My first 1/8 BL conversion

[Steeni]

Well hello to all and since I'm new to this forum, I'll start with my newest project, a Losi 8ight T. Used a Race Roller chassis I got from a german teamdriver and started out with a MMM & Castle/Neu 2200kv Combo and ofc Mike's motormount.

Setup right now is almost stock, need to get it running for a few packs to start finetuning, weight balance seems ok now. Using a 4s custom made pack with 5000mAh and 25C. Some action pictures to start with:




After that run though in roughly 10 minutes my MMM (probably a V3, as I bought it as combo, but no sticker to mark it as a V3) spat out flames then started smoking.. ..fried. I'm using a Spektrum DX3S radio with telemetry, and having only 1 temp sensor mounted on motor it showed 23 C (about 73 F) and the esc was slightly warm at touch.
I assume that I was not running it to the limits. I use a 13 tooth pinion right now with the stock steel spur and diffs. I just got a message drom CC that my replacement esc is on its way to old Europe, but meanwhile I got an MGM Controller with a blackbox for even more telemetry, because it seems to me I'm getting extremly high start peak currents.

Here some pics after the run, still with the Castle MMM in it:



I'm waiting for next weekend to get all the telemetry and the new esc fixed to the chassis for another testrun, although right now we seem to be caught in a snowstorm.

I'll update with new pictures as soon as I have it running again and I'll post some of the xls files from the blackbox about peak currents. 1 thing I already can tell after my first testruns on the workbench is that peak "liftoff" currents occuring at starting form a dead stop are in my opinion extrem: 194 Amps were max measured, with around 130 Amps as an average....because this was measured with wheels spinning freely these peaks lastet only for app 0.5 seconds and after that even accelerating more did not draw more then 6-7 amps.

Could I ask what pinion/spur combinations other 8ight T drivers here use for fast offroad track conditions?

Btw in current setup (with those Savage XXL rims and tires I use for testing) The truck reaches topspeed at 72 km/h (44.7 mph) which seems a little high for a 4s setup?

Cheers

[plettenbergs]

looks good...i like those action shots!

[himalaya]

Nice conversion, pretty similar thoughts to mine, laying down both betteries as low as possible.

I am running 15/48 gears under 6S 25C 5.2Ah LiPo for the winter, motor temperature is well controlled around 40~50C. when summer comes I think I may have to gear down to 12/49.

[Steeni]

Hmm....seems you're running an even higher gear ratio then me...with 6s!

What motor do you use in that setup, All I can see it's no Castle/Neu and it seems smaller then mine?

And yes, I did try and keep the weight center as low as possible while keeping the best left/right weight ratio possible.

[himalaya]

The above picture is just for the first run, I then switched to Neu/Castle 2200KV.



You're right my gearing is way too agressive, as long as the motor temperature is okay(by the help of a fan) and my batteries still happy, I can keep on driving this setup, but not too long before spring comes.

Tekno conversion kit has very limited gear mesh adjustment range, I have only 12T and 15T pinions, the 12T doesn't fit perfect(gear mesh too loose even at the closest limit). That's why I have to use that agressive gearing. I bought a 49T Robinson spur which is just one tooth larger than stock, so that I can use the 12T pinion and get a reasonable gear ratio for the coming warmer seasons.

I'm currently running the Losi brushless conversion kit in my 8T. I've got their 45t spur and I'm running a 16t pinion. Using the Mamba Monster setup on 4000mah 6S lipo. Motor is barely warm to the touch after a 15min drive.

Edit: I guess I should add I'm running the 2200kv motor in it.

[Overkill]

Hi all

Having a great read through all forums for lots of info on the 8-T brushless setups, and threads like this have been incredibly valuable to me. If you don't mind me jumping in and asking a question on shocks as there has been a couple of pic in here that show what my question is about.......

What is a great spring combination you can use on the 8-T without using/adjusting the preload for the stock springs on a BL setup? I have read that you can use the rear springs up front but I have not read how well it worked. Any help would be appreciated, so far choosing the MMM combo was due to reading threads on RCM so hoping you guys can sort me out on the spring combos

[SlidSlide]

Nice build dude. Give us some vid too!

[George16]

Originally Posted by Overkill

Hi all

Having a great read through all forums for lots of info on the 8-T brushless setups, and threads like this have been incredibly valuable to me. If you don't mind me jumping in and asking a question on shocks as there has been a couple of pic in here that show what my question is about.......

What is a great spring combination you can use on the 8-T without using/adjusting the preload for the stock springs on a BL setup? I have read that you can use the rear springs up front but I have not read how well it worked. Any help would be appreciated, so far choosing the MMM combo was due to reading threads on RCM so hoping you guys can sort me out on the spring combos

Welcome to RCMonster Josh . Sorry , can't help you with the springs since I don't own an 8T.

