need to go slower to go faster??

[rootar]

after racing with the fastest guys i the state is past weekend it became very clear that my buggy is just to fast, on the straight it was great but almost every where else i was at a big disadvantage due to wheel spin, and low traction i REALLY had to pay attention and go easy.

I also cannot get 20 minutes safely out of my 5s 4000 packs im using, so im wondering if i went to a 1512 (1500kv) or a medusa 36x60 1500kv, i could be sligthly slower, and squeeze those extra couple laps in on a 20 minutes main safely.....so would the 60 or 1512 1500 kv pull less amps in my buggy when geared almost the same, (they would be geared for 40, now im geared for 44) and i you dont know im running a 1515 2.5d 1700kv.

temps after our 30 minute a-main this weeked was
161-nue 1515
121-Mod 1 MM
113-protek 5s 4000 20c (did a battery swap halfway)

[brushlessboy16]

I would adjust the punch control maybe 40 percent or to a degree where you do not get wheelspin.. then i would drop down a few teeth on the pinion and drop my timing down.. Combonation between puch and gearing will bring down the amp spike a good bit, and the timing will keep motor temps down... less wasted heat means more power and runtime..

[stum]

Originally Posted by rootar

after racing with the fastest guys i the state is past weekend it became very clear that my buggy is just to fast, on the straight it was great but almost every where else i was at a big disadvantage due to wheel spin, and low traction i REALLY had to pay attention and go easy.

I also cannot get 20 minutes safely out of my 5s 4000 packs im using, so im wondering if i went to a 1512 (1500kv) or a medusa 36x60 1500kv, i could be sligthly slower, and squeeze those extra couple laps in on a 20 minutes main safely.....so would the 60 or 1512 1500 kv pull less amps in my buggy when geared almost the same, (they would be geared for 40, now im geared for 44) and i you dont know im running a 1515 2.5d 1700kv.

temps after our 30 minute a-main this weeked was
161-nue 1515
121-Mod 1 MM
113-protek 5s 4000 20c (did a battery swap halfway)

The medusa 60mm v2 2000kv is great in buggies.. around 2000kv is perfect becasue this allows you to run a 4s 5k even 6k pack with no weight gain vs your 5s 4k packs. That said you should be able to regear as stated above and net good results with slightly longer run times as well on your current equipment. To be honest it is going to be nearly impossible to finish a 20min main on 4k packs, so I would make the move to 4s 5k packs.. you may not even need to re-gear your setup.. you may find the reduced speed on 4s is perfect. I race weekly and have a very similar top speed as the nitro buggies, but with brushless torque you get to top speed so much faster you still have the advantage in the straights.

[Arct1k]

Punch control is not the way to go - It causes a lag in the throttle reponse which then makes it much harder to time jumps and whoops etc

I think you are in the right directo with a lower KV 1512 - I would gear for high 30's though - 37mph should be enough...

[E-Revonut]

Great advice so far but I think just regearing your current setup would help you alot. As Arct1k said try gearing for high 30's. A different motor would be ideal but much more expensive than a gear. The 1515 is better suited to MT and truggy, buggies don't have as much weight and a lot less rotating mass, therefor don't need the bigger motors. The Medusa would be a great alternative to the Neu at half the cost and close to the same quality.

[Tempted]

How fast are the turns? If they are slow, gearing down will add even more wheelspin. It will increase the torque at lower speeds. Have you tried running the track on 4s? It would take the edge off the power but still be fast.

[lincpimp]

Better driving usually helps me get around a track faster... Lowering gearing will help runtimes, although the power will still be there. More precise throttle control will help the lap times, so it sounds like you need a bunch of practice. Not that I can talk, I need practice too!

A smaller motor will produce less torque, but will be pricey.

Not sure if going down to 4s will do much, the motor will spin slower, and required higher gearing (more load) to do the same speed. So the pack capacity will have to go up for the 4s pack. Then it will weigh the same as the 5s pack. The 5s setup should be more effecient, so runtime will not necessarily be better.

A smaller motor with similar kv to your current motor, and lower gearing will produce less torque, lower top speed and increase runtimes. That is about the only way I can see to meet all of your goals.

[rootar]

thats really what im after linc, i dont have a 4s to run id like to stay, I can ALMOST make a 20 minute main with it, but its a 50% chance of if my pack my start to dump right there on the last lap or next to last lap.... just need to squeeze a little extra are teh Y winds of nue motors more effecient?

im looking at a 1512 2Y????? its 1400 kv

[bdebde]

Yes the Y winds are a bit more efficient.

[stum]

Originally Posted by rootar

thats really what im after linc, i dont have a 4s to run id like to stay, I can ALMOST make a 20 minute main with it, but its a 50% chance of if my pack my start to dump right there on the last lap or next to last lap.... just need to squeeze a little extra are teh Y winds of nue motors more effecient?

im looking at a 1512 2Y????? its 1400 kv

You need a good 5% buffer when racing, after a couple months of racing your pack will start to hit LVC's with less mAH run through it and then where will you be? If you want to fix this you need to think longer term iMO. That is unless you can get lipo's for 20.00 a pop or have more money than god in that case hook me up!

