Originally Posted by valk
Still having difficulties with my x12 17.5. Im trying to run it in 12 stock with a tekin rs. I ran it in my tourin car with someones posted timing settings which were a lot and it was fast as shyyyte but in my 1s car for whatever reason its a real dog.
Running 4 dot insert. I tried timing assuming 4 dots is 27.5 deg advance which was slotslowslow at 76-79 rollout and then tried assuming no timing. So added about 50 deg as ie seen others doing with 4 dot. Was fast but went flat in 2 minutes.
Wasnt really hot. Has never come out of my 1s car over 160. Just dunno what to do with this motor. Maybe just use it for pure blinky cars where it seems to worj great.
Ran it blinky for one qualifier. Rolled out around 105 an it was easy as fast as the boosted cars. Dunno.
The X12 will run with 'em all in boosted or blinky. You'll need to do some fiddling with roll out and gear as well as your boost profile. It's not as simple as setting a roll out pouring in tons of boost. What you've described for your boosted profile is a classis heat fade condition.
12th boosted rollout is somewhere in the mid 70s to mid 80s?. Might want to check that with the guys that routinely run a boosted 12th. Stay with that 4 dot insert for any boosted profiles.
Try this (I learned this method from my buddy Harry):
Boosted profile from scratch
When I'm starting a profile from scratch, I use the rough kV to figure out where I want my RPM range.
For 17.5 I take 2400 * 7.2 [you can use the battery ending voltage if you think your profile is pretty close, otherwise I use nominal voltage] = 17,280.
You can use this for your end RPM, but I usually knock around 1k RPM off that figure, so call the end RPM 16,000.
For start RPM, I usually set it for the top 60% so 16,000 *.4 [take 40% off] = 6400. Pick something close from the list of calculated Start RPM values.
After that, it's just a matter of fine tuning to preference. If you want more pull off the corner, raise the Start RPM up about 1,000 RPM. If you want to smooth out power deliver on bottom end, lower the Start RPM about 1,000 RPM. Repeat as necessary.
The amount of boost you run is gearing/roll out dependent.
I only use Turbo if I'm visibly lacking in straight away speed, and don't think the added speed is going to hurt corner entry at the end of the straights. The most Turbo I'll run is around 10, ramp 1 or 2, with .4 delay [almost always]. I don't remember if I was running any today or not.
EDIT: Forgot to mention, if you feel like you want mid-throttle acceleration snappier, lower the End RPM down 1000 RPM at a time until you're happy. If you feel like mid-throttle acceleration is too aggressive, drop the Boost down in increments of 5.
To me, if you see the car kind of "shifting gears", your profile is likely going to upset the car and make it needlessly hard to drive, and slower. I'd rather see the car accelerate smoothly, but very quickly instead.
For 1S, just recalculate as above for half the voltage.
FYI: I use 3400 kv as my rough estimate for 13.5, and 4200 kv for 10.5's. Every company's motor is a little different, but the above calculations have served me well when building a boosted profile.