Recently we had a Mk7 GTI with a IS38 turbo swap in the shop. The car had a brand new turbo from a Golf R and a Unitronic Stage 2+ tune on it.
Under hard acceleration, his car was loosing boost pressure and the waste gate needed to be adjusted. I did a visual inspection on the swap and everything looked to be in order. However I noticed that the diverter valve was a Ver C, Part No.: 06H145710C.
Most of you know that the old Ver. C had a rubber diaphragm and that the Ver D was the one to upgrade to. I removed the DV and found the updated Ver C., which had the piston and correct for this turbo and year vehicle.
I did a lot of research and found out that there are two Ver C DVs. The old Mk5 Ver with a rubber diaphragm, the new Ver C with a piston and the Ver D.
There was no info in our VW technical manuals. So I went online. Lot and lots of debates about which one is better.
The only thing I can see that is better is that the Ver. D has no o-rings and potentially could last longer and not wear out as fast. in conclusion, if i had to replace it, I'd buy a Ver D due to those facts. But I'm sure they will work the same and have no difference.
