Yeah we P&P TGV's.
Can't think of any reason whatsoever to coat them though, although we have in the past for a couple of customers who just wanted them black... although even that's pushing it since you can barely see them when they're installed. There's just no coating that would be functional on them. Since they bolt directly to the cylinder heads they're going to get really hot whether or not they're coated... simply doesn't matter. If you barrier coat them, all they're going to do is retain even more heat than they might have before. The coating I would
consider doing is the thermal dispersant coating that we do on intercoolers, radiators, cylinder heads, oil pans, brake calipers/rotors, etc... anything that you want to dissipate
heat as quickly as possible. Can improve the efficiency of an intercooler or radiator or the like by up to 20% and it really does work! However... it needs airflow to function. The TGVs don't get a lot of air flowing over the outside of them because of their location in the engine bay and because they're surrounded by all sorts of other stuff. It just wouldn't be functional.
^^^ so.... don't waste your money on coating them $0.02
What we do
is a FULL P&P on the TGVs. The rods get taken out, the dividers get ported out, the TGV's get gasket matched to the intake port gaskets and absolutely everything inside of the TGV is ported smooth and then it is professionally finished with the correct texture. ALSO... the holes where the rods used to be are first TIG welded shut and the weld is ported smooth. No crappy "plugs" screwed into the outside holes
. These puppies are welded solid before the porting is done.
It's $200 and that includes return shipping to you and the welding, etc.
All of the top-feed injector cars (WRX) have identical TGVs.
This is near the beginning of the process... the TGV's have been fully roughed out at this point. You can see there are NO holes from the rods (on the inside sides or external wall sides of the runners)... they were TIG welded shut and then ported smooth.
This is a finished product