MP777 SP2 Brushless
 

Ok, so for those of you who viewed my thread questioning buggy weight, here is the beast:
Details:
Kyosho MP777 SP2
Losi 8ight shocks
Ofna Spider center diff
Novak HV4.5 brushless system
Century 9T mod1 Pinion (from Tower Hobbies)
Aluminum Battery Boxes
Pictures:
http://mcclive.com/files/rc/mp777front.JPG
http://mcclive.com/files/rc/mp777profile.JPG
http://mcclive.com/files/rc/mp777side.JPG
http://mcclive.com/files/rc/mp777sideclose.JPG
http://mcclive.com/files/rc/mp777top.JPG
http://mcclive.com/files/rc/mp777topclose.JPG

The buggy currently weights 7.4 lbs without batteries and the battery boxes are designed to fit Maxamps 2s 10000mAh batteries (will hold 2 batteries for 4s total voltage).
Due to the weight issues, I might convince myself of 5000mAh batteries, but the verdict is still out.
I calculated that my battery boxes weight a combined 0.6lbs, so I figure I can thin them out (mill/cut off un-needed sections) and save maybe 0.2 lbs.
I have a few other things I am going to try to save weight with, hopefully getting the buggy down to 7.0 lbs without batteries.
I have yet to finish the battery straps (velcro based) and I still need to mount a short antenna post.
The "o-clamp" motor mounts are from megamotorsusa and I cut the Novak heatsink down and mounted a fan on it to try to keep the heat down.
My plans for this buggy is mostly as a basher, but I also plan to take it to a local track to "race" (they probibly won't let me accumulate point for their championship, but I really just want track time.)
So... How bad is it?

One thing to consider, many of us are using Mamba Max ESCs which weigh 2.5oz. according to Tower. The HV-Maxx ESC weighs 4.8oz. That's a 0.14lb. difference (not enough to account for the weight difference you're seeing, though).

How much does your buggy weigh as a RTR nitro with/without fuel?

You need to get rid of those Tamiya connectors and get something to handle the amps, like Deans. I can't understand why Novak would put those crap connectors on their brushless system.

First things first..... Ditch those white battery plugs! Get youself some proper deans plugs (or other high current connector).

Other than that it looks like it should do nicely for you. Nice job.

How is that century pinion holding up. I didn't have much luck with those lasting very long against a steel spur. They worked well on the plastic spurs though.

Referencing the mamba maxx:
It isn't rated for 4s, and I want to stay within manufacturer recommendations, additionally I am not going to wait for the MMM which was due out 2 years ago initially.

Referencing the connectors:
I will be changing to deans, I just haven't yet.

Referencing the buggy weight in Nitro form:
I don't know, I bought it as a roller but kyosho advertises it as 7.5lb, I do not know if that is with or without fuel.

Edit:
As for the century pinion: I don't know yet, I haven't had this thing running yet, between the cold/snowy weather, and the lack of good batteries, I have yet to turn it on.
Thanks for the input

I also didn't have much luck with the century pinions on a steel spur. I tried it in my crt.5 and it only lasted 2-3 runs.

I got one run with a century pinion on a steel spur. Get a Kyosho plastic spur or RC-Monster hardened pinion

as far as the mamba max goes... its rated for 4s with a suitable BEC... they dont say it in the manual but they imply it in the manual ( i believe it went like anything above 3s, a External Bec is required ) and in fact it works quite well with a nice little novak fan on top of it.

and 7.4 pounds without batterys? damn mine weighed that with batteries if i remember right... ( not sure, but definatly lower than 8 lbs.)

That diff could be adding some weight. And, your deffinetly going to need a chassis brace in the rear if you plan on jumping this this.

Why would the diff be adding weight? because of the metal spur? or is a spider heavier then a regular?
As for the rear chassis brace, I know, I am in the process of making one, the stock one won't fit with the motor being centered.

That weight sounds reasonable to me. My buggys are generally in th 8-8.5lb range fully loaded with lipos.

