark kV as the hobbywing so i'd be looking at similar gearing. I have struggled to find rated kW for the HW though which does leave a grey area. if it can pull 3-400A at 12S it should be enough. I did look through the APD ESC's though and they look really good. I have pulled the trigger on the max4 already but i definitely think the APD would be the go for a bigger project bike or cart, especially with regen capabilities. Also surprised to see they are manufactured in Sydney. I did see they do a cap bank for ESC's relatively cheap so i'll be keeping that in mind.
I'd prefer to go for LiFePO4's but think i'll end up with LiPo and some fire mitigation strategies.... Charging is something i've yet to get into to deeply so will have a look as a consideration for batteries. I definitely want to charge in the vehicle so it will be important.
Sounds like a huge trip hope you got some decent rest and made it safely. Junk on the road is so frustrating, I hit a piece of rebar not long ago that cost me one of the tyres i hadn't planned on replacing.
@88fiero I took a look at the neumotor and they are the in the same ballpark kV as the hobbywing so i'd be looking at similar gearing. I have struggled to find rated kW for the HW though which does leave a grey area. if it can pull 3-400A at 12S it should be enough. I did look through the APD ESC's though and they look really good. I have pulled the trigger on the max4 already but i definitely think the APD would be the go for a bigger project bike or cart, especially with regen capabilities. Also surprised to see they are manufactured in Sydney. I did see they do a cap bank for ESC's relatively cheap so i'll be keeping that in mind.
I'd prefer to go for LiFePO4's but think i'll end up with LiPo and some fire mitigation strategies.... Charging is something i've yet to get into to deeply so will have a look as a consideration for batteries. I definitely want to charge in the vehicle so it will be important.
You need to look at the C rating on batteries. The C rating is a factor times the amp-hours of the battery that tells the maximum discharge or charge rate. A123 LiFePO4's have a discharge C factor of 10 to 15. LTO batteries are typically at least 10C discharge. Typical LiPo are 1C. So with LiPo you need a lot of amp-hours to get a high discharge rate.
Sterling Power makes a 12V to 48V DC
C charger but it is a bit pricey. I'm looking at 110V AC to 48 V DC chargers and a 12V to110 AC inverter to see if I can find some that is reasonable quality and cheaper.
SpikeG
New member
Hey Alex, love the work you've done so far. Its been fun following your builds and learning from your hiccups. I'm about to start my own build with a group of fellow Electrical Engineering students as our capstone project but adding some controls into the mix (feedback systems, PID, Observers, etc). We are limited on time so I'm going for faster-easier assembly of mechanical parts over cheaper ones so we'll be going the P2 route and I have a few questions for you.
If you were in our shoes, would you go the TP/VESC or Castle/Hobbywing route? I'm leaning Castle/Hobbywing route since it seems to just work, however the VESC data logging would be beneficial to us and the hobbywing looks like it uses a proprietary logging system.
The system doesn't necessarily need to go onto a vehicle for the project to be a success, however it would be nice to test in a real world scenario. We have 3 options for test motors and unfortunately the smaller engines are more accessible to us. This setup would be overkill for all but one of the engines. Realistically, do you think we'd have issues testing on a smaller motor (~3.0L)? I'm assuming the higher restriction would cause us to hit desired RPMs easier, meaning we will either have to choose a smaller drive pulley than you did, or run at a lower duty cycle. Do you think a 14 tooth pulley would be sufficient for a more restricted motor? We're aiming for 5psi.
Also pertaining to the belt/pulley method, did you incorporate a "tensioner" or slot in your motor mounting plate to adjust belt tension? Or do you have any tips on mounting with ideal tension without causing motor shaft deflection or belt slippage? Given how hard it is to source belts and the limited time, I'd like to avoid a catastrophic failure with belts or motor bearings.
Lastly, since this will be mostly a bench-top setup for now, we don't necessarily need expensive batteries but it seems everyone is making their own packs from larger individual cells. Do you think we'd have success in some low IR 4s LiPo packs (12s total) or is the cost-benefit not really there? (if so, any recommendations?)
Again, thanks for all your hard work and I'll take any advice you've got for someone just starting this journey!
If you were in our shoes, would you go the TP/VESC or Castle/Hobbywing route? I'm leaning Castle/Hobbywing route since it seems to just work, however the VESC data logging would be beneficial to us and the hobbywing looks like it uses a proprietary logging system.
The system doesn't necessarily need to go onto a vehicle for the project to be a success, however it would be nice to test in a real world scenario. We have 3 options for test motors and unfortunately the smaller engines are more accessible to us. This setup would be overkill for all but one of the engines. Realistically, do you think we'd have issues testing on a smaller motor (~3.0L)? I'm assuming the higher restriction would cause us to hit desired RPMs easier, meaning we will either have to choose a smaller drive pulley than you did, or run at a lower duty cycle. Do you think a 14 tooth pulley would be sufficient for a more restricted motor? We're aiming for 5psi.
