I'm sure with a lot more power, it would NEED 4WD. If I go BL, I might just get a Medusa 36-50 or similar. There was quite a bit weight removed; just the diffs and top shaft alone were quite heavy. But the biggest savings was drag removed. Put it this way, with 4WD, I almost didn't need to apply the brake at all. With 2WD, the XL5/Titan doesn't have enough braking force at max.

Stock body. Call me easily amused, but I rather like the way the stock 4-tec body looks.

I kind of like it too, but prefer the old 2.5 body a bit more. Looked more exotic.

Wow this is a pretty darn cool build!

Update:

Speed on 2s is pretty poor outside. Maybe 20mph with a tailwind. So, I then tried the XL-5 on 3s lipo. Much better. Seems to handle it ok, but didn't want to take chances, so I put my spare MM/UBEC and configured it to brushed mode. Even with the MM brake force at 100%, it hardly works. Actually, I can hardly see any difference between full brakes and just letting it coast to a stop. Can the Titan motor really be that bad? I disconnected the motor and spun it by hand with the wires touching and then not touching. Almost no brake effect.

Looks like I'm gonna get a motor sooner than I thought! Probably will settle for a Medusa 36-50-3300 or 36-60-3100 on 3s.

Yes, the titan 12T's are that bad.

Small, hard, enclosed brushes = NO brakes. No matter what controller you use.

EDIT -

On a second look, are the .3uf caps soldered onto the motor? No brushed motor will brake well without them.

Must be that specific motor, all of my 12t motors brake fine. The 12t setup in the blackfoot will stand on its nose with full brakes.

KMN: Yeah, the caps are on there. One from + to the can, and one from the - to the can. Nothing between the two terminals though, but it came that way from Trx.

Linc: Do you have a Titan 550 12T? Maybe other 12T motors are different, but the Titan does not brake well at all. Then again, maybe the motor is on it's way out anyway since I was running 10 cells on it in the Slash for a while.

I have a few of the traxxas 12t titans, all work fine for me... I think you have a bad one...

Well, I'm not gonna go buy another throw away Titan motor when I can get a Medusa. Until then, curbs/people/trees/cars are gonna have to serve as my braking method.

Sounds like the problem, she's on her way out. Brushes provide all of the braking force in a brushed motor. When they start to wear out, the brakes go first, and after a while they go into "kick start" mode. You'll have to give it a nudge to get it going.

Being labeled as a "12T" motor, and having no experience other than seeing a few peoples problems with them... They're pretty cheap stockers. All of the closed endbell motors that I have run in the past have eventually had the "no brakes" problem though.

Kinda figured. I really didn't care about abusing it since it's a crappy motor anyway.

But, even when brand new in the Slash, brakes were always piss poor. So, either the motor was not perfect from the start, I broke it in wrong, the XL-5 ESC brakes suck, or I'm just used to BL braking...

Option E all of the above... :)

Ok, I'm shopping around for a motor for this setup. I have no more than 67mm mounting length to work with and I'll be running 3s.

I was gonna go with a Medusa 36-60-3100 (SE version), or a Medusa 36-50-3300 (regular or SE version), but I'm also eyeballing the VXL motor. I really like the solder tabs and cover, it's between a 50mm and 60mm motor (55mm), and it's slotless. For this project, I don't need the torque of a slotted stator style, so this might work out the best.

How do these compare to a similar Medusa temp-wise?

Well, the vxl motor is just a feigao s can motor. So based on experience with those it should be ok, I would still go with a 50mm medusa. But that is just me. I have had good success with the 15l in my 4 tec, temps are great on 5s. Even geared for 60mph. For some reason tires will not stay on the car though...:lol:

A hacker b50 s can would be a better choice over the vxl motor. But the vxl motors are cheap, and many people can get emaxx's to do 140mph with them on 1s lipo, or something like that...

lol, 140mph on 1s in a maxx, eh? Did they mention this was falling off a cliff?

After I posted this, I did some more research and it appears that the VXL is indeed an S motor; the 10s to be exact. Same turn count/kv, and is slotless 2 pole. Yup, a Feigao all right. Hmm, too bad too. I really like the solder tabs; would've made hookup much cleaner. Might contact Mike to see if he has just the motors. 3s 3300mAh lipos won't last a really long time and I'm not shooting for stupid speeds, so temps should be ok. I dunno. Why does Medusa have to have those stiff exit wires? Probably to make my life difficult... :no: :smile:

And a Hacker is more than I want to spend for this project TBH, unless you can get one is really good condition (prefereably new) for ~$70-90.

