Best place to set timing, torsion value etc

[hutchysrs50]

Whenever I've set timing up using vcds I've always set the torsion value to zero, knowing it can go anywhere between -3 and +3.

Recently doing a job where it needed adjusting I changed it forward to +1.1. The car felt abit better but might have just been in my head...

So for performance, where's the best place to have it?

[hutchysrs50]

Bumpy.

[sepulchrave]

Whenever I've set timing up using vcds I've always set the torsion value to zero, knowing it can go anywhere between -3 and +3.

Recently doing a job where it needed adjusting I changed it forward to +1.1. The car felt abit better but might have just been in my head...

So for performance, where's the best place to have it?

 

In effect you are slightly shifting peak torque lower in the rpm range by advancing the cam slightly, such a small amount of advance might be noticeable but I doubt it.

 

The problem with PD cams is that you are also slightly shifting the point at which fuel is compressed in the unit injector, this can result in less net fuel pressure and therefore poorer atomisation, particularly at low rpm and around idle, the dwell of the PD system is fixed by the cam profile but the ECU can't tell that fuel pressure is lower because it bases it's injection cycle on piston position and engine speed.

All this means that the engine has a theoretical fuelling advantage at higher rpm that it cannot use because cylinder pressures are actually lower, this usually means more black smoke which means less poke.

 

You aren't going to do any harm by advancing the cam such a tiny amount, but I very much doubt that there are any benefits either, since it's within spec. it's your call.