I'm installing a T4 twin scroll setup with twin precision 46mm wastegates. If I run 10.5 psi springs in both will 20 psi be the wg psi or is there a formula I need to use to figure this out?

 

each valve will open @ 10.5psi.
10.5 psi + 10.5psi = 10.5psi.

 

What psi do you guys think I should use? I'm going to do a pump gas and e85 tune but want to stay at or under 500 wheel till I get my block built. Turbo is a comp tripple ball bearing 6065 .81 t4 divided housing.

 

each waste gate will work at that PSI its set to. if you want a 20psi base WG pressure then you need 2 20psi spring rates fr EACH gate.

 

You mean ONE 20 psi spring for EACH gate. Which brings the total to 2 springs you have to get.

 

yes but no. there is no 1 psi spring for 20psi. you will need ''i think'' 14.X and a 6.X spring in each. 4 springs total. 2 in each gate.

 

WTF did i just say??? i have no clue



lets start over


hello. to run 20 psi BASE waste gate pressure you will need 2 springs in each waste gate because they do not make a single spring that will net 20psi. in each waste gate you will have a BIG 14.X psi spring and a SMALL 6.X psi spring to equal your target 20 psi base pressure.



how is that?

 

Sounds good thank you for the advice. One other thing I need advice in is a vacumme line diagram for a twin scroll setup using a mbc.

 

here you go.

http://www.tialmedia.com/documents/w3_tial_44_sp.pdf

 

ok. you will use the SIDE ports on the waste gates. T them together. then run a SINGLE line to the SIDE of the MBC. the bottom of your MBC will run 1 single line to either your intake manifold, bov line, or if you have a fitting on the compressor cover it can go there. you just need a pressure source.

the top ports on the waste gates you just leave them alone.

 

Just FYI for everyone if you get a precision wg it comes with every spring variation standard which saves you lots of money.

 

Thank you so much for your help Dan.

 

As a typical rule of thumb you can only run boost up to 2x wastegate spring pressure. Using this assumption, if you ultimately want to run 36psi of boost you need at least 18psi base rating for the wastegate(s).

 

i ran 25 psi ''back in the day'' with 23psi waste gate spring's i never had an issue

 

hahah....reading this made me laugh...that is all!