This is a POWERCAP for the famous LEXMAUL inlet manifold opel/vauxhall C20XE engine. Adding this part will result in more responsive throttle and power gain. The diameter of the inlet pipe is 80 mm, the diameter of the small branch pipe is 20 mm. Recommended ABS (or TPU) printing, mechanical and chemical post-processing.
I recommend after printing to align the irregularities of the plane under the throttle gasket. Use 240 grit sandpaper, then 500 or 1600 grit on glass and with added water.
Feel free to write to me if you need additional variants of shape or part size for your particular variant. I will gladly complete the additional options.
Works great with this gasket https://www.cgtrader.com/3d-print-models/hobby-diy/mechanical-parts/opel-c20xe-throttle-gasket