Does anyone know what thread pattern the nuts that hold the downpipe to the stock turbo on our cars is? I need to get 2 new nuts for it and I can't find any that fit.

 

Since no one with better info has chimed in, I'll tell you what I could find out in my garage. I have an S4 turbo under the bench with nuts.
A 3/8x16 tap will thread easily into the nut for about 4 turns, then gets tight; which would make sense as it should be metric. So, 16 threads per inch = .0625 inch per thread = 1.59mm
So, I took the few metric taps I have and lining up with the bolt, the 1.25 thread is too fine by a bit, so a 1.5 thread is probably it. Size wise, 3/8 converts to around 9.5 mm. Since there is no 9mm bolt size i could find, I would think it would be a 10x1.5

hope that's useful

- kel -

.

 

^ That's a good guess. I checked the turbo on my workbench, and the studs/nuts are in fact M10x1.5.