P2 Supercharger Thread

Don’t know if anyone else had this problem?
I took my P2 unit apart as I had part of the gear drive that was loose and wanted to investigate further, found out the assembly wasn’t pressed together enough in the bearings, but when I corrected it then the compressor wheel would foul on the housing, im going to use a small washer to correct the spacing problem,
https://www.dropbox.com/s/cl8aav4ra4hfuay/Photo Feb 12 2023, 5 31 50 PM.jpg?dl=0
 
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Marco Mansi said:
Don’t know if anyone else had this problem?
I took my P2 unit apart as I had part of the gear drive that was loose and wanted to investigate further, found out the assembly wasn’t pressed together enough in the bearings, but when I corrected it then the compressor wheel would foul on the housing, im going to use a small washer to correct the spacing problem,
Click to expand...

Does you P2 have helical gears that step up about 3.6:1 similar to a Vortech V2? I have seen some info that says that they can come with the step up gear and other info that says direct drive
 
88fiero said:
Does you P2 have helical gears that step up about 3.6:1 similar to a Vortech V2? I have seen some info that says that they can come with the step up gear and other info that says direct drive
Click to expand...
Its the standard T5 belt drive that’s mentioned earlier in this post
 
Marco Mansi said:
Don’t know if anyone else had this problem?
I took my P2 unit apart as I had part of the gear drive that was loose and wanted to investigate further, found out the assembly wasn’t pressed together enough in the bearings, but when I corrected it then the compressor wheel would foul on the housing, im going to use a small washer to correct the spacing problem,
https://www.dropbox.com/s/cl8aav4ra4hfuay/Photo Feb 12 2023, 5 31 50 PM.jpg?dl=0
Click to expand...

Looks like I'm having the same problem. If I press on the nut holding the impeller, the impeller shaft will slide enough that the impeller drags on the backplate. If I press on the pulley to push it back the other way, the impeller will hit the compressor housing and drag. Looks like I'll be needing 2 shims to solve this spacing issue

Has anyone taken the impeller off this thing? I'm worried about keeping it balanced given how much material was removed from the nut to balance it at the factory
 
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S
SpikeG said:
Looks like I'm having the same problem. If I press on the nut holding the impeller, the impeller shaft will slide enough that the impeller drags on the backplate. If I press on the pulley to push it back the other way, the impeller will hit the compressor housing and drag. Looks like I'll be needing 2 shims to solve this spacing issue

Has anyone taken the impeller off this thing? I'm worried about keeping it balanced given how much material was removed from the nut to balance it at the factory
Click to expand...
Is the outer race of the bearing sliding back and forth? One would thinkl there there would be something like a circ clip to keep the bearing in place or maybe a thrust bearing.
 
Went ahead and took it apart tonight. the teeth are machined directly into the impeller shaft, the runout bearing is pressed on tightly, and the spacer that sits on the inner race of the backplate bearing is loosely fit on the shaft. This was concerning before as it is not tight enough to remain concentric and I'm worried it will cause balance issues.

https://imgur.com/qJgdNLn
https://imgur.com/pfyCo5v
https://imgur.com/O74VIgY

First thing I did was get some dykem and see where the impeller was rubbing on the back plate

https://imgur.com/OitrOUj
https://imgur.com/LNl190c

Then, started thinking about making a spacer so the inner race would hit the back of the impeller without letting the impeller hit the backplate... then I realized I was making a mistake. The cover plate (and housing for the runout bearing) prevents the shaft from backing out. duh. I reassembled and sure enough it prevents the impeller from rubbing the backplate with no issues so I'm only worried about the impeller moving into the compressor housing (which it certainly was).

I decided to remake the spacer that goes against the gear teeth and inner race to proper spec. I reassembled and measured everything to see how much I needed.

https://imgur.com/5EVMGFw
https://imgur.com/WQI3mBd
https://imgur.com/8sKOKjw
https://imgur.com/nkFcieQ

In the end it was 0.7mm too short (I'll double check when I have it apart again). I made it slightly oversized but when the cover for the pulley was tightened, it made the bearings difficult to turn. After some lapping, it now spins freely and does not shift laterally. I think they expected the bearings in the backplate to be press fit tight enough to hold but their machining on the impeller shaft was less than perfect. Overall a fun project as this is a bit out of my wheelhouse as a EE.

