Top Speed post
 

Enter Top Speed, vehicle, motor, controller, and battery type/cell count, and weight if you know.

Have fun...

I'm sorry, I have to put my .02c in every time this thread comes up. Your post needs to state "verified top speed", otherwise you are going to get, "it seems like" or "I was keeping up with traffic so I must have been doing..." or "my friend says his truck goes XXmph and mine is faster than his so I must be doing..."

The only way this topic is any fun is if you have it verified by radar or gps.
Thanks

you know what, you are absolutely right... ;)

How do i stop a stupid thread?

this thread was here some time ago.

I guess yours is 50mph on 2 dewalt motors at 700 watt output..

I am still waiting for the answer how you measured both speed and power.

Serum, im telling. Those dewalt motors were measured by kershaw designs, they measured 300 watts @ 14.4 volts. I would be getting somewhere around 700-775watts with dual motor setup, dual EVX. Do you actually think it TAKES 1200 watts to get a RC truck to 50mph?? Again Serum, whats your deal.

Haha, these threads are fun but tend to quickly degrade. Lots of tangents, and few people with verified results, but here goes:

2.5R Revo, stock everything but emaxx tranny
8xl/ 5s Lipos
16/51 gear

=>48 mph radar, repeated runs in two directions

Its entertaining puttng top speed threads to nitro guys, you get answers (obstufications) like, "well it was running rich", or "it was cool outside", or "the barometric pressure was falling". I don't really care, just put the speed up, how fast does it really go?

you are telling stuff about a 7XL doing 65 mph, and a 1940 with a lower kv doing 70 mph..

You obviously have got no experience with these things, and you are telling everything like it's an absolute fact.. That's what's wrong.

You mean you didn't actually measured the amps it took? you used it as a fact in another thread. That's what's bugging me.

Serum, Kershaw Designs is a company, you are just talking out of your @$$ now.

Which was about the same i thought when you said your 700 watt truck did 50 mph..

You know a small lehner XL motor which is rated for 1300 watts can do 3000 watts?

and you know a Lehner 1950 suited for 1800 watts can do 6000 watts (output power)

that's why i asked if you measured them at all.. You based your facts on the wrong numbers, you see?

Oh boy!

:007:

I'm with Serum, though. Throwing incorrect "facts" around just makes you look silly, zeropoint.
When you come up with "numbers" here, be prepared to meet some experienced guys' opinions.

Thanks
DAF

What numbers?!?! What are you talking about!?

Here:
The truck weights 8.5 lbs, i was running 5s A123 pack. I did highway testing along side a car, the truck did a little over 50mph (82kph) ride beside the car. Also, running on a large street beside the cop-shop, they setup a radar gun to test it, and again it did 50mph. This was the absolute limit for these motors however. These motors are big, they can handle the load, they sure don't have the the torque of a brushless motor to get up to speed, but thats not the point. The point is, ~750 watts is enough to get an emaxx to 50mph. The gearing was 37/66 gearing direct drive to diffs, the motors are 5 pole motors.
Now i really don't see your argument.
Dafni, what incorrect 'facts' was i throwing around?

This isn't helping your story either.

50 mph on a radar gun is like 54 mph on a cars scale.

The fact that MANY other people on this and other forums did use a GPS or a radar-gun to see how fast their trucks go and used an eagletree or such to measure the power it took to get their, and as well as much experience from many, many other users (including myself) that you need a minimum of 20 cells (which roughly equals 20 cells) to reach the 60 mph..

Somehow you don't bother what experience others have, do you?

Who are you to question the things others measured/experienced?

Again, i told you, either your setup was taking more, or the speed wasn't 50 mph... (that was the reason why i asked you WHAT did you use to measure them..) Not to put your story down, but to get to the facts..

Promod has hit 50 in a EMaxx on 12cells with I believe an 8L. I have no idea how this fits into the discussion but it seems applicable.

I said 50mph, not 60mph.

Does other ppl 'experience' mean it's truth? Do you use eagletree to see how much power is used to GET THERE, or WHILE THERE? I'm sure these little motors pump out more than 750 watts together. I don't get what you are trying to say. Your not saying i'm lying are you.

No, i am not saying you are telling lies, i am just saying that the car must have had a calibrated speedo-meter..

i allready posted my results from my eagletree in another thread i posted in reaction to you yesterday. If you took time reading it, you would have known what the measurements where.
Not going to search for them, if you want to know, dig it up.

Yes, you are right Glass, it was with an XL3100. 12 cells brought him to 50 mph.

12 cells can do about 1200 watts, and his truck was very light. 1200 watts on a 93 percent efficient motor, that's 1116 watts. that's what is needed to get a light maxx to drive 50 mph.

Well i think it's safe to say that it's not SO much the power as it is the motor handling the load for a certain amount of time... everyday bashing. I must add, i wouldnt be able to run on grass with this, hardly gravel as the motors got too hot, too hot to touch. The dual EVX were up high and right in the path of wind, i had no body on the thing.

While we are at it, my maxx did 120 the other day! LOL

I don't doubt you for a single second newe..

Was it still in one piece when it landed fromt he 7th floor?

