Dudes.. 12 cells w/MM5700 and FT TC4

[JeffEmbracedDC]

Okay, seriously I don't know how to say this. Maybe it's just me but I just experienced the most crazy RC thing I've ever seen.

So I have a FT TC4 and a mamba max 5700. I just went to the parking lot of walmart with 12 cells.... I couldn't freaking believe it. It was just.. ridiculous. It was easily going 70+mph and probably closer to 75. Unfortunately........ the BEC wire of the ESC apparently wasn't tucked well. and it came through one of the holes in the bottom of the chassis. You could imagine how fast it would grind right through the wire. Well, it did.. and I lost all power to the car and it crashed through a row of carts breaking:

Front shock tower, front wheel, front arm, steering knuckle, and the C hub thing. So, that was a pretty expensive little run. Next time I'm using a wedge body rather than a stupid Eclipse body.

So, I guess that's about it. Dudes - it was awesome.

-j

Edit --

Oh, and by the way... My 12 cells didn't budge out of the 3racing battery strap that I used. Even in the crash they stayed put.

-J

[N3wGuy]

:eek: Have any pictures of the carnage?

[JeffEmbracedDC]

haha I'll take one in a few minutes :)

-J

[Smib]

Wow, I have to see this wreck.

[vashon10]

.....those pics should be interesting to see

[Jayboy]

70mph!!!!
WOW! i bet the motor was hot!

[JeffEmbracedDC]

Actually, incredibly neither the esc or motor were extremely hot. But then again, I only made about 5 passes. I'll try and get some photos today. I was pretty busy last night :)

-J

[Quinton]

I'm thinking about getting a MM this summer for my sedan. Any reason why you didn't go with the 7700? Wouldn't the 7700 be faster with either 6 cells or 12?

Thanks!

[Jayboy]

i think the 5700 is slightly better when it comes to more cells...

[JeffEmbracedDC]

If you use 12 cells with the 7700 it voids the warranty. The fastest motor you can get that will run 12 cells under warranty is the 6900 which I believe was just released. Previously (when I purchased mine a few months back) the "fastest" motor available was the 5700. The 7700 is faster with 6 cells. I hope that makes sense.

-J

[pinolelst]

Only because you may over spin the 65000 rpm limit on the bearings and rotor on the 7700 with 12 cells ..12v nominal x 7700 kv = 92,400 rpm...even taking drag chassis and wind drag into acct you're still going to be way up there.
I have a 7700 in my xxx-t MF2 buggy and have run it on 3 lipos...it never got to it's calculated top speed of 80+ mph (maxed out at ~55 mph)because of the rough road surface and truck tires but in a touring car on smooth surfaces you may get to the destruction point at full throttle dunno..try it..take video :D

pinolelst

[Quinton]

If you use 12 cells with the 7700 it voids the warranty. The fastest motor you can get that will run 12 cells under warranty is the 6900 which I believe was just released. Previously (when I purchased mine a few months back) the "fastest" motor available was the 5700. The 7700 is faster with 6 cells. I hope that makes sense.

-J

Perfect sense - Thank you!
So IF I get it and IF I only run 6-7 cells the 7700 would be the "best" for me since I'm a speed freak?

[N3wGuy]

haha I'll take one in a few minutes :)

-J

Um what happend to the pictures Jeff?

To: Quinton
For over all top speed you should get a 5700kv cause who knows if you want to go faster. Later on if you have the need for more speed all you would have to do is add more cells.

[JeffEmbracedDC]

Perfect sense - Thank you!
So IF I get it and IF I only run 6-7 cells the 7700 would be the "best" for me since I'm a speed freak?

If you're gonna run 6-7 cells and pretty much only care about speed - yep. The 7700 would be the choice for you. However if you plan to race competitively you should consider the size of your track. If you can't get to full speed on the straight away your motor would be considered "too fast" for the track. If you're gonna race on a normal 1/10th scale track I'd probably suggest against 7700. If you're just bashing and want super fast fun go for the 7700 :)

Um what happend to the pictures Jeff?

I know, I know. I'm sorry. I've been really busy working today and yesterday :) I'll try to get them later tonight maybe or tomorrow. It's almost midnight and I'm still working!


For over all top speed you should get a 5700kv cause who knows if you want to go faster. Later on if you have the need for more speed all you would have to do is add more cells.

This is true. The 5700 will probably be fast enough for any track, and should satisfy your bashing speed desires. And if it doesn't satisfy your need for speed you can always add more cells.

-J

[N3wGuy]

I know, I know. I'm sorry. I've been really busy working today and yesterday I'll try to get them later tonight maybe or tomorrow. It's almost midnight and I'm still working!

-J

It as long as we see pictures. Well worst thing I had to do where I work was inventory day not fun at all opened the store at 9am and close a little after 2 or 3am, worst of all I forgot to go on break :( .

