Rb25 Cam Change

[brad 110]

has anyone dynoed back to back rb25 std cams with vct operational and fitted pon 256 tommie cams with no vct

[PM-R33]

Yep.

VCT off on the poncams, loss in down low power, VCT on, better down low power. Keep the VCT if its a street car, Tomei Poncams are made for VCT so why are you asking about Poncams with VCT disabled?

Making power at high revs on an engine is easy, making power at low revs is difficult.

Edited December 13, 2009 by PM-R33

[brad 110]

Yep.

VCT off on the poncams, loss in down low power, VCT on, better down low power. Keep the VCT if its a street car, Tomei Poncams are made for VCT so why are you asking about Poncams with VCT disabled?

Making power at high revs on an engine is easy, making power at low revs is difficult.

its not a streeter, the amount of oil the vct feed returns to the head when its deactivated at 6500 is an issue, and when using 8200 revs even with extra oil returns and restricted feeds is an issue. did the pon cams loose bottom end over std sticks even with vct active

[PM-R33]

Did a whole lot of headwork at the same time therefore can't compare. Only comparison we did was moving around the VCT change point and turning it on and off to see how it was affected. If its not a street car, and it's going to be in high rpm constantly, than the VCT not being enabled wouldn't make a difference.

[brad 110]

Did a whole lot of headwork at the same time therefore can't compare. Only comparison we did was moving around the VCT change point and turning it on and off to see how it was affected. If its not a street car, and it's going to be in high rpm constantly, than the VCT not being enabled wouldn't make a difference.

The only reason i want to ditch the vct is the amount of oil it releases into the rh rocker box when it is deactivated at 6400, it has a 6 speed box so the ratios are pretty close i can afford to give away a little responce but the std cams are no good with out vct operating, i may have to fit a set of 256s and run it. what other head work did you do at the time and what where the net gains. cheers