tial 44mm spring rate

[LiEast]

how do you know what spring to use in a waste gate? is it if your running 20psi on your turbo you need a 20psi/1.4bar spring?

whats the equation?

what spring are people running with different setups?

[triplejumper18]

I believe you'll want a lower pressure spring than the maximum psi that you want to run.

[bmylez]

There are various rules of thumb that people throw around, but the one that I've heard many times is, you don't want your max boost pressure to be more than double your spring pressure.

So, the equation is: Max boost/2 = Min. Spring Pressure

That's not to say you NEED a 10psi spring if you want to run 20psi. It's the minimum recommended. It's always good to have room to grow, so if you know for a fact you want to run 20psi right now, get at least a 15psi spring so you can bump it up to 25psi down the road and still have reliable boost control.

As I said earlier, that's just a rule of thumb that I have been told. It's not necessarily the *only* way to do it.

[rigor]

im running a 14 psi spring and it runs around 17-18 psi..

it all depends on your setup

[wette460]

It depends on what you want the spring to do. If you wanna control boost off of your spring pressure instead of using a MBC or EBCS, then get the spring for the boost that you want to hold. You will have to eventually replace the springs though for the best control.

If you are controlling boost any other way, then +1 to to what bmylez said. Spring should be at least 50% of what you are shooting for. However, keep in mind that you won't be able to control boost below what your spring pressure is. Say you want a 20 psi setup, so you choose a 17 psi spring, but want to have 10 psi in 1st and 2nd gears for traction purpose...you won't be able to do it because the spring pressure is greater than your boost pressure you want to hold.

Hope this helps and I didn't just state the obvious, lol.

[Realgib3]

Originally Posted by wette460 It depends on what you want the spring to do. If you wanna control boost off of your spring pressure instead of using a MBC or EBCS, then get the spring for the boost that you want to hold. You will have to eventually replace the springs though for the best control. If you are controlling boost any other way, then +1 to to what bmylez said. Spring should be at least 50% of what you are shooting for. However, keep in mind that you won't be able to control boost below what your spring pressure is. Say you want a 20 psi setup, so you choose a 17 psi spring, but want to have 10 psi in 1st and 2nd gears for traction purpose...you won't be able to do it because the spring pressure is greater than your boost pressure you want to hold. Hope this helps and I didn't just state the obvious, lol.

Not entirely true in regards to boost by gear. You can run below spring with the right tune. I did this test last year.

Edit: Not sure if this is possible with boost tuning but with load based tuning it is. Basically if u request load that doesn't reach the wg crack pressure the ecu does a VERY good job of modulating the throttle plate to control boost / load since the turbo can't produce more boost without more air being allowed to come in.

I think the old thread was something like "Full control of load in each gear"

[bmylez]

Yeah, I didn't think about boost by gear or speed applications. Not too many people run them, though, so it's less of an issue.

[dooderek]

ebc's can only increase boost not decrease it below the wg's spring rating. also running pure spring pressure is somewhat conter productive. springs will start to crack wg open sometimes before the target psi hence chasing's ones tail until it is fully open. if you start to get boost creep on spring pressure it is normally attributed to not have a big enough wg. the wg cannot push enough exhaust gasses out hence further spooling the turbo

[bmylez]

He's not gonna have boost creep with a 44mm wastegate.

[superskaterxes]

44mm is way overkill for the amount of exhuast gas anyone can flow on this motor.

ive always been told WG spring pressure should be 2/3's of the PSI you plan to run.


P.S. ive been running straight spring pressure for over a year now and i havent seen any problems or had any wear on my spring. its always the same in the winter and summer and the only thing you need to worry about is making sure the boost lines are tight otherwise you never have to worry about boost spike and your PSI holds all the way to redline with no drop.

[mighty mouse]

I have a 14psi spring in my 44mm wastegate on my miata, running upwards of 20psi FWIW.

[SSinstaller]

IMO the 1 bar spring is a good place to set your WG, unless your planning on running >28psi you should have good control of anything between 15 and 27psi..

I've got a V44 with a 1 bar spring, it will hit ~18psi and creep to about 20 at redline... I think the WG placement on my manifold is very poor..