I purchased two sets of Wossner pistons to be used in nitrous bikes. They are a tall deck, heavy duty piston, similar to a Turbo piston, but with less dish to them. They have been running in two nitrous bikes (1, 1397 only making about 275HP, the other a stroker 1535)
We were planning on seeing what kind of power the bigger bike woudl make, but the crank let go on the dyno.
Crank didn't hold up so well, but the pistons are still great with no issues and the pins still slide out of them (I have seen some VERY tight pins in some other pistons after use, not necessarily a bad thing I guess, but these didn't get tight).
Not trying to be a huge Wossner nut swinger, but I have a set of turbo pistons in my bike as well. I haven't torn the top end down since the build since there is still nearly zero blowby on the motor and it still runs strong. there may be pistons as good as these available, but that said, I have not yet found any issues with these, and the price is reasonable.
The pins are a very heavy duty, thick wall design. This does add weight to the piston, and with a very high revving normally aspirated application, likely are not worth the extra weight. The thicker wall does add a considerable amount of stiffness to the pins.
They come with a graphite-like skirt coating as well
I have no reason not to use them in my future builds, and probably will
Ring gaps are wider than most probably use, but I have been using these wider gaps without any problems. Here they are for future reference when someone searches for "ring gap"
84mm Nitrous pistons have ring gap at ~.022 top, .025 second
81mm Turbo pistons have ring gap at ~.018 top, .023 second
This is a picture of the nitrous pistons when new (kind of shitty since it was a cell phone pic). They still look similar, obviously with some coloring on the tops
This is the crank....it looked a little different when we put it in
Another point to note is that the rods from this motor seem to be fine. They are being check today I believe, but still going strong, even after the crank broke in half (Bearing surfaces look like new on the rods and mains, other than some edge issues on the broken journal rid from the journal machining a bit of the bearing away.
John