Cam duration on 2zr-fe - Need help with numbers please

[charlie rosenzweig]

I know that the 2zr-fe has dual vvti which of course means both the intake and exhaust cams opening and closing can be varied. The attached document shows the intake cam opening can vary between 1degree and -56 BTDC. The intake closing can vary between 65 degrees and -10degrees ATDC.

I want to calculate the duration of the intake cam. The problem I am having is that even while I know that the duration of the cam cannot vary, when I do the math on the extreme advanced opening numbers I get a different number of degrees of duration, as compared to when I do the math on the extreme retarded opening and closing values (as published on this document.

Can someone tell me what I am doing wrong?

For example when using the extreme advanced numbers I get this:

1degree BTDC, and (negative) - 65 degrees = 1+ (180-10)= 180 = 171 duration.

For the extreme retarded values I get this:

(negative)- 56 ATDC + 65 degrees ATDC = (180-56)= 124+65= 189 degrees duration.

Help?

Charlie

 

[charlie rosenzweig]

I found out what I did wrong so I will post the answer here in case someone else is curious.

The duration on the intake is actually 246 degrees and the exhaust is 234 degrees.

following the intake numbers above, for the advanced range of phasing you get 246 by adding 1+180+65 = 246. or on the other end of the phasing range it would be 56+180+10=246.

Charlie