The century pinions are not hardened (not enough to work with a steel spur). Get a kyosho plastic spur, it should fit that diff just fine, 46t should be you best bet. Also you may want to upgrade the novak to a 5mm shaft rotor. I broke my hacker c50 maxx 1/8 motor shaft yesterday and others break their novak shafts too.

Otherwise the buggy looks good. I would find a way to tie the tops of the center diff bulks together, it will help the pinion/spur mesh stay more consistent.

I am going to work on the center diff brace, not sure if I will buy and mod one, or just make one, I will upgrade to the 5mm shaft once they are available, but last I checked they are still "order pending".
Additionally, I am thinking of getting the kyosho spur and trying to modify it to fit the spider diff, as the century gear wasn't the best choice I guess.

There is always the RC-Monster hardened pinions with a bore adapter for your 1/8th inch shaft. Then they will also work when you go to the 5mm shaft.

I picked up a 12T RC-Monster pinion last week, but I have read that the Novak motors require smaller pinions to prevent overheating, so the 12T will be for if I want to make a speed run or two, while the 9T (if I change to plastic spur) will be for regular usage, unless my results differ.

To update, I have shaved around 1.5 oz (total) off the battery boxes, they look a bit weaker now, but they should be fine, I might even change over to plastic boxes (would save me another 1.5 to 2 Oz.) but that would be either A) more cost or B) lots more time, as I would be machining them at home (using a drill press and dremel).
I have ordered a few more parts:
-CF Diff brace that I will need to trim to fit into place
-front chassis brace (which I will use in the back, hopefully)
-kyosho 46t pinion (will try to modify it to fit the spider for now)
-stronger front shock springs (they are curently using the stock 8ight-T springs, so rear should be ok)

Hopefully, this weekend I will find time to:
-Swap out the battery connectors for deans
-Remake a few of my small aluminum parts out of UHMW (wont crack and ~1/3 as heavy as Alu), that should save me an once or so
-I need to mount the antenna still (probibly use a small piece of UHMW to make a mount)
-Make up my battery straps (I have the materials, but haven't gotten to them yet)

Anyone else notice any small modifications I have yet to do?

Because it has more gears and the case is aluminum instead of plastic.

For the record, the MM was not even out yet 2 years ago... I would say the MMM is going on a solid year of waiting.

Or has my mind skipped an entire year??

how do you adjust the gear mesh on that motor mount? I was jsut looking at it wondering since you picked up a 12T.

I would put a spacer under the motor mountr (raise it up).

I decided to be analytical here so:
I found "coming soon" on message boards dated May 2006,
I found "any news/wait for/I am gonna buy" on message boards dated December 2005,
Still haven't found CC's initial announcement, but they seem to have a track record of announcing things that they haven't even prototyped yet, and then keep pushing back the production dates. Based on the recent posts that claim later this month there is enough hesitation in the wording that makes me expect it won’t be out before June, but I wouldn't be surprised this it took until this fall or later.
I understand that they want to release the best, most reliable product. But they need to not announce things so far in advance, and not keep setting release dates that they can not meet.
So, you are right, 3 years was over exaggerated, I can only trace back 27-28 months of MMM talk.

Wasn't trying to beat you up on it LOL... but let's not forget (I think some here have....) that back in 05-06 they were working on the MM, not the MMM.

They did tell us while they were working on the MM that a MMM version was in their future plans, but never claimed it was anywhere close to being a reality, prior to the release of the MM. Since then... yes we've been waiting.... and it seems like years sometimes...

I think what they were working on and what they had talked about as "coming soon" are 2 different things. I think its fairly obvious at this point that they weren't working on it until after they released the MM.. But I seem to remember the MM and the MMM "coming soon" announcements being released at around the same time if not even at the same time.
In my mind "coming soon" means 2-3 months... not 2-3 years.:tongue:

I'm not trying to argue with you here, but you have to admit, CC put their foot in their mouth pretty far on this one. Its very obvious that they started talking about it WAY before they had anything solid.

