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View Full Version : Hottest motor I can run on stock mr02 asf board.


Nsxtat
2017.01.01, 08:50 AM
As title States, what is the hottest motor in a stock asf board? Pn racing's website says a 50t, but not sure if that is on a AM board with only 2 FETs or a asf board with 4 FETs? Thanks

byebye
2017.01.01, 11:03 AM
I would be comfortable running a 50t on stock 2x2 3010 FETs...

Kris

Nsxtat
2017.01.01, 12:28 PM
So a 43t would be pushing it right?

byebye
2017.01.01, 08:33 PM
So a 43t would be pushing it right?

Yeah. I would go with lowering gearing in both cases as well.

Kris

EMU
2017.01.01, 10:04 PM
What conditions are you running on? Size of track, grip level, driver experience?

I have driven just about every motor with stock fets on MR02. I only fried my fets once, when it was 98 degrees ambient temp, with an Anima2 motor.

These fets are pretty robust compared to how they were on AM due to the additional layer on the bottom of the PCB. I would be perfectly comfortable running a 43t motor on an ASF MR02. Once you get below 40, you really have to start being careful with conditions, and gearing. I would advise staying above 40t with stock fets unless you want to risk it.

I personally prefer the linearity and throttle control of the stock fets compared to upgraded fets, and is one reason why I would run non modified boards for modified class... but would use modified boards for stock, where you need every little bit of power and dont need as much throttle control.

The Atomic ASF motor is 38t, and is the lowest turn motor that they recommend for a stock ASF pcb. So, anything above that should be safe with relaxed gearing. That would be equivalent to around a 35t in PN brushed motors (Atomic armatures are slightly smaller, so there are more winds with the same length of wire).

If you are looking for a good consistent motor for racing, the Atomic 48t Stock BB has been one of my favorites, and I have raced it in mod races for smaller or more technical layouts where i wanted good punch out of the corner, but didnt need as much top end.

Typically, the lowest wind motors have more torque later in the RPM but may lack a little in the lower RPM range. While the higher wind motors have it a little earlier in the RPM and have a lower RPM. A lower turn motor may not necessarily be faster on the track dependant on layout and conditions.

Gearing may also be a concern. Low wind motors need a shorter ratio, while higher wind motors need a taller ratio. Typically, anything lower than 35t, you will always use a 9t 64t pinion. PN 39t, a 10t or even 11t can be used depending on layout. 43t, 11 or 12t.... Speed wise, they can all be similar. It really depends on where you need the acceleration. Coming out of slow corners, or out of fast corners... and how much drag brake you want. Cars with more mass, I prefer 43/39t. Less mass, 35/33t.

TLDR: 38t would be the minimum recommended wind for a motor. But, in cool conditions with low gearing, a 33t PN or 35t Atomic can be used (9/53). I would not try anything less than a PN 33t with stock fets, so definitely would be my hard cut off.

Nsxtat
2017.01.02, 07:35 AM
I plan on running 4.8:1 ratio which is 53t spur and 11t pinion on a 43t motor. This is going on a mr02 and I want it to be as fast as my mr03 ve LM with a pn 5500kv motor running a 4.8:1 ratio.

Conditions are indoor carpet in a very tight course. Straight away are around 22-24 feet the the track is only 6-8 feet wide. Track config gets changed every month but they average around 10-12 corners. Due to setup and being completely reliant on tires we never use the brakes even at the end of the long straight after hitting top speed, but we coast or half throttle through the infield corners.

I also run them 30-40 minutes at a time during practice.

EMU
2017.01.02, 03:56 PM
On a track that size, I would think that a 48t or 43t would be ideal. Faster motors won't have the distance to open up, and since the majority of corners are low speed, you want better low end torque than high end.

I would start with a 10t pinion first, and see how it feels. Ideally you want to hit top speed midway down the straight. Any later, and you still be accelerating into the brake zone. The shorter gearing will also increase runtime, and reduce temps.

It will also increase drag brake, allowing more control through the corners. Drag brake is one of the reasons that I prefer brushed motors over brushless with 2wd. Also, they don't cog out of slow corners or from a stand still.

