I'm about to have my Evo8 tuned so I'm picking up my last few parts. Will a
Forge Adjustable Wastegate Actuator help my stock turbo any? If so how stiff of a spring should I get?

 

I and a few others have had some bad experiences with the forge WGA. Even more-so with the piston-type version

If I were you I would quicker look at the FP actuator, or stick with the OEM one. If you really must, however, the red spring that most of them ship with now a days is the one you'll want to run. That's the 18psi spring

 

The Forge is adjustible from 18-24psi depending on the preload. I had mine preloaded to 24psi. It's a good step up from stock.

 

Agree with myron. I have the piston type actuator and have had tons of issues. As of right now i havve it fixed and working fine but for how long i do not know. The first iissue was with the bbracket slipping and letting the preload off gradually. Then one of the o rings broke and caused a spike of 29 psi and boost would not go below 27 psi even with no preload. Once i fixed that i couldnt get boost to go any higher than 15psi even with the preload so tight i could not get the buckle back on the flapper. Turned out to be the spring had lost all tension. I bought a 25 pound spring nd replaced it and with 6 turns of preload could only get 18 psi out of it. I finally said to hell with it and used my ebcc to get to 25 psi. I would opt for a different wga.

 

Stay away from the Forge piston-type actuator as the others have mentioned. I have had a couple of the Forge VIII diaphragm-type actuators and they are not too bad. Note that I had to tinker with mine to get it to work the way that I wanted. Sometimes the Forge is not exactly plug-n-play depending on which turbine housing that your turbo has and how much boost you want to run.

Like the others have commented the FP 18 PSI actuator is hard to beat and a lot more user friendly than the Forge. The FP is way cheaper as well. With the VIII turbo on pump gas the FP 18 PSI unit is all you'll ever need.

However, you might as well try the stock unit first. Why go and spend money needlesly? If you will be running on pump gas then the stock one should be serviceable up to about 22-23 PSI.

 

Haha funny I should find this thread while searching on info about setting up the Forge you gave me Clyde! Yeah I'm finally putting it on now...

 

It isn't funny really. Just call me at (415)248-6502. No need for PM's as I am in town. I can swing by tomorrow if you run into any trouble.