Also pertaining to the belt/pulley method, did you incorporate a "tensioner" or slot in your motor mounting plate to adjust belt tension? Or do you have any tips on mounting with ideal tension without causing motor shaft deflection or belt slippage? Given how hard it is to source belts and the limited time, I'd like to avoid a catastrophic failure with belts or motor bearings.
Lastly, since this will be mostly a bench-top setup for now, we don't necessarily need expensive batteries but it seems everyone is making their own packs from larger individual cells. Do you think we'd have success in some low IR 4s LiPo packs (12s total) or is the cost-benefit not really there? (if so, any recommendations?)
Again, thanks for all your hard work and I'll take any advice you've got for someone just starting this journey!
If you are looking at the PCE-P2 supercharger and if it similar to a Vortech with Si trim, it is a large unit for a 3.0L engine. The Vorteech Si can support a big V-8. Assuming a 3.0L engine is at 6000 rpm with 90% volumetric efficiency (4-valve head), the supercharger would need to flow about 360 inlet cfm at 77 'F and 1 bar (close to one atmosphere). It would need to spin at 27,000 rpm to make 5 psi of boost. At 2000 engine rpm the Vortech will surge at 27,000 rpm. It could be slowed down to avoid surge but then you give boost. Probably want to look at a blow-off valve for turndown. A smaller supercharger would be more appropriate.
I personally find it easier to look at things in terms of horsepower; especially since the compressor map's X axis is fairly directly relatable to hp simply by multiplying by 10. So in the above referenced example, spinning at 27,000 rpm and 5 psi, you'd be somewhere around 500 hp. That would indicate n/a hp of around 370 hp. Engine displacement literally doesn't matter. And yes, without modulating speed, it's likely you'd hit surge at 2000 engine rpm. But more importantly, you'd possibly hit uncontrollable detonation at 27,000 blower rpm and 2,000 engine rpm due to extreme cylinder pressure and erratic fill, resulting in severe engine damage. Torque isn't your friend. Torque breaks things. I've blown up pistons and split engine blocks due to too much low speed cylinder pressure in my positive displacement DIY blower setups (using both Eatons and Lysholm/Whipples).
That said, I'd first do the Castle/Hobbywing setup and then a VESC/Castle setup. I honestly wouldn't use a TP Power motor simply because of the pole count; but I might try also try a TP/Hobbywing combination. The VESC is really problematic at high eRPM and the day-to-day lack of repeatability really makes me question any sort of data it spits out - obviously, something's wrong with it, but it's not my prerogative to make their stuff work as intended. I purchased it as fit-for-purpose, and I think I've proved unequivocally (to myself anyway), that it isn't. I honestly don't even think it's the best choice for electric skateboards. People sometimes seem to have a hard time accepting that a product like VESC is flawed. That's where life experience and ability to set aside confirmation bias is imperative, especially after dropping $500 on something that doesn't work as promised. I simply don't look at it as $500 wasted, but rather $500 spent on learning that something doesn't work.
As for batteries, I'd personally look for two 6s packs to minimize connectors, and I'd certainly not hesitate to use SMC lipos (or some other high-quality lipos, but I'm quite confident in recommending SMC stuff after my conversations with the owner of the company and his point of view on the industry - at least you'd be getting what you paid for.
I didn't use any sort of tensioner other than a slotted bolt mount to set the belt tension manually. Since it's a toothed belt with steel wires inside, it simply hasn't been necessary. I can't say the same for conventional serpentine belts in other applications.
Oh, and as for finding a smaller supercharger - yeah, that would be great, but I haven't found a reasonable smaller unit (price, availability and ease of application). Plus it's always better to have too big of a compressor rather than too small.
HTH.
That said, I'd first do the Castle/Hobbywing setup and then a VESC/Castle setup. I honestly wouldn't use a TP Power motor simply because of the pole count; but I might try also try a TP/Hobbywing combination. The VESC is really problematic at high eRPM and the day-to-day lack of repeatability really makes me question any sort of data it spits out - obviously, something's wrong with it, but it's not my prerogative to make their stuff work as intended. I purchased it as fit-for-purpose, and I think I've proved unequivocally (to myself anyway), that it isn't. I honestly don't even think it's the best choice for electric skateboards. People sometimes seem to have a hard time accepting that a product like VESC is flawed. That's where life experience and ability to set aside confirmation bias is imperative, especially after dropping $500 on something that doesn't work as promised. I simply don't look at it as $500 wasted, but rather $500 spent on learning that something doesn't work.
