Stock Wastegate spring pressure from evo III

[minbrx]

I just swapped an Evo 3 engine into my talon

just wondering what the stock wastegate spring pressure is?

i was told the engine came from a 95 evo

 

[romeen]

The WGA on my EVO3 16G begins to open at 12psi and is completely open at 14psi.

 

[Imback]

11psi on mine

 

[JusMX141]

It will vary depending on boost source location, how much tension the arm places on the flapper, and the flapper's size.

The only way to find out is the run a vacuum line directly to the actuator from a boost source in the intercooler piping.

 

[AWD_Hybrid]

You'll get around 35psi before exhaust presure will open the door if you
take the hose off the actuator. (DON'T take the hose off & blow #4 piston)
A combination of (boost pres & exh pres) is the so-called spring rating.
Cheers !

 

[JusMX141]

You'll get around 35psi before exhaust presure will open the door if you take the hose off the actuator.

Are you sure you don't mean 25psi? The only way an Evo III 16G would make 35psi is if you welded the wastegate flapper shut and gave it hell.

There are a few guys that have run the internal gate to 30psi but the pressure will drop to almost 25psi as the RPM's climb because the spring inside the actuator isn't stiff enough to pull the flapper shut again once exhaust flow starts to bypass the turbine housing. This is the reason I designed this actuator system: http://www.dsmtuners.com/forums/tur...oking-strong-internal-wastegate-actuator.html

Of course those running a 34mm internal flapper will have a lower achievable boost level as the larger surface area of the flapper makes it more difficult for the actuator to hold the flapper shut.

The general rule of thumb is you can *safely* double what the spring tension of your actuator is using a boost controller. By safely I mean no spikes or drops in boost.

 

[AWD_Hybrid]

jusmx141 I'm saying a combination of (boost pres & exh pres) is the so-called spring
rating. Exh pres alone is not what opens the actuator.

*This bellow is for jusmx141 only.
The boost controller bleeds off boost pres so the actuator gets less boost entering it.
The actuator now has less boost than it should have going to the diaphram.
Depending how much you bleed off, determines the boost from the turbo you use.
A std Evo 3 bov will start wasting boost over 16psi from memory.
jusmx141 your stronger spring will be good. Makes the actuator opperate quicker.
The actuator I refered the 35psi about was a 1.2bar rated one btw. More
If you want to test it with NO vac hose, be ready to back off before 6000rpm !!!!!!
*I'm not responsible for holes in pistons if anyone removes their actuator vac hose*
Cheers !

 

[JusMX141]

...and I'm saying the flapper door will open well before 35psi from exhaust pressure alone without a boost source hooked to the wastegate actuator.

The 34mm flapper on my buddy's Frank 5 20G opened the Garrett-style actuator we were using at 17psi no matter what. I had to switch to an AGP actuator for a SRT4 with a stiffer spring just to be able to get him to 22-23psi. Of course this was before I discovered the Holset actuator trick.

 

[AWD_Hybrid]

My turbo is a 16g/20g w 34mm door & 1.2bar act & std bov.
A bung in the vac hose from the act. Killed the 1st R33 that came along.
I might try the Holset actuator trick later myself. Good tip thanks !
Cheers !