ok well here is what im trying to figure out im about done putting my sts kit on my T/A, i have a AEM tru boost controller dual boost settings, well on the first setting i want run 5psi and 8 on the second setting, well for my 38MM Tial WG these are the springs i found on their website

BAR PSI DESCRIPTION O.D.
0.250 3.626 Small Yellow 1.875 In
0.400 5.802 Small Red 1.875 In

so now the question is which spring to buy, i know with the rear mount and FMIC i will have 1.0-1.5psi loss so now should i go with the 5.8 since its only going to see about 4.5psi at the motor and use the boost controller to up it to a 5psi even and hold it there or get the smallest spring and use the controller to up it to 5 but then i know you can only doulbe the spring pressure in the WG so in that case if i go with the smallest one then i wont see 8psi on the second setting right?

thanks for all the help in advance.. matt

 

anybody?

 

anybody know anyone i could call or get ahold of to find out?

 

If the controller is accurate, you can always go smaller spring and set the first setting at a little higher than what the spring is rated for. You're kind of in a tough spot, as the .25bar spring is too small to measure 8psi exactly as the rule of thumb for wastegate springs is typically twice the measured boost level (you'd end up with 7.5 lbs...which is still close to 8 and may be fine as long as you don't lose any boost). If you go with the .4bar if you're expecting loss from the 5.8psi, you could have it tuned for the lowest it could support as the base boost level, and 8 or 9psi as the 2nd setting on the controller.

I have the same F38 wastegate on my setup...and every setup is different, but I see 9.5psi with a .6bar spring (rated at 8.7psi) with the cutout open...so I'm seeing a bit of creep...but mine is a front mount so it may not be a good 'rule of thumb' to go by.

 

how can you tell a large spring from a small spring?

 

Go with the 5.8 at least....you'll want to go over 8 down the road antways.