Making a custom chassis is not a bad idea, but i would not run a single speed. Firstly because of the heat generated with motor braking, secondly if you are going to run huge gearing it cogs really badly. Better to run a two speed and have a smaller first gear to get it up and running and than the huge gear for 100MPH
I was running 6s on a spare MMM 2200 combo i had. I had it geard for 30/44 i think in second. I dont have a radar gun or GPS, traction was an issue and it will need a lot of room to get to a decent speed. You may need to soften the standard shocks and i would pull the diffs out and re oil and shim them. Body wise before you cut up wings and such just see how it goes.
Be careful, especially with speed runs as the big gearing will kill the motor.
If you are going to make a custom chassis remember before you drill anything to mount you motor and batteries to place the car on 4 scales and workout what the weights will be front to back and left to right. It will improve the handling a great deal
I wouldn't use motor braking at all on a speed run car. If you look back at my first post I suggest using a mechanical brake. I think motor brakes are a lot of what gets people in trouble when they gear higher. I also think that the two speed will be an issue going that fast. Eliminating as much rotating mass as possible is critical for speed runs.
100 mph in a car that big is pretty serious. I would just like to see him go the best route possible and not the cheap route which will lead to issues.
Make sure you have several assorted pinions to work with. Also make good use of the gearing/speed calculator located at the top of this forum. Remember to start low and work your way up. This will get you used to the speed and handling while also gradually allowing you to find out what the limits are. Definitely make sure you have an infrared temp gauge on hand for the motor and ESC. The dynamite one works well and can be picked up at most hobby shops for around 20 bucks.
Make sure you have several assorted pinions to work with. Also make good use of the gearing/speed calculator located at the top of this forum. Remember to start low and work your way up. This will get you used to the speed and handling while also gradually allowing you to find out what the limits are. Definitely make sure you have an infrared temp gauge on hand for the motor and ESC. The dynamite one works well and can be picked up at most hobby shops for around 20 bucks.
Thanks for all your help I'll check out the speed calculator and I do have temp gauge
Not sure that battery for my starter box nitro cars
What he's getting at is that the Tamiya power connector is not well suited for hugh current draw, as in 1/8 scale brushless cars- especially speed run cars. I'd recommend Deans as a minimum, 5mm or 6mm bullet plugs would be better.
Power wise, it doesn't matter. Balance and setup wise, two would be better.
Two of these would do nicely and are a good price. At 55c it gives you a 143 amp continuous rate and being lower capacity it will keep size and weight down.
little update;
recieved my mamba combo and made top plate for mounting esc
next batterys and battery trays proboble its going to happen beganing next months spend all my budget for rc this month