Recently got a Z1 plenum installed and now there's a vacuum leak. All bolts are tourqed to spec in the correct order except the two that aren't long enough to put a nut on (in the install manual it says "Studs #12 & 17 can be removed or left installed. They will no longer be used."). im not exactly sure what do from here, i've checked all the hoses and retorqued everything. please help if you have any idea what's going on.

 

That's why I don't like Z1 and their I/E products, most of them are nonsensical. Motordyne is the only spacer I'll ever use.

 

I would give Z1's support a call. If the Z1 plenum is sealing correctly, then the only other thing I can think of is a compromised vacuum hose somewhere. If the hoses are original, it's very easy to crack when during the removal process. Which engine do you have and which specific Z1 product did you purchase?
Good Luck!
-Icer

 

FWIW, I've been running the Z1 angled plenum spacer since 2015 with no issues. It's been so long, I don't recall what I did with studs 12 and 17. Probably removed them.

 

I'm running theirs also without any issues, other than the sturt bar sitting on the manifild!!! And it will only do that when the engine is hot, cold it clears it. Do the aftermarket ones clear the manifold?

 

Some aftermarket strut bars have proper clearance while others don't. Usually they'll advertise if they will fit something with a spacer. I don't remember if the Z1 plenum came with strut bar spacers. Apparently, Motordyne does.

https://my350z.com/forum/intake-exha...um-spacer.html

 

I'm rocking the MD kit, and it comes with aluminum spacers for the tower bar, clears both the upper plenum and the hood without issue. You could easily cobble together your own spacer solution, I would not exceed anything thicker than 1/4in, otherwise you risk the tower bar bashing into the hood. I never measured the spacer washers that came with the MD kit, but I suspect they are 3/16in - 1/4in thick.
Cheers!
-Icer