Mysterious Boost/vacuum leak with TDR Rotrex... Help?
 

Originally posted this in the supercharger forum any a week ago, but didn't get any sort of traction so going to try in this thread to see if I can get some advice:

Hey all, have a NB with the TDR Rotrex kit installed, it's been running well until a couple weeks ago when it started idling really high (~3k) unless dragged down to below 1200 by leaving the clutch engaged all the way down. Everything else seemed to be good, figured it would be a simple vacuum leak. Fast forward a couple days, while troubleshooting possible vacuum leaks, went for a short drive to check the idle condition and I could no longer build any boost pressure, and heard lots of air rushing... somewhere... Sounded like it was on the LH side of the engine, so that's where I started looking more in depth.

Thought maybe a bad brake check valve, booster diaphragm or cruise control actuator diaphragm. Brake line valve checked good, brake booster held pressure after engine shutdown, and I capped off where the cruise control line T-d in (all separately, in case one was bad, so I could isolate it). Smoke-tested the lines (thank you baby oil, soldering iron and some redneck ingenuity) and absolutely no smoke exciting from anywhere except the intake filter. Separately introduced smoke at the brake booster hard-line and where the PCV line connects to the IM.

The only part/area I can think of that relates is the BOV/Recirc valve if it somehow failed open and has a torn diaphragm? Would this actually cause a vacuum leak and failure to build boost? As best I can tell, the valve supplied from the kit is a no-name generic vacuum-actuated one (picture attached). The tape on the vacuum line is not there for a leak, I wanted to prevent the line from kinking, so used some electrical tape to reinforce it. I wouldn't be surprised if it actually was the problem.

Any thoughts are appreciated, thanks!

Separately, pretty sure I have an exhaust leak; when I started the car after the smoke test, my cabin got filled with smoke that was emanating from the transmission tunnel, and it smelled like burning baby oil, so that's now on the to-do list.

https://cimg8.ibsrv.net/gimg/www.mia...cbfe54c29e.jpg
https://cimg9.ibsrv.net/gimg/www.mia...57b46719f9.jpg

Bump? Any ideas on where to look?

You haven't included enough information. Need pics of everything to understand your plumbing.

IAC testing may be useful and some pressure testing can help.

I bought a pressure tester from siliconeintakes.com and pressurized from the air filter to the head and found several small leaks on mine.

I think your BOV is oriented incorrectly but it's difficult to tell from the insufficient pics.

I’m made a ghetto pressure tester.

https://www.miataturbo.net/g/picture/19008914

Tire check valves from the auto parts store, PVC pipe caps, and cheap silicone couplers of different end sizes.

You’ll want a few hose caps of varying sizes, so you can block off various hoses to test each one separately.


I didn’t think there was a diaphragm on most BOVs, just a spring…? So you light just check it’s still easy to move and not gummed up.