Successful buggy conversion!
 

GlassDoctor is da man. After reading some of his posts about his brushless 1/8 scale vehicles, I was inspired to convert my MBX-5 to brushless. I read everything I could on RcMonster and went with the setup recommended by GlassDoctor. Let me tell you, that setup was dead on. The buggy performed above and beyond my expectations and I couldn't be happier with it. I went with a Neu 1512/2.5d motor, Mamba Max ESC, UBEC, dual 2s6000 MaxAmps Lipos in series and a 14/46 gear ratio. Mike made up a custom motor/diff mount that was a work of art and allowed me to run the Kyosho 46 tooth spur. Thanks Mike, GlassDoctor and everyone else on RcMonster that helped me out.

Impressive!!!!
I want a 1/8 buggy, too.

what thickness aluminum are you using for that mount

That is nice.
It looks about 8mm or 5/16 thick for motor mount.
How the test run go?

Welcome to the forum bmmermazda.

It's 8mm aluminum.

The test run was incredible. I wanted the buggy strictly for racing and the 14/46 ratio was perfect. I can't imagine what this thing will do a 16 tooth pinion. After a 15-20 minute run the motor and ESC were at about 160*. The ESC was very smooth. I had a little cogging from a standstill, but I found that if I eased into the throttle the cogging wasn't a problem. Braking was very smooth too with the Mamba Max. I was a little concerned with the batteries being so far rearward, but after a little chassis tuning that car felt great.

Cool.... glad you like the setup. It's worked awesome for me...

I think it's a killler racer's setup. The 14/46 is a nice starting point.. that's what I was running. But if you really want to see some jaws drop, slap in a 16 or 18T pinion. :) :) It really comes to life then hee hee

That motor mount looks serious! Pretty nice...


Now we just need to get CC to fix the bit of cogging off the line and it's all good.

Wow I am thoroughly impressed. That thing looks VERY good...almost factory...

How hot did your MaxAmps batts get on your test run?

I forgot to check the battery temps. I'll run it again Friday and check that out.

that thing is nice! hope you're racing next sat. i can't wait to see the look on everyones faces when the race is over. i'm finally going to race my g2r, so we'll just have a brushless party! lol!!!!

...i thought that if you put your throttle EPA into a negative number on your propo that it would cure, or at least improve the cogging off the line...It wont BURST off the line but its better than sitting there choking on itself...

...This MIGHT be a silly question but the in the closeup of the motor pic it looks like the ESC doesnt have a case on? You took it off? the thought had crossed my mind but the pros and cons of doing this? I was worried about getting goo in it...Thats not an issue?

Your buggy looks AWSOME :027: . How did you get the kyosho 46t plastic spur to fit ?. I was told it would not fit the mugen center diff.

That is the UBEC with the white heat shrink. The ESC has the green cooling fins on it.

...yeah but what about the black case on the bottom of the ESC? I cant see it...Is it on a lower level? Gone altogether?

You're right, the Mugen diff won't work with the Kyosho spur.
Mike made a custom diff mount that uses the Hot Bodies center diff.
It works great and mounts in the original diff mounting holes, so the chassis didn't need to be altered at all.

How much does the whole setup weight ?

Thx !

Looks great !

PS, the only thing I would alter in that setup is the motor mounted high like that... it really puts the center of gravity much higher. The motor is about a pound, much heavier than the head on a nitro. I think you will find the buggy leans a lot in corner and if it doesnt, you're losing on traction by compensating with heavier springs.

It weights around 8.5 lbs.

Yeah, the high-mounted motor wasn't the ideal setup. Mike wanted to mount the motor to one side of the diff and use a 4s pack on the other side. This would have made for a nice balance and everything would fit on the chassis. However, this would have required moving the center diff and machining custom center shafts which I didn't want to do. This setup works pretty well once I stiffened the rear a little to compensate for the added rear weight of the batteries.

Very nice conversion. I like how clean it looks. Also, that motor mount looks amazingly strong.

-Chris

First Race Results
 

The first race with the converted MBX-5 went well.
On the first qualifier, the car broke the 1/8 Buggy track record and TQ'ed for the main. Everyone was really impressed with the car and had a LOT of questions.

The second qualifier was not as good. I flipped the car once and it cogged so bad that it just sat there stuttering until TallyRam gave it a push to get it going again. That cost 2 spots, but luckily the 1st qualifying time was good enough to hold onto the TQ spot.

The main was interesting. I was still wondering about that cogging issue, so for the start I had someone hold the buggy up like all the nitro cars so I could spool it up. I sure would hate for the buzzer to go off and my buggy just sit there cogging while everyone piled into me. It worked great, but I got nailed in the second turn and came out in last place by the time the car was righted. I managed to work my way back up to the front with about a minute to go. I made one bobble on the last lap and got tangled up with a lapped car. That was enough for the guy behind me to get by for the win and I finished about 3 seconds behind in 2nd place. Aside from that one cogging problem, the car did great. Several of ther nitro drivers want to do the conversion too, so I plugged Rc-Monster as much as I could.

