Savage Flux Conversion to 1717, Center Diff, XL Length, Mech Brakes
 

Have been enjoying the RC for less than a year now, this forum has provided a lot of insight to the hobby through its members and their great conversions, tips and experience. I feel I need to return something back by posting my humble conversion. Please remember this is my first Conversion with minimal tools; In fact my first RC truck, not counting my sons MLST.

Lots of ideas have come from different conversions and forum members, a thanks to all.

It started with the need for more power and a center diff. I enjoyed my standard Flux a lot, but wanted to lessen the wheelies and of course more power. I pefered to do it the custom way as much as possible. And obviously with the recent Castle Creations sale; got my self a 1717.

Design Considerations:
To limit Wheelies, i thought of 2 things; Motor Forward as much as possible, and a center diff.
Moving the motor forward and reversing it, the steering servo had to be relocated.
Batteries for now will remain in the side trays.
I got the HPI Racing Wheelbase Conversion Set Savage Flux; # 102404, I am aware of the many aftermarket TVP's available and motor mounts, but decided on a bit of challenge and decrease the cost. Another thing for the price of HPI # 102404 it includes the 4x widened axles also, i happened to have them on my Flux and broke one of them; now i have 3 spares ;)

I used a hot bodies diff which I got cheap on ebay, hope it holds; may upgrade later after everything works out fine.
Obviously I will be using the monster mamba ESC of my stock Flux
Intention of using mechanical brakes to lessen the load on the ESC, this will come later.

For starters here is the general idea:

https://lh5.googleusercontent.com/-U...25202%2520.jpg

Another view:

https://lh4.googleusercontent.com/-V...52001%2520.jpg


Comments, Feedback and Ideas Most Welcome!

I am a bit ahead in status, but want to go through the steps.

Here is a blowup of the parts for the center diff and motor support:

https://lh3.googleusercontent.com/-C...view%25201.jpg

I'll be using 3mm Alum plates attached to the TVP's; 6mm top and bottom alum plates for supporting the center diff; and 6mm motor mounting plate. the motor will be supported on the back plate using 4 screws; 3 screws going through the 3mm plates will be used for mesh adjustment.

https://lh5.googleusercontent.com/-l...%2520mount.jpg

Mechanical brakes will come later, but here is the general idea. Will have to mount the springs on the other side; and probably gotta notch the back 6mm motor plate. Haven't tried mech brakes on a brushless setup before, i dunno if while ESC is in forward does the servo rotate as if applying throttle in a nitro?

https://lh4.googleusercontent.com/-b...rings%2520.jpg

https://lh4.googleusercontent.com/-m...25202%2520.jpg

Well on with the build.

Here are the first cut plates:

https://lh5.googleusercontent.com/-B...672_resize.jpg

First test assembly, to check alignment.

https://lh6.googleusercontent.com/-a...701_resize.jpg

I offset the Motor and Diff as much as possible to lower the motor as much as i can, to achieve a lower CG.

https://lh6.googleusercontent.com/-2...704_resize.jpg

Now with the first test fit, I used the XL rear dogbone in the front and found a 109mm dog bone at my LHS fit perfectly, even with the offset motor and diff. Servo already relocated as shown.

https://lh6.googleusercontent.com/-6...693_resize.jpg

https://lh5.googleusercontent.com/-Q...698_resize.jpg

I supported the whole mount with motor and diff using 6 screws going through some holes in the TVP's and even used the rollbar screw as a support also, I tapped the 3mm plates for easy installation and dismantling. I like how low the motor is. The mesh adjustment moves the motor up and down, so as i gear up the motor has to be raised, buts its minimal. now installed with a 15mm pinion and 50 spur.

https://lh6.googleusercontent.com/-A...749_resize.jpg

View of the rear, hoped by lipos would fit there. actually they don't.

https://lh6.googleusercontent.com/-0...751_resize.jpg

View of the Front. The Motor actually clears the TVP's by a mm.

https://lh6.googleusercontent.com/-u...753_resize.jpg

And please excuse the cleaning of the truck :oops: and the crude cuts in alum :neutral: Was anxious getting everything together and testing. Will grind and file the pieces later on.

Also to mention the servo arm clears the motor; here the servo is at full swing. hoped i could swap the dogbones to move the motor more forward but they would get in the way of the servo arm.

https://lh6.googleusercontent.com/-j...755_resize.jpg

Why is your plans to keep the Mechanical brakes?
They wouldn't be needed really.
Oops missed that one piece.

