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Old 02-06-2013, 01:38 AM   #1
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Default Durango DNX408 brushless questions

Hello people

Im sorry if this had been talked about befor but I cant seem to find ansewers when I search.

I have a Durango DNX408 with venom brushless kit. 2250KV xerun motor , Mamba monster ESC and Turnigy 4500Mha 30c 4s LiPo .

Last race meeting I had a Tekin RX8 in it but it did the big smoke and I dont know why ! So I put a new Monster in it.

I have not raced it yet but I am worried I might nuke the monster If dont get advice.

I have a 12tooth pinion and standard spur and it seems to get hot when ruuning in the basement car park. I dont know how hot as I dont have a temp gun but I think its too hot.

When I accelerate it seems to lag and then push hard , I have looked at the Castle web sight and it says the Lipos might not be good enough , but it accelerated great when I had the Tekin in it with the same Lipos .

My questions are

What sort of range of pinion I should be running ?

Why is it lagging on acceleration ?

Could the lag be because I have gone from sensored to non ?

What setup should I have the ESC ( I have a castle Link for it)

Any advice would be great as I have a big race meeting this weekend !

Cheers

Vaughan

Last edited by vorn; 02-06-2013 at 03:45 AM.
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Old 02-06-2013, 06:48 AM   #2
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Just a few pointers, the Mamaba has the lag because it's non-sensored, that motor is really a bit much for a buggy but the 12 pinon should be ok, 1/8 E-buggies really need 50c+ batteries because of the amp draw from the large motors and I have no idea about the Mamba's settings.

For what it's worth I have had great luck with the Orion R8 Pro esc in all of my 1/8 E Buggies and Truggies.
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Old 02-06-2013, 11:28 AM   #3
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The "lag" you are noticing is typically referred to as cogging. This didn't occur with the RX8 because you ran it sensored. This is the downfall to running these setups unsensored. Also, I would gear it around 17 to 18/60 with that motor. The 12T pinion is pretty low, even with that motor. Does it feel like it's running at Top End a lot? This could easily be creating a lot of the heat.
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Old 02-06-2013, 12:13 PM   #4
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Quote:
Originally Posted by 4ptss View Post
Just a few pointers, the Mamaba has the lag because it's non-sensored, that motor is really a bit much for a buggy but the 12 pinon should be ok, 1/8 E-buggies really need 50c+ batteries because of the amp draw from the large motors and I have no idea about the Mamba's settings.

For what it's worth I have had great luck with the Orion R8 Pro esc in all of my 1/8 E Buggies and Truggies.
I do not think that is the case with C ratings for batteries when it comes to ebuggies. My impression is that running higher voltage (4s) lowers the need for the high C ratings. I am running dual 28c 6000mah 2s packs with my T8 1900kv and have no issues. Now maybe with a 2250 it might be, but it would not be as much of an 8th scale issue as a motor choice issue. I am also running a 16t pinion, and come off under 115* motor temp. It is not summer yet though, so that will rise some.
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Old 02-06-2013, 01:12 PM   #5
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Hi Guys

Thanks for that , it dose seem to be reving out quite fast . Wow I would of never though I was under geared as I thought low gearing lower temp -higher gearing higher temp , But I am new to brushless and only going off brushed experiance I have.

I though the Lipos were ok as it ran very good with the same Lipos with the RX8.

Now I know fist hand what the simptoms of cogging are

Cheers

Vaughan
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Old 02-06-2013, 01:41 PM   #6
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Definitely undergeared. Go to a 14 or 15 tooth and check your temps with a temp gun. You want the motor under 170. The batteries you have are totally sufficient. I've run the super cheap turnigy 20c hard case 4s packs with zero issues. For more gearing suggestions look up the dnx thread and post in there.
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Old 02-06-2013, 02:44 PM   #7
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Quote:
Originally Posted by vorn View Post
Hi Guys

Thanks for that , it dose seem to be reving out quite fast . Wow I would of never though I was under geared as I thought low gearing lower temp -higher gearing higher temp , But I am new to brushless and only going off brushed experiance I have.

I though the Lipos were ok as it ran very good with the same Lipos with the RX8.

Now I know fist hand what the simptoms of cogging are

Cheers

Vaughan
Gearing lower is generally a good thing, but gearing TOO low, as mentioned is referred to as being undergeared. When undergeared, the motor has a tendency to run at max revs a lot, thus causing heat. It's all just a matter of finding the happy medium, and then adjusting from there depending on the track you are on.
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Old 02-07-2013, 04:29 AM   #8
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Ill get a few more pinions for the weekend and see how I go
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Old 02-07-2013, 06:27 AM   #9
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If you do need more help, the people following http://www.rctech.net/forum/electric...go-dex408.html will help you out. http://www.rctech.net/forum/nitro-of...rld-title.html if you ever feel the need to convert it back to nitro
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Old 02-07-2013, 01:25 PM   #10
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Thanks EKT

I didnt look there as its a DEX thred. But had a look through and very helpful info .
Ive had my days of nitro

Cheers
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Old 02-10-2013, 11:19 PM   #11
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With people that have done the venom conversion, where are you placing your rx out of harms way?
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Old 02-11-2013, 04:45 AM   #12
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Mine is behind the motor , that's the only place I could fit it
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Old 05-03-2013, 08:04 AM   #13
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All infos are in this thread

http://www.rctech.net/forum/electric...it-dnx408.html
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