OK, why do so many threads around here seem to migrate to a MM discussion lately?

cmc, I am with you on this one. Based on their track record on this product, I would not be shocked if the MMM didn't come out for a while yet. However... at this point, if they are saying it will be in March still (its March now), they had better not have their heads stuck that far up their backsides that they miss it by months. If they did that, it would border on the ridiculous and whoever the project manager over there is should be fired. I know my company would not tolerate missing dates by that kind of margin without some people being "held responsible." Especially such a high profile project.

I don't think there was any "MMM coming soon" stuff until after the MM was out. They did mess up by putting that on their site like in the fall of 06??

Anyway.. yeah things get sidetracked to the MMM pretty easy huh? LOL

Back to the 777 SP2:

I should dig up some old pics of my 777... it has a similar layout, sorta. The motor is up over the center diff like this one. I always liked that....

Ok, I finally finished the buggy this weekend (I was mostly waiting on the batteries and a few small parts).
Final Weight: 9.34 lbs ready to run (I know it is heavy, but the buggy is still fast).
Batteries: 2x 2S 10,000mAh Maxamp (couldn't pass up the price per cell)
Motor: Novak HV4.5 w/ HV-Maxx ESC

Hopefully in a few weeks the 1/8 track in my area will dry out and I can show off my RC, assuming that I figure out how to drive this thing properly.

Pics:
http://mcclive.com/files/rc/mp777side1.jpg
http://mcclive.com/files/rc/mp777side2.jpg

How about a shot from the other side? :)

Body on or off? I can take a pic when I get home (not for another 6.5hrs). Just let me know what you are looking for.

Naked of course!

K
I will do my best to remember when I get home tonight

thank you! Nice job by the way...

here is a pic of the other side, let me know if this will do
http://mcclive.com/files/rc/mp777side3.jpg

Nice job- I see you made good use of all the available space :mdr:

The motor mount idea is rather clever makes for good weight distribution.

Speed update!
I just ran 7 passes by a 100ft section of road to calculate top speed and after eliminating the fastest and slowest time my top speed is........
44.2mph with a standard deviation of 1.7.

here are the detail
tires: worn out dirtpaws
gearing: 10t thunder tiger (e-raptor) pinion & 46t sur
motor: Novak HV4.5 w/ 5mm shaft
batteries:2x Maxamps 2s 10,000mAh lipo

In all I took about 10-15 runs, messed up the stopwatch on a few, forgot how to drive for a few ect. In the end, the motor was only slightly warm, the esc and batteries were room temp.
Sunday I am taking it to the track to find out how long it can last without thermaling (and to see how badly I drive)

what kinda runtime are you going for with 10,000mah lol

That is a cool buggy.

Be sure to update on how it goes at the track

Long enough!
Honestly, I have seen a few times at the track I race where they have made one class run their second 5 minute qualifier and then run a 20 minute main 5 minutes later.
I wanted to make sure that I could get 25 minutes of racing without being out of battery.
Hopefully, in an ideal world, I will find that these batteries do last way to long, and I can get a pair of decent 5000mah or 6000mah to save on weight, but since the cells were cheap, I figured I would go overboard first and then, if I can, go smaller, instead of going to small first and not being able to run.

Went to the track yesterday...
Not so successful.
I had a few motor mount screws come lose which allowed my spur gear to strip (plastic spur).
Fixed that and then cracked the ball cup on one of the front CVDs. I bought the CVDs off of ebay from China, so it is likely they were poor quality, I ordered a new set of fronts (stock kyosho this time).
assuming the parts get mailed today, I should get them be Wednesday, and I will take it out to the track Thursday.
In terms of performance (for the 5-10 laps the buggy lasted) it seemed on par with the Nitros, I was trying to be cautious as to not break anything. I let a nitro guy try it out (I wanted his opinion as to performance) and he was in no mood to be cautious (both broken parts were from him).
Hopefully Thursday it will be more reliable and I cam come back with useful data (motor temps actual competitiveness vs nitros) ect.