The need for speed with XL5000... need assistance! [Archive]

dawn_skd

02-22-2008, 04:58 PM

Hi,

I just got a new Lehner XL5000 from a freind and I'd like to use it for drag racing (NFS). I have a FT TC4 I'm not using and since RC10 are very tough cars - I think it should do fine.

I have some questions...
Which ESC will hold 4s with no problem using the lehner motor ?
Is it the Mamba MAX ? (I'll use CC BEC).
Will that combination will run fast using large pinion and small spur AND 4s ?

Is it possible to run 2s orion 3600 and 2s orion 4800 using y-harness to create it as 4s ?

Thanks a lot !!!
Dawn.

dawn_skd

02-23-2008, 02:03 AM

Top speed it what I'm looking for...

kufman

02-23-2008, 10:14 AM

Your lipo idea is a bad idea. The low voltage protection will not protect the lower capacity battery.

4S is too much for the Lehner motor, it would be reving at 74000 rpm... too much.

Not sure if the MM will handle that motor or not. It will be close. On 2S it will probably work.

GSMnow

02-23-2008, 12:37 PM

From the Specs on the XL5000, I would not run it any higher than 3S. That is 55,000 rpm or so. A Mamba Max will run it okay, but I would recomend a fan. The XL5000 is rated for 125 amps, so it can handle over power a little longer than the Mamba Max, but for a drag run, it should hold up fine. You battery should be rated at 100 amp constant, so a 20C would be a 5000mah to really get all the performance possible. The Max Amps packsa carry a 30C rating for 30 seconds, so you could go to a 3000 or 4000 to save weight, but you will have a little less spank out of the hole.

If you were going to parallel your 2 2S LiPos, you might get away with the different capacities. The smaller pack would drop voltage a little faster, and the larger pack will end up putting out more current to keep the voltages even, but you should only pull the current rating of the larger pack to be safe. In seires though, you can't get away with different capacities. The current through both packs is always the same. So the weaker pack will be your current limit, and it will go dead first. And like Kufman said, the weaker pack will go dead at a much lower voltage than is safe long before the total pack low voltage cutoff is reached. Don't series non matched packs.

dawn_skd

02-23-2008, 04:25 PM

Hi,
Thank you for your quick responses!
I will only use identicals packs if I'd like to use Y-harness connector.

Do you think this XL5000 will help me get to high speed ?
I own 3.5R GTB sets and they goes fast but I'd like to go much much faster on that FT TC4. I tried using sensorless motors before (Fiegao 6S and this new XL5000) using an old BK Warrior 9918 I have but it was horrible!!! it was stuttering on high speed and I lost brakes after 2 minutes (using more than eight 3800 cells).

Will the MM will be more stable than that BK ESC ?
Since you said that the XL5000 can handle only 3s - will it push the car to go much faster than the GTB?

Or should I just replicate the spec from that BALISTIC rocket using HV-85 and Neu 2Y and 8s (LOL)...

Dawn.

http://pic.hevre.co.il/Files/6A04AACBE72B4DEE8D811B305108BE31/orig_3C68544411E94207A7631DC0ED7961F9.JPG

GSMnow

02-24-2008, 01:40 AM

The XL5000 on 3S should be able to do an easy 60+ mph. If you give me the gear ratios of the transmissions and the size of the tires, I can figure out what you would need for a pinion and spur for 55 mph, 60 mph, 65 mph, and 70 mph. Start withthe low, do a run for 1 min and check the temperature of everything. if it is okay, go to the next gear and try again. If you really want to go fater than 70, you should invest in a data logger to get a better idea of what is going on. When you gear for very high speed, you need to be easier on the throttle trigger. The very high load on the motor from the tall gearing will make for extremely high currents at lower speeds. So just roll on the trigger and feed in a little as it accelerates. This will keep the motor, ESC, and battery temps much lower, and give you the full power up at high speed where you need it to push through the air.

dawn_skd

02-24-2008, 02:36 AM

tire diameter are: 138mm
spur/pinion (48p): 72/21
car internal ration: 2.5

should I replace the BK esc to MM ? the BK was stuttering on high speed and I lost brakes after 2 minutes (using more than eight 3800 cells).

how fast goes GTB5.5 and GTB3.5 using the same spec as above (2s) ?

