First time buggy conversion - need some input
 

I'm new to this forum and new to the world of brushless. I plan to convert a Mugen MBX5 so I could use some input from you guys. I already got a lot of great tips from Serum, but you like to have some more input from more than 'just' one person. ;)

Motor and ESC: I don't want to spend too much money, so my idea is to use a Feigao motor and the Warrior 9920. The idea is to start with 12 (or 14) NiMH cells. Now I cannot decide between the 8XL and the 7XL. It seems that the 7XL is on the edge for the 9920?

Gears: as far as I know, the nylon Kyosho spurs won't fit the Mugen diff. So I want to fit a Kyosho diff in the Mugen. Gears I want to use: 46 tooth spur and a 14 pinion.

Engine mount: it seems that a modified E-Maxx engine mount is the easiest way to mount the motor. I have seen some very nice engine mounts on this forum, but will the E-Maxx mount suffice?

Hi Martin, Welcome.

No, the emaxx mount is not a wise thing to use. since it's a simple straight plate it's hard to get it on the chassis/diff without too much flex. (flex is killing for the spur/pinion)

You are better off with getting an L profile aluminum and make your own mount.

the kyosho won't fit the mugen. that's for sure.. You could ask Mike to have you made an adapter plate to fit the Mugen diff. that way you can use a 51T spur.

The 7XL works very well in a buggy on both 12 and 14 cells. The 8XL will give you slightly longer run times and will get a bit less hot.

I used the 7XL and loved it in terms of power and temperatures.

The 7XL is most certainly not the limit for the 9920 on 14 cells. Some users here even used it on 18 cells on the 9920.. (it RIPS) that is pushing it, though but since you are leaning towards the C can with the heatsink you will be fine with the 7XL on 14 cells.

The 8XL however will run slightly cooler and give you a bit longer runtime. But it will also run a tad slower.

RChippie can confirm the power of the 7XL on 14 cells in a Mugen buggy.

I can't recall if the HB diffcup fits the Mugen diffholder, this HB cup would enable you to use the kyosho diff, but you would also need a set of new internal gears (HB uses a 4mm x-pin) and it also uses 6mm output cups, so you would need these as well. (that is, if it fits at all)

BTW i think you might find this handy;

OK, I was already afraid the E-Maxx mount would cause too much flex...

So the Kyosho diff won't fit the Mugen diffholder? I bought a second hand Mugen MBX5 and I still have a Kyosho diff lying around. As soon as the Mugen arrives (I don't have it yet), I will try to somehow fit the Kyosho diff. If it's too much work I will look for a solution you suggested.

You could design a new diff holder out to fit your chassis. Then you
wouldn't have to worry as much about flex.

@m_podt: I too am converting a buggy (Hyper 8) and I sent the whole thing to Mike so he could custom make a diff mount/motor mount unit. Send him an email describing what you want and he can quote you an estimated price. I won't mention the actual price, but I will say it is more than fair considering he is going to custom machine a mount from scratch according to my specifications.

I just designed them myself brian. Then got mike to machine them out.
It works and you are right. The prices are good to me.

I wasn't too happy with NiMh weight...

4-5LiPo 10L

Artur

I know you mentioned that the last we spoke (actually "typed"), but wasn't sure since there are a few minor changes to yours. Maybe if Mike does use your design, it'll be a tad cheaper. :) Even so, still worth it IMO.

Yeah, I read the thread about your conversion. However, I live in the Netherlands, so sending the whole buggy to Mike and having it sent back will be quite expensive...

You could either ask Mike to make you the adapter get a HB diff. Worst case scenario with the HB diff; you need to make a lower plate to place the two centerdiff holders a bit further from eachother.

Perhaps a 5 to 6 mm adapter will put you where you want to be, using the kyosho spur and the Mugen diff.

OK, thanks for the input up to now. First I will order the parts I need. I decided to order the 7XL and the 9920, the 46 tooth nylon Kyosho spur and a 14 tooth pinion. A decision on the motor mount will come later, as I want to fully rebuild the Mugen first and get an idea where to put all the parts.