[Overkill]

Originally Posted by George16

Welcome to RCMonster Josh . Sorry , can't help you with the springs since I don't own an 8T.

Cheers Lito, you showed me the way and it has been a great place for info that is for sure.

By the way.....Steeni and himalaya they are two great looking setups

[js058515]

Originally Posted by Overkill

Hi all

Having a great read through all forums for lots of info on the 8-T brushless setups, and threads like this have been incredibly valuable to me. If you don't mind me jumping in and asking a question on shocks as there has been a couple of pic in here that show what my question is about.......

What is a great spring combination you can use on the 8-T without using/adjusting the preload for the stock springs on a BL setup? I have read that you can use the rear springs up front but I have not read how well it worked. Any help would be appreciated, so far choosing the MMM combo was due to reading threads on RCM so hoping you guys can sort me out on the spring combos

I run the Race Roller spring set-up which is pretty much the same when compared to the other set-up sheets from Drake and Truhe. Black springs in front and Grey in rear. The reason others use rear springs in the front is because you have to turn the shock collar all the way down to the almost the bottom to get the stock ride height for the 8T. I have also used White rear springs in front and Purple in back. Purple was a little stiff for the rear, but White fronts were similar to the Black fronts except the shock collars barely needed any adjustments. Hope that helps some.

[Overkill]

Originally Posted by js058515

I have also used White rear springs in front and Purple in back. Purple was a little stiff for the rear, but White fronts were similar to the Black fronts except the shock collars barely needed any adjustments. Hope that helps some.

Legend!!!!! That's what I was wanting to hear. I also have the race roller and may just get the rear shock kit and have a play, starting with information given by yourself. I have also read that the rear grey springs work well up front, but that was the only one I could find and they did not state what batts they where using, or what motor.

Are you able to give details of your setup please? Mine is the 1.0 RR with Losi conversion kit, MMM 2200Kv Combo and a Zippy-H Lipo weighing in at approx 629grams (22.2 ounces). Once they all arrive, I'll get pics in my own thread and try different spings and weights that I will hopefully find other guys/gals using. There has to be one that will suit my style

[js058515]

Originally Posted by Overkill

Are you able to give details of your setup please? Mine is the 1.0 RR with Losi conversion kit, MMM 2200Kv Combo and a Zippy-H Lipo weighing in at approx 629grams (22.2 ounces). Once they all arrive, I'll get pics in my own thread and try different spings and weights that I will hopefully find other guys/gals using. There has to be one that will suit my style

I definitely would like to hear your results with different spring set-ups. My set-up in detail is: 8T 1.0 RR, Tekno V3 conversion kit, mechanical brake servo, MMM with Tekno Neu 1515 3D, Tekno 3 shoe clutch (add a few grams for that), the batts I use are Rhino 6S 3700mah (615g). Let me know if you want more details.

[Steeni]

Hey and thanks for all the feedback...

Well the MGM controller seems to do fine now and had my first full run. Reading the blackbox data and "feeling" the thing move gave me some directions, that I'll try to explain here:

1. The springs...Well, due to the enormous torque the 2200 kv motor gives out I'll have to go stiffer in the rear, I managed several times to get the rear touch the ground by accelerating only, and my setup allows to put the batterie more in front for weight distribution pourposes, which somehow improved the effect of the truck wanting to pull wheelies all the time but did bring him "down to its knees", as explained.

2. Differential... While I'm happy about front/rear, I'll have to try out to lock the middle one further, the truck is unable to tranfer the torque to the rear wheels, making the front wheels balloon, got better with more front load, but still needs tweaking.

3. Controller lockouts due to Batterie voltage... I'm afraid there will be no easy way out of this one. I can perfectly run the truck on a track to under 10% capacity, but if I spin out and don't have brakes applied, the currents the motor is taking for a relaunch whilst rolling slowly backwards are too high and controller locks out due to sudden batterie voltage drop. I'll try to alter controller setup to see if it helps....a slipper would be the perfect solution to this, but sadly, as far as I know, it's current not possible to use a slipper and a differential in a 8ight T, makes me thinking of Mike eventually wanting to release more versions of his "slipperential" then just the Revo one.

Well before this post gets "epic", I'll stop with the fact, that I was marvelled by the behavior of the truck on the track, it's very agile and the power you can pull out at accelerations makes me smile each time I'm pulling the throttle, I ran those things on nitro and must say that it's a complete different thing. Still have to learn the setup, as it seems this one needs something quite different from the nitro version and I don't want to loose the agility the chassis has right now.

[fastbaja5b]

Are you getting the MMM sorted under warranty?