A bit of info please (savage conversion)
 

Hola amigos!

Been bashing with some colleagues during spring. They drive nitro savages and Ive been driving a brushless Tamiya buggy (Baldre). On flat ground Im faster and has better handling... but whos bashing on flat ground? As soon as we hit some rough off-road action Im left in the dust... and often with some broken parts! Ive lost count of the number of times Ive been told that batteries is what they use to start their nitro engines.

Now its time for a change!!

Ive bought a used savage chassis on e-bay & the eZrun 150a ESC + 2000KV motor combo.

I plan to lock the transmission in 1st gear (same as the flux gear ratio). In order to fit the motor in between the TVPs Id like to run with the smallest possible spur... but will the flux heavy duty spur fit the standard savage transmission (Id guess so but dont want to order it if it wont).

If/once the standard transmission break down Im guessing the easy route is to buy the flux transmission from a chop shop on e-bay... or?

Another question for the pros: What tooth count would you pick on the pinion with a 43t spur and a 2 speed tranny locked in 1st? With a 22,2volt setup and a 2000kv motor that is. Im not really looking for crazy top speeds...

Battery tray and motor mount will be home brewn... we have a really nice workshop at work :)

I did consider running this setup with 4 cells... but would I be able to trash the nitro guys (4.6) with the ezrun setup on 4 cells? 6 cells will most likely break gears and flip me on the lid.

some of the nitro savages i've seen that are built for speed runs have the flux spurs. if i were you, i'd just try the stock plastic 47t spur first. it's mod1 and pretty hard to strip.

i'd just go for 6s. 4s will move a savage pretty fast but 6s will blow you away. you can program the esc to have a lot of puch control to help prevent diff and tranny issues.

If you want to convert your tranny to the flux spec just get p/n 100905. It replaces the "spur" gears of the 2 speed with a single steel gear. The flux tranny has the same ratio as a std tranny locked in 1st, and the top and output shafts and gears are the same parts in both trannies. Plus that part number I gave is about 10 bucks, so it is super cheap.

I would go with 5s myself, good motor speed and more power than 4s.

The flux spur will fit, and will give you needed clearance if you plan to mount the motor flux-style below and to the right of the spur. If you plan to make something like the kershaw "high cg" mount then you can use the 47t spur with no issues.

Just did a few savage conversions so if you have any other questions ask away!

James

Thank you for the feedback guys :)

I really dont want to place the motor in the "hight cg" position. So I'll order a 43t flux spur. Do you think the eZrun motor with heatsink/fan can fit the TVP's in flux style? It is a slightly fat lady :mdr:

Good info about p/n 100905 - cheers!

Which ez run motor is it? The 36mm motors, or the big ole 44mm? You can take a cue from the flux and make a tvp for that side that has a "window" in it that will allow the motor to sit slightly outside of the tvp.

I did a savvy a while back (hv savage was the name of the thread, I think) and I managed to put a feigao lx can (36mm diameter motor) on a custom L bracket on the stock nitro engine plate and fit up to 18/47 gearing. That was with the stock tvps. It was a tight fit, but it worked well, I adjusted the mesh by sliding the L braket side to side as you would with the nitro engine.

Oi Kermit :)

Its the big 44... figured that if I should kick Nitro arse I might as well do it right. Guess it would have been viser to get a 36mm motor? :(

Or I could try to fit one of those Losi 8th center diffs... looks like an easy way to do the power transfer.

Ahh well... Im off for a weeks holiday... hope the HW combo has arrived once Im back... then I can see for myself whats possible and whats not :smile:

It does seem like I'll have a hard time fitting the fat HW motor with heatsink + fan in between the stock TVPs. Hmm... any reason why I cant add some spacers on each side of the tranny+front/rear diff housings? If I could move both TVPs 1cm "outwards" I should have enough room to make a tight fit... or?

Anyway... be back in a week with more questions or maybe some pictures of a fat Savage.

I saw someone make a fat savage before, looked ok. I would just make 1 tvp with a clearance window, but that would depend what tools you have at your disposal!

Back from holidays and I get the msg that HW has stopped all sales of the 4465 motor due to some internal error in it... bummer!

KD or KD motors seems to be junk... price/performance is likely ok tho ;)

So whats the cheap solution? Feigao? Or should I just bite the bullet and get a medusa 36-70/80? Kershawdesigns has Feigao, RC-Monster has Feigao...is it an ok motor at 22,2 volt? Thinking XL 8 or 9...

Don't waste your money on a feigao... Get the medusa 70 or 80, 1600kv is good for 6s lipo.

I would definitely skip the Feigao and get a Medusa or Neu. Better quality+ better overall performance...

http://www.impaktrc.com/product_info...oducts_id=2618
They are coming down in price.

If you go with 5s the castle Neu would be a great choice. They can be had for a little as 110 on ebay if you bid well. I see them go for 125-130 all day... You can also get a black one that way! Or get the flux motor, same thing.

There ya go. $110 is even cheaper than the Medusa, and quality and performance will be better!