HAHAHAHAHAHA! thats a easy way to get it going fast. I think i got bout 35-40 mph max. It was when i had a 9L with 16 cells. This was a while ago

What units is that figure in? MPH or KPH? :p

Nope, 120 pieces that is! LOL

Or was it 120ms to be destroyed? :017:

My Rustler went 57.5mph GPS-verified. The setup was a Feigao 540 12s, MGM Compro 12012, 4s 5400mah 8C LiPo (the pack was constantly causing the LVC to kick in). The radio range at that time was terrible, maybe 150ft. in each direction (NOT enough for a good speed run).

Almost 60 with a rustler is great. I ran my T4 on 3s lipo with a lehner 3600XL geared 23/78 and was able to keep good pace with my buddy's jato 3.3. Of course I had to really feather the throttle to stop from launching my truck onto it's lid. I never got to get an official speed recorded because running that setup on 3s lipo is way too much for race conditions and my 3s packs are normally in another truck. Mike reccommended the motor to me and I have to say that it's great in the T4.

What rene is saying to you zeropointbug.
Just because a motor is rated at 700 watts or even 1000 watts.
If you gear higher. Put more of a load on motor than what they are tested at.
You will get a higher wattage.
I have had a few fast trucks. I have no idea on speed. It was fast enough for me.
I would like to go faster though to. :D

That's exactly what i was trying to say, they could HANDLE the extra load. I may have been putting 1000 watts peak in it, but i know i wouldn't be getting much more power output at the shaft. 300 watts was tested on a little dyno, so thats what you are getting out the thing.

And the thing i was trying to explain that you can get 6000 watts of output power (at 94 percent efficiency. not input, but outputpower) from a 1950, which is rated for 1800 watts.

Yah, thats true. But for how long? The efficiency goes down fast as you up the load too you know. If it were 94% effcient even at 6000 watt burst, thats 460 watts of heat from that little thing, thats more than a Pentium Prescott CPU! :026: (120watt) I know that you can get more out of the rating of a brushless motor. The 300 watts output (14.4v) is the absolute PEAK for the 820 motor, I was running 16.5 volts so power would somewhere around 700-775 watts (duals). I guess these motors just handle a higher continuous output than other motors, it wasn't shy of 50mph thats for sure.

well, the point was 6400 watts vs the 1800 watt rated. the efficiency might look high, but for the size it's hard to desipate 400+ watts of heat. But it's measured and proven to do so. For a few seconds it's okay, which is okay to set a speed record, agree?

600-700 watts on an mt is not enough to get it to 50 mph. (trust me on this one, i know it's hard for you) so it must have been pushing out more, or the speed must have been lower than 50 mph.

But what about the heat coming from your dewalts? 700 watts output, at 60 percent eff. that's a good 235 watts per motor too.

How can you say that you was pulling that many watts?
Did you have the same load as the motors was tested with?
You say 16.5 volts as well. Is that the battery voltage under load or rated at?
A titan goes way up in watts as well. It is only rated like 175 but can draw much more.

6400 watts, ya i would say is good for a speed run, thats hellishly fast what ever you put it in...

The Dewalt's have fans like the titans, only alot bigger and they blow like a MOTHER, you could cool down a family of 5 with the wind coming off it. WEll, if you SAY ~750 watts isnt enough to get to 50mph, then it must have been pushing out a little more. They rate the truck will go 45mph easy with them, thats at 14.4v.

Thought I'd ad my two cents. I used to run one dewalt 820 on 18 cells in my maxx. It was very impressive, mid 40's easy. I now run a 9xl on 18 cells. It wasn't that big a difference in performance but my run time is about 5 minutes longer. People under-estimate the 820's power. The dewalts are about 80% efficient, on 18 cells that's about 1400 watts. Kershaw over-gears his setups also, so don't go by his results. If used correctly the dewalts are great motors. I still run one in my jugg 2 with a super duty and 14 cells. I would put it up against the hv maxx any day.

It is not so much the dewalt motors. It is the amount of watts claimed to
draw verses the amount it is accually drawing. You admit that your system
was in the 1400 watts range. Not 775 or so. You said mid 40s the other says 50.

I am not zeropointbug. I can not speak to his claims. I was talking about my experiences.

With 66 spur and 22 pinion 4s lipos on a 7xl my truck does 40mph
The same setup on 6s did 50mph but it was over the limits of the motor and was only done for a couple runs. Not to mention the fact it was extremely hard to control.
I got my speeds from a bushnell radar gun.
When I checked it out on Brian Gs' speed calculator it was very close. I guess I could have saved $79 and just trusted his calculations but were is the fun in that?

Your story adds up. I say yes it is very possible. I just have questions on other. Either it ran 50 on more wattage or less on 775 watts. :002:
Anything is possible though.

Coolhandcountry You say the titan is rated for 175 watts? On Kershaw Designs he says the Titan puts out 129 watts on 14.4 volts. That might explain why i am able to get to 50 mph on "750watts", so maybe the dewalt setup is putting out something more like 1100 watts or more? Maybe his testing rig is messed, or he just doesn't know what he is doing...
Also, he says 80% peak efficiency, but i don't know what power output that is at? (seems reasonable)

And ppl DO under estimate the 820 motors, they capable of very high power. Apparently you can run them on 18 cells no problem. "600 watts" from one motor... in his watt ratings.