GSMnow

02-24-2008, 11:18 AM

138 mm is over 5 inches. That can't be diameter. Circumference maybe, but 1.73 inches in dia sounds a little small. Double check the Dia. with a ruler.

dawn_skd

02-24-2008, 11:44 AM

http://www.mathsisfun.com/numbers/images/pi.gif
http://www.rbproducts.com/images/GRP(Ellegi)/06GVX04C.jpg

Hi,

This is a regular on-road foam 26mm tires.
diameter is 69mm-70mm.
Sorry for writing wrong numbers...

Dawn.

GSMnow

02-24-2008, 02:10 PM

I figured it was just a typo, no big deal. 70 MM it is.

8 cell NiMh = 9.6 volts
XL5000 5,000 KV, max RPM 48,000
Novak 3.5R 10,500 KV 100,800 <this will probably destroy the motor
Novak 5.5R 7,500 KV 72,000 70,000 is a limit for most motors

The true top out speed will likely be a little less than the ideal calculation due to losses from internal resistances, etc.

21:72 = 3.43 x 2.5 = 8.57 FDR
70 mm tires = 8.658 inches per revolution

Wheel speeds and MPH with each motor using the same gearing.
XL5000 = 5601 rpm = 45.9 MPH
5.5R = 8401 rpm = 68.9 MPH
3.5R = 11762 rpm = 96.4 MPH

The gearing on the XL5000 is pretty good, and it might even hit that speed, probably 40-42 after losses. The 5.5R is a bit over geared. Unless you batteries can put out serious current, and it is just a short speed run, that will most likely result in something frying. An 18 tooth pinion gets you down in the mid 50 mph range (56 topped out). That should hold up, but it is still a huge load. The 3.5 will probably self destruct on 8 cells, that is really a 4 or 5 cell motor. Even 6 cells is pushing max safe rpm limits. On 2S LiPo it turns 77,700 rpm, which is still very high. That is still over 74 mph with the same gearing. It may top 70 in the real world, but only for short runs and careful trigger use as the current draw will be extremely high.

If you want total smoothness, you can't beat a full sensored system, but the Mamba Max sensorless with the new 1.17 firmware is almost as smooth, even at very low speed, and it will pull higher, and does not need the sensor cable at all. The Mamba Max will also take 3S under warranty, and run 4S all day long with an external BEC. If you really want speeds over 60 mph, you need at least 3S, and for 70+ go with a 4S and a lower KV motor to make the power. Voltage makes more power without the heat losses of high current. The top speed cars all ran 4S or more, and the record was set on 8S.

dawn_skd

02-24-2008, 02:45 PM

SpEEdyBL

02-24-2008, 03:39 PM

Y0u should be able to gear the xl5000 much higher than the 5.5r. Keep in mind that the GTB/3.5r on 2s is still capable of nearly 80 mph as confirmed by novak at the fastest rc car challenge.

GSMnow

02-24-2008, 03:41 PM

Hi,

your answers are ammmazzzing !!!!
thank you very much !

As I can see, (XL5000 with 3S) and (GTB5.5 with 2S) will turn the motor at the SAME speed.

Does it mean I can install a larger pinion on the XL to go faster ?
Will the XL can handle 3S ? or more ?

Dawn.

PS - I never planed on running the GTB on more than 2S (6cells).

There is one big thing that I have not taken into account, and I don't have enough info to know for sure, and that is the wattage that each motor can take at various voltages.

By going up in voltage, you increase the motor RPM. You can keep goping in that direction until you reach the RPM limit of the motor or the voltage limit of the system, usually the ESC. Motors can also have a voltage limit, but it is usually RPM limited first. Current is limited by how much heat can be disipated by the motor can and any heat sinks for long term. For short term, it is the wire fuse limit. Many motors can handle double constant current for a few seconds. The larger a can is, the more area it has to disipate heat, so it can shed more wasted watts. To figure out the loss though, you do need the internal resistance of the motor. For example, my Mamba Max 5700 motor has 0.0075 ohms of internal resistance. At 50 amps it will have a drop of 50 x 0.0075 = 0.375 volts 0.375 x 50 = 18.75 watts. A 540 size can will shed about 40 watts constant. An XL can is more like 50 - 60 watts.

So given the same disipation, a lower KV motor running on higher volts to run the same rpm will put out more power for a given current. It get's a little trickier though, because as the KV goes down, the same size motor usually has to have thinner wire, so it will have more internal resistance. This is why the Novak motors gain wattage as the KV goes up (turn count goes down). But they also only rate all of their motors at 7.2 volts. An 8.5 motor on 3S LiPo will handle much more wattage than a 6.5 on 2S.

