Talk about engine building here. New products, tricky questions or showcase your work - If it's engine building related it's welcome here.
I currently have an SR20det 200SX S14 with custom adapted ITBs from a GTI-r, I've been looking at adapting the P11 VE head for a while now and watching the SR86 build series has just motivated me more to do it.
I was wondering if custom machined pistons are required to clear the extra valve lift from the cams? Or are standard forged det pistons fine?
you are restricted to using the p11 std cams on std sr20 det pistons anything larger in the cams and you will need custom pistons with added valve clearance
If you're running low-ish boost/combustion pressures you may be able to fly-cut/notch the pistons for a little more clearance - but I'd be wary of taking more than a mm, or two, off.
On the other hand, with new, aftermarket, pistons with the required valve cutouts, you're going to have a stronger piston and it's a great time to go for oversized pistons with a rebore to optimise clearances and bore finish.