Voltron989

iTrader: (5)

Na was just curious how much one is better then the other from someone that has/had both. Being his was the RTR version I'm not surprised the serpent is much better.

Almost bought one when tower had dropped the price from $489 to $368( plus $50 off) can't beat that deal $318 for the kit. My friend Lesh had me order one for him and he should be ready this Saturday to drive it so I can't wait to drive his

scooby61

iTrader: (1)

Yeah the pro is a lot better out of the box but a lot of aftermarket is starting to show up ill probably keep both for a while as I like different stuff about each. Some the next upgrades ill do should make the car as good or better than the pro. I wasn't downing the gtv just saying the cobra looks like it will be a really good car for me.

scooby61

iTrader: (1)

Finally took the cobra out for racing today. Tuned it a little and already turning better lap times than my gtv very happy with this cars performance. The combination of the tekin 2650, and this chassis is very smooth and tunable. Running a 16 t pinion and highest temp was 145*.

SouthFloridaApp

iTrader: (6)

I am just curious how long is the run time with 7200 may. Batts...approx on a large 1/8 scale track with a race worthy setup. I know there are a lot of variables....just trying to get a general answer....

scooby61

iTrader: (1)

I'm running 2-2s 5000mah in series with a tekin rx8 ant t8 2650 after a 7 min race heat +a few warm-up laps I finish with around 7.8 volts and and recharge takes around 3100 mah to top them off . If that helps that's with a 16t pinion and stock spur on a parking lot track.

SouthFloridaApp

iTrader: (6)

I do not own this on road car, but I do own a Serpent 1.0 be buggy. I actually took it a 1/8 scale on road track and it handled pretty well with a couple of minor adjustments. I used the somewhat short track on our large on road 1/8 track. It was pretty fun... and a great guy lent me a pair of Alphas.. they were great... I love my buggy and the quality is top notch.

I would love to see this class evolve and run approx. 12 min. races. The Serpent is pretty heavy and would need either a 6s Setup and the need for removal of the battery holders and/or lighten up the car. I have a Losi 810 1/8 scale ebuggy (basically a SCTE) that I ran on 3S weighing approx. 6.5 lbs rtr and it had the same speed of heavier cars on 4S. I may see if I can install a 4S batt. in this car and convert it to on road. I bet the run times would be quite good with the latter. The latter car is pretty durable... not the same beefiness (invented word) as the Serpent... I am wondering if a car that is lighter would be better for on road applications. Thoughts?

Voltron989

iTrader: (5)

We run on a large 1/8 track, one of the largest in the country. It is probably similar in size to the Homestead track in Miami.
I run 46/21 gearing in my Cobra GTE with a Tekin 2650 with 2 x 2s 7200mah 80c Trakpowers. We have a long back straight roughly 220' so 55-60mph is the ideal speed to gear for to be competitive. After 2 or 3 slow practice laps and a 7 minute race when I pull my car off the track my batteries are at 3.7 - 3.8 per cell. Technically if you connected a lipo voltage checker to the batteries it would say there is 40-50 percent power remaining but really there isn't much run time left to keep racing and still keep the lipos at a safe cut off voltage.

Just to be clear these are figures for the fastest cars on our track which seems to be consistent with 4s 7200mah lasting to about 3.7-3.8 per cell.
slower cars on the track would use much less power for the same race

Voltron989

iTrader: (5)

12 Minutes race on our track just would not be possible

D.a.v.e

iTrader: (8)

I have the SCTE and I think the biggest problem would be finding a motor you could run that would fit it. I don't think a Pro4 or 550 could hang with the 1/8 scale motors we run in these. Both get pretty warm running off road, I can't imagine what on road would do to them? Then you would have to find the right springs, shock towers, etc. You would prob need the tuning kit to change the caster angles, a stiffer chassis, and maybe smaller tires? I suspect this would be an expensive conversion? Even if you bought a worn out losi eight and did the conversion (that is made for this) I would guess you'll have spent $3-400 vs the extra $100 so to buy this or another kit new.

I've run with folks that had the 810 in the 1/8 scale off road classes and your right they do keep up but they don't seem to take the beating as well, for me that's part of the reason I like this class. I've run this class all summer and still crash a fair amount, last week was the first time I've damaged anything (broke my servo & bent a drive shaft) after hitting a wall at 50+.

