Need advice on custom micro
 

A project in a design class is to create a custom electric powered car to run a 32 ft sloted track, 10 or less alkalines batteries must be in the car, i used a speed 300, 14/46 gr,double 5 series batteries connected in parallel, a brp 18 modified chassis and my time was 3.71s, speed 6.12 mph(i know it is slow but the sponsor was the pinky bunny), the best time was 1.51s(14 mph) it was a 1/24 that resemble a Parma slot drag, full ball bearings, 3v custom-winded gunmetal-color neomags motor very similar to below, but he was just using 4 batteries?, id try 4&5 batteries for weight adjustment but can get any close. Since the car does not uses any electronics I am considering using a stock MiniZ or DTM drivetrain and just 4AA Alka but what motor?
Regards

That sounds like your problem - if you connected them in parallel, then you were only getting 1.5V to the Speed 300 - try it again w/ the cells in series!!!

Sorry is my fought for a bad explaining....
I did"double 5 series batteries connected in parallel" for the speed 300, 5+5 ,7.5V total.
The best time did the same 2+2,3V total; theres a world in weight difference ..I think the guy deserves some merit for doing a 14 mph car with just 4 cells....but i want more