So if you have a 5000 KV on 3S and a 7500 KV on 2S, yes they turn the same rpm, and if geared for the same speed, the 3S 5000 setup should pull quite a bit less current. This can allow you to gear it up a bit, but at the higher voltage, the current will climb faster. If the 2S 7500 can go 40 mph safely, you might get to 55 MPH with the 3S 5000 setup. Just keep in mind that you should still test the temps as the higher resistance of the lower KV motor could cause alot of motor heating.

Maxx42

02-24-2008, 04:30 PM

You'll be lucky not to shred the whole drive train in your FTTC4 with that motor - especially on 3S lipo. The XL Lehners are great motors with high torque and efficiency. I use an XL 3600 in my T4 with a mamba max controller. I drag raced a buddy's 3.3 Jato with a tuned pipe one day. On 2S lipo he blew me away. On 3S lipo I blew him away - that is when I was able to keep it from flipping over backwards from pulling wheelies so hard - and it wasn't even close in terms of acceleration or top speed. Just realize the amount of power you'll have with that motor on 3S lipo and be ready for it.

cart213

02-24-2008, 08:40 PM

tire diameter are: 138mm
spur/pinion (48p): 72/21
car internal ration: 2.5

should I replace the BK esc to MM ? the BK was stuttering on high speed and I lost brakes after 2 minutes (using more than eight 3800 cells).

Did you use a separate BEC with the BK? If not, that is probably your problem. Get a BEC and the BK should work better.

dawn_skd

02-25-2008, 01:14 AM

Hi,

GSMnow - here is the spec of that motor. maybe it will help with the calculations:

Basic XL5000 (1300 Watts @ 125 Amps) 5000kv (Weight 215g)
"1300 watts! Up to 65000 rpm! 7.5oz/215g. The Basic XL is designed to be used in 6 to 10 cell applications. Comes with 1/8th inch shaft and factory installed gold female socket plugs"
http://www.finedesignrc.com/motors/BASICxl.gif

What does is says when it's 1300 Watts @ 125 Amps ?
because it's rpm limit is 65K - that's means 13volt.
13volt = 3s safely, right ?!

Should I look for stronger ESC than 100amps (like MM or BK) ?
Should I worry from that frightening number "1300 Watt" ?
I'm using 2S 3600 Orion 25C Lipo's and 12guage Novak wires.

(I'll buy 25C-30C EVO's 3s if it will be faster than the GTB3.5r)

Dawn.

dawn_skd

02-25-2008, 01:26 AM

Did you use a separate BEC with the BK? If not, that is probably your problem. Get a BEC and the BK should work better.

Yes - I tried both external BEC and a 6v receiver pack.

dawn_skd

02-25-2008, 01:37 AM

Y0u should be able to gear the xl5000 much higher than the 5.5r. Keep in mind that the GTB/3.5r on 2s is still capable of nearly 80 mph as confirmed by novak at the fastest rc car challenge.

Does that means - nothing I'll do with the XL5000 motor will never be as fast as GTB3.5r ?

porra

02-25-2008, 01:47 AM

Keep in ming Lehner rates their motors with a load. They have specs of the motors on their website. I have that same motor and I haven't used it yet. I also own a few Basic 5300 and this little guys are powerful.

GSMnow

02-25-2008, 02:38 AM

Does that means - nothing I'll do with the XL5000 motor will never be as fast as GTB3.5r ?

Real wrod long term power, I would bet your XL5000 will run away from the GTB3.5R package. Though you do need a serious ESC to keep up with it.

1300 / 125 = 10.4 volts Watts = volts x amps

That is a 3S LiPo for sure. And rpm wise, 11.1 x 5000 = 55,500 rpm.
65,000 / 5000 = 13 volts, and a fully charged 3S with no load is 12.6 volts.

It all adds up, that motor is meant for 3S LiPo.

The GTB3.5R setup can make serious power, but to put out 1300 watts on just 7.4 volts, it would take 176 amps. At the power, a 540 size can will burn up. Sure, they geared it for 80 mph, rolled the trigger on very slowly to avoid a surge of current, and got it up there before it melted, but could it do it a second time??

Gear the Lehner to go 80 mph at 55,500 rpm, and it will run to 80 mph faster than the 3.5R and live to do it again. The Mamba Max ESC with a cooling fan should be up to the task. And use a 20C constant rated 6000 mah 3S LiPo to power it all.