That is what I paid for my flux motor, new. I have also seen the castle motors go for that too. Considering an xl feigao is 75+ throwing in an extra 30-40 bucks is a no-brainer.

Definitely, and Medusa's are $120-130 new...

Feigao's are just reverse-engineered Hackers that perform ok. But when the option is there to get a Castle/Neu for a little more. I'd definitely go that route.

A little more $ will always get you a notch up in performance... the only problem is that there seems to be no end to the amount of notches you can go up.

I think I'll have to go the completely other way grab one of those hobbycity motors. Slightly bummed that the 36XL cans only are available as 1100 or 1900 KV... would have liked something in between.

The KD36 motors are junk. Waste of time and money. You might as well buy a brushed motor, it will last longer.

Arg :)

And the fat ones? KB45 08XL should have a nice RPM @ 22,2volt ~ 35-36.000ish... but then Im back at the low CoG issue as it wont fit in between! Merde ;)

The KB45 motors aren't bad for the price, and they are little powerhouses. But the KD36 motors are garbage.

Cheers!

KB it is then! Any opinion on the motor choice? Im thinking the 12L 1400KV will be more than enough... but the 08XL 1600KV is teasing my inner power junkie.

Go with the 8xl, it will stay cooler due to the longer can and more torque. Either will require good lipos, 25-30c min with 5000mah min. Something like the flightmax zippies would be a good inexpensive option. I ran the L can KB motors in my gtp conversion and they did fine, but I am sure your savage will be heavier and have more wheel/tire weight.

Thanks again-again guys :)

Any idea what these alu bulk heads are? And did I read something about shimming somewhere?

EDIT: If I hold the diff by the shafts there are some play when I pull them apart push them in. Is that what I should get rid of?

hi just some questions for you
i have the savage21 i want to convert to flm
i got the flux tranny and 52t spur form my 21
going to use mmm 2200kv combo just need help with spur & pinion
thanks
and i must say that my 21 was just in storage. than i found rc-monster.
next i am getting flm parts in the mail........i think we know the rest....
thanks guys

Just got word that the 4465 will arrive in a new and improved version next monday... Now I have 2 motors en route.

Regarding gearing of a Flux tranny with the mmm 2200 KV combo... look at the flux and get the same gear ratio.

Regarding gearing of the 4465 and KB45-08XL... I take it I cant go totally wrong if I aim at around 45 mph and take it from there.

45mph should be fine on those motors. No problems, just watch your temps if you want to gear for more.

Worn bits :)
 

Mkay... got the 4465 motor and 150a ESC installed. Pictures later when my colleagues have left the lab :lol:

For now I only have pictures of the worn parts.

The spur gear wasnt uber tight when I made the 1st test run. 44.000rpm will do that to a spur gear in 1½ minute!

After swapping the gear and tightening the slipper fully... the hex shape of the wheel stopped being hex shaped... its round now... time to play with epoxy!!

E-Sav v1
 

Ok... hex hubs epoxyed into the rim.

This guy does standing back flips and wheelies at crazy speeds... Guess HW was right when they claimed the C4 combo to be crazy powerfull :yipi:

It is currently in a version 1 state... it can drive but the motor mount + bat trays are plastic.

Hope this works.

Nixpus E-Savage v1:
http://www.rc-monster.com/forum/atta...7&d=1246634608

Mortor mount v1:
http://www.rc-monster.com/forum/atta...6&d=1246634608

ESC + motor mount:
http://www.rc-monster.com/forum/atta...8&d=1246634608

Question time...

What is the strongest diff I can put into this guy? The one thats in there is quite tight and favours one of the wheels over the other.

Whats the best wheelie bar out there?

What type of slipper should I put into this guy? The standard either slips all the time (and then the plastic spur gear melts) or I tighten it all the way and it doesnt slip at all (at least I cant tell that it does)

What kind of wheels baloon less? The standard tyres I have atm is double size at top speed. And one of them is about to leave the rim. So even tho Ive used the calculator to gear for 45MPH... its much faster due to balooooooning.

I'll do a serious attempt at mounting the motor below the spur... its gotta be possible!! Will have to remove the motor mount of course. But I can make some other construction to stiffen the TVPs.

Found a set of XL wheels with 17mm hex and all for 70$ delivered to my doorstep. Hope those guys will be a tad more durable than the old ones.

Battery trays made out of a stiff plastic box wasn't that sexy... but they got it up and running.

Time for battery tray v2. Found a stick of U shaped aluminium. Made a cut out in each end and bend them. tadaa... battery tray!

Added a strip of velcro to the bottom of the tray and the bat. will have 2 velcro straps around each tray. The straps are from lab top PSU's... they are used in order to manage the cable length.

Made a plastic insert in each tray. This way I can use standard hex screws. The "head" of the screws is sitting slightly lower than the edge of the plastic insert. Battery safe from harm... at least they wont get damaged by the screws ;)

Placed them at the front of the sav... should be ok balanced once motor + ESC is installed in the back.

http://www.rc-monster.com/forum/atta...1&d=1247124422

http://www.rc-monster.com/forum/atta...1&d=1247124422

http://www.rc-monster.com/forum/atta...1&d=1247124422

http://www.rc-monster.com/forum/atta...1&d=1247124422

Motor mount v2!

