I'm running a blue spring with no shims and all that I have done is CAI, test pipe, and motor mount. I might switch back to yellow with one or two shims.
A lot of people run the blue spring, even with shims ( i have even ran it with blue&2 shims) and no compressor surge.
you usually want to run the highest spring possible. If you use the yellow spring, it may not hold boost therefore you will lose power. Plus using the yellow shim it pings too easily, im trying to keep my car a sleeper relatively.
Personally, I like the sound more than the typical bov. And for the record, the blue spring is rated for 13-15 psi, which is where all of the disi's run. I felt much better performance making that change from the yellow spring...
Personally, I like the sound more than the typical bov. And for the record, the blue spring is rated for 13-15 psi, which is where all of the disi's run. I felt much better performance making that change from the yellow spring...
My recommendation, which will change if new information presents itself:
Yellow, yellow with shim - Stock
Yellow with shim, blue - Mild upgrades with only a negligible increase in boost
Blue, blue with shims - Common bolt on parts with significant increase in boost
Blue with shims, Red - High boost applications