Using these specs from before
21:72 = 3.43 x 2.5 = 8.57 FDR
70 mm tires = 8.658 inches per revolution
Just going to 3S pushes your top speed to about 53 mph

To hit 80 mph (WOW, that is FAST!) you would need to change to a 31 tooth pinion gear. The current draw will be insane. It could easilly esceed the 125 amp rating of the motor if you get traction and pull too much trigger before it unloads at speed. The Max Amps 3S 6000HV LiPo pack is rated to 30C for 30 seconds, that would be 180 amps. That is getting into arc welder territory. Be sure to shoot some video of the attempt.

Do yourself a big favor, add at least 3 pounds of dead weight to the chassis. It will help alot at speed to keep the air from throwing the car off the ground. Aero downforce is also good, but to generate good downforce requires aero drag. Dead weight does take off some acceleration, but does not add any drag as speed increases. And the weight will also help traction at low speed before aero downforce will help at all.

dawn_skd

02-25-2008, 05:53 AM

Hi,

Can 10x3800 Nimh Intellect cells will do the job as 3S Lipo ?
I'll buy Lipo if not. I'll also need a Balancer and a charger (I guess) - since I'm not using any more than 2s (Orions) and I dont carry any special equipment.

I do think my charger can handle "Balancing"... I'll have to check.
http://www.rceasyshop.com/images/RC/TLPX1503.JPG

When I tried the BK ESC using more than eight 3800 cells - it was stuttering on high speed and I lost brakes after 2 minutes. It won't happen with MM ?!

I already have 28t 48p pinion for a kick start.... (76 mph with 10cells)

Should I replace to MM ?

Dawn.

............or should I wait for MMM?

GSMnow

02-25-2008, 09:21 AM

In my opinion, 10 cells of NiMh is not even close to what 3S LiPo can do. The nominal voltage is close with the NiMh being 12 vs the 3S being ONLY 11.1 but that is just 1/2 the story at best. Each cell has an internal resistance. My IB4200's are about 0.005 ohms per cell, and my LiPo's are about .007 ohms per cell. But you have 10 of the IB's for a total of 0.05 ohms while with the LiPo you have just 3 for .021 ohm, less than half. At 100 amps that works out to a drop of 5 volts for the NiMh while the LiPo drops just 2.1 volts. So the nominal volts fall to just 7.0 volts for the NiMh while the LiPo is still at 9.0 volts. That is a big difference under load, where it counts.

I have never used a BK ESC so I have no idea what was going wrong. On a brushless system, the brakes should be using the same FET's as the drive, so it should not be a thermal issue. I have not pushed my Mamba Max to the currents you will be seeing, but I never had mine thermal in any way, even seriously over geared. I had it geared to push my XXX-T over 45 mph on 6 cells of NiMh and it still had the torque to pull a wheelie at over 30 mph. The motor got very hot (about 205F oops), the IB4200 battery was too hot to hold (230F ouch), but the ESC was just warm at 135F on the heatsink. I don't remember anyone reporting losing brakes.

I did have a stuttering issue. It turned out that the factory supplied bullet connectors between the ESC and Motor were crap. I don't know if they have changed them yet, I hope they did, Castle shows much better stuff on their web page now. But any loose contact between the battery and motor will kill the performance at these currents. If the poor contact is between the ESC and Motor on a sensorless system, it cause all kinds of problems, and stuttering is the most common result. Poor startup, and even radio glitching will also occur, as well as breaking up at high power. I would assume the same issues could happen withthe BK. Run it hard, and see if any of the connector feel even slightly warm. If they are, you have a problem. I replaced all of my connectors with Deans ultra plugs. It was a huge improvement over the bullets.

GSMnow

02-25-2008, 09:31 AM

Oh, the Mamba Monster Max setup will be crazy powerful. The motor it will come with is only a 2200 KV, so you may have trouble gearing it fast enough in a touring car, even at 6S which it is rated for. That comes out to a bit over 48,000 rpm when it unloads at speed. You could use a different motor, the ESC won't break a sweat with a 200 amp rating. A Neu 1509 1.5D would be a good choice. It has a 3200 KV so it will run over 70,000 rpm as it tops out. It is a bit fatter around than a 540 motor though.

dawn_skd

02-25-2008, 11:00 AM

Hi,

Thanks for your quick response.
I'll order 6000HV 3S from MaxAmps.
Does 4000HV 3S wll do the same ? I don't need that long run time.

