Quote:
Originally Posted by Noir
I doubt they could tell if you had them installed  |
One guy called me and thought I sent him some stock parts. He sent me a picture and I pointed out the changes. He was looking at the 'ramps'.
I do not change the 'ramps'. That is a complicated 3D shape.
I change the 'position' of the supports which change the geometry of the lift ratio.
They are like adding 1.6:1 roller rocker arms in a Chevy small block instead of the stock 1.5:1 rocker arms.
Downside?
They add just over +1mm to the intake valve lift. That is maximum lift. And only to the intake valve. This additional lift occurs when the piston is near BDC (bottom dead center) so no piston interference will occur. They only add the additional lift at over 80% eccentric cam position which is about 80% throttle to WOT.
So if you 'never' go over 80% throttle, you will never experience the additional lift. Because of the way that the Valvetronic mechanism works, there will be no additional 'anything'.
Now at baseline, like idle, the hydraulic lifter will be slightly more compressed, less than 0.010" more. This is well within the range for the hydraulic lifter.
Over 80% throttle, they will also add 2-3* of duration to the cam lift cycle. More lift and more duration equals 'more area under the curve' for the intake valve opening profile. More air is 'ingested' into the engine.
Variable lift and variable duration, below and above 80% throttle position
Only downside is 'you should have done it sooner'!