Hi
Here my 2 cents about 2 upgrades I did on Roost 1/18 motor. The reason for the upgrade was the original 25T getting hotter and hotter which finally burn. My son run the Roost in the garden on a offroad circuit, almost no run on road, we don't look for extra speed. Project was to find replacement solution, I find 2 :
First solution: brushed
I got a 380 15T motor on ebay for 12.9€, a very common model for 1/16. Fit perfectly with the original ESC, even with Lipo 2S. Only issue is the servo which I replaced some months ago by a ES3074 which seams to need a little more power than original one. Side effect is servo become lazy when NiMh lack power (original 900mAh ok but a Dynamite 1200mAh pack not ok). No problem with Lipo.
With 380-15T, 62T gear and 16T pinion (both metal), Roost is smooth and fast. Maybe a little less nervous at low speed than the original 25T but it's an advantage because Roost was lacking of adherence on ground with the original 25T. So a better speed and an easier to drive car. This 380 stay almost always cool, no more temperature problem.
Of course, going faster on offroad need adjustement on shock absorber, default setting is too soft at high speed. Front need spacers to become harder with 300CPS oil. Rear need a different oil, I tried by mixing 300 and 900, I think the good setting is between 450-600 to have a good balance for jumps and good adherence.
Runtime is better than the original 25T on our offroad track:
- NiMh 900mAh (original) : 15-20min
- NiMh 1200mAh : 20min
- NiMh 1600mAh : 25-30min (with this one the Roost is more nervous)
Second solution: brushless
I wanted to challenge the Roost with more power, so I buy a Surpass Hobby combo on AliExpress: 35A ESC + 2440 4500kv. I choose a 2440 for the 2.3mm pinion hole size because I already have some. I hesitate a lot about kv : more ? less (to run on 3S) ? 4500kv seams to be a good balance. For the receiver I pick a DumboRC X4 for about 24€. Great price and quality, better than the STX2 (my son was fan of it but he definitly prefer the DumboRC).
After several days, it's a good choice, on offroad circuit more power give more control on jumps and the ESC seams to better handle the ES3074 servo (remember it need more power than the original servo). Roost is faster and more nervous. We are still making some test, pinion is a 15T, with the 62T it's a bit too little, I will probably change to a 58T (metal). Yesterday I suspected a default with the rear diff, I checked it but everything was ok. I filled it with a 2000cps oil because I feel it too smooth.
Runtime is again better than the brushed 380 15T on our track: with 1000mAh of a LiPo 2S we can expect 25-30min ! I'm waiting for a Dean-EC3 adapter to check with NiMh.
Last point: Roost is running with 63mm tyres, the cheapest I find on AliExpress, 3€ for 4x tyres. Good onroad and offroad for the basic version (no relief), there are little bigger than the original from ECX (and cheaper...) which give a little extra speed. I'm waiting for bigger tyres (nearly 75mm !) but softer to give extra adherence. Will check transmission impact (brushless + bigger tyres give extra load !).
Here my 2 cents about 2 upgrades I did on Roost 1/18 motor. The reason for the upgrade was the original 25T getting hotter and hotter which finally burn. My son run the Roost in the garden on a offroad circuit, almost no run on road, we don't look for extra speed. Project was to find replacement solution, I find 2 :
First solution: brushed
I got a 380 15T motor on ebay for 12.9€, a very common model for 1/16. Fit perfectly with the original ESC, even with Lipo 2S. Only issue is the servo which I replaced some months ago by a ES3074 which seams to need a little more power than original one. Side effect is servo become lazy when NiMh lack power (original 900mAh ok but a Dynamite 1200mAh pack not ok). No problem with Lipo.
With 380-15T, 62T gear and 16T pinion (both metal), Roost is smooth and fast. Maybe a little less nervous at low speed than the original 25T but it's an advantage because Roost was lacking of adherence on ground with the original 25T. So a better speed and an easier to drive car. This 380 stay almost always cool, no more temperature problem.
Of course, going faster on offroad need adjustement on shock absorber, default setting is too soft at high speed. Front need spacers to become harder with 300CPS oil. Rear need a different oil, I tried by mixing 300 and 900, I think the good setting is between 450-600 to have a good balance for jumps and good adherence.
Runtime is better than the original 25T on our offroad track:
- NiMh 900mAh (original) : 15-20min
- NiMh 1200mAh : 20min
- NiMh 1600mAh : 25-30min (with this one the Roost is more nervous)
Second solution: brushless
I wanted to challenge the Roost with more power, so I buy a Surpass Hobby combo on AliExpress: 35A ESC + 2440 4500kv. I choose a 2440 for the 2.3mm pinion hole size because I already have some. I hesitate a lot about kv : more ? less (to run on 3S) ? 4500kv seams to be a good balance. For the receiver I pick a DumboRC X4 for about 24€. Great price and quality, better than the STX2 (my son was fan of it but he definitly prefer the DumboRC).
After several days, it's a good choice, on offroad circuit more power give more control on jumps and the ESC seams to better handle the ES3074 servo (remember it need more power than the original servo). Roost is faster and more nervous. We are still making some test, pinion is a 15T, with the 62T it's a bit too little, I will probably change to a 58T (metal). Yesterday I suspected a default with the rear diff, I checked it but everything was ok. I filled it with a 2000cps oil because I feel it too smooth.
Runtime is again better than the brushed 380 15T on our track: with 1000mAh of a LiPo 2S we can expect 25-30min ! I'm waiting for a Dean-EC3 adapter to check with NiMh.
Last point: Roost is running with 63mm tyres, the cheapest I find on AliExpress, 3€ for 4x tyres. Good onroad and offroad for the basic version (no relief), there are little bigger than the original from ECX (and cheaper...) which give a little extra speed. I'm waiting for bigger tyres (nearly 75mm !) but softer to give extra adherence. Will check transmission impact (brushless + bigger tyres give extra load !).