The same thing could be accomplished with some M17x22 shim washers such as these:

I ordered some to test fitment. I'm hoping the runout bearing can be removed easily because it would allow me to trim the pulley position.
 
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I'm thinking if attempting this for my racecar. My car is a 1.9L MX5 that pushes out 220whp at 9000 rpm. I'd be shooting for 400whp with a supercharger.

I have good experience in battery building and VESCs from making eSkateboards, plus can fabricate parts easy enough.

I was thinking of making a couple of battery packs similar to the skateboards with Molicel P42s. Something like 10S10P so it can push 450amps sustained and last for a few sessions.

I'm also thinking of using a Maytech 18kW motor with their 400amp escs both of which are water cooled. Fitting a closed loop cooling system with a radiator helps keep the electronics happy.

Any major issues with my ideas? Should be a fun project.
 
Since you are wanting to near double the HP you are going to need near double the mass air flow rate. You are probably looking at 15 psi of boost. If your engine is high compression to start, then pump gas is not going to cut it octane wise. Maybe E85 or race fuel.

With a pressure ratio of 2:1 to get 15 psi of boost and with your small displacement engine, the P2 supercharger will be about at it surge line with the engine at 9000 rpm. There will have to be a blow-off valve to keep enough flow through the supercharger to keep it from surging at lower engine rpms.

The estimated air flow is 2400 lbs/hr at 9000 rpm. With 15 psi of boost the P2 supercharger will require a 30 kW motor. With a 10S LiPo battery that means over 800 amps.

Attached is a compressor for a Vortech Si trim, The P2 is a clone
 

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88fiero said:
Since you are wanting to near double the HP you are going to need near double the mass air flow rate. You are probably looking at 15 psi of boost. If your engine is high compression to start, then pump gas is not going to cut it octane wise. Maybe E85 or race fuel.

With a pressure ratio of 2:1 to get 15 psi of boost and with your small displacement engine, the P2 supercharger will be about at it surge line with the engine at 9000 rpm. There will have to be a blow-off valve to keep enough flow through the supercharger to keep it from surging at lower engine rpms.

The estimated air flow is 2400 lbs/hr at 9000 rpm. With 15 psi of boost the P2 supercharger will require a 30 kW motor. With a 10S LiPo battery that means over 800 amps.

Attached is a compressor for a Vortech Si trim, The P2 is a clone
Click to expand...
thanks for the reply,

yes I already run E85 fuel, engine is currently very high compression. I'll likely need to change cams and compression if pushing 400whp plus.

Actually given the huge overlap of my current cams, the P2 might not surge at low RPM as most of the boost will just blow out the exhaust. It's only until back pressure builds around 4500-5000 rpm that the boost will stay in the engine.

The current engine has very high VE, so I'm hoping that 10-12psi of boost will be enough. Is there another supercharger head unit that might work better? What about modifying a turbo impeller housing to remove the exhaust side?

What are your thoughts on the Maytech motor? It could run 12s but it maxes at 10,000rpm so will need to be geared at 3:1 or more.
 
Tell me as much as you can about your engine particularly the cams and I will model it in Dynosim5 software. I have modeled a 2.6L GM Quad 4 with an Eaton M62. That engine has is high VE with a 4 valve head. Dynosime predicts 300 hp with 10 psi of boost at 6000 rpm.

The Maytech motor is 18 kW peak and 9kW continuous. Compare it to a NeuMotor 8057 with 191 KV. That motor is $489 and is rated at 21.4 kW peak and 10.6 kW continuous. The max torque for both motors is the same.

The P2 has got a lot of attention on this site because it is cheap. But size wise it is more appropriate for a V-8. Rotrex makes some nice size superchargers for smaller engines but they are spendy. The Rotrex C30 series would fit your engine but depending on boost may need a bigger motor than the Maytech. NeuMotor does make some bigger motors.

