I was bored and had an old messed up '03 Evo turbo laying around. I decided to take the stock wategate accuator apart and see if I could modify it to hold more boost.
The unit was already dented up and kinda leaning to one side, so I wasn't worried about destroying it.
I carefully bent back the metal that holds the pressure cap on (not sure of nomenclature, but that's what I'm calling it).
Inside is the diaphram with the accuator rod bolted to it in the center. I removed the nut and the entire thing comes apart. (I was carefull to be ready for the spring to shoot out; it didn't).
Next I worked on getting the body back into shape. It was dented pretty good on one side and leaning the same way. After I got the dent out I noticed the upper part of the body was the only part leaning. I measured each side. The leaning side was 3mm shorter than the other side. I used this to my advantage. I took a huge shocket and hammered the other side down. Now the body was straight and the over-all height was 3mm shorter.
This should make the spring have more pre-load, thus it should take more pressure to compress it.
I cleaned the whole thing up, reassembled it. (It took about 45 minutes to slowly hammer the metal lip back over the main body and diaphram.)
It not as pretty as new, but seems sound.
I had to loosen the accuator rod adjusting nut and screw the flapper arm connection in 3 or 4 turns to make up for the shorter body.
I put it back on the bad turbo and attached my home-made pressure tester. I use a vacuum pump (output side), some vacuum line with a tee and a good tire gauge, (just the gauge part).
I pumped it to 30 psi and sprayed soapy water on the pressure cap...NO LEAKS!
I released pressure and slowy pumped and watch the wategate rod and pressure gauge.
It didn't budge until 15psi and was fully open at 21psi. I repeated several times to verify.
I know the stock accuator is set for 10psi. I'd like to know if anybody has tested it like I did mine?
Anyway. Tommorow I'm going to put it on my car and check it out. My turbo is only a 9.8mm, but has been ported. I also had it rebuilt at Turbochargers.com.
I currently have my HKS EVC set at 100%. ( I run water/methanol injection on 91 octane).
I'm getting 23.9psi or 25psi depending on if I go off the HKS EVC (23.9psi) or my Autometer C2 boost gauge (25psi) (they both use MAP sensors).
It tapers back 2-3psi by redline (8000rpms) depending on gear/load.
I'll take pics and post results tomorrow.

 

It's great that your making as much boost as you are, but what was your "baseline" before the modification and with the same settings on the boost controller?

There is no quantitative measure of improvement without a baseline comparison!

 

Mike,
Don't get me wrong. I'm not trying to out-do your accuator. My next two mods planned are Forge accuator and recir BOV, (my turboxs H34 leaks even after lapping the seat and putting all four washers in).
I will find out tomorrow exactly what I have here. I already know what kind of boost I making with the stock accuator.
I switch them out and see.
I'll also do the same pressure tests with my stock accuator and see if it's any better.
I'm a big do-it-yourselfer and I was just experimenting.
I'm sure I could make a good accuator, I just don't have the tools to do it.
It would be neat if my "Frankenstien" accuator works though .

 

I'm sorry, I don't mean to give you a hard time.

I'm all for the DIY mods and everyone has their right to experiement. (please don't think I expect everyone to buy our products just because they exsist.)

I just couldn't find any real evidence that anything changed based on what you had done. If you have it, all the better.

Again, I appologise!

 

haha new crushed wg actuator mod.

 

Forgive my ignorance but wouldn't it be easier to get a stronger spring than banging and bending things?

 

You are correct. After looking at what I did, I realized I didn't really do much.
Crushing the housing only compresses the spring about 1mm, because the pressure cap hits the diaphram. You would have to crush it even more to get anything, but you are sacraficing total movement. You could do the same thing by just adjusting the rod shorter.
So, I went to Lowes and got a few springs. I installed the smallest one I bought. The WG does begin to open until 14psi.
After the install my max boost went from 25psi to 27psi with same boost controll settings. Not bad for a $3 part.
I'll try the stiffer spring next and see what I get.
I'm on leave and bored and just playing around.
I plan on getting the Forge WG soon.

 

OK, I put on the bigger spring today.
Bench tested, it didn't budge until 17psi.
After install, same boost controll setting I got 28.5psi.
WHOLEY CRAP, those extra 3.5psi make this thing an animal. I did sense a bit of knock around 5500rpms, but then it pulled hard to 8000.
It also spools abit sooner, max boost right at 3000rpms in4th gear.
Boost did drop off to 25ish by redline. Not bad for stock 9.8mm turbo.
I'm going to drop my boost controller back to 27psi. As it cools off here in the desert, my HP should increase alot.

 

OK, I put on the bigger spring today.
Bench tested, it didn't budge until 17psi.
After install, same boost controll setting I got 28.5psi.
WHOLEY CRAP, those extra 3.5psi make this thing an animal. I did sense a bit of knock around 5500rpms, but then it pulled hard to 8000.
It also spools abit sooner, max boost right at 3000rpms in4th gear.
Boost did drop off to 25ish by redline. Not bad for stock 9.8mm turbo.
I'm going to drop my boost controller back to 27psi. As it cools off here in the desert, my HP should increase alot.