Over the last year or so, I've noticed some strange behavior on my factory twins. I use a Greddy Profec Type-S electronic boost controller.

Two issues:

1. Squealing at Full Boost - When I hit full boost, I noticed a squealing coming from the turbo area.
2. Decrease in Boost pressure - Over the last year, I've steadily watched my max boost pressure decrease from a max of around 12lbs to 9lbs today regardless of boost controller setting.

In response, I decided to integrate the latest Tial Q BOV into my system. Honestly, I needed some whhhhpssshhh in my life but my major motivation was to get the bypass valve out of the system.

Well, I finally got the proper spring in the Tial Q and took off. I noticed the nice whhhhpssshhh sound right away. I hit the select button for high-boost on the Greddy and stomped on the gas..........

15 PSI!

I had suspected my bypass valve leaking all along but this obviously confirmed it. It looks as though the spring and/or diaphragm got weak over time and was just leaking pressure. Well no more! I've got that schit grin from ear to ear now as the *** gets loose instantly.

I think I'll be limiting the boost at the recommended 14-15 pounds to save the turbos and tranny....for now. I hit 290whp/290wtq at 12psi. Now I'm looking forward to getting a run at the full 15 pounds.

 

yea the stock bov struggles to hold 13 psi .I got the block of plate and a greddy rs and i boost 18 psi without issues.

 

What are you using to plug the bypass hose on the intake side? I do need to make a plate but haven't figured out how to plug that hose.

 

Lol, it might sound funny but i used one of those circle flasher units you find on older cars. Fits perfect in the hose .You can find it at autozone if you want to go that route.

 

hahahaha!!! Like this?

 

Haha yes!! The aluminum version. Works fine to this day.