4wd Baja 5e based on stretched truggy chassis

[othello]

After having red this thread and this one i always had this idea spinning in my head as i really like the look of the baja 5. Converting a true Baja 5 was no option as it would remain 2wd and would require a new ESC + motor. Powering 20lbs+ with authority would consume a lot of energy and quickly recharging would become problematic. So i decided to go another route with parts i had laying around.

After studying the manual of a baja 5 i ordered the needed parts to reproduce its look: front bumper, main roll cage, center roll cage, roof and clear body. I took 2 1:8 truggy chassis (Robitronic Mantis), overlayed them to get the wheelbase of a Baja and testfitted the roll cage, body and front bumper. I mounted wheel extenders and used proline lpr half offset wheels to extend track width.

I then cut the two chassis plates and fitted basic mounts for the roll cage. I mounted the centerdiff including a Neu 1515/2Y (1100kv) motor. I cut the rear center CVD and used an aluminium tube to extend its length.

There is plenty of room for batteries behind the center diff. I did not want to reconfigure my battery packs (5s1p and 4s1p A123 for my truggy, buggy and truck) so i placed them on the chassis to get a 50/50 front/rear balance. I'm still using a Kontronik Jazz 55/10/32 (55A cont and 10s lipo max) with car mode (forward, brake, backward) to power this car as it has proven to be very reliable in all my 1:8 cars. For peace of mind 2 40x40mm fans were mounted over the motor. 2 single A123 cells were added and gearing was adjusted to 1:14,86 (46t kyosho plastic spur with a 13t pinion). With 11s1p A123 (around 33V under light load) the 1100kv motor should rev up to 36000rpm calculating to a speed of 40mph (65km/h).

This is a pic of how i run the baja. It wheighs 5.5Kg (12.12lbs) with 11s1p A123. The painted body will add around 3.53oz (100gr).




Here is a video of its third test run.

Body is not painted yet, so i run it without it. No shock adjustments were made. I run it with my truggy setup without anti-roll bar -> offroad setup. Acceleration was good (still quite some unloading to the front tires) and ESC braking was amazing. Turning circle was impressive for such a large car ... Crimefighter tires provided huge amount of grip resulting in 3-4 tip overs.

I run the car for 6 minutes. Motor, ESC and Batteries were warm but not hot (outside temperature was 62°F (17°C). I could keep my finger on the motor as long as i wanted. Batteries took 1470mAh back while recharging. With 2000mAh utilisable, runtime would have been around 8 minutes with this driving style. This translates to an average Amp draw of 15A. With 33V (11s x 3V) average power calculates to 500W. Motor temp will climb and runtime will fall depending on how hard i drive.

There is more then enough room for improvements. Especially shock and anti-roll bar setup. This car is meant for offroad and not for onroad. It was sort of a proof of concept run and to get an idea if my lengthened CVD is up to the job (it vibrates too much but remained in one piece: a steel tube would be more apropriate).

What do you guys think?