Did you ever figure out the cogging issue? It sounds kind of strange.

i don't know what it was either. it just cogged really bad for a few seconds. aside from that the buggy was awesome! rcaddict is a great driver and really made the buggy shine. he was out-jumping the other buggies by around 5 feet aff the triple.:018:

I am running the same motor/ESC combo as you Rcaddict (motor on the side and 5AH Li-Po on the other side). I sometimes see it stutter just a bit from a dead stop. On rare occasions it stutters enough to be annoying. Only once has it cogged really bad for me like it did for you at the track.

My Mtroniks Truck ESC was very smooth with the Neu 1512 2.5D..... for the 5 minutes it lasted. That is what prompted me to try the Mamba Max. Even with a little bit of cogging from the Max/Neu, I think it is a great combo.

I ran 13/46 in my Hyper 7. It was still plenty fast for the track, but I do have a 14T headed my way.

Congrats on the race. It sounds like the car and your driiving are to notch.

Matt

I saw the same major cogging happen on the track the last time I raced. But it had never done it before. It seems to be worse the last time and I don't know why and I haven't run it since.

Both of my cars seemed to have more problems last time out. I hope this isn't a trend because prior to this everything worked great and any cogging, etc was very minor and never an issue while racing. But now it seems it's becoming a more common occurance.

One thought I have is concerning the batteries and the ambient temp. The day I had more problems it was colder and I didn't monitor the battery temps. It's possible the batteries were not performing as well because they were cold. The same goes for nickel cells too. I don't know exactly if this was a factor but it seems logical.

So has anyone else noticed a difference running in cold weather?

I'm not sure why, but Lipo's are definitely flatter in temperatures below 55 degrees. I used to fly them in RC planes and on cold days the difference was noticable.

What do you mean by flater? Not as much amps put out? Did the voltage fall way down when running them hard?

It's hard to say b/c I didn't take any measurements, but the power output was down by about 25%. My little 3D plane would usually hover at 1/2 throttle, but on the cold days it took between 3/4 and full throttle to keep it in a hover.

If you go to www.ezonemag.com there is a lot of info on Lipo's. They've been flying them in rc planes for close to 10 years now and have a lot of experience with the technology.

Which wt. oil do you use in the centerdiff?

I'm using the box setup of 3,3,1.

This has to be the most maintanance free vehicle I have ever seen. All I have to do is hit with the air gun when I get home and that's it.

That's a light oil setup... is the track a loose surface?

As far as cold lipos go it's known that they don't like cold. Some of the older generation cells are completely worthless if they are around freezing temp. Even at "room temp" they don't perform as well as when they get warmed up a little, more like 90 or 100 degrees. THey work better the hotter they get. Nimh are the same... run them when they are a toasty 120-140 degrees for best performance. They do feel flat when cold (both types).

So in the heat of summer it's not an issue, but when it's in the 40's or 50's outside, some lipos will only crank out about half their power... the airplane guys keep them warm and even put a "blanket" around them in the plane in the winter.

Not all lipos are as sensitive to temperature, and I don't know how much effect if had on my cars that day I had trouble. In the future I will warm the packs before running.

That's a great looking conversion! Job Well Done!

Thanks procharged.

glassdoc,
I now realize that you meant are there more cogging problems in cold weather. I might have to bring a heating pad to the January race.:005:
We race year round here in Florida and the high temps are only in the 50's, but keeping the packs warm might help a lot. I haven't had a chance to experiment with diff oils yet in the MBX-5, so I'm running what it came with. I'd like to try a 7,5,1 setup and see how that does. Our track is usually pretty slick on practice days, but lately we have had a nice blue groove going.

This makes me want to do a buggy! WOW! Nice and clean job! Hope your races go well for you!

Nice conversion, very clean! Looks great. One burning question for you, as a racer also I've thought many times about coverting my buggy after the motor stalls in the middle of a race. How are the brakes on the buggy though? When you hit the brakes will all the braking power not just goto the rear wheels since when your on the brakes the rear tires will have less grip? Basically, does it stop as fast as it did when it was nitro?

To be honest, the motor brakes are ALOT stronger than the nitro brakes...I would leave the nitro brakes though since it will be less strain on the motor and ESC, thus less heat. Not to mention, you can tune the brakes f/r bias.

I don't know about the buggy. The truggy or emaxx with center diff or other
does not stop as fast. The thickness of the center diff oil has alot to do
with braking then. The thicker the oil the more brake power was to rear.

I have been using the ESC brakes and they work really well. You can dial in or out as much as you want with the Mamba Max ESC. The same goes with drag brakes. You don't get the front/rear tunability like you would with nitro brake discs, but I've found that with the right amount of drag brake the car will setup perfectly for the the corners without having to even use normal push brake.