So I am going to run dual wastegates on my 8.1 STS setup. I want to run a Low bost of around 4-5 and a High of about 8...ish. I have one Dial 38mm, and I'm getting ready to order the other. What springs do I need to have in them? I am going to run the Electronic Boost controller that comes with the STS setup. I think it has two accuators or whatever those things you hook to the wastegate are called, so it should be ready to go...right? How do I tell what spring is in the one I already have?

 

you will have to take the top off of the waste gate and see what color the spring is. for the presure you are looking for it looks like you want the small yellow spring. the spring determines your lowest boost. then with a boost controler of some kind you can push that number up as much as 2-3 times. that means if you see 5psi with the small yellow spring a boost controler might be able to be adjusted to as high as 15psi.

bar/psi
0.250 3.626 Small Yellow 1.875 In
0.400 5.802 Small Red 1.875 In
0.500 7.252 Small Green 1.875 In
0.600 8.702 Small Blue 1.875 In
0.700 10.153 Large Yellow 2.360 In
0.800 11.603 Large Red 2.360 In
0.900 13.053 Large Green 2.360 In
1.000 14.504 Large Blue 2.360 In

you might just try the one waste gate for starters and see if it will keep the presure down where you want it. if it wont then buy a larger wg or add a 2nd one. you do not need two wg's in order to have adjustable boost.

 

 

it a SOAP wastegate.
Sorry, "Tial"

 

I would start off with one. not many people that ive seen have to run 2 WGs.

 

Yea, but not many people want to run a low boost on a 496 cubic inch motor either. I might try one and see what happens.

 

The 38mm is a bit small for a big block system i would think it will see alot of boost creep.. But you use a boost controller to control for 100.00 with a high/low setting if you want to have a 6/12psi setup at the flip of a switch the size of the wastegate is what controls exhaust gas pressure going into the turbo ......... Twice the parts = twice the problems ... I think i would try and run a 55 or 60mm Wastegate and be done with it...

 

You will most likely need two waste gate, BUT not to have two boost settings. You need to be able to bypass enough air to control the turbo. Ether one large gate, or two small gates. As far as two boost settings go there are many ways to go about it, but if you plan on running two small gates, be sure your controller can control both...

 

you can control 2 gates just like you can one. you just t the vacume line and then hit both gates.

 

Yes, but if you have a controller like mine (sts controller with reg) I doubt both gates could exhasust through one sts e-valve.