So I am in need of some clarification from some turbo gurus in regards to wastegate selection. This will be my first external wastegate application and I have been trying to read up as much as I can...

When selecting my wastegate spring, the spring psi should be the lowest level I intend on running? So I can't run, say, 5 psi on an 8 psi spring? My boost will start at 8..
Now.. If that's the case, why are there higher rated springs? Does each have a limit? Like 8 psi spring would be like, 8-20? Kinda strange little critters they are..

 

Because running above wastegate spring has limits for the average joe. Id say like x2 to x3 max.
Again for the average joe.

 

I think I found out some really helpful info. WG spring starts at what it is rated that is half it's max.. For instance.. 8 psi spring is good for 8-16 psi. 10 is 20.. At least that's only info I dug up somewhere on the interwebs. H

 

The spring pressure is the base regulating pressure. Higher rated springs/spring combinations just start at a higher base pressure...ie: if you want to start your base tuning pressure at 14psi; then use a 14psi or 1 bar spring combination and turn up from there. You can't use a 1 bar combination and start regulating at 5 psi.

 

Yeah, I got that. I am looking to start no higher than 8 psi, so a base spring from 5 to 8 psi is what I will use. Where I am starting to get confused is using multiple springs. Say; a 7 psi and 10 psi. Looking at exploded views of a WG and the mechanics of it, where I am getting lost is how would I be able to use 2 springs, based on how they sit? Physically speaking, each end is equally spaced between 2 parts; the spring seat and upper cap? I don't know if I can properly explain what I am thinking so I would just ask... *** If I use an inner and outer spring combo of 8 and 10 psi, I will be able to boost between 8 and 20 psi? ***

 

No, 2 springs used together will give you a base pressure of the total of the indivdual 2 springs (if using a Tial gate). For example a Tial MVS uses a black 8.7psi and a red 5.8 psi spring. Individually they regulate at those pressures. When running both springs at the same time they regulate at 14.5 as the starting point. (an 8 and 10 psi would net 3 springs...and would be 18psi)

 

Ok, NOW it makes sense. I was confused on multiple springs. Thanks for that clarification! So I should probably just stick with 1 spring that is close to, if not at my intended boost level until such time that I want to "cut her loose". Seems fair enough just to stick with 8 psi. I will be running a precision 5431 (unless I find something comparable for a better price), which should give me a solid starting point with lots of room to move forward.

 

 

I've always went by the spring rate was good for 1.5x psi the base psi the spring is rated at.