DC2Mex

Confused about what psi spring to get for boost by gear. My goal is a 400whp daily driver. I was told i shouldn't boost more than twice my psi spring.Turbo is a pte 5858. i was thinking a 10psi spring, but want a lower psi spring to have better traction in 2nd and 3rd. If i get an 8psi will i be able to hit my 400whp goal without having any issues. i assume about 18psi on the 5858 on 91 pump gas will get me to 400whp.

84mm benson sleeve gsr
cp 9:1
manley rods
clevite bearings

stock port gsr head and cams
full supertech valvetrain
3 angle valve job

topmount
5858
38mm tial wastgate

hondata s300
pwm boost controller

91 pump gas
toyo proxes r888
stock ls transmission
what would be my best option for this setup.

Muckman

iTrader: (2)

You need to establish what kind of range you can get with your ebc first. Depending on the solenoid, how you have it plumbed, back pressure etc will factor into how much range you can get. I suggest you start with a 3 or 5psi spring. 1st gear may be impossible to get traction in at any psi, so make 2nd gear your low boost target. And hopefully you wont run out of pwm duty until you reach your target power. If the boost range isnt high enough then you will need to increase the wg spring or plumb the ebc differently.

Pro Tip: If your boost is tapering off at high rpm you can ramp duty to hold psi up with the boost by rpm table.

D-Rob

To elaborate on Muckman's post:

Most high-flow turbo setups on Honda engines (with larger turbo's too), don't taper off boost, but rather have some "creep" to their boost curves. You can also do the opposite of what he mentioned by bringing more solenoid duty in at lower RPM to raise pressure and flatten the boost curve.

BUT! This is usually counter-productive to most FWD cars, as it makes for a surplus of torque earlier.

Muckman

iTrader: (2)

Ah good point. I have a very high flow head and cam setup but my GT30 still tapers so it must be more turbo back pressure related.

I def agree. I like to soften that boost spike punch with less duty too. This is typically where peak torque is and the quick rise in torque equals tire spin.