A good 4s 25c to 30c 5000mAH will easily last that with some buffer so as the pack wears you don't have to replace it as soon. My SMC 28c 5k packs started out taking 5200mAH before hitting LVC and after 3 months of racing are down to about 4850-4900mAH, this is just fact and will happen to all lipo's in all system no matter who makes them. My polyquest (enerland), SMC's, Neu Energy, Maxamps.. they all do the same thing. You will actually be killing those 4k packs even quicker due to taking them down to the bottom that often as well... if you don't send them to LVC every time out they do tend to last longer.

#1 you don't need more than 40mph to win against anyone on any track
#2 4s is more then enough voltage to keep a 1:8 scale in good temps if you have decent equipment.
#3 the 4s 5k packs will last longer every race vs a 5s 4k pack, it may only be 2 minutes but that is often all the buffer you need.

[Dafni]

Originally Posted by stum

#3 the 4s 5k packs will last longer every race vs a 5s 4k pack,...

are you really sure about that?

[stum]

Originally Posted by Dafni

are you really sure about that?

If you test on equal grounds yes.. mAH is mAH so unless you are pulling more C's than a battery is capable of it will hold its voltage through the entire mAH of the pack and the 5000 will win every time. Higher voltage doesn't change how much gas is in the tank (mAH). Higher voltage will reduce the amps needed to perform the same wattage which is nice if you have weaker cells, but again unless you have a 4s lipo not capable of the demand you are after it's not going hit an early LVC. Anyone who gets different results didn't do the test on equal grounds. Higher voltage w/ less amperage or higher amperage w/ less voltage, the trick is if both packs can handle the amp draw there is no advantage to the higher voltage setup other than a potentially cooler system as voltage is normally your friend. If you have a battery that cannot comfortably meet the amperage demand (low “c” rated 4s pack) you will hit a early LVC and at that point a smaller mAH high voltage battery could beat out a larger pack. But with today’s 4s 30c lipo's being the standard you won't see what you saw just a year or two ago when 12-20c 4s lipo’s couldn't handle the amp load and would go into early LVC leaving the higher voltage system running even with less mAH.

This isn't like comparing a 8s system to a 4s sytem where other things do come into play that change the relationship a bit more, we're looking at 4s to 5s.

I'll use these specs as they are most a like in size/weight

14.8v x 150a = 2220 (5000 30c)
18.5v x 100a = 1850 (4000 25c)

but to show even a 5s 4k 30c that does weigh more and again changes the relationship in the car (heavy = more work for the motor & higher avg amp draw) you may net the same output but again the weight is now a factor as it is an even larger battery so the favor would still be to the lighter 4s 5k pack. Also keep in mind if you go just off these numbers you have to reduce gearing to match the actual MPH of the 4s system to even start to compare for run time. If you run the same gearing or are geared for more MPH than the 4s system what I was saying above is what you need to pay attention too.. to figure out run times. So again you have to gear for the same MPH for this to have any effect even on the 6s + setups.. to match or exceed run times.

18.5 x 120 = 2220 (4000 30c)

[rootar]

ummm a 4s 5000 and a 5s 4000 have the same amount of energy, if ANYTHING the 5s would run longer due to being more efficent, and i didnt say i needed more than 40 but it helps with the motor temps by never letting it wind all the way out, besides the mm is only 120 after 30 minutes my gearing is fine when i gear below 40 my temps go up 20 degrees on the motor due to staying wide open alot the time. and i dunno what cells an smc 5000 uses but i have over 30 cycles one of these packs and it still takes 4200 mah if i go all the way to 3.2 volts percell, most of the time i dont run the pack dead only about 10 mins of practice and i switch packs, but every now and then we'll run 20minute mains instaed of 15s, now i can run a few practice laps and a solid 15 minute main no problem but the 20 cuts it close might get 1-2 laps in after the race or might go dead on last lap i never know, it has alot to do with traction and how i drive.

and if your wondering send me a pm on the lipo price as i wont post it on here. but i can 3 on them for one enerland pack and yes ive ran enerland cells and they kick ass BUT im running these as kinda an advertisement type thing for the local shop because alot of guys are wanting to get into it, if they start giving me any trouble ill switch back to enerland cells. but hey i guess i shouldnt have sold my 5s 5000 FP pack as i ran a 30minute main with it no problem......but it was jsut to big and heavy and wouldnt fit under a body well at all.

[rootar]

with a 4s pack using a motor to obtain the same power and rpm as my motor on 5s with the same power and rpm they will be the same or the 5s will have better runtime no questions asked.

we are not comparing a 4s and 5s used on the same motor but a 30,000rpm 4s setup and a 30,000rpm 5s setup.......


and i dont run an LVC a 5s pack will "dump" considerly right at about 3.3 volts percell and by the time it gets to the pits your at about 3.2

Originally Posted by stum

Higher voltage doesn't change how much gas is in the tank (mAH).

You should measure how much energy is in a battery using this formula. Ah x V = how much energy there is. (Watt/hours)

4S 5Ah
and 5S 4Ah have exactly the same amount of stored energy.


Are you saying that a 20s 8k pack has the same amount of energy as a 2s 8k pack?