Low to Hi Cam Angle @ VTEC (From 30 to 50 degrees @ 3000rpm)
Posted: Sun Aug 12, 2007 4:19 pm
I got a question to ask...
Well for those who are fimilar with cam angle tuning, it takes 0.1 second to rotate 10 degrees physically. My VTEC point is set at 3000rpm, which was dyno tested to be the most suitable for my supercharging setup.
At the dyno, we tested 30 degrees in low cam made best power, while 50 degrees in high cam made the best power. After my tuner has completed the tune, I took a look at the dyno graph and the calibration when I got home.
I noticed that my tuner, instead of starting to change the cam angle at the low cam map from 30 to 50, he did that on the high cam map instead... so that may explain a significant dip in the dyno graph from 3000rpm to 5500rpm.
Becuase of where the VTEC crossover set at 3000rpm, I can only start rotating the cam angles from 30 to 50 degrees in the low cam map starting at 2000, 2250, 2500, 2750 to 3000rpm.
The question is, I'm not quite sure if there's enough time for the cams to rotate 20 degrees in 1000rpm worth of time (*I know gearing will play a factor, but let's assume 3rd gear pull which is about 2 seconds or so)...
Should I make the change and have it start rotating at the low cam instead or the high cam?
Example:
LOW CAM MAP (Wide open throttle):
2000 and below - 30 degrees
2000rpm - 30 degrees
2250rpm - 35 degrees
2500rpm - 40 degrees
2750rpm - 45 degrees
3000rpm - 50 degrees
HIGH CAM MAP
3000+ rpm - 50 degrees
thanks!
Well for those who are fimilar with cam angle tuning, it takes 0.1 second to rotate 10 degrees physically. My VTEC point is set at 3000rpm, which was dyno tested to be the most suitable for my supercharging setup.
At the dyno, we tested 30 degrees in low cam made best power, while 50 degrees in high cam made the best power. After my tuner has completed the tune, I took a look at the dyno graph and the calibration when I got home.
I noticed that my tuner, instead of starting to change the cam angle at the low cam map from 30 to 50, he did that on the high cam map instead... so that may explain a significant dip in the dyno graph from 3000rpm to 5500rpm.
Becuase of where the VTEC crossover set at 3000rpm, I can only start rotating the cam angles from 30 to 50 degrees in the low cam map starting at 2000, 2250, 2500, 2750 to 3000rpm.
The question is, I'm not quite sure if there's enough time for the cams to rotate 20 degrees in 1000rpm worth of time (*I know gearing will play a factor, but let's assume 3rd gear pull which is about 2 seconds or so)...
Should I make the change and have it start rotating at the low cam instead or the high cam?
Example:
LOW CAM MAP (Wide open throttle):
2000 and below - 30 degrees
2000rpm - 30 degrees
2250rpm - 35 degrees
2500rpm - 40 degrees
2750rpm - 45 degrees
3000rpm - 50 degrees
HIGH CAM MAP
3000+ rpm - 50 degrees
thanks!
