Thinking of XL brushless conversion

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craig911

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Hey ladies and gents

I'm currently in the thought process of converting from nitro to lipo and want to build a list of what i need & prices before i start what will be a slow process of acquiring parts and proceeding to the conversion.

This will be a budget build i want to keep the cost down as much as possible

What parts would i need since I'm having a hard time finding the correct info?

The kind of info that would be helpful would be stuff like, what motor mount can i use with the standard nitro XL TVPs
What size motor eg 450/550 etc & spec such as kv/turns

I know i will need an ESC of around 150 amps or more, my thought on an esc though i could get away with a forward only one like in my helicopter and use my reverse module for well reverse

Mainly i need help on finding what size motor and specifications of said motor and a mount for the standard nitro TVPs

I'm probably going to keep the 3 speed gearbox instead of direct drive for the moment i want to try and use as much of my current truck as possible to keep the budget down and get the bare essentials once that's done i can make adjustments from that point to suit me


i'm not looking to build a speed demon or a torque monster (I'm not a fan of wheelies) just something that will give me similar or a bit better performance over my current 4.6 engine in the truck and maybe allow me to do some crawling if the mood takes me

thanks in advance
 

olds97_lss

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The cheapest proven route to take would be a hobbywing/2200kv combo and run an alza center diff mount. The guy that made the "conversion" kit with mount passed away late last year, Dan at Kershaw Designs. Other than the alza, I don't know of another conversion that doesn't require you to replace the chassis plates and trans. Then again... I think the alza is for a flux...

Regardless, if you come up with some other alternative, I'll keep an eye on this thread as I have a savage X I wouldn't mind converting... :)

That's what I intended on doing last year, then before I got the full conversion kit from Dan, I found out his health was failing and got a refund a month after I ordered it, then bought a used flux off ebay for $450. Not my proudest moment, but it was a complete truck and I've had a lot of fun with it.
 
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craig911

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The cheapest proven route to take would be a hobbywing/2200kv combo and run an alza center diff mount. The guy that made the "conversion" kit with mount passed away late last year, Dan at Kershaw Designs. Other than the alza, I don't know of another conversion that doesn't require you to replace the chassis plates and trans. Then again... I think the alza is for a flux...

Regardless, if you come up with some other alternative, I'll keep an eye on this thread as I have a savage X I wouldn't mind converting... :)

That's what I intended on doing last year, then before I got the full conversion kit from Dan, I found out his health was failing and got a refund a month after I ordered it, then bought a used flux off ebay for $450. Not my proudest moment, but it was a complete truck and I've had a lot of fun with it.
thanks for the info, i saw hobbyking have a similar esc and motor combo for £60

what would the difference be between a motors KV 1900 v 2100 v 2300

i think the main issue is going to be finding a motor mount, i think it could be possible to use a dremel and use the standard flux setup, i will look into it more,

integy made a mount for a 540 motor but from looking it's no longer in production
 

olds97_lss

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The kv on brushless is how many rpm's it will turn per volt supplied. Lower kv usually means higher torque.

My savage flux hp (non-xl) came with the blur (mamba monster, old not waterproof)/2200kv torq motor in it. I recently replaced it with a mamba monster x sensored with a 2200kv castle motor. I hated running without a waterproof setup. The previous owner said he coated the internals of the esc with something, but I'd rather just keep that for a backup. I only run 4S total and it's plenty fast for me. Can't recall the gearing, but it tops out around 40-45mph. I had to dial the punch down to 80% as it was a real pain to drive. If I went WOT anywhere below 2/3 throttle, it would flip on it's lid. It still will, but not quite as often.
 

craig911

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The kv on brushless is how many rpm's it will turn per volt supplied. Lower kv usually means higher torque.

My savage flux hp (non-xl) came with the blur (mamba monster, old not waterproof)/2200kv torq motor in it. I recently replaced it with a mamba monster x sensored with a 2200kv castle motor. I hated running without a waterproof setup. The previous owner said he coated the internals of the esc with something, but I'd rather just keep that for a backup. I only run 4S total and it's plenty fast for me. Can't recall the gearing, but it tops out around 40-45mph. I had to dial the punch down to 80% as it was a real pain to drive. If I went WOT anywhere below 2/3 throttle, it would flip on it's lid. It still will, but not quite as often.
Thanks That makes it easier to understand, in that case i think i would at lowest go with a 2200kv motor, since i down need to wheelie constantly but would like torque so i can run large wheels.


i will probably only run on 3s for simplicity sake and that's all the power i would probably need.

i saw that hobbyking have some 5000mah 20c 3s lipos for a good price would those be suitable for use or would i want a higher C of 25 or 30

my thinkin was that my helicopters 2200mah 20C packs are rated at 44 amp so 5000mah should be 100 amp
thats if what i read was correct,

although I'm thinking at a minimum i would need 20c and 25c would be more than i would require 30c overkill

so far i have found an esc motor combo for £60 that would work, but I'm not going to pull the trigger until i find a motor mount
i have potentially found the batteries i will run

just the task of finding a motor mount, or finding the stock flux motor plate and mount for a reasonable price and modifying my chassis ( last resort )
 

olds97_lss

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I'm not sure you can get away with 3S on a rig like that. You may stress the esc too much trying to pull the amps to drag a truck that heavy around. I run 4S with 60C and 90C packs. With older 60C packs that are tired and starting to be fussy on charging, I do get a bit of stutter half way through the pack when I pin it. I'm guessing you could gear it down to avoid straining the esc, but it would be pretty slow.