Yep, hard to find a hacker like that, You could also look into the feigao 380c L can motors, or a novak hv, like a 6.5. That is a nice motor, maybe too long for your setup, but would work great for 3s in that beast, and has solder tabs... 2 pole as well.

If I'm gonna go Feigao, I might as well just get the VXL motor. The Novak HV is too long (72.1mm and I have no more than 67mm) and pricey for what it is IMO.

This isn't a really "serious" setup, so I hesitate to spend a ton of cash on it. Most of it was put together from extra stuff I had laying around and a couple custom parts.

The vxl motor will be fine, but how much can you get one for? Better be cheap, like 30-40 bucks, new.

Don't know yet. Ebay has them for $59, but I might give Mike a call and see if he offers them seperate from the ESC.

60 bucks is a bit steep, IMO. Just a feigao motor. See what Mike can do!

I'd take a castle over feigao. get the 4600 castle?:neutral:

Ugg. The 4600 is an "ok" motor, but is really smaller than a true "S" size motor because of the space taken up by the coil wire to noodle wire connections. If CC had a series of motors that were 60mm long, that would work I think; the kv and can size (torque) would be a better match for this setup. Besides, this is geared kinda high and I'll need the extra torque that a slightly longer motor will provide to get going; either that or go with a slotted stator type in a shorter can.

My buddy has been torturing his 7700 in his rustler with 3s 20c 5000mah zippys. Burnt up two sidewinders, numerous drivetrain issues, but that motor keeps taking it. Your right about the smaller size. I just can't see an "s" feigao over a castle. an l or xl, sure, but I'd put the cc motor over the s feigao anyday.

Well, it's done!

I ended up ditching the front drive and totally re-doing the layout. This allowed for much better weight balance - now the center is only about 5mm off center! Aside from the batteries, all the other components are as far right as I could make them.

Total parts list and other points of interest (taken from my BL Conversions page because I'm lazy):

• Spektrum DX3r Radio
  
  
• Mamba Max ESC with the BEC disabled
  
  
• Dimension Engineering ParkBEC
  
  
• Medusa 36-50-3300 motor with added heatsinks
  
  
• Elite 3s 30C 3300mAh lipo battery
  
  
• Geared 45T spur, 15T to 26T pinion depending on desired speed
  
  
• Modified the chassis around the spur gear to allow easier gear changes
  
  
• Custom 6061-T6 aluminum motor mount
  
  
• Custom 6061-T6 aluminum top plate
  
  
• Custom 6061-T6 aluminum battery tray with lexan shield for the bottom of the battery
  
  
• Custom 1.5mm thick aluminum shield under the rear differential to protect against rocks
  
  
• Servo mounts from an Xray XT8 to mount the steering servo
  
  
• Front toe links from an Xray XT8 for the steering linkage
  
  
• Rear wing stay from a Mugen MBX5r for one of the top plate standoffs, the rest are custom cut 6061-T6 aluminum tubes
  
  
• Turnbuckle from the Traxxas Jato for a chassis brace
  
  
• Converted to 2WD to allow better placement and balance.
  
  
• Upgraded to Traxxas steel outdrives
  
  
• Upgraged to Traxxas aluminum rear axle carriers
  
  
• Moved steering assembly to the other side for more even balance
  
  
• Moved rear shock mounts to the same bolt as the body mount to allow for more ground clearance.
  
  
• Removed first gear and modified the two speed hub to be locked into second gear to enable motor braking and reverse

Anyway, here are the pics:

http://scriptasylum.com/bl_conversio...ges/4tec_1.jpg

http://scriptasylum.com/bl_conversio...ges/4tec_2.jpg

http://scriptasylum.com/bl_conversio...ges/4tec_3.jpg

http://scriptasylum.com/bl_conversio...ges/4tec_4.jpg

http://scriptasylum.com/bl_conversio...ges/4tec_5.jpg

http://scriptasylum.com/bl_conversio...ges/4tec_6.jpg

This last one just showing the weight balance. I don't have a scale, so a thin piece of wood will have to suffice. :smile:

http://scriptasylum.com/bl_conversio...ges/4tec_7.jpg

Any runs with the BL yet? I'm curious how the 2wd will handle the power... Looks great tho!!

I just finished it tonight so no runs except for in my basement. Even with 100% punch control, it lights up the tires easily. Donuts are easy. Not sure how it does at high speed yet; if it's nice tomorrow when I get out of work, I may take it for a spin and get a small video.

