XRAY - Model racing cars

Hi, I am very new to RC cars and even newer to touring cars.

I have just built a T4 '15 with the following equipment in it:

Orca 17.5T TX series motor
Orca Vritra VXX Competition ESC
Savox SC1251MG servo
Wolfpack 25C 7.4v 37Wh 5000mAh battery
Pinion gear 30T
Spur gear 84T

My two other RC cars are an XRay XB9e and a Losi 8ight 3.0

When I finished building the T4 I was expecting that it would blitz the other two off-road cars and (admittedly they are using 3s and 4s batteries), but to my surprise, the T4 is a lot slower. I strapped a GPS on the back and got a top speed of exactly 40kph. I have not done that with the other two, but I know just from driving, that they are nearly twice as fast.

I have not adjusted my ESC and it is still running in blinky mode and I know that I could get the car faster if I adjust it, but what I am surprised by is that even after 7 or 8 minutes of 90% full throttle, the motor is only just warm and the battery, is stone cold. It suggests that I am not getting adequate voltage.

Can anyone give set me straight? Is this normal, or is really slow as it seems to be.

Cheers, Al

Try putting a 40 or even higher pinion in and it will be faster, but you are limited by the 17.5 motor.

That's not a very powerful and is considered the 'Stock' class, one of the slower classes available.

I should think the flat out speed of a 17.5 should be around 35-40mph depending on gearing, (55-60kph)

change the gearing,the 84t spur gear is too large for a 17.5t motor,you dont say if you are using boost/turbo,if not try 38/66
that should see 40/42 mph

Ok, so I did a little testing and my two off road cars will do

60 kph with a 3s and 80kph with a 4s battery.

That is straight out of the box with no tweaking done to the ESC, motor or anything.

I will definitely try a bigger pinion, and / or smaller spur, but to get only 40kph is a bit surprising.

The thing that has me concerned the most is that the motor and ESC are still cool to touch even after 10 mins of running.

I thought that should at least be warm. Is this normal?

Better than if they get too hot!

They should get warmer with the taller gearing

You're basically asking why a car with a 1.2 litre diesel engine won't keep up with a 5 litre supercharged V8.

It's nothing to do with the car, its about the motor you've put in it.

If you want to go fast, fit a faster motor. A 4.5t modified should be enough to ensure you have some very expensive crashes.