the same version of Box2d cause the different result

[marvelyyc]

I'm develop a Box2d game with cocos2dx 3.1.And the version Box2d in cooc2dx 3.1 is 2.3.0.

Before this,I have test my game in the "Tests Framework" of Box2d downloaded from the github.
The version of Box2d is 2.3.0 too.

I add a "car" in the game and when press the keyboard.It will set the speed and torque on the back wheel.
And the car will run.I have set the parameters of speed and torque in the "Tests Framework".And it works well.
But when i transplant the code to cocos2dx 3.1.The game will have a different result.Like if I add the speed and torque the car will "hypsokinesis".
It's so strange!Is it normal?

[iforce2d]

hmm... I really don't know about that. It's probably better to ask about it on the cocos2d-x forums, since it's the different version of cocos2d-x which is causing the change. As I mentioned yesterday, they don't seem to be very interested in backward compatibility