If you adjust the neutral zone of throttle on the ics to wide, you can control the drag brake a little more with your throttle trim. Trim forward for more roll, trim back for more brake.

Nsxtat
2017.01.02, 05:53 PM
Thanks for the tip, I just ordered the 43T motor, and I was considering running a 10t pinion just to be on the safe side since I am running on carpet. Since you told me that there could be a speed advantage by doing shorter gears, I will definitely be doing that. I will want more roll off the throttle because I don't want to lose momentum while taking the slower turns. So if the drag brake is too much I will use the ICS to make neutral wider vs reducing virtual inertia.

Also EMU I see that you are from NYC, is there any other places around here other than bruckner hobbies that runs mini Z's? I am still 1-1.5 second per lap off pace from the A main guys with my brushless, so I would be annihilated by the guys at maj if they are fast as they claim to be. The problem is the setup is sooo different at bruckner vs running on rcp. I would probably traction roll if I use my current setup on any other surface other than carpet, but I do want to try a more larger, and open track.

EMU
2017.01.02, 07:06 PM
There is maj, and Cruizin with rc's in Waldwick new jersey. All of the other tracks have seemed to dry up over time. Think Brooklyn hobbies may still be running as well.

Majs is fast, but don't let that deter you. They are all helpful and share setup advice and will help you improve.

Cruizin is a table top rcp track now, and should be similar setup besides tires compared to your carpet track. Best thing to do would be to call the track and find out when you can run.

One of the most important things to focus on is average lap per race, not fastest lap. That is where you see the true pace. Consistency will pay dividends as you increase speed. It's no good to make the car faster if you stuff it into the wall more.

I personally disable virtual inertia. I can't stand it with a passion! Everyone that I have raced with disabled it. I feel that it gives a burst of throttle as you let off the throttle, which is something that I don't like. With it disabled, you can increase the roll with a little throttle trim, just test the brake/reverse as you adjust. Too far forward and you will not be able to engage reverse.

I haven't been racing the last couple of years. Haven't been able to fit it into my schedule. Want to get back to a track though.... Hopefully soon.

Edit: what tires do you guys use?

Carpet eats up speed, and slows the car down more than rcp does, which is why you probably prefer low drag brake. On carpet you have to push through the pile of the carpet, where rcp you ride the surface. The extra low end torque on the 43t should definitely perform better than a 50t, and would be muy motor of choice for the size track and surface that you race on. I think you made a good choice.

Nsxtat
2017.01.02, 07:40 PM
we run kyosho super soft in the rears, and 20 degree's in the front. They also run ks compound but I have no idea on the hardness. They also rub their tires with wd40 to add even more gripe. I only started doing this last week because I saw it as cheating, but everybody does it.

They also run the pn2.5 chassis, and almost all run pn double a arm front, they run a rear damper disc setup with only the bottom plate. I tried it and I honestly didn't feel much of a difference so I put it back on so it wouldn't so weird. They also run crazy powerful brushless motors such as 7500-9500kv motors but with the throttle turns down obviously.

I wanted to keep the mr02 as a stock motor car, but I never go out there to race. I only do practice because my schedule won't allow for it, but no body there races stock . I can semi keep up with my brushless car ( as in i get lapped every 5-6 laps ) vs every 3 laps with my mr02 so I just said screw it and build it up faster. Now with me using the wd40 and actually adding camber to the front of my brushless hopefully I can come within less than a second.

EMU
2017.01.02, 08:29 PM
once one person starts doping tires, everyone has to... On carpet with Kyosho tire, you're not going to find enough grip without it of others are doing it. The problem is that it wears off after 5 minutes or so... So traction starts going down at the end of a stint. It also makes the racing line slick if you aren't doping as well.

That setup sounds like a Roland based setup. Allows for a very aggressive front end, with enough rear droop to keep the rear end behind the front end at corner entry.

Nsxtat
2017.01.02, 09:00 PM
yeah Roland is one of the regulars there. I haven't seen him in a while though. I can only manage to go out there once every 2 weeks if I am lucky. If time is an issue EMU the track is permanently there. So it is available to anyone as long as the store is open. There is also no fee to practice, and they open 7 days a week.