i ave a xtm X-cellerator and i want to know what i can do to get it to 40 mph i was thinking a ezrun 8.5t with a lipo but i dont know if 2s can do the job of if i should go 3 plz help

You could do it on 2s, But it would be better to go 3s and gear down for 40. less heat and stress etc.

[link=http://www.scriptasylum.com/rc_speed/_top_speed.html]play around with this[/link]

Not to hijack this thread, but I purchased a XTM for my nephew thinking it was a Rustler because it had a Traxxas esc in it.  It looked like a decent RC.  SportsStarr298, how does your XTM do?  Once I recieved it, it did  very well, my nephew is 4 years old.  I controller has the "learning" mode which allowed us to turn it down for him.  40mph would be too much for him now!!!

as this being my first electric i thought it was pretty good for the first week then i got bored of it because it wasnt capable of high speeds like nitros.  but i want to know if 2s lipo will give me speeds up to 40 mph

So if im not mistaken you own this rc? If so I would really NOT recommend any kind of brushless motor. This car is not meant to go 40+ let alone 30. Keep in mind you will break parts going faster than 25mph (same with pretty much all stock rc's). I dont really know but Im sure this car does not have the parts support you will need. As it being your first car you didnt do to bad but I would suggest a better car. It will save you a lot of frustration in the long run.

its my first electric car ive had 3 nitro offroad cars. and i will be able to get parts if they break because i dude 10 minutes away is a distributor for xtm products so i willl have no problem getting parts and he also said it can handle a brushless. but will 2s lipo be enough to get me car going 40mph

Is there any way to determine what you should have for a gear ratio? Ive seen the fomulia to get what you have BUT what should you aim for?

Like i currently have a 3s 4x4( Acme Raptor) The origional motor was undersized but it was a rocket! Now i have a 13.5T, Much bigger motor with a 23t pinion and it was alot slower. And got real hot!

You cant slap a battery in and expect "X" number of mph.
It depends on gearing, tire size, tranny ratio, etc.just to make sure you understand, heres a full list of factors.
The esc your using
The car
The gearing
The size of the tires
How your radio is calibrated
Your epa
How much voltage your esc is putting to the motor
The amps being supplied
How much resistance your bearings have
The resistance of wind and the friction of the tires
The temperature
The wind speed and direction
The angle of the road
The force of gravity
The weight
If the chassis is dragging on the ground from it having no suspension
How many wheels are spinning
The weight distribution


But geared right, yes a 2s can go 40.Whether its geared high enough to burn the motor up in one pass, well.Depends on ^^ Those factors.Go 3s and gear down, rather than 2s and gearing up.Better on the motor, less strain on the battery.