I only run SMC 2S lipo's in all my rigs, the 7200 and 9000mah packs. The savage and brushless revo I have both can run 6S, but running 4S is easier on the drive train in both rigs. Besides, with gearing that runs fine in grass pack after pack, I top out around 42-45mph, which is plenty fast for a MT. They tend to get a bit squirrelly above 40mph anyway.

2200 @ 14.8V (2s x 2) = 32000rpm
2200 @ 11.1V (3s) = 24420rpm

In a perfect world, that would be a 25% speed loss, around 33.75mph max with the gearing I have.
 

craig911

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I'm not sure you can get away with 3S on a rig like that. You may stress the esc too much trying to pull the amps to drag a truck that heavy around. I run 4S with 60C and 90C packs. With older 60C packs that are tired and starting to be fussy on charging, I do get a bit of stutter half way through the pack when I pin it. I'm guessing you could gear it down to avoid straining the esc, but it would be pretty slow.

I only run SMC 2S lipo's in all my rigs, the 7200 and 9000mah packs. The savage and brushless revo I have both can run 6S, but running 4S is easier on the drive train in both rigs. Besides, with gearing that runs fine in grass pack after pack, I top out around 42-45mph, which is plenty fast for a MT. They tend to get a bit squirrelly above 40mph anyway.

2200 @ 14.8V (2s x 2) = 32000rpm
2200 @ 11.1V (3s) = 24420rpm

In a perfect world, that would be a 25% speed loss, around 33.75mph max with the gearing I have.

looks like a 4s would be roughly equal to running a .21 or .28 nitro engine RPM wise but with heaps of torque so that would actually work quite well for myself,

i was looking at a few of the flux mounts from other HPI vehicles they look like they could have some potential with some mods
i was thinking maybe the hpi vortex mount - hpi 103661 then modify the engine mount plate with new mounting holes with a dremel or something,
 

olds97_lss

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Part of the issue is that to get it geared usefully, the motor hangs off the side of the chassis a bit, so you may have to cut up the chassis rail on the pipe side, which could make it weak. Might be less annoying if you remove the engine plate itself and make a mount that bolts/slids on the cross beams that the plate screwed to. Not having that plate will weaken the overall structure some as well, but at least you can move down 2mm which gives you more gearing room. Besides, if you make your own L bracket for the motor to bolt to, having that clamped down using 4 4mm bolts should add some structural rigidity back.

With the flux hp motor plate, they don't have cross beams like the nitro version does. They do, but they run parallel with the TVP vs perpendicular. I'm guessing that's so they could lower the motor plate as far as possible as the plate is nearly touching the rear center dog bone. The motor plate connects to those parallel beams on the outside edges. Take a look at the parts explosion for the flux hp and you will see what I mean. I have a center skid on mine that I don't want to take off at the moment or I'd show you.

I disconnected the roll bar so you could see how the motor is scooted clear over through the TVP. The outer motor mount adjustment bolt heads are actually outside the TVP vs inside like nitro.




You can kind of see the clearance between the motor plate and rear center cvd:
 

craig911

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I figured i would need to mod the pipe side, i have already done it to an extent as my engine back plate was quite large and i couldn't get the gears to mesh properly, structurally I'm not sure it would cause too much of an issue what i have done so far has made no difference from what i can tell

i can see from your pics that the motor is quite low though so it would be off to the side quite a fair bit in my case,

i'm not going to lie for a few minutes there i forgot how to upload images,

excuse my ghetto exhaust plug and tank.

IMG_3301.JPG


Part of the issue is that to get it geared usefully, the motor hangs off the side of the chassis a bit, so you may have to cut up the chassis rail on the pipe side, which could make it weak. Might be less annoying if you remove the engine plate itself and make a mount that bolts/slids on the cross beams that the plate screwed to. Not having that plate will weaken the overall structure some as well, but at least you can move down 2mm which gives you more gearing room. Besides, if you make your own L bracket for the motor to bolt to, having that clamped down using 4 4mm bolts should add some structural rigidity back.

With the flux hp motor plate, they don't have cross beams like the nitro version does. They do, but they run parallel with the TVP vs perpendicular. I'm guessing that's so they could lower the motor plate as far as possible as the plate is nearly touching the rear center dog bone. The motor plate connects to those parallel beams on the outside edges. Take a look at the parts explosion for the flux hp and you will see what I mean. I have a center skid on mine that I don't want to take off at the moment or I'd show you.

I disconnected the roll bar so you could see how the motor is scooted clear over through the TVP. The outer motor mount adjustment bolt heads are actually outside the TVP vs inside like nitro.




You can kind of see the clearance between the motor plate and rear center cvd:
 

olds97_lss

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Yeah, you would have to take out even more. I had to notch mine a bit on my old 21 when I ran an OS21RG in it. Had pretty low gearing and it had a large starter housing.
 

craig911

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i looked at a few more mounts but it would seem any that were purouse made are discontinued

unless i want to cut the chassis sides up and make extensive mods its likely a dead end project

think i will keep an eye out for a X or XL flux roller, failing that depending on availability and price i may pick up one of the new ones when they eventually hit the market depending on price = hpi 112609
 

olds97_lss

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i looked at a few more mounts but it would seem any that were purouse made are discontinued

unless i want to cut the chassis sides up and make extensive mods its likely a dead end project

think i will keep an eye out for a X or XL flux roller, failing that depending on availability and price i may pick up one of the new ones when they eventually hit the market depending on price = hpi 112609
That's kind of how I ended up, but I got a complete used flux hp, which is the shorter one like the X vs XL.
 

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