HI everyone, currently building my s in my garage and need advice on wastegate spring size. Its going to be a tial 44mm, but im stumped because im trying to get 400whp on a pfab log manifold. Ive heard nothing but negatives with this manifold, but it made good friends with my wallet., considering every tubular manifold is like a grand. Id like to know what size spring to get with the wastegate. Could it be done with a flash pro, and a 3m headgasket? thanks for all the help, input!!

 

yes it can be. and for 400 whp i would suggest aprox 10psi spring. i am also putting together a pfab manifold setup with a precision billet 6265 and e-85. im going for 500whp on my stock f20c.

 

Just heads up I put down 429hp at I think 18psi (not impressive), and it was with stock wastegate spring on inline pro log setup.....which is what 7psi.

 

A good rule of thumb is to get a wastegate spring that is no more than twice less of a spring rate as to what boost psi youre running. What I mean is, if your end boost psi is 20 psi, you dont want a wastegate spring any less than 10 psi or boost creep is possible. I run a 10.15 psi spring along with a 5.8 psi spring with an end result of about 16 psi wastegate spring pressure because I plan on running anywhere from 24-30 psi of boost on my Precision 6262 turbo.

 

Thats correct, the spring is 7psi.

 

Do you fellas know where i can pick up a set of some arp head studs for my car. I was thinking bout getting them since im going to do the 3mm head gasket also Spoolin thank you for the explanation of the spring, i was backwards on it.(noob-kinda)

 

No problem man.

 

I bought the tial 38mm W/G. I ordered the W/G with the option for 12lbs, apparently it has two springs in it or something like that? I was going to buy a 6lb one, however I was told I already have it I just need to take one of the springs out?

any truth to this

 

Probably not. Jus look at the spring colors. Pretty sure the smallest psi the big spring is like 10, and the smallest small size spring is something like 3.63 psi. So that would be closer to 14. Just open it up and check

 

If running 2 springs, you have to have one larger diameter spring and one smaller diameter spring. You cant run two small springs or two large springs as they would bind up. The springs that are available for the Tial 38mm wastegate are:

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 cant get 12 psi on your 38mm wastegate with two 6 psi springs so I dont know where you got that info that you could remove one and have 6 psi wastegate pressure. You could possible have the small red spring for 5.8 psi but I'm not too sure which other large spring you have in there. Maybe the large yellow spring but that would have you at about 16 psi wastegate pressure with them combined. If you truly have a wastegate spring in there that is at about 12 psi, then it's just the one spring and that would be the large red 11.6 psi spring. So, that would mean you cant just remove one spring to get you to 6 psi because there isnt another spring in there to remove. Make sense?