As my current plan to run the 1717 on the MMM 5S at first and then 6S, heard a lot of mixed opinions about the 1717 and MMM, thought to go safe, and plus i liked the challenge. Wouldn't you think it relieves the ESC of additional stresses.

Now on with the electrics, installed the MMM,

https://lh6.googleusercontent.com/-Y...765_resize.jpg

Took it for a test run, with the following setup:
5S 2S + 3S Turnigy 5000 mah 40C Lipos
15t Pinion
50t Spur
GS Wheels and tires, close to mashers 3.2 in size and weight (150mm dia)
put the lowest settings on the MMM especially brakes
Punch 100%
motor timing lowest
Brakes 30%

Well everything was fine in the first couple minutes, still not going full WOT. And all of a sudden the MMM smoked!

According to my calculations the gearing is close to a standard Savage Flux. Gearing was for around 96 Km/h around 59 mph. Anyway long story short, got the courage and hooked up my other MMM, and guess what, it was great. got more courage and went WOT, this 1717 is really impressive! cool temps, plenty of torque, and with this setup wheelies were minimal.
Seems will have to send my new smoked ESC to Castle.

EDIT: gearing is for 96 km/hr on 6S, assuming 3.7 Volt per cell, with the 5S run gearing is for around 79 km/hr

here are the eagletree graphs of my run:

https://lh5.googleusercontent.com/-g...ee%2520log.jpg

same graph but zoomed:

https://lh3.googleusercontent.com/-h...lowup%2520.jpg

What impressed me was the temps of the ESC, (hadn't hooked up the motor temp sensor yet )

https://lh4.googleusercontent.com/-V...p%2520crop.jpg

Here is where i need some opinions and comments!

Should i gather more courage and try 6S?
I like speed, so how high can i gear up safely? this motor should have plenty of reserve torque.

The controversial part, will the Mamba Monster (MMM) extract all the power of the 1717, i know its rated for 120 Amps, and more for short bursts, but the 1717 also if i recall correctly is rated for 2000W (4000w surge) or should i invest in a bigger ESC?

Mamba XL, Phoenix ICE 200, or a Hydra Ice?!

Given the 45,000 rpm limit of the 1717 can it be run on 7S or maybe 8S?

It could have been a bad part in the esc.
Good to see you got it going though.
Why did you change the timing before testing?

I had the same experience with 1717 and mm, its extremely important to use high discharge batteries and good connectors, like the castles 6.5mm. i also recommend a cap bank and gear it closer to 70kmh.. the 1717 is just brutal power wise.


btw nice project, fun to see custom builds.

...this is why I abandoned the MMM (Which I am very cautious on at the best of times) and went the MMXL, and I'm only intending to gear for 40mph on 6s (granted at 5b length)

Its just that i was fiddling a lot with the settings when it was still stock with the 1515 2200kv motor, and thought as a start to get everything back to normal settings while trying the 1717. Is there a recommended timing for the 1717 with MMM, i went with the lowest for my first test runs.

Honestly, got the Cap Pack, just need to install it. my batts are Turnigy 5000mah 40C should be able to give 200 amps continuous, or close. Well given the graphs posted earlier, I think i will keep it there, i mean my temps are fine till now. Will have to do more rigorous testing, WOT back to back continuously, and I'll report them back.

And THANKS for the encouragement :smile:

I understand, how much does your truck weigh?
just weighed mine:
truck with body; no wheels and no batteries 4436 grams
tires and wheels 1163 grams
Batteries (5S) 770 grams
so all in all 6369 grams = 14.63 lbs full load, including eagletree and gps module (i know they are negligible but just for accuracy)

Edited Post #8
EDIT: gearing is for 96 km/hr on 6S, assuming 3.7 Volt per cell, with the 5S run gearing is for around 79 km/hr.

Body work and wing
 

Just an update, still have to work and sort out the mechanical brakes, in the mean time did some work on the body and installed a rear wing. Got a bug beetle proline body, its not quite XL length but i really liked it! i feel the wing offsets the general look, if you look closely you can see a bigger horizontal gap between the rear wheel and the arch.
Anyway here are some pics:

https://lh5.googleusercontent.com/-K...e%2520crop.jpg

https://lh4.googleusercontent.com/-4...2520resize.jpg


Need some opinions, i want a simple 2 color scheme, nothing fancy, will be using spray cans, here are some options, what do you guys think? which one?

https://lh4.googleusercontent.com/-D...tions%2520.jpg

I like paint options 02.

