Bl D8 setup huge dilemma

[wallot]

I have Tekno V4 on the way and can't decide on ESC Motor setup.

I plan to run on 4S (racing rules), mechanical brakes, RX Lipo Pack (I use HV servos and if I end up with small ESC I want to offload it as much as possible)
It needs to handle 10+minute race heats without having to worry about overheating.

ESC candidates:
RX8 - Had to repair one of my old RX8 (some thing fell of the board, but resoldering it back fixed it) but otherwise it has always been rock solid, however I sold all my old RX8s

MMpro - I like the fact the ESC is quite small and should handle 4S in a buggy with mechanical Brakes and RX pack

MMM - it is too big and heavy but it looks like V3 is solid

Ezrun SC8 - have not heard much about this ESC

Motor candidates - I want to run traction drive or clutch (i am not going to hack the car to make slipperential fit) and I have ton of 16t and 17t clutchbells so I need motor that will work with 48/16-17 gearing with 36+MPH speed based on the calculator

Castle 2650 - I am not sure about this motor as my old 1518 in truggy was quite hot so I am worried about heat. Same probably goes for 2200kv motor

Tekin buggy 2650 or Truggy 2250- After so many rotor failures in truggy motor I am not sure I want to risk another tekin motor

Xerun 4165 (2250kv) - Looks like a solid motor but have not seen many references

I like MMP + Xerun combo the most as it is the lightest and should handle buggy racing but need some confirmation

[slimthelineman]

The cc 2200 on 4s is wicked fast and runs cool(130-160) in our rc8's all day long at around 7.75 lbs geared 15-17/46 with an internal of 4.3. No probs with heat just a touch heavy is all. I switched to a neu 1512 2.5d 2050 on 4s and it's alot lighter and runs about the same temp wise after a ten minut run. I gear mine 17-20/46. I would say use the mmpro without the rx pack and just up the bec voltage. I never have probs with my mmpros becs when your above 7.4. I only say use the smaller 1512 anD the pro without a rx pack cause it sounds like wieght is a concern. On that note why ad the extra rotating mass of a clutch system?

[simplechamp]

Yeah I don't see the point of using an RX pack in a 1/8 electric when you already have a 4-6S voltage source on board. An external BEC will be smaller, lighter, won't have to worry about charging it and monitoring it, and it will provide a constant voltage of whatever you set it at.

[Overdriven]

Slipperential doesn't require "hacking up" your car either. It fits in between the center diff mounts just like any other center diff.

A lighter alternative to using an Rx pack is an external BEC. Castle's BEC's have programmable output voltage also.

I haven't run the 2650, but I never had much issue with my 2200. Except in my revo geared high with tires that were really heavy and way out of balance because of all the sand in them. The 1518 is an awesome motor, have it in my buggy now geared for over 50mph and it stays stone cold.

[wallot]

slipperential does not fit my D8 as it is too short . I tried it :) and it requires hacking the top diff brace.

why clutch? to get some drive train protection. slipperential is also 40grams heavier than standard center diff.

so you think that MMpro bec set to 7.2V can handle two high power servos?

[Overdriven]

Check out castles site for the specs on the BEC, but even high torque servos have amp spikes under 1amp so the regular cc BEC will be fine and it's smaller and lighter than the pro.

[slimthelineman]

I've never ran a clutch in my rc8 for the last three years and have not worn out or broken anything in the driveline on 6s. Save some weight and use motor brakes and no clutch. Will save rotating mass and close to 100 grams for the mech brakes. The mmpro should run one servo fine on 4s. Most of the issues with that were on 7.4. Just thinking out loud. 20 minutes on a four cell setup will be close no matter what motor you run. The 2200 is super fast but power hungry. The 2050 I use is a little softer and smoother with less amp draw.

[simplechamp]

Originally Posted by wallot

slipperential does not fit my D8 as it is too short . I tried it :) and it requires hacking the top diff brace.

why clutch? to get some drive train protection. slipperential is also 40grams heavier than standard center diff.

so you think that MMpro bec set to 7.2V can handle two high power servos?

Use an external BEC like the CC BEC. The MMP BEC can only go up to 7V, and tends to have trouble with amp-hungry high torque servos.

How many grams of rotating mass will a clutch system add?

Couldn't you raise up the center diff top plate with some spacers/washers to make room for the Slipperential?

[bigbadtaz]

i run the hobbywing 2250 on my converted ofna dm-1 on 4s and in drag racing i had i clocked at 57 mp and i love it does not over heat and i have plenty of room to go up on the pinon i run a 25 tooth a will try a 27 tooth when i weather gets better here

[wallot]

sure i can raise the top plate but the slipperential is very hard to ship as it is too short compared to standard d8 diff

i wont add as much weight as slipperential and i wanna try it. used slipperential for two seasons in my old mugens.

Of course I will try all the options with/without mechanical brakes, direct drive, clutch, traktion drive.

[simplechamp]

OK just definitely get the CC external BEC instead of the RX pack!

[wallot]

looks like I will go for RX8 + CC bec as it is 5g lighter than MMpro at least based on specs.

[simplechamp]

Really the RX8 is lighter than the MMP? I wonder if it's because the MMP has wires attached, which add to the weight, but the RX8 doesn't? With wires, the RX8 might be heavier. Might want to check.