And then... batteries. I limited by choice to the following cells:
GP 3300 mAh
GP 3700 mAh
GP 3900 mAh
GP 4300 mAh
As far as I know these are all suitable for high power applications. Is there any difference in quality?

Imo get the gp3300's or maybe the gp3700's for a little more runtime ;

They are VERY durable cells, Just and FYI, The higher the capacity of a cell - the less it can put out.

GP3300's and 3700's are the ones that push out the largest power.

stay away from the 3900's. somehow they are worth poop. i never heard a good story about them.. (only one time; when they went to town, got drunk, jadajada) the 4300 are nice for runtime but not for the durability and voltage under a high load.

IMO a nice in betweener would be the 3700's.

So that limits the choice down to only two cells. Thanks for the input.

Somehow I completely missed this remark...:007:

Indeed, the problem is that the diff outdrive for the Mugen is 5 mm, whereas the Kyosho spur is meant for 6 mm outdrives. Do you know if somekind of 5 to 6 mm adapter is available? Probabaly not as I have not seen this on other brushless Mugens...

Conrad pashulsen

This could be it... 5 to 6 mm adapters.

It's in Dutch but at least Serum should be able to read it... ;)

Hmmm, what does that say? LOL:002:

Sounds like an aluminum shim would be an easy fix.
Do you know anybody with a lathe?

RC M Mike! He has to turn by hand though unless he got the new belt for his!

Yeah, try RC monster Mike, i would make a 6.something to a 5mm adapter, the link doesn't work Martin, but i know these things.. i would ask Mike to make you an adapter that is a tight fit for the kyosho spur with a nice 5mm hole.

Brass is the way to go.

I corrected the link...

This question is indeed whether is fits tightly or not. Probably it would be better to make a custom adaptor. I will send Mike an e-mail.

Yeah, having a snug fit in the spur is my advise.

Brass would be the material i would pick.

By the way, one of the forum members contacted me about a motor mount for the MBX5. With this mount the motor could be mounted to the rear right side. But... the diff is already mounted towards the right, so mounting the motor on the rear right side would create an extra weight imbalance? And is there even enough space to mount to motor without removing the chassis brace? I don't have the rolling chassis and motor yet, so I cannot try myself...

A brace that connects to the right side? that wasn't GriffinRu who contacted you then.. I would not go thru the trouble with moving the centerdiff. Much easier to make a new motormount.

Wasn't me...

Artur

Yours doesn't move the diff to the other side, so i knew it wasn't you..

Have you still got a mount for the mbx5 Artur?

Working on it...
First batch is gone.

Artur

End of the project... :mad:1

Today the Mugen MBX5 roller arrived. The seller said it was in perfect condition, no parts needed to be replaced. Yeah, right! I have been using internet for my RC hobby for many years and have been in this hobby for about 20 years, but I have never seens such a piece of shit like this. Almost the whole drive train needs to be replaced! So, no perfect condition at all and no good starting point for a brushless project at all. :mad:1

So, I first have to overcome this minor 'problem' and then I will start with fresh courage again. But all thanks for your greatful help! I will postpone this project, but will pick it up later again. But maybe (or probably) with a Kyosho of Hotbodies instead of a Mugen.

Did you get it off Ebay? If so, you can file a claim against the seller for mis representation. Send ebay the pics of what you got and the ad you bought it from.

No, I got it off a Dutch site. I already contacted the seller, but he is not willing to come to a fair solution. Thus I contacted my legal aid insurance (or how is this called in the US?).

Before I bought it, I specifically asked him whether parts needed to be replaced. He answered that the buggy was in perfect condition. However all CVD's need to be revised, all diff outdrives are worn, etc... Anyhow, not worth a conversion.

The parts I ordered for the conversion will have to wait till a have another (better) buggy. ;)

Well, hopefully you didn't pay too much. A Kyosho would be a nice conversion....