SHOULD I wait for MMM? what do you say ?

Dawn

-------------------

Yes - I see differences with the Lipo packs :
4000HV Spec:
20C Constant(80 amps)
30C Sustained(120 amps)
50C Burst(200 amps)
6000HV Spec:
20C Constant(120 amps)
30C Sustained(180 amps)
50C Burst(300 amps)
8000HV Spec:
20C Constant(160 amps)
30C Sustained(240 amps) <---- Is it too much for MM and XL ?!
50C Burst(400 amps)

GSMnow

02-25-2008, 05:04 PM

I run the 3000HV pack, only 2S for my MM5700, and it makes serious power, but I can get it warm if I work it hard, and I am only geared for 38 mph. I can stack the pair and run them parallel to make the same as the 2S2P 6000HV. Even with the extra weight, I can clearly see the increased power from the higher burst current ability. Even for a short run time, trying to hit 80 mph is going to need a lot of current. The 4000 may do it, but without datalogging your setup, it is tough to tell if it is destroying the battery or not.

Using a higher current capacity battery is really not going to change the real sustained current by much, so even the 8000 is not going to make much more ESC or motor heat. What it will do is have less resistanceto give you a bit more punch at full current and be able to get you to speed faster. The battery will last longer, and not just on a charge, I am talking number of charge cycles, since you won't be stressing it as much.

As for the Mamba Monster... I want one for a 1/8 project. I hope it comes out in March like they promise. I am sure it will show up in many top speed challenge cars. It has all the right specs for it. The Mamba Max is fine for 3S and 100 amps, and will handle 4S with an external BEC. The MMM will take 6S all day long with a warranty where the MM is out of dpec over 3S. The MMM also has a switching BEC that will take it as well with no concern. And the 200 amps rating makes sure it will handle any motor you can throw at it.

You need to decide if your speed goal needs 1200 watts, or 2500 watts.

dawn_skd

02-26-2008, 01:38 AM

I think I'll wait...
I promise to update you about that FT TC4 and the XL.
I don't have enough words to thank you (all of you).

Mean time I'll buy this 3s 6K/8K max amps pack and an appropriate charger to go for more than 2s packs.

Dawn.

dawn_skd

02-26-2008, 01:42 AM

http://pic.hevre.co.il/Files/6A04AACBE72B4DEE8D811B305108BE31/norm_D179E70923CE462F95B3A4A218D262E7.JPG
http://pic.hevre.co.il/Files/6A04AACBE72B4DEE8D811B305108BE31/norm_EA65A8B956EA4A8E8902F0A7F79438EB.JPG

dawn_skd

04-10-2008, 10:45 AM

Hi,

I've just got my electric stuff to do the testing.

--------------------------
Product ID: Eos6i-AC-DC
Product Name: Hyperion EOS0606i AC/DC Balance Charger

--------------------------
Product ID: Lipo-6000-111-Pack 30C Sustained(180 amps)
Product Name: Lipo 6000HV 3S2P 11.1V Pack
> > > Plug : Deans Ultra Female
> > > Balancing Taps : Hyperion/Apache Taps (standard)
> > > Wire : 12awg Deans Ultra wire (upgrade)
> > > Hard Plastic "Skin" : Built in Skin (Shrunk into Pack)

http://www.pic.co.il/Files/6A04AACBE72B4DEE8D811B305108BE31/norm_57D3ABD35BB94D2CBC6EAD49A7D9A603.JPG

http://www.pic.co.il/Files/6A04AACBE72B4DEE8D811B305108BE31/norm_269FCC9CEEA74F1D93769731B7E7B7DD.JPG

http://www.prolineracing.com/images/product/large/331_1_.jpg

Here is my starting point:
Kit - FT TC4
Body - Protoform DNA2
Bearings - Ceramics
Associated Lightened Steel Differential Outdrives
Steering Servo - Futaba S9402
ESC w/BEC- BK Warrior 9918
Motor - Brushless Lehner Basic 5000 XL
Pinion - Lightened Steel Robinson 28T 48P
Spur - Robinson 72T 48P
Radio - 3PK w/Spektrum DSM SR3000 3CH Receiver
Battery - 30C Sustained(180 amps) Lipo 6000HV 3S2P 11.1V Pack
Receiver Capacitor - 10v 15,000uf
Tires - 26mm Arrows 35 (ultra soft)
Wires - 12awg + 6mm motor bullets and Deans.

