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Old 01-08-2012, 10:22 AM   #1
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Questions?? Studdering with 25.5

I am running an Xray T1 in VTA with the speed passion combo (cirtix esc and 25.5 motor). Every now and then the car will studder and not move. Push it forward a few inches and everything is back to normal. This only happens occasionally after tapping a wall or just starting out from a stop (again also only occasionally). Here is what I have done thus far.

1. I have checked the car and everything is free (no binding),
2. swapped out sensor wire with a new one and that seemed to help some but same problem
3. swapped out a HK 35a sensored esc and again a small improvement but still there

I'm really tempted to pick up a viper motor or another speed passion 25.5 but really don't want to keep guessing. Thus far my experience with sensored motors makes me want to stick on the sensorless bandwagon, always works and really the cogging at low speeds has been minimal in my experience....

TIA!
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Old 01-08-2012, 10:25 AM   #2
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Possibly have dirt/debris on one of the sensors. I had that happen on one of mine once.
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Old 01-08-2012, 11:02 AM   #3
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Interesting.... is this something I can clean or does it need to be sent off?

If I can do it, just use normal electronics cleaner or microfiber cloth? Thanks for the quick reply!

edit: Just looked at the motor again and its a closed bell. No screws to remove and take off an end.

Last edited by mkiiina; 01-08-2012 at 11:40 AM.
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Old 01-08-2012, 12:41 PM   #4
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It's the motor, its the only thing left it could be. Most motors you can switch the sensor board yourself, I'm sure you can with the Speed Passion motors too.
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Old 01-08-2012, 01:00 PM   #5
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Was afraid of that. Just as a last ditch effor I yanked the sensor wire on both the motor and esc and ran it around some. Same problem (just worse actually). Anyone running the Novak, Viper, or Epic with the Hobbyking 35a esc?
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Old 01-08-2012, 01:54 PM   #6
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I have no problems with the Novak Ballistic 25.5 and Cirtix. FYI, The Cirtix is not a Hobbywing product, SpeedPassion contracts that model through another mfg. in China.
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Old 01-08-2012, 02:28 PM   #7
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We use the SP 17.5 motors and ESCs in our mini racing series. They are sensorless motors but we were having the exact same issues on a grand scale, because everyone was using them.

The problem admitted by Speed Passion was the connectors that are between the Motor and the ESC. Everyone was told to direct solder the wires together and I don't think I have seen an issue since. So if you have the same connectors in between, I would suggest you direct wire the motor to the ESC. I always Assumed a sensored motor would not have the same issues but its worth a shot in your case.
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Old 01-08-2012, 02:54 PM   #8
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This very much sounds like a sensor problem, either the board, cable or the connector in the esc. Try a different motor since you tried the cable. Also check for any shorts between the wires from the esc to the motor, focus on the solder tabs at the motor or if the esc has solder posts at them. Any arcing at those locations will give you similar symptons.
By the way a 35a esc is pretty small for a 25.5/540 motor. I would recommend at least a 60a and best a 120a.
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Old 01-08-2012, 02:58 PM   #9
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i will add one more thing. I believe that the Citrix esc has a similar setup to Hobbywing. If so try lowering the punch control. On a Hobbywing it is called DRRS. Reducing the number is in a sense limiting the max current and it softens the initial launch. A low c rating on a battery is another good reason to adjust that setting downward to avoid stuttering.
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Old 01-08-2012, 03:14 PM   #10
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Quote:
Originally Posted by JonesyCGY View Post
We use the SP 17.5 motors and ESCs in our mini racing series. They are sensorless motors but we were having the exact same issues on a grand scale, because everyone was using them.

The problem admitted by Speed Passion was the connectors that are between the Motor and the ESC. Everyone was told to direct solder the wires together and I don't think I have seen an issue since. So if you have the same connectors in between, I would suggest you direct wire the motor to the ESC. I always Assumed a sensored motor would not have the same issues but its worth a shot in your case.
I do have 4mm bullets installed. I'll swap over to direct connections and see what happens.

I'm running 40c batteries so I should have enough current on tap.
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Old 01-08-2012, 03:47 PM   #11
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Check your wires from the ESC to the Rx... i had some issues there.
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Old 01-09-2012, 02:09 AM   #12
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This has been covered often in the Speedpassion thread.......change the sensor board, they are quite delicate and known for this exact problem. While you are at it, try one of the new 'added timing' sensors, they are much more robust in their design and add more power, of course you'll have to regear to take advantage of the increased rpms.

IF the motor has sp adjustable end bell.....

Good Luck
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Old 01-09-2012, 08:20 AM   #13
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Just a curious question. Why are you fighting this speed passion motor so much? Before you start spending more money to fix a motor that is not vta legal just get the Novak. You can find good condition used motors here or on eBay for $40.
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Old 01-09-2012, 01:28 PM   #14
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For our club level races anything that is 25.5 stamped is legal (Viper, Epic/Trinity, Speed Passion, Novak)

I have intentionally avoided Novak as I have had poor customer service from them in the past (nothing but great things from epic!).

I was going to try and swap out the board but its a locked rear bell (3 little tabs folded over) so I cannot really service it or change the physical timing.

Last night I bit the bullet and purchased a new Viper motor from A-Main and well see how that works. Pros are it is a serviceable motor and has (imho) a better sensor port mounting (similiar to Novak's) where a side hit wont make contact.

Hopefully this will fix my woes, thanks to everyone who chimed in. I plan on hooking the SP motor to my tekin RS in the next few days and checking it with the LED's to verify.

Anyone know if SP services these motors if you send it in? Time to call china...
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Old 01-09-2012, 01:32 PM   #15
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CHECK AXLE CVDS! i learned my lesson on this(look for filings from pin moving out) my car would stutter.....and or ON throttle would drive to the right...(like steering is off)
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