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How do you approach a tuning session that you have to work and tune continuous variable cams and the owner of the
car tell you that the engine have aftermarket cams with more lift and duration . I think its very difficult to work with that type of system
if you dont know the fisic limits of the more advance position of the inlet camshaft or at least know that the engine builder is a reputable guy and answer the tuner questions with some grade of accuracy.
How do you approach that theme if you did not made the engine blueprinting before ? always ask the engine builder or only tune little increments ?
Want to know some comments, thanks.
I would hope with larger cams or valves if there was anyway there could be piston to valve issues then the engine builder would have checked this and made a mechanical lock/stopper so the cam cannot swing to far.
This is something we have seen/done on numerous occasions.
A great place to start would be check out the webinars on VVTi tuning.
This should help with knowing what steps to take and how to optimize vvti tuning on the dyno.
As Chris said, it's the engine builder's responsibility with any cam upgrade to ensure that there is no valve to valve or valve to piston contact at either extreme of the cam travel. If this is an issue then a mechanical stop should be fitted. The reason for this is that even outside of our own cam control mapping, it's possible to have a malfunction of the control mechanism that results in maximum advance/retard despite the values in our actual map.
Thanks for the comments Chris and Andre,
Well, I see that it is very important that the engine builder take care and take notes of the piston to valve and valve to valve clearance
especially in the intake valve most advance position and also know which is the most advance possibility without interference problems in terms of degrees before tdc , that info is going to be very useful for the tuner in this type of engines. Also a very good idea the mechanical limiter or lock. The engine I am thinking now is the Honda K20 , I found that Toda Racing sell an intake advance limiting sprocket so its worth the investment .
Thanks for the webinar link, just saw last week Continuous variable valve tuning with the Haltech and the 350z , next webinar I am going to see is the recommended . thanks