The compressor side of a turbo could work but turbos are typically designed to run high rpm and then the challenge is to how to drive it. 100,000 rpm with a belt drive is probably not doable. With a high rpm motor and direct drive, aligment could be an issue. But other here are trying it.
 
My engine is about as developed as a MX5 engine can get. So currently very high compression (14:1), ported head, oversized valves (+2.15mm intake, +1.65mm inconel exhausts), 316 degree cams, solid lifters. 4-1 exhaust 3", high flow ported intake. It's all built for high revs. The cams and maybe the compression might need to be changed to suit forced induction.

I have been looking at running a C38 series Rotrex on the engine. A lot of the Honda guys run them on similar spec builds with high duration cams so maybe thats a formula I can follow.

I had a new thought last night. Since I'm so familiar with VESC and skateboard motors I'm actually thinking of attempting dual motors, something like Radium Performance 205kv 6485 (8kw) motors. These have air cooling and can be run for decent times at 6-7kw sustained. I could run a spur / pinion gear setup to gear it 3:1 which would allow for easy gearing changes. I could use a dual 300amp VESC or go single VESCs for each motor. I'd run these off a 16S Molicel pack.

At least then if it all doesn't work, I can always slap them onto my skateboard instead. haha
 
MadJak said:
My engine is about as developed as a MX5 engine can get. So currently very high compression (14:1), ported head, oversized valves (+2.15mm intake, +1.65mm inconel exhausts), 316 degree cams, solid lifters. 4-1 exhaust 3", high flow ported intake. It's all built for high revs. The cams and maybe the compression might need to be changed to suit forced induction.

I have been looking at running a C38 series Rotrex on the engine. A lot of the Honda guys run them on similar spec builds with high duration cams so maybe thats a formula I can follow.

I had a new thought last night. Since I'm so familiar with VESC and skateboard motors I'm actually thinking of attempting dual motors, something like Radium Performance 205kv 6485 (8kw) motors. These have air cooling and can be run for decent times at 6-7kw sustained. I could run a spur / pinion gear setup to gear it 3:1 which would allow for easy gearing changes. I could use a dual 300amp VESC or go single VESCs for each motor. I'd run these off a 16S Molicel pack.

At least then if it all doesn't work, I can always slap them onto my skateboard instead. haha
Click to expand...
What is the lift on the cams? Also what is duration at 0" lift and 0.05" lift
 
I ran DynoSim5 with the following:

bore - 86 mm (assumed 1 mm overbore to get 1.9L)
stroke - 82 mm
4 valve pent roof head wth race porting
29.65 mm exhaust vale
35.15 mm intake valve
14:1 compression
100% ethanol with 7.7 A/F (no E85 option)
Honda type standard runner, large volume intake
Large tube headers with muffler (no cat)
316 degree duration seat-to-seat for both intake and exhaust
129.5 degree lobe separation angle to give 57 degrees of overlap (seat-to-seat)
intake vale opening 46 degress BTDC

This resulted in 208 HP @ 8500 rpm and 209 HP peak at 10,000 rpm
Peak torque of 138 ft-lbs @ 7500 rpm

This sounded reasonable but the program is calculating unreasonable volumetric efficiencies e.g. 195% at 7500 rpm. The intake CFM is crazy high. So when I calculate the thermal efficienecy of the engine its only about 16%. When I have modeled my 2.3L GM Quad 4 engine it comes up with reasonable volumetric efficiencies and air flow. That engine makes 190 HP from 2.3L with a thermal efficiency of 38%.

Madjak, can you confirm the overlap and also the intake valve opening. I'd like to talk to DynoSim about the model for your engine.
 
My bad. I think I was way off on the inlet valve opening. Playing with that the volumteric efficiencies have come back in line. The model is making more power so now having to play with intake and exhaust to get power back in line with predicted.
 
88fiero said:
My bad. I think I was way off on the inlet valve opening. Playing with that the volumteric efficiencies have come back in line. The model is making more power so now having to play with intake and exhaust to get power back in line with predicted.
Click to expand...

I actually think the Lobe Separation angle is around 102 degrees. The overlap I quoted is likely the duration @ 50 thou. The overlap at advertised would be something ridiculous like 120 degrees.