What wheels\tires are those? They look like a 1/2 offset? Weight?

Thanks for your opinion, These are GS tires and wheels, found them at my local LHS pre glued, they were quite cheap. They weigh 291 grams per tire and wheel pre glued with some foam inside. don't like the inside foams, quite soft. Need to dismantle soon and replace the foams.

This is a previous photo when i bought them new.

https://lh4.googleusercontent.com/-0...520_resize.jpg

edit: They are offset, but dunno if half or full gotta measure them. half offset is half inch? or what is the nomenclature?

Half offset is half inch.

Great weight, they look like a good monster truck tire. They are a fairly low profile and decent width so should be quite nice to drive on. What height are they?

After a quick google they seem to be the tire from a GS Racing SUT but hard to find info on or a place to buy.

Yeah i like them, they are holding up well, i recall they are couple of mm's higher than the proline mashers 3.2, will have to measure them when i get home. But the foams i suspect aren't that good, i am not able to balance 2 of them, seems the foam is loose or torn inside, or got plenty of debris and sand inside, will know when i dismantle them and replace the foams.

Nice project :yes: I agree with the blue and white colour scheme, since your wing and wheels are white.

Doing all you can to keep the esc cool is probably a good idea if the truck is now heavy over the front, it'll be needing more power at full throttle acceleration if it doesn't wheelie. Probably why you have cooler temps WOT.

They are 147 x 85mm as per my measurements, Here you go:

https://lh6.googleusercontent.com/-5...895_resize.jpg

https://lh3.googleusercontent.com/-F...888_resize.jpg

Cheers, thanks for that. Not quite as large diameter wise as I had hoped though.

hi everyone, haven't painted the body yet...
thought just to update, project is still ongoing, but put it on hold for a while because of my cnc build. got some bits and pieces and building myself a cnc to better finalize this project. its close to be finished now, some pieces needs remaking, when done will get back to my savage and put the MAMBA XL in it!

here's a pic of my mini cnc in the making:


https://lh6.googleusercontent.com/-f...20cnc%2520.jpg

hope to get it finalized soon!

Hello everyone, have been quite busy lately, finally had some time to tinker back on my project.

Well the previous design did work well but had some quirks of its own, and i never did manage the mechanical brakes. here is my second attempt to get things going.

Here is the design idea:

https://lh5.googleusercontent.com/-V...2520brakes.jpg


preferred to rotate the brake pads to a vertical position and use aluminum arms to apply the pressure.

Here is a sequence of pics showing the CNC milling process, did not post all the pics, left them on the picassa album for any interested.

The right plate being milled:
https://lh5.googleusercontent.com/-S...005_resize.JPG

Left and rear plates milled, milled the internal cutouts and drilled the holes, then reclamped to mill the outer profile, this saves time realigning the mill or having to keep tabs or bridges and cut them later.
https://lh6.googleusercontent.com/-3...024_resize.JPG


Re clamped and outer profile milling
https://lh4.googleusercontent.com/-c...054_resize.JPG

While milling i left the bearing seat holes smaller, now internally boring the bearing seats:

https://lh5.googleusercontent.com/-Q...691_resize.JPG


Test fit before removing from the mill face plate. all fine so far.
https://lh6.googleusercontent.com/-8...708_resize.JPG

The components of the Center diff support, the center piece is the motor mount plate; the motor gets screwed on it and it is supported to the front plate which is the one above it in the pic.
Had to do this t clear the brake disk.
https://lh6.googleusercontent.com/-l...716_resize.JPG

Drilling the holes in the front and rear plates, kept a bearing in place and clamped both plates on the vice to have a good alingment.

https://lh6.googleusercontent.com/-b...736_resize.JPG


Well now comes the problem part....

forgot to offset the tool bit while drilling the holes, if you look closely on the following pic in the bottom left corner, notice the right plate is extended lower than the left :(:(:(:(

https://lh5.googleusercontent.com/-j...746_resize.JPG

https://lh5.googleusercontent.com/-f...748_resize.JPG

https://lh4.googleusercontent.com/-2...750_resize.JPG


More problems, while test fitting of the plates to the TVP's the measurements i did were messed up, the whole assembly had to be offset 2 mm , thats the reason for the additional holes laterally. the vertical holes are due to the later reason of forgetting to offset the tool bit.

https://lh4.googleusercontent.com/-T...738_resize.JPG

Whats more worse than the above, the motor support plate also had the dimensions for mounting on the 1717 wrong. I just opened the files i had from the last conversion like 5 months old and started designing without rechecking and measuring again....