Before I got the Medusa motor in, I threw in a spare CC 5700 motor I had laying around. It worked fine, but not as smooth as the Medusa and it heated up pretty quickly even geared as low as I could (45/14). The Medusa is geared 45/15 and never got even luke warm.

I ran it for a while today. As expected, the back end is a little squirrely. Did some high speed runs and without a GPS or radar gun, it's hard to tell the exact top speed, but it's close if not over the calculated value. The 3s lipo retained over 3.7v/cell for around 3-4 minutes, so that helped. To get the thing under control, I did some burnouts/donuts/drifting to heat the tires up. Worked too; got them up to 127*F. After that, traction was a TON better and had much better control. The road in front of my house has a crown (uneven at that), not to mention a manhole cover, so getting it to steer perfectly straight was impossible. Still pretty fun though. :smile:

Temps were good: barely over ambient (65*F) for the batteries, 108*F for the motor, and 113*F for the ESC. Not bad for extended speed runs. Those clip-on motor heatsinks had partially came off and had a ton of sand/grit between them and the motor; so they were actually insulating the motor rather than cooling it. I bet the temps would be better if they were actually mounted right. I'm gonna tack them on with some thermal adhesive to keep them in place, yet not so much that I can't take them off if I want.

The 3s 3300mAh 30C elite batteries help up great. Like I said, they held higher voltage for quite a while. I'm not running the LVC since I use 6 NiMH cells or 3s lipo depending on if I'm in the house or outside. When I noticed a drop in power/speed, I stopped. Two minutes after stopping, the voltage was 3.32v/cell. A little lower than I like to run, but I'm sure they would drift back up more to a more acceptable ~3.5v/cell after 15-20 minutes unloaded.

Runtime was a hair under 25 minutes, which puts average current draw at ~8A. Given this is 2WD, low vehicle weight, and limited traction, I can't see this setup drawing more than 50A bursts.

Putting them on the charger, they only took in ~400mAh before they reached 3.8v/cell. The voltage was pretty steady after than until the last 600mAh as they rose to CC/CV threshold. Seems these are decent cells. Probably not good for 1/8 scale, but perfect for 1/10 2WD applications.

Anyone know where I can get wider tires for this thing (rubber, not foam)? I have some foams that it came with, and they are a good 5mm wider, but are wearing out fast. They work quite well though. Something with about the same wear rating as the stock trx slicks would be fine, just wider for a little better grip.

if it takes 12mm hex, you can get the HPI 26mm rims and rubber, just check out tower, or amain, or stormer.
http://www3.towerhobbies.com/cgi-bin...&I=LXM981&P=SM

Nice clean layout Brian

Looks great Brian.

Thanks guys.

mjd: I saw those but wasn't sure they'd be "solid" enough. I think I saw those at my LHS and they felt too "squishy" and would balloon badly, especially given the extra width. The foams in the stock tire is denser (or maybe the rubber is thicker), so they don't balloon as badly. For the price they want for tires, you'd think there would be more to it than simply molded rubber.

I have been using these on a tamiya F201 car and my 4-tec. They work well, the great thing is they use 12mm hexes

fronts 30mm foams
rears 40mm foams.



made by Kawahara - great name in tires.

I have only ordered them from Hong Kong, but Mugen is the distributor in the US.

They come in many shores 35, 37, 40, 42.

Egr mart in Hong Kong is where i have ordered from

http://www.egrracing.com/shop/sponge...9_196_194.html

Kawahara website description

http://kawahara-racing.co.jp/Ekawa.html

Enjoy

Cool! Thanks.

How about these ones...

BSR

I believe they custom make for speed runs also

Hmm, I took a closer look at both those links, and the tires with the width I like are foam. I'll be doing more bashing in the street and paring lots than anything (not racing on carpet or high speed runs on a prepared surface) and would prefer something with a little more wear to them. I'm not sure what type of foams I had, but they wore down quite fast on the street. Great traction, but didn't last long.

On a related note, I was looking at that John's BSR site and am curious what "caps" are? http://johnsbsrracing.com/cap/index.htm

I prefer Jaco over Kawahara and all the other tires.

What I run on my MTX4R (nitro on road TC) There super dialed! And they look pretty sick also!

Jaco foams are very nice. Ive had two sets. One for my ext and another for my raven bx. Both lasted a very long time and really lightened up both vehicles. The tires way almost nothing.

I'm not exactly sure, Nic Case & others doing 100mph+ speed runs use BSR almost exclusively...might have to send an email & ask?