Specs are:
Lift: 10.5mm
Duration: I - 316 deg, E - 316 deg,
Full Lift: I - 102 deg ATDC, E - 102 deg BTDC
LTDC: I- 4.26mm, E - 4.14mm
Timing: 56/80 , 80/56

I have tried tweaking the advance on each to tune power in the 6500 - 9500 range, but we run into valve - piston and valve - valve contact issues if they are moved more than a few degrees.

I run a Honda Skunk2 Ultra Street intake manifold which has a fairly large plenum and 70mm throttle body. Exhaust is are large 4:1 into 3" straight pipe.

My plan now is to basically match Alex's TP Power build with a water cooled 5870 driving the P2 around the 35,000 rpm mark. I'm thinking of trying the GO-Foc300 VESC (300a sustained - 500a peak) at 50.4v (12s). I'll build dual 12S5P Molicel P42a packs and run them in parallel for 400+amp and decent run time. These packs can then be charged quickly via 25amp chargers that I already have. This should give me around 15kw sustained and it will just be a matter of keeping both the motor and VESC cool enough to run for a few minutes.

I'm pretty sure on my motor I won't be hitting surge at high RPM, but if I do, I could always run a BOV and control it to vent some boost. It's just going to need to be tested to see how it will work. You can get a Kenne Bell bypass valve that uses a throttle plate which would be perfect as it could also act as a bov.
 
I ran the above cam specs with a 70 mm TB, Honda short runner, factory volume intake and small tube headers with an open exhaust. These assumptions gave:

268 flywheel HP/ 228 WHP @ 8000 rpm and 183/155 ft-lbs @ 7500 rpm

With an LSA of 102 degrees DynoSim gives 112 degrees of overlap seat-to-seat and 60 degrees of overlap at 0.05" lift. The max VE was 116.7% @ 8000 rpm. Maximum inlet air flow was 314 acfm @ 8000 rpm. This was based on 60 'F, 500 feet of elevation, and 50% relative humidity.

The predicted power will go up if I assume Honda short runner, large volume intake and large tube headers, open exhaust but the latter assumptions seem to match your actual dyno results.

Just for grins I did run a Crower stage 3 race cam which has 280 intake duration and 272 exhaust duration and DynoSim predicted more power and torque with that cam. 295/259 HP @ 8500 and 201/171 ft-lbs @ 7500 rpm. Are you sure you are not over cammed?

Do you want me to run simulation with boost?
 
Hi, I am newish here, lurked a little bit. I am interested in using this P-2 Supercharger as an electric supercharger on a 4.5 liter engine in a 1800 kg / 3950 pound sedan. The scenarios are drag strips and time attack/ track days.

My first question is how reliable are these superchargers? I see this thread is a couple of years old so I assume the reliability is a known factor now.

The next question I have is endurance. Obviously the P-2 can be spun for the few seconds on a drag strip, but what about for a flying lap or a few. Say the supercharger is only used at 60% or higher throttle opening on a 90 second lap, maybe 60 seconds of that at full throttle. And then say 4 or 5 laps. How doable is that with batteries?

And a third question I just thought of, relating to the laps, how easy is it to adjust the compressor speed relative to the throttle position. I don't think having boost come fully on halfway around a sweeping corner in 3rd gear would be a lot of fun, it might look interesting to spectators though 😆

Cheers
 
Reliability, hard to know because their is not much working set up. I personally have reliability issues 😂 I burn 2 MGM esc and now it looks like I burned my hobbywing .. I did make some error that leads to this. Anyway it can be reliable with the right knowledge!
It is possible to run it the time you want but 2 main problem is heat and battery.
 
WB projects said:
Reliability, hard to know because their is not much working set up. I personally have reliability issues 😂 I burn 2 MGM esc and now it looks like I burned my hobbywing .. I did make some error that leads to this. Anyway it can be reliable with the right knowledge!
It is possible to run it the time you want but 2 main problem is heat and battery.
Click to expand...

Reliability of the P-2 is what I was thinking about, but given it's price I think I'll try it out anyway. Thanks for the reply 😃
 
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