I know this is a n00b question but im a little new to wastegates. Can someone explain to me what the spring rating means?? and hopw much boost it holds?

 

thats all the boost you can make on that spring without a boost controller

As far as upping the boost you are going to either need to get a stiffer, or EBC or MBC

 

what ever the spring is rated is the lowest boost pressure you can boost. I think that asnswers your question.

 

ive got a turboxs MBC but thanks you guys answeared my question

 

the spring rate psi is the lowest boost (psi) you can used. so let said, with no boost controller the turbo will only go up to 7.8psi before the wastegate open. But with a boost controller you can up the psi to anything above 7.8psi (20psi if you want)....

 

rule of thumb... dont go double your WG spring pressure. IE 0.5bar spring, dont boost past 1bar on the spring.. Chances of creeping and spiking greatly increased, also you cant run lower then your spring pressure.

 

You'll want a larger wastegate depending on Manifold design and Turbine size you'll wanna have. The higher the boost the easier it is to control, its harder to control 5psi than 30psi.

Simple example.

84mm LSvtec, 8500 rpms.
35mm wastegate 6psi spring.
InlinePRO manifold

W/ a .63 AR turbine I was able to control 6psi all the way to 26psi, rock solid.

W/ a .84 AR turbine I was able to control 10-11psi all the way to 26psi, rock solid.

The .84 AR wouldnt run less than 10-11psi because the turbine was flowing so well exhaust was less willing to exit the gate to control 6psi.

This is just a basic example.

With a log manifold a 35 or 38mm is plenty depending on turbine AR size and intended low boost.

With a nice flowing tube manifold, a 38 or larger is a must. Some people use 2 38's or a 44mm to help maintain low boost pressure.

hope i helped.. some? its late and i'm tired