I'll start with 28T Pinion and keep monitoring tempartures (70 MPH).
My goal is to increase to 32T Pinion (To go over 80+ MPH).

Any last suggestions before test runs ?

Shachar (Dawn) K-D.

ElectricThunder

04-10-2008, 03:04 PM

Make sure your diffs are good to go, if you can somehow lay down the maxamps pack then do that too, and maybe also secure the maxamps with another strap perpendicular to the one going the length of the battery (so it doesn't slip out in an accident or something).

That's going to be a FAST car.:)

dawn_skd

04-11-2008, 12:17 AM

Hi,

thanks for the quick response..
I had the diff upgraded to steels using Lightened Steel Differential Outdrives.
I've tried to lay down the MaxAmps pack and I had two problems:
1. the weight balance was not better checking it with a setup board.
2. the current strap and the "Associated Factory Team Battery Strap Kit" was pressing the pack wires so the can be damaged.
All MaxAmps pack's wires are in the middle somehow and it's not smart in my opinion.
http://www.gpmd.com/image/a/ascc3216.jpg
I also had the pack secured by using a double sided servo type at the buttom. It cannot be shown on picture.

Any more great suggestions before test runs ?

Shachar (Dawn) K-D.

ElectricThunder

04-11-2008, 09:01 AM

When I say make sure the diffs are good to go, I mean make sure they're adjusted right. If a ball diff is slightly loose (especially under that much power) it'll unload and could fry after repeated acceleration under such conditions.

Looks good otherwise. I see what you mean about the wiring and battery pack issue. I also have a pack that has wires coming out the middle, and it is kind of annoying to mount (had to dremel the front wall of the battery tray in one of my stadium trucks.....talk about extra work).

dawn_skd

04-11-2008, 09:15 AM

Thanks !
Oh, I did adjusted the diffs tightness right. That sould be fine now.
I'm going to test run the car today with "only" 28T pinion (70+MPH).
I probably will have some videos to upload later.

The only thing I'm worry about is this crapy ESC (BK 9918 Warrior).
I've ordered MM last night (Since there are no traces of the new MMM yet),
and now someone told me I might needed to order the new Tekin R1 Pro instead.

Does anyone tried that R1 Pro ESC ?
Is it better for my needs (NFS) than the Mamba Max ?

Thanks for all your great answers,
Shachar K-D.

ElectricThunder

04-11-2008, 11:16 AM

I don't think you NEED the tekin R1 pro. The mamba max is a perfectly good ESC and is made by a good company. The R1 pro has its own issues that Tekin has resolved with a completely new system.

dawn_skd

04-11-2008, 05:02 PM

...The car was balistic fast on the first 100 meter run.... but the pinion screw just lost grip and there was no connection between the pinion and the motor shaft...

I didn't had the tools to fix it on the track....
....next time.... I'll update. )-:

dawn_skd

04-12-2008, 03:59 PM

Ohhhh My God.............
That was FFFFFFFAAAASSTT !!!!!
The car was BALISTIC fast.
I had tuned the car to go "only" 70MPH and that was quite fast.
The protoform DNA body has so much down force I saw sparks comming out of the graphite chassis at high speed. I guess I'll need to change the stock springs to something less soft.
After 8 full throttle runs, the temp was not that high as I expected (motor, wires, bullets and ESC) and that good for me, since my goal is to slowly upgrade to 32T pinion and
pass the 80+MPH barrier with only 3S Lipo's.

I'm not sure I'll do that with my lame ESC, but I'll wait for the new Mamba Max controller I've just ordered and it's on the way here.
Do I need to make sure the Firmware is 1.17 or something ? Can I still use the build-in BEC since I'm using only 3S Lipo's?

The MaxAmps pack was not even working hard. I only charged it 1050mAh out of it's 6000mAh after those 8 full throttle looonnnng runs. Not even sweating.... That's great.
That Lehner XL Motor has so much torque I cannot explain. Every throttle touch - the back of the car was shifting one side because it's a shaft drive and the motor torque.
I had to accelerate very gently. I guess belt drive would be more stable here - but TC5, for example, won't carry the power like TC4. I'll need Serpent VETEQ Kevlar belts for that task...

Does anyone knows how to upload movies here ?
I have some nice shots my wife took.

Shachar K-D.