mbx5t conversion questions
 

hey there guys
i have just taken delivery a mbx5t chassis that i am starting a brushless conversion with.i plan to use a mmm v3 2200kv motor esc combo on 4s 5000mnh lipos with rcmonster mounts. what size/type of pinions should i use.i dont want super huge speeds,more looking for decent run times.

First, welcome to RCM! On my mbx-5T I run a 15 pinion w/the same motor esc combo you have and so far so good as far as temps go. I am running my set up on 5s though....I will post a pic in a few mins...

wow,that was fast:lol: i have been looking thru the forums on here while i waited for my membershipto be activated.there is alot of directly relevant info on here which has been really helpful.from what i read the mmm system sounds pretty good.i am sure the tekin etc systems are good to. i come from a touring car(1/10) back ground but go sick of the rulebook stiffies ruining the fun so have decided to go 1/8th offroad for a some fun.does the rcmonster mounts bolt straight in or is there some drilling involved? can i re-use the reciever box i just pulled out of my chassis? it looks like it would keep the reciver etc dry and dustfree.

here are a couple of pics. of my conversion. Yes, the RCM mount bolts right on...no mods. Many of use put our rx in balloons as I did...simple, yet effective. What I did was use a piece of the stock carbon fiber mount...cut it and put spacers under it to allow clearance on top of the new servo mount for my cable ties

http://i271.photobucket.com/albums/j...e/DSC02943.jpg

http://i271.photobucket.com/albums/j...e/DSC02945.jpg

http://i271.photobucket.com/albums/j...e/DSC02944.jpg

http://i271.photobucket.com/albums/j...e/DSC02947.jpg

that looks nice and tidy. i was wondering where to place the esc. have seen some pictires of esc on top of the center diff which i thought might be a bit top heavy. your placement makes it look clean. are deans plugs ok for 4s 5000s? the batterys i am looking at (http://www.hobbycity.com/hobbycity/s...idProduct=9179) have plugs i have never seen before so was planning on swapping them for deans

if u get a 5s pack and gear down u would have a cooler running system, more on demand torque and extended run times, u will have a bit more weight but make up for it in power, alot of people here are running 5s in their truggys with good results

As far as batts. go I would go for the 30c version of the ones you were looking at...I am running the 5s 30c version and love them and you can't beat the price. The mount I used is this one..http://www3.towerhobbies.com/cgi-bin...?&I=LXVEC2&P=7. I actually bought the mount for another project, but never used it and remembered I had it and it worked great for this truggy. just need to drill 3 holes and you are done.

Deans are widely used and work great.

Here is a pic. of the esc mount...not the best pic..but it does allow air flow below the esc. You can see the 3 screws you would need to drill

http://i271.photobucket.com/albums/j...e/DSC02946.jpg

to gear it down do i change pinion and spur or just one of them?

what is 'normal' operating temperature range for mmm? i should definatly look into a temp gun as well aye:yes:

pinion is all you need to change. Run it with say a 15 t to start and constantly check temps...and then adjust gearing accordingly...in case you haven't see this...this is a great guide


Although not always true, a rule of thumb is:
Hot motor, cool controller, cool batteries = undergeared
Cool motor, hot controller, hot batteries = overgeared
Warm motor, warm controller, warm batteries = happy components

Hot, warm, and cool vary as well, so here's another general rule:
Hot for a motor = generally over 160F (71C)
Hot for a controller = generally over 150F (66C)(or "thermal" range for the controller)
Hot for batteries = generally over 150F (66C) for nimh, 130F (54C) for lipo
Warm for a motor = generally 100F (38C) through 150F (66C)
Warm for a controller = generally 100F (38C) through 130F (54C)
Warm for batteries = generally 100F (38C) through 130F (54C) for nimh, ambient temp through 120F (49C) for lipo
Cool for all components = generally ambient temp and up to 10 degrees F (5.6C) more

are you running a 15t on the factory spur gear that runs in a nitro mbx5t?

Yes I am...I haven't been able to test a full batt. though...only 10-12 mins on 3 different occasions, but, the temps were v/good after 12 mins. Of course, I am only using 80% of my throttle...any more and it is just stupid fast

i read people mention the metal pinions/spurs are very noisey? do you find this to be the case. i would imagine these things would chew thru plastic spurs pretty fast.

It is a little noisy, but, the way I look at it is I don't have change spur gears! I have never chewed up a stock 1/8 spur gear yet....so I am sticking w/what works.