Mugen MBX5T runtime help

[xsmoker]

Ok, got my Mugen from ebay, and I really like it. Took my hobbywing 80A and 2000kV motor and dropped it right in since it came converted already. Bought a set of AKA city blocks (premounted) and hit the track. My setup is duel 7.4 lipo's 5000 at 35c. My gearing is this:

front/rear dif ratio: 4.3
transmission ratio: 1
spur gear: 46t
pinion gear: 18t
battery voltage: 14.8
motor: 2000kV
tire diameter: 5.5"
ballooning: 0.5"

This gives me the the following results:

Spur reduction ratio: 2.56:1
total reduction ratio: 10.98889:1
Tire Circumference: 20.42 inches (518.68 mm)
Rollout (?): 1.86:1
Total Motor Speed (?): 29600 RPM
Theoretical Maximum Vehicle Speed (?): 52.09 mph (83.67 km/h)
Calculated Loaded KV Value (?): 2000
Calculated KT Constant (?): 0.68 oz-in/A

My problem is I think that I'm overgeared. I was going to drop to a 15 or 16 tooth gear. I need to make 15 minute main and I only lasted 9.5 minutes!

I could run 2 4s 5000's in series to get the time but I don't want to run that much battery if I can avoid it.

What is the ideal numbers I'm trying to get with gearing? What total reduction ratio should I be trying to get, final spur reduction ratio?

Is it possible to go 15-20 on a set of good 5000 30-40c batteries running at 14.8 (7.4x2)? I want to avoid running at 5C because the 80A hobbywing is rated for 4C.

Thanks,

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