Originally Posted by
stefan
Hi Roelof,
I think the info you are giving here is a bit too general and could lead people to mess up their engines.
First of all, you have to find out the timing of a crank, before you can decide how to modify it.
For example: a Picco .12 based crank opens very late at 40° ABDC and closes at 60° ATDC. On this kind of engine, you'll see much better results to make it open 5-10 degrees earlier, i.e. take material off the other side than in your graph.
Oh, and stay within 220° of total induction, other wise it will be hard to tune and fuel consumption will go throught the roof.
so your saying the picco crank, has 200 deg of duration ? i actually measured 205 deg on all 3 picco engines i have. one an IDM evo 3, a JL std, and a JL tuned. so if one was to open up the duration further to say 215 like nova based motors, would one see a big difference ? i agree the opening would have to opened up,a s there is about 10 deg difference here from the nova engines. just thinking out aloud at the moment, i am in the process of degreeing all my engines. so there is about 4 more to go . so far the plus 12-3sct has the most duration of all the engines i have checked so far.