[Joe Ford]

If you use 12 cells with the 7700 it voids the warranty. The fastest motor you can get that will run 12 cells under warranty is the 6900 which I believe was just released. Previously (when I purchased mine a few months back) the "fastest" motor available was the 5700. The 7700 is faster with 6 cells. I hope that makes sense.

-J

The 6900 was just released, BUT max cell count under warranty are the same as the 7700...2s lipo or 8 cell NiMH max. ;)

[Quinton]

Sounds like 7700 is the one for me! My 8000 rc18t is way too fast for our little track BUT I can just soften all the settings and drive at half throttle through the track and then "hammer down" the back stretch and blow away everyone! It's just a fun track we set up on Sundays and play on. No timed or serious racing at all. Its fun to hear people go "WHOA" when they see the "cute little toy" smoke the nitro's. LOL

[Quinton]

What is a good gearing range for my tc3 and 7700?

[JeffEmbracedDC]

standard.. I'd try a 20t.. do some laps checking temps.. if it seems cool enough and you want to go faster. try a 22.. etc. I use the 5700 and I generally stick with a 24t pinion with my TC4.

I apologize for not getting photos. I was really trying to get my car fixed up for a race and so I was frantically ordering parts and putting it together as soon as they came.. so unfortunately I didn't get any photos :( I'm sorry. Haha. I think I still have the pile of broken parts though.. or at least some of them. I'll see what I can do.

-J

[Demon-TC3]

C'Mon Jeff leets see some pics!

Hehe but if it was going 70MPH+ into something as jagged as a shopping cart, thats not HUGE ammount of damage...at least the chassis didnt break...


Parts for the TC4 are cheap anwyahy :D

[N3wGuy]

:( no pictures

[vashon10]

Only because you may over spin the 65000 rpm limit on the bearings and rotor on the 7700 with 12 cells ..12v nominal x 7700 kv = 92,400 rpm... pinolelst
Maybe you (or someone) can clear up the 12 cells and 5700 w.r.t. the max limit.

Even using 1v/cell (instead of 1.2) gives 12v x 5700 > 65000. But isn't 12 NiMH cells considered within spec by CC for the 5700 ?

[JeffEmbracedDC]

Maybe you (or someone) can clear up the 12 cells and 5700 w.r.t. the max limit.

Even using 1v/cell (instead of 1.2) gives 12v x 5700 > 65000. But isn't 12 NiMH cells considered within spec by CC for the 5700 ?

The "limit" for the 5700 motor is 12 cells. Anything past that will put it out of warranty. The motor is still warranted if used with 12 cells or less. The 6900 and 7700 have an 8 cell limit. I wouldn't even really see it as a "cell limit" as much as I would see it as a "voltage limit". The "voltage limit" for the 5700 motor is somewhere between 14.4 and 15.6 volts.

And sorry guys.. I think I threw away all of the broken parts :(.. and I repaired the car so there's no damage to be seen there either.. haha I'm sorry, guys. I probably won't be running 12 cells again for a long time.. at least till I'm prepared. I need a nice wedge body and a much better place to run than the walmart parking lot. I'll also need a higher ride height so I'm not scraping the chassis over every little bump. Haha if you want you can look at my ebay page and see everything I've been ordering... http://cgi6.ebay.com/ws/eBayISAPI.dll?ViewBidItems&userid=jeffembraceddc&sort=3&rows=50&ViewBidItems=&all=0&completed=1&guest=1 and it might give you an idea :) Talk to you later, guys.

-Jeff

[Demon-TC3]

well thats a hefty purchase ill give u that.

congrats on buyin most from RCboyz, their service and price cant be beat!

i was gona buy from Maxpower once or twice but include postage and its about $1.00 more per item and when ur buyin 20 things at once it build up...so i sticked with RCboyz

[Mod Man]

The FT TC4 will tolerate ALOT of horsepower and very high speed without any problems what-so-ever. The big issue is that darn center shaft resonation that occurs above about 60MPH. I modded my shaft to handle more RPM.

The theoretical top speed you will see out of a mostly stock TC4 (with alot of horsepower) is about 90 MPH. However, getting above 80 really takes huge horsepower. I saw 92 MPH with a Stratus body on my FT TC4 running 7S lipos through a 3500 KV Hacker C40 12T. Of course, I smoked that motor after a number of runs (pulling 2212 watts through a 500 watt motor will do that) ;). On 6S, the little car would push 88 MPH consistantly without overheating or breaking anything. That was with a 35 tooth pinion and 69 tooth spur.

The TC4 is a heavy car, but very willing to take horsepower.

Matt

[Eli the rc guy]

Erm.. Noob question here. Seeing how you used a touring car, how did you fit 12 cells in it? and cus its the mamba how was the stick config??

[JeffEmbracedDC]

You just make custom battery holders. You can mount pretty much as many cells as you want. I basically stacked two sXs packs on top of eachother.. bonded them together and used a velcro strap. Even in the crash they stayed put very well..

-J

[Eli the rc guy]

o.o... isn't that really really heavy then?? Thats a lot of pressure on one point of the car.

[JeffEmbracedDC]

Pretty much.