Thats the price you pay for being hasty. Note to self : MEASURE 3 TIMES AND CUT ONCE!

here is the second version of the motor plate, had some fun on CAD to get this design...

https://lh3.googleusercontent.com/-P...768_resize.JPG

I will go on with the Plates, to get a test run then cut new ones.

This is the general view of how i am going on with the mechanical braking, the brake arm will have to be supported to a block support, then on to the right plate. a pin is needed to have the arm sway correctly and inline.


https://lh4.googleusercontent.com/-D...25202%2520.jpg

https://lh6.googleusercontent.com/-1...2520layout.jpg


Turning the brass pins for the arms, they will be supported in place by a set screw.

https://lh4.googleusercontent.com/-R...820_resize.JPG

The finished pin
https://lh4.googleusercontent.com/-U...824_resize.JPG

https://lh3.googleusercontent.com/-M...826_resize.JPG

Was having fun on the CNC, my pinion remover....

https://lh4.googleusercontent.com/-M...830_resize.JPG

Well after long hours of remodifying, finally the finished support with the mechanical braking working!

https://lh6.googleusercontent.com/-N...832_resize.JPG

And the Final test assembly pics. Wiring still needs to be sorted out. The mamba XL is huge, and with the Cap Pack not an easy fit in the Savage. Looks like a good place for now, the cap pack has no place but to have the wires bent as in the following pics.

https://lh6.googleusercontent.com/-8...845_resize.JPG

https://lh6.googleusercontent.com/-x...841_resize.JPG

bottom view

https://lh5.googleusercontent.com/-O...847_resize.JPG

https://lh3.googleusercontent.com/-3...857_resize.JPG

Did a test run on 5S everything looks fine, the brakes are awesome!
need to add a skid plate, as the last time i was bashing, i ran over a fist sized rock at full speed it dislocated the center diff assembly, sheared the TVP and a huge dent in the 6mm bottom plate and broke the plastic diff bearing support, the dogbones were also dislocated and bent, just have this pic forgot to take more pics. note the sheared TVP and the dent in the alum plate.

So skid plate then 6S WOT......

https://lh5.googleusercontent.com/-q...138_resize.jpg

Got a video uploaded to Youtube, this is my first time posting and editing videos so bear with me.

[YOUTUBE]http://www.youtube.com/watch?v=2bFtCzT4rss&feature=youtu.be[/YOUTUBE]

Got a video uploaded to Youtube, this is my first time posting and editing videos so bear with me.

http://www.youtube.com/watch?v=2bFtC...ature=youtu.be


how do you link youtube videos so a thumbnail appears or and embeddment is there?

more vids...

http://www.youtube.com/watch?v=8SgIv...hannel&list=UL

Just use the short bit of code after v= , and place it between some [ youtube] [ /youtube] tags ( without any gaps ):

[youtube]2bFtCzT4rss[/youtube]

[youtube]8SgIvFlVzNA[/youtube]

:great:

Thanks suicideneil, will give it a try on my next video ;)

Ok lets give it a try, third video i forgot to post.

[YOUTUBE]zvYH9U0kk5U[/YOUTUBE]


current setup i missed to post earlier;
15t pinion
50t spur for center differential
mashers and badlands standard mt size.
trenchers 30series stretched on 3.2: standard mt wheels
obviously a 1717on XL2
running 5S in the previous 2 vids, 6S in this one.

Next is to add a castle creations 10amp bec for the servos to have the Mamba XL2 internal bec not loaded. currently have the standard sf-50 as steering servo and an sf-10 for braking. have in my tool box a hobby king HK15298B 20kg-cm on 7.2v; thought to give it a try before i fork out 100usd or so on a quality one.

will need to add another bec to have 7.2v for steering and 6v for the braking servo. let me see how it goes...

Need some Help Please!

Was trying to hookup my Servos to an External BEC without going thru the Rx, as i am planning on running the Steering servo on 7.2v and the throttle on 5.5 or 6v and both from external BEC.

This is the Layout i have in mind, which I actually tried but it did not work?!?! any thing wrong i am doing?

https://lh5.googleusercontent.com/-i...7/Clip_100.jpg