Piranha 25K Ball Bearing Motor

[HomeRacingWorld]

[Broman62]

Nice report Harry!!! Looks like it will be a winner on the track too!! :auto-layrubber: :auto-layrubber: :auto-layrubber:
I like the new test stand design also...yep...probably...will copy that too!! :D :D

[steeveew]

It has some magnetic attraction as well.


Steve

[HomeRacingWorld]

The magnetic properties of the magnets in the can for traction are out of my wheel house. Thankfully :)

[TuscoTodd]

Appreciate the review Harry! Have a pair of them inbound for SCC to be used in "Expo" class for the Hole Shot Challenge - looking forward to giving them a run! :D

[munter]

Nice work on the test and report...so it is advertised as a 25k rpm motor but turns 27k rpm?


I have that laser tach too, does it generally read a couple of thou rpm high?

[HomeRacingWorld]

Thanks. No it is actually quite accurate. I bought 3 different tachs and have access to a calibration source at work. One tach was about 400 low and others about 200 high.

The interesting thing is the app on the phone. It literally has identical numbers.

[SuperSlab]

Thanks for this Harry. Coincidentally Dan (VTECFour) and I were talking about the motors at racing this afternoon. Neither of us knew whether the motor had ball bearings on both sides: this clarified it. Looking forward to receiving mine and running them in a car.

Good info on the cellphone tach app as well: thanks.

Alwyn

[Brumos RSR]

[Audi1]

Thanks for the report, Harry.

The 21.5k Piranha usually tachs out in my hands at 23.0+k rpms after break-in, so it's not surprising to see this motor perform above spec.

Under-promise and over-deliver; nice paradigm.

Allan

[HomeRacingWorld]

Yes, not much break in time really. I ran them for about a minute. It isn’t odd to get a “hot” one in a batch, but most times they are always over the RPM rating.

[RichD]

I have a sample of the new motor on the way for evaluation. I check the RPMs after I have run in the motor on the bench for 30 minutes at 6 volts. After the run in I flush the commutator with contact cleaner and oil the bearings before I do the RPM reading. My tachometer came from a scientific equipment supply company.
I take readings of all of my motors, since I race my cars I check them from time to time, especially if I suspect that the performance has fallen off. Most motors will read higher than their factory spec. I have measured Scalextric 18K motors as high as 23K. Most of the 21.5K Piranha motors that I have read 23K. I scratch the reading on the motor case for future reference. If the RPMs have dropped a shot of contact cleaner may restore performance or it might not. Some motors have good performance for a long time, others drop off rather quickly.

[HomeRacingWorld]

For anyone wanting to begin testing yourself, here is my advice from the skills taught to me over the years:

1. A low cost "Ebay" laser tachometer is just as accurate as a high dollar one. I have access to 2 different tachs that cost ridiculous money. The results? The same. Most are within 15 to 25 rpm. That is basically nothing when you are measuring these motors. I have tested 5 or 6 brands over the years against my calibration machine. Trust me, a $15 tach does the job.

*** I will add that one needs to read the initial post above. This new SOUND APP is just as good. I am just impressed by it's accuracy***

2. Motors go through a break-in period before delivered to dealers. The only thing you will gain by more break in run time is usually slight increases in RPM as the small brushes improve their seating against the commutator. I bench test the motors for 2 minutes at 12 volts. This is the voltage 98% of end user/enthusiasts will do, so that is how I test them.

3. An easy way to make a disc for the motor is to use plastic pinions. They are easy to press on and off, but hold tight during testing. Glue the pinion over some styrene plastic and paint it flat black. Reflective tape is easily found in the cycling area of Walmart or even in the scrapbooking section. Reflective chrome auto pinstripe is not as reliable as you would think.

4. Sometimes a "slow" motor does not have the brushes seated properly. The tabs that hold the brushes through the endbell are sometimes not mounted evenly. You can take them out on some motors, or using a needle nose pliers you can adjust them. The one shown in my test has a removable mount, so it was easily pushed out.

5. Other times the bushings on either end might not be seated well. This causes binding. Normally I have not had luck trying to seat them correctly.

6. You will soon discover that there is literally no difference between a "name brand" high dollar motor and a lower cost alternative such as the series of motors from SCC/Cloverleaf, MT Racing, etc. They are all made in the same place most instances and the only difference is the wrapper/markings on the outside.

7. Some companies DO field test motors and try to match the motors they install in their models. Yet, the variance is still 800 to 1000 RPM in my testing results.

8. Acquire a low cost, adjustable bench supply. I cannot stress how convenient it is to have a dedicated supply. I run my Tire Razor, SCC Roller Test Bench, and my motor testing all from one supply.

9. You WILL see different readings from other people testing. These motors are made in batches. The variances can sometimes be quite a lot. I have tested motors from Fly for example that had a 3000 RPM variance. This was in the same model, just different paint schemes and release dates.

10. All the data in the world doesn't amount to a hill of beans. It is ON TRACK TESTING that is the best way to find out if you like a motor.

All of us have different tastes in speed, braking, etc. All of us have different tracks. I might like a motor...you might hate it. My testing just combines some of the data, with a good road test.

I like this motor, but not as much as I like the standard Piranha. The original has proven itself in our Showdown Series over the years to be a very quick, responsive, and durable motor. We have enough speed for my smaller oval...so I won't be changing the rules.

But I am betting this new ball bearing version will reveal itself to be just as good for some of you out there looking for a new "Spec" motor.

[Kevan]

I have the same digital tacho and Giri app. I too am impressed by the app, you can use it for 'in-car' checking, it's 200 rpm down due to the drivetrain but a great way to quickly check a car without removing the motor. The background noise and gearmesh do get picked up but the app will pick out the steady sound of the motor.
I've not found any instructions for the app but if you click the Pacman icon (top left) you can rotate the open bit round that seems to let the app focus on a rev range.

[RichD]

The new Piranha motor arrived today and I tested it using my regular procedure. The motor measured 26.8K RPM, it has holes in the top and bottom of the case so if you run on conventional sectional track or on a track with Magnabraid you will get some extra downforce. My club runs strictly on wood tracks, so we don't usually check for magnetic downforce, but the motor did grab the rails of my skidpad, which is made up of Ninco track.
I have seen several reviews of the Giri app, it seems to match up very well with readings from a digital tachometer.