GCM Racing R/C Tech and Tips:
-------
Blitz Suspension Setup notes:
GCM offers a Billet Machined Aluminum rear toe block and Zero pin block replacements. To maximize the effect of this upgrade we recommend the following setups:
Short track, high grip, higher than 10 turn brushless motor: Use 3 or 4 deg toe blocks, set up with 2deg camber on the rear and wheelbase set up for mid to front position on the arms. This and a fwd position battery mounting will improve corner turn in, and keep the truck controlled when powering out. You should see a difference right away on the turn in over a stock Blitz 3 deg or 4 deg setup. Using 1 or 2 mm spacers under the wheel side ball stud will help stability.
For long track, high grip, 10 turn or lower brushless motor: Use 3 deg rear toe blocks and a mid to rear position on the arms. A 2 deg camber setting will help with high speed, as well as raising the ball stud position on the toe block. 2 or 3 mm spacers on the wheel side ball stud will help high speed stability and power-on cornering stability.
-------
Gearing Chart for E-Savage Trucks:
This Chart will help users choose initial gearing when using BL motors and aftermarket tires.
Pick the equipment you DO have, (battery, motor, tire) and the line should show you what we would use for gearing.
-------
Tuning your gearing with a Temp Gun:
Brushless motors consume and deliver much greater power than similar sized brushed motors. Because of this the heat buildup can occur much faster than you have seen with brushed motor setups. Careful tuning with gearing must be done to ensure your Motor and ESC will have long life and operate efficiently. Using an Infrared Temp Gun or similar device is the best solution for track-side gear tuning. Here are the guidelines we use for gearing.
We like to see the motor and the ESC Temperature readings under 160 deg.F at all times. Lower is better in any case.
The way to achieve this is to run your vehicle and check the motor and ESC temps and adjust gearing on the pinion and spur gears.
Part 1 of the rule for gear tuning, If the Brushless motor is hotter than the ESC, add tooth count to the pinion, or reduce tooth count on the spur.
Part 2 of the rule is, if the ESC is hotter than your Brushless motor, Reduce tooth count to the pinion, or increase tooth count on the spur gear.
Based on the above gear chart as a baseline, we will make a run with the vehicle, under 1 minute.
Using your temp gun check the temps of the motor and the ESC. Record the values on paper.
Repeat another minute of running and then re-check your temperature readings.
Make Gearing adjustments and run again, check, continue. It is best to keep the Motor and ESC temperatures as cool as possible for best performance, and this is a very important part of any Brushless motor setup. Take the time to do these steps and you will have a reliable power setup that will perform its best for the life of the equipment.
-------
Choosing a good Brushless motor (non-scientific method)
Battery Supply : 4s LiPo battery or 2s x 2 LiPo Batteries in series.
I like running the BL motors at around 80% max rpm at the battery nominal. so....
Many BL motor maximum rpm : 50k x 80% = 40krpm.
4s lipo nominal volts =14.8
40,000 divide 14.8= 2702 Kv.
I'd be looking for a motor that has the torque to move a lipo e-sav (which is light) and around 2700 Kv. I'd be looking for a 50mm long motor for a truck under 4500 grams, and I'd be going for the 60mm long motor for any trucks from 4500 grams to 5000 grams RUNNING weight. Over 5000 grams look for a motor that is longer than 60mm. For reference our Bulletproof E-Savage article truck weighs 4589 grams with NihM 12 cells battery supply.
-------
FLUX Savage Gearing hints:
Concerning the gearing, we like to use 2 tests to guage gearing considerations. Test one is the total weight of each wheel/tire combo. Test two is motor temps. The equation goes like this:
If your tire combo change is getting heavier, drop one tooth pinion for every ADDED 100grams per wheel added. If you have a 250gram tire combo, and move to a 350 gram tire combo, drop one tooth.
If your motor temp is ambient + 50 stay gearing. Every 10 deg F rise from +40, drop one tooth. So if you run at 90deg F outside, and motor temp is 140, you stay. If the motor temp is 160, drop 2 teeth.
These calculations are stackable, so you may have a tire change, and run in a grassy area with lots of drag, and therefore loose 3 teeth on the pinion at one time. (can also compensate with a larger spur as well).
As a guideline, this works well. Tire diameter is a consideration as well, but not as much as weight. A set of Big Joe tires on beadlock rims is the same height as a savage XL stock tire, but much heavier, and will require a pinion change.
Stock 20/44 is a good place to start any setup, 4,5,6s lipo. Use the guidelines above to adjust accordingly, remembering that Brushless motors like to be loaded up to run cool, so if you are getting a 140 motor temp already, that's reasonable as long as it's consistently 140. The higher voltage you run will be more efficient, and likely not require a gearing change with the larger tire.
-------