You might get 12min running 6 cells on a small track. They would have to be pretty big and would not fit in the car very well as after a 7min race my 5000's (6s) only have 40% left and my lap times are about 3sec off Voltron989's. I'm guessing if he drove my car it would come in around 25% or less.

scooby61

iTrader: (1)

What he said I am on a small track and once get tuned in better will be staying in the throttle and brakes a lot more. I will have t upgrade to 7000mah packs most likely to avoid hitting lvc. And also remember that running 6s gearing will be critical you will probably generate more heat wich means less efficiency. Having seen these 1/8 cars on 6s unless youre doing speed runs you're creating way more power than you can put to the ground on a road course imho.

Voltron989

iTrader: (5)

When Dave speaks of 6s he's referring to running a lower KV motor
He runs a 1700 tekin on 6s which would be geared identical to a 2650 on 4s
Both setup will create nearly the same motor RPM so pinion size wouldn't change when gearing for the same speeds.
On the batteries and ESC its suppose to be more efficient though on motor temps I'm not so sure. It seems to be working well for him. I on the other hand have been fighting lipo issues. When u drain a battery so quickly you start to develope problems with the cells balancing out evenly as they drain(I think). I've basically had all my(3 pairs) Genace 7000mah 50c lipos go bad within a 2 weekends of racing on each pair. Also have had a pair of IP intellect 7200mah 80C lipos go bad. I'm currently using trakpower 7200mah 80c 2s lipos and they are holding up really well, have a pair of Venoms that also seem to be able to handle the abuse of 1:8 onroad.
I've had good luck in my 1/8 buggy with cheaper lipos like gensace but they aren't any good for me on road.

SouthFloridaApp

iTrader: (6)

It is my understanding that running a car on 6s with a lower kv will operate more efficiently....less heat... Also a somewhat large battery on 6s...say a 5000-6000 will yield longer run times. The drawback may be a little added weight. I am not sure lap times would suffer that much with a small amount of added weight as the acceleration is unreal with these cars and we often do not fully utilize their current potential due to track limitations....I.e having to slow down for corners etc.... I just would like to race for more than 7 minutes I.e.

As to the durability of these cars... I am glad to hear that this car is bulletproof...like my buggy. I guess a small price to pay is less runtime when compared to lighter cars. The latter is better than fixing a fragile car....

I may pick up one. I checked tower and did not see this car. Did I miss something?

FYI I will be going to homestead with my on road cars.....not too many electric cars there, but a bunch of great guys....

scooby61

iTrader: (1)

Yes with a lower kv should even out the heat.
Tower doesn't sell serpent you'll have to go to Amain, absolute hobbies, or desoto racing to get the kit I believe amain has a 50 dollar off coupon code right now as well that's where I got mine it was 540.00 or so. I highly recommend some of the option parts mentioned on this thread and have a 3mm tap handy for the build.

Voltron989

iTrader: (5)

Like I've mentioned. Dave runs 6s 1700 and I run 4s 2650
Even though I'm geared slightly taller and drive harder there isn't much motor temp difference. His ESC and lipos may stay cooler though but I don't think very much.

More weight = more heat. U may not feel the loss of power with the extra weight but the motor will feel it.

Stored power in each setup

2 x 3s 5.0a lipos = 114Wh
2 x 2s 7.2a lipos = 106Wh

About 8% extra power with 6s 5000mah setup

Weight difference.

2 x 2s 7.2a hardcase lipos = 311grams x 2 = 622grams (trakpower 2s 7200 hardcase)
2 x 3s 5.0a hardcase lipos = 442grams x 2 = 884grams (gensace 3s 5000mah 50c hardcase)

That additional 8% of power is an extra 40% of weight
Going to a 6000mah 6s will probably balance the power(Watts) to weight ratio a little bit better but you would still be hauling over 2lbs of batteries at that point

D.a.v.e

iTrader: (8)

Would be nice if we used the same battery connectors so I could hook up my eagle tree to really see whats going on with the watt meter, rpm, and temp to compare our two setups as we mostly have the same bits and set up.

Want to make a bullet to dean or EC5 conversion cable? Then we can put this 6 cell thing to rest

I'm also wondering if going to two small 4 cell packs (3500's) would help you? I would try the soft packs. Bet it would provide less stress on the batteries. Packs usually did not come out as puffy in my boats in this configuration.

Of course I'm sure this would just let you push the car harder to get the mythical 20 sec lap.