Originally Posted by
guinnes.s
... 110119 with sp13.5 v3 at 7.4 fdr ,max temp 72c
4 DRRS 8
9 boost timing 55
10 turbo slope 24
12 turbo timing 30
13 start rpm 2000
14 turbo delay 0.4
timing acc 200
the car felt really quick in the infield and at beginning of the 30 metre straight,but the turbo did not felt to have any punch.what setting could help?
thanx
Originally Posted by
sizheng
You almost used up timing in boost, 2000+200*55=13000 , and with 7.4 FDR, the speed of your car is only 20km/h at this RPM.
I think 'sizheng' meant that as the 110119 has a total of 60deg of timing available. At full throttle you only have an additional 5° (turbo) left as you have already used up 55° (boost) up to just before full throttle.
on another note ... I have been thinking of the calculations ...
How did 'sizheng' get 13000?
With start rpm 2000
Boost timing 55º
Timing acc 200rpm/°timing
RPM at full boost in effect, 200 x 55 = 11000
plus start rpm when the timing comes into effect, 13000
With a fdr of 7.4, for each revolution of the pinion, the wheel will turn at 1/7.4?
At 13000, the wheel will turn at 1756.757rpm (rev per minute)
Assuming your wheel diameter of 60mm, the circumference is 2πR or πD, R being the radius or D being the diameter, and π (pi, a T with 2 vertical stroke) having a constant value of 3.14159.
So 1 revolution of wheel, the car will move a distance of 188.4954mm.
At 1756.757rpm, the speed at the wheel is 331140.6mm/min.
To convert to km/min, / 1000000
To convert to km/hr, x 60
So you get, 19.86km/hr
Originally Posted by
sizheng
you can get your speed by the following (assume diameter of rubber tyre 60MM).
car speed(km/h) =0.01131*RPM(MOTOR)/FDR
so please think of the speed of your car on the track, and then it may help you to set your ESC better.
The 0.01131 is derived from,
0.01131=3.14159*60*60/1000000
3.14159, pi constant
60, diameter in mm
60, to convert to /hr
1000000, to convert to km from mm
My query is does the motor only turn at 13000rpm, just before full throttle? Why do I say before full throttle because at full throttle you have the additional 5° timing, which 'sizheng' have not inculded in the 13000.
BUT ... start of blabbing ...
A silver can turns at about 15000rpm at max efficiency, what ever that is, but thereabouts.
???
So are the calculations correct?
The timing acc (#15 on the setup list) of 200rpm/°timing does not determine the rpm I think. It is only an acceleration figure, that the motor will increase the timing of 1°, at each incremental motor speed of 200rpm, but each timing increase will also increase the rpm of the motor, does it not??? and so the acceleration will not be linear.
We are ignoring friction and drag as well ...
If I am blabbing
cr@p, please correct me ...
