comm cutting question

[jackhammer74]

after having your P2K comm cut, the very next step is to replace the brushes and springs, right guys?? So if I'm looking for high rpms, high torque or a nice compromise between rpms and torque what spring/brush combo should I go with?? Thanks :confused: :confused:

[Car_Head12]

go with the stock ones, (purple and green?) but if you ever want more RPMs just throw on a spring that is "harder" doing this will also cause more wear on the comm.

[jackhammer74]

so do I keep the old springs or get new ones also should I get the same brushes too?

[XXXER]

Reedy 767 brushes are great! If you are using this in a truck, those are the best, but if it is a buggy, and you want more RPMs, then go for Reedy 766 brushes, i forget which one they are, but they have a slot, or a cavity, either way, they will give you more RPMs.
When you put stiffer springs on, it gives you more torque, it does not make you go faster because the comm wears faster, when you put ligher springs on, it gives you more RPMs because there is less friction. You can tell if your are running too light of springs by looking at the brushes after a few runs, if they have a black powder, that means you are running too light, and the brushes are bouncing up and down on the comm, and messing up the brushes.

You do not have to replace the springs, it is only suggested, especially, if you have gotten it very hot.

[jackhammer74]

cool!! thanks guys. I knew there had to be some good people in the hobby, at the track it's like pulling teeth. I'll post my results

[jackhammer74]

cool!! thanks guys. I knew there had to be some good people in the hobby, at the track it's like pulling teeth. I'll post my results

[Car_Head12]

lemme clear this up.... the 767's are fine, but will cause extra wear on the comm. incase you are wondering the stock brushes are trinity 4499's AKA the E-brush. I prefer these ones, but whatever floats yah boat!
CH

[Car_Head12]

xxxer- im not sure but i believe its just the opposite of what you said... lighter springs=more torque heevier springs=more RPM's
someone else know?? (Griz, Steve???)

[FilthyPierre]

I think I'd have to agree with XXXER about the springs - basic physics says that a harder spring causes more pressure on the comm which means it needs more force to turn it therefore less revs. Seems to make sense to me.
Interesting about the black powder - I wondered where that was coming from. If I go with heavier springs though, my comm only lasts a few runs (literally, 2 if I'm lucky).
I've found that the Fantom F315 high-silver brushes work well for me - seeing as Fantom OEM lots of their stuff from Epic (Trinity) and Yokomo ( Reedy), the F315's are probably the same as 4499's or 767's anyway, it's certainly difficult to tell them apart just by looking....

[Grizzbob]

You got it, Pierre, harder springs improve brush to comm contact, but increase brush & comm wear, 7 also reduce rpms. Tuning a motor with brushes & springs is really a balancing act between contct/conductivity & friction, there's always some trade-off. As for Fantom 315's, i was told that they are in fact repackaged Reedy 767's, & if you look at them & feel how stiff the brush shunts are, they certainly seem the same, as well as the same on the dyno. For most stock motors, I do prefer those, though I've tried a polarized set up with Green Machine 3's & I like Niftech's brushes in the MVP..... :)

[Emaxx3]

I use Reedy 767 racing brushes in my P2K. they are serrated brushes and breakin is fast. they make great RPMs and torque. As for springs I use the Trinity ones..., I can't remember the color, I want to say purple red and green but I'll have to look when I get home. Good luck!

Happy Maxxin'!
Emaxx3

[Car_Head12]

aahhhhh... here is what I was told: heavier springs cause more wear on the comm, but also transfer more energy (current) to it, thus you would get more rpms.

[noobie]

766 brushes are full face brushes with no mods. they are just a different compound than 767s. 766s are stock in MVPs. work great in MVPs when narrowed. Integy now sells 766s already cut for MVPs, although they could be cut a little more. #3202, I think.

[Car_Head12]

http://forums.about.com/ab-rcvehicles/messages?lgnF=y&msg=7421 please read that post. You guys were right and so was I!!! Cool, this is a storybook ending... lol

[Car_Head12]

oh and its post 3700

[Car_Head12]

BTW Griz your more wrong then right... :D ;) ;) ;)

[Grizzbob]

I'm just going by my own experience, keep in mind, he can also be wrong on a few things. It's opinions, everybody's got one..... :)

[Grizzbob]

Actually, the word is he's worked for most of the motor manufacturers, & supposedly has been fired from most of them....

[Car_Head12]

HAHAHA... thats a lame reason not to trust him

[Car_Head12]

Im not trying to stir up trouble but, do you know who Big Jim is? (you prolly do) If not throughout that discussion he talks about what he does. Basically he used to work for some motor company (Orion?) and now he has started his own motor business. I trust this guy.
CH

[Grizzbob]

Believe what you want, like I said, there all opinions, he has his & I have mine. If you don't want to believe me, whatever...

[bryceanator]

actually big jim worked for epic aka trinity

[JK1]

Hey Carhead,
Maybe I don't understand what I'm reading, but Big Jim in his post you referred to seems to be saying exactly the same thing that Grizz said and the opposite of what you stated.

Big Jim says, "Usually, on the track, adding tension will give you more punch with the possibilty of less top end speed, more brush/comm wear, and a hotter running motor."

Since speed=rpm, higher tension=less rpm.

As Dennis Miller says "Just my opinion, I could be wrong"