I have a TiAL 50mm BOV and a 44mm wastegate (which I think is fake) that I need to pick out springs for. I have read that a smaller spring in the BOV than TiAL calls for based on your engine's vacuum works more efficiently because it takes less vacuum to open, thus opening quicker at a lower vacuum level. How much truth is there to this? My engine idle's around -20in/Hg, and will flash to -26in/Hg on a hard decel. Should I follow their recommendations and use the unpainted spring, or will a BOV work more efficiently with a lighter spring?

As far as the wastegate goes, I am planning to run a manual boost controller to hold me around 10lbs. Would it matter what spring I run in the gate, as long as it's smaller than the .7 bar, -10lb spring? Thanks for the help

 

run a 5# spring in the gate and use A 2 stage manual boost controller. I had a 5# spring in the gate on the sts,flip a switch and had 12# set by my controller. And on the BOV follow there recommendations on the spring rate. What color spring is in it now?

 

I'm not sure if I'm gonna do a single or dual stage boost controller yet... Won't I need two different tunes if running at two different boost levels? I don't have any tuning software, so I was just planning on running a single stage MBC around 10lbs and having it dyno tuned. The BOV came with the silver spring in it, which according to the TiAL site is what I need. Will my engine vacuum change after the turbo is on?

 

as long as you get the truck tuned with both boost levels the truck should run fine! I had my tune set up for a fail safe so anything over x psi would pull timming and add fuel. When it got cold i started seeing the map pressure raise up more and causing it to run bad. Got it retuned for the little extra boost the cool air provided and runs like a charm!

I would get a 5 psi spring or a 3.5 psi and run a eboost or some type of electronic boost controller. I will end up running the eboost on mine when i win the lottery haha!