Who said you cant place a 44 can under the spur gear in a standard savage?

Found a sheet of 2mm stainless steel. Bend it into a U shape that fit inside the TVPs. Did a few test bends in order to get the right fit. Made a slot in each side. The gear mesh will be adjusted by moving the mount up and down.

Metal bend into shape:
http://www.rc-monster.com/forum/atta...1&d=1247125492

Cut out in order to make maximum room for drive & spur axle:
http://www.rc-monster.com/forum/atta...1&d=1247125492

Here you can see the slot. Placed a washer on each side of the mount - it slides quite neatly. I dont have a ton of adjustability... but I can gear this guy from 40-55ish MPH with a 47t spur (not counting ballooning in).
http://www.rc-monster.com/forum/atta...1&d=1247125492

Photo taken from the top.
http://www.rc-monster.com/forum/atta...1&d=1247125492

I had to grind away a little of the center gear box - The area where the top screw from the disc brakes were inserted. Other than that the opperation was pretty painless... the hardest part was drilling in the titanium TVPS. I increased the screw size at the mount from M3 to M4.

Motor mount & battery trays on the chassis

http://www.rc-monster.com/forum/atta...1&d=1247126816

http://www.rc-monster.com/forum/atta...1&d=1247126816

Will shorten the wireing as much as possible once I figure out where to put the ESC.

Turns out that my rear diff was ok.

One of the rear dogbones had a tendency to get stuck in the axle cup (in lack of better words). A bit of grease added and now it runs like a dream :)

Im wondering if there is a good low budget steering servo out there? The one that came with my chassis can hardly move the wheels when the truck isn't moving... and its slow.

Conversion is starting to take shape. Have you thought about mounting the ESC above the tranny? Just make a plate and you're done. As far as a cheap steering servo goes, the hitec HS-5645MG is great. Good specs and about $50 USD.

I have... but then I would have to increase the length of the wires between ESC & motor. But I guess your right :yes:

I had started to bend an alu mount for it. Was thinking to put it on top of the motor. But it will sit less protected up there and it will be annoying to fiddle with the motor if it sits up there.

If it becomes too nose heavy I can move the battery trays a bit backwards.

Epoxying the hex nuts didn't work btw... so now Im running with a pair of XL tyre/rims with the 17mm hex. Looks good so far. And bigger wheels = I can run in taller grass :lol:

Will see if I can get ½ an hour to mount the ESC properly and take a picture or two of the current state of the truck.

Cheers!

Wire length increased and now it runs in rewerse when I pull the throttle?

Is there any logical explanation to this - other than I have swapped two wires? :whistle:

Had a look at my steering servo. Its a Hitec HS-645MG. Would the digital version of this servo (that you mentioned) be able to turn the wheels when the truck stands still or is movement of the truck simply a requirement with this size of RC-car?

You swapped two wires during the process. About the extended motor wires- longer motor wires are not as big of a deal as longer battery wires, although it is best to have the shortest wires possible. The 5645MG is much stronger than the 645MG, you should be happy with it.

The 5645 will not be much of an upgrade over the 645. If you want to have very strong steering, a good hi torque digital is a must. I like the jr 9100t, solid, powerful and quiet...

The 5645 is fine in my 12lb truggy...

Remind me... whats lb? 12lb doesnt make sense to me... Im a metric kinda guy.

Had a minor problem with one of the Turnigy batteries. On of the tracks on the PCB where all the wires are soldered simply burned over:

http://www.rc-monster.com/forum/atta...1&d=1247826273

http://www.rc-monster.com/forum/atta...1&d=1247826273

Fixed it with some fat wire and solder... but slightly annoyed. I want to buy great quality at low cost damn it!!!:rofl:

I covered the solder pads which I didn't need to work on with insulation tape. Shorts in a LiPo is bad I hear! Just a little security tip if anyone reads this and has to do similar repair work.

Time for a few more questions :)

Must say that this truck is tough! Been doing some really silly jumps with poor landings. High speed turns that went wrong - resulting in some serious tumling action. Backflips with poor landings. High speed wheelies... with subsequent crashes. AND IT STILL LIVES!!

However... it seems that a standard Savage with XL tyres and the big hobbywing system is build to crash. The turning radius is somewhat huge and it flips over if im not really carefull during high speed turns. Also it wheelies/backflips like mad.

So... I have been looking at the XL solution for making the wheelbase wider. What are you guys experience with that? It seems to me that the bearings will be seriously punished in that setup - unless the wheels are perfectly balanced. Would that be an option to make the turning more stable?

Ive also been looking at that FLM conversion chassis. Looks sweet... but will it help my truck handle better? EDIT: Ive been looking but cant seem to find the ansver: What is the maximum battery dimensions in that chassis?

One of the other guys have a brushless revo en route... so to prevent him from going in circles around me I really need to enhance the driveablity of this thing... raw power and silly stunts wont cut it anymore ;)