by Relic » Fri Feb 15, 2013 2:38 am
Do you mean recalibrating the N75/VNT ?
On mine VNT map 3 and Turbo map 3 are the only active maps.
Boost hysterisis table 2 upper and lower is used for openloop and feedback mode.
1. raise the upper hysterisis to 75mg/str across all rpm
2. raise the lower hysterisis to 73mg/str across all rpm.
This locks the turbo in openloop mode and disables the N75 controllers.
3. Set gear limiters to the column you want to work on .. eg. 1st gear 60nm (10mg/str) if you want to calibrate 10mg column.
4. Set drive recorder on HDS .... record IQ, requested boost, actual boost, n75 duty cycle, turbo mode status.
Use 95% pedal as the trigger. Records for 30 seconds with the offset 2 seconds before trigger.
5. crawl along in 1st gear...floor it from idle to 3500rpm on a flat road 2-3 times.
6. compare requested boost vs actual boost. If actual boost is too low then raise the VNT duty in the 10mg column at that rpm...0.5% increments.
7. rinse and repeat until requested boost = actual boost.
NB changes in atmospheric pressure and temperature will throw the calibration out.
Perfect one day will be slightly out the next.
You should do this at night when temps are consitant from day to day.
When completed restore the hysterisis maps back to standard.