As for batteries, I'd personally look for two 6s packs to minimize connectors, and I'd certainly not hesitate to use SMC lipos (or some other high-quality lipos, but I'm quite confident in recommending SMC stuff after my conversations with the owner of the company and his point of view on the industry - at least you'd be getting what you paid for.
I didn't use any sort of tensioner other than a slotted bolt mount to set the belt tension manually. Since it's a toothed belt with steel wires inside, it simply hasn't been necessary. I can't say the same for conventional serpentine belts in other applications.
Oh, and as for finding a smaller supercharger - yeah, that would be great, but I haven't found a reasonable smaller unit (price, availability and ease of application). Plus it's always better to have too big of a compressor rather than too small.
HTH.
The Vortech Si trim supercharger has a very flat curve at 27,000 rpm. The pressure ratio at 360 cfm is 1.35 (5 psi of boost). The pressure ratio is actually a tad lower at the surge point of ~220 cfm. I wouldn't think that detonation would be a problem at low engine rpm. Given the flat curve the supercharger could be just run at 27,000 rpm but a blow-off valve would need to be tied to engine rpm or mass air flow. It wouldn't work to have it pressure actuated given the flat curve. Or the supercharger could be left off until engine rpms are high enough to keep out of surge but that takes away some of the allure of an e-charger which in my mind is boost throughout the rpm range.
SpikeG
New member
Thanks for all the info Alex and 88fiero! I wouldn't be opposed to a BOV for the smaller engines for now, even if it means losing boost until we're out of the surge zone.
Alex, do you have a preferred U.S. supplier for the T5 belts?
I was going to get the pulleys and belts from McMaster-Carr, but it looks like everyone is using 260mm belts. Mcmaster only has 245mm or 270. Since we're going with the smaller 14T pulley, do you think the 245mm belt would have enough clearance so the motor mount wouldn't interfere with the impeller pulley housing?
Lastly, would you consider the capacitor bank a necessity?
Alex, do you have a preferred U.S. supplier for the T5 belts?
I was going to get the pulleys and belts from McMaster-Carr, but it looks like everyone is using 260mm belts. Mcmaster only has 245mm or 270. Since we're going with the smaller 14T pulley, do you think the 245mm belt would have enough clearance so the motor mount wouldn't interfere with the impeller pulley housing?
Lastly, would you consider the capacitor bank a necessity?
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Give me some more specifics on your target engine and I can give you a better estimate of minimum engine rpm to stay out of surge. To keep things simple, just leaving the supercharger off until engine rpms are high enough to avoid surge may be the way to go initially. Adding a BOV with appropriate controls could be added later.
SpikeG
New member
Unfortunately, the most available engine would be a 2006 Chevy Colorado with a 2.8L I4 which the P2 is WAY overkill for but it is what it is at this point. Goal 1 is to demonstrate controls via either OBD data or selected sensors (or both) so functioning on a a real vehicle would be bonus.
Not sure if you have seen those guys in the UK:
Timing Belt T5 5mm Pitch 25mm Wide 24-105 Teeth CNC/ROBOTICS - Choose Size | eBay
Find many great new & used options and get the best deals for Timing Belt T5 5mm Pitch 25mm Wide 24-105 Teeth CNC/ROBOTICS - Choose Size at the best online prices at eBay! Free shipping for many products!
www.ebay.com
I got from them my 260mm / 52 teeth belt ... but they have a vast choice of sizes ... you could order different belts and "experiment".
I did my belt length calculation after taking some measurements and drawing a picture
SpikeG
New member
Not sure if you have seen those guys in the UK:
Timing Belt T5 5mm Pitch 25mm Wide 24-105 Teeth CNC/ROBOTICS - Choose Size | eBay
Find many great new & used options and get the best deals for Timing Belt T5 5mm Pitch 25mm Wide 24-105 Teeth CNC/ROBOTICS - Choose Size at the best online prices at eBay! Free shipping for many products!www.ebay.com
I got from them my 260mm / 52 teeth belt ... but they have a vast choice of sizes ... you could order different belts and "experiment".
I did my belt length calculation after taking some measurements and drawing a picture
Thanks for the tip! I'm worried international shipping times might slow us down but I ran some numbers based on your build and I think I'll be OK with the 245mm belt from McMaster.
You have a picture of the motor position with the 260mm belt and 18T drive pulley in this thread.
Given the impeller pulley is also 18T, the specs from the CAD drawing lists the diameter at 28.8mm, that puts the center of each shaft at 85mm apart. With a 245mm belt, 14T drive pulley and 18T driven pulley, that puts me right at 82mm apart, or 3mm closer than your pic. It looks from your pictures that I'll sill be able to swing it low enough to tension the belt with a slotted mount so I'll give it a shot!
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