Yesteday I installed a Forge WGA. Went out and tested it a bit and had to turn down my MBC which was expected. I stopped the testing due to weather and darkness. This morning I continued and found that I was getting boost creep. It would go to about 20-21PSI at normal MAX boost RPM around 3200 to 3500 RPM but then all the way till redline the boost would keep going up. So I did a search and read all the posts I could. I decided based on those threads that I might need to loosen the pretention on the WGA. I went out and took 1.5 spins (3 half turns) out of it to lenghten the rod. I put it back on, it still has a good amount of pretension. Went out and tested. Now it is over boosting. Got into it and it went way past my desired setting. MBC was left alone. It didn't even get to see if it was still getting boost creep since it was going past my normal level. I will attempt to take out more tention out once the car is cool but that was the opposite effect i was planning on. Any ideas?

 

To set the baseline boost pressure on the WGA.... disconnect the MBC and connect the vaccum hose directly to the actuator. Use zero preload to prevent over boosting the car.

After setting that up, then start with the MBC all the way up and start playing with the MBC until you reach the disired boost level.

Hopefully, you will be running 24+ PSI of boost. If not, you wasted money on a higher pressure WGA. My FP 18 PSI WGA at zero preload will reach 18 PSI and creep until 20-21 PSI. I am running 25 PSI so.... no issues for me while my boost is over 23 PSI.

If your target (based on your signature) is 21 PSI, I am pretty sure you will run into boost creep issues with the Forge WGA. You will have a boost creep from 18 PSI to 21 PSI or will be over boosting like crazy on higher gears.

Just my 0.02!

 

i fell as though i might have wasted my money since it ended up not being necessary. good think is that i can swap in a lighter spring in the Forge Unit. i will try and go higher in PSI. I just didn't want to overboost. I'm running 92 pump. I can tune it myself but want to wait until I install my LC1.

 

you need to adjust your Wastegate Duty Cycle, on the spot where it starts to pickup more boost.....

 

23 PSI will be good for 92 OCT.

I did not mean that you wasted your money. I meant that for 21 PSI of boost, a higher pressure WGA may not be needed and may cause you some problems. Like the ones you are describing.

Good luck with the lighter spring! Keep us posted!

 

Wastegate Duty Cycle? I think that you are refering to the use of the stock EBC.

The guy is using an MBC... the only adjustments for his setup are: WGA Spring, Preload on the WGA and the spring/tension on the MBC.

 

I didn't take it bad. I understood your point and agree. I will see if i can get it pretty stable (no boost creep) at 21 by connecting the WGA directly to the turbo outlet. If not I will look into either the softer WG spring or tune for 23ish PSI. Can the car be run like with the WGA directly connected if I don't want to go any higher than baseline PSI?

 

Short answer is yes! You can run the car w/o any boost control device. I did it for a couple of days while analyzing different preloads on the FP WGA.

However, on my case my car will always creep after been in the preset boost for a while. It will hit 18 PSI and gradually move towards almost 22 PSI if I am not mistaken. I used the JDM Map Sensor to log the behavior.

Tuning the car with a boost creep is a pain in the a$$ because it is very hard to predict and adjust the timing/fuel accordingly.

If you are going to run 21 PSI, my suggestion will be to set the normal WGA open pressure to around 15 PSI (instead of ~10 PSI of the stock WGA) and reach the 21 with the MBC. If the WGA creeps from 15 to 18 PSI, do not worry.... it will go away once you hook up your MBC. Hopefully, this help you somehow!

 

i will probably for now go back to the stocker. I was not having any issue then. I bought the WGA just because I like to get the car ready for future plans. I should have read more first to know of what I might face. I'm not accusing any parts, just poor planning on my part. I will order the lower pressure spring and reinstall since the Forge unit is very nicely built. then I can upgrade the spring back when my mods warrant it.

 

dont mean to steal the thread but...more boost on higher gears. (1st-20psi, 2nd 22psi..etc...) is that considered boost creep also?

 

I imagine that this is going to sound illogical but I've found that you should do things in the following sequence. The first step is to turn your MBC out couterclockwise to its loosest(least boost) setting.

Next, you should adjust the wastegate's actuator rod to its loosest setting. This is the length where the eyelet in the turnbuckle just slides freely on and off of the flapper valve's pivot arm peg. Do a WOT run in 5th and note boost. It should be about 11#.

Now, rotate the turnbuckle 3 complete rotations clockwise, effectively shortening the rod. Reinstall it onto the flapper valve's pivoting arm and test it. Boost should be about 14 PSI.

Once again pop the turnbuckle off of the flapper valve pivot arm and shorten the actuator rod another 2 turns. This should get you up to about 16-18 PSI of preload.

If you are still under 18 PSI then shorten it again. But, this time only do it in 1/2 turn increments until you get preload to 17-18 PSI. From that level of preload take it on up to your target boost level with the MBC.

 

Did step one and two, still overboosting. I'm going to put the stock WGA on just to make sure i didn't break or disconnect something else. What is weird is that it worked ok this morning (except for the creep) then i tried to adjust the turnbuckle out for less preload and now it overboosts. It's easy for me to throw the stocker on and check. if it still over boosts, i'll go from there. maybe the WGA is not getting a signal. If the stocker does the same, i will figure out the issue and maybe put the Forge unit back on.

 

Set peak boost in either top gear on level ground or 4th gear on a slight uphill grade.

 

If your lucky enough get boost to hit 21 psi at peak load then steadily climb towards redline, I wouldn't change a thing and set the timing to control knock, do what is available with the fuel, and make use of all that free boost up top .

Let me see, too stiff WGA would would cause a high spike instead, and even with a stiff WGA with a MBC turned down it should just spike a little at first then taper off with a stock turbo. Sounds like mucked up MBC/WGA plumbing lines or MBC not bleeding but turned up high.

 

Yeah, I'd test the stock WGA in comparison. Good idea!

The point that I'm trying to make though is that you may find that it'll spike and creep less with higher levels of preload than it does with lower levels of preload. That's why it spiked higher when you decreased preload. It' seems contrary to logic but I've found that it works that way with the high performance actuators.

I always get much more positive boost control with preload at 18 PSI and using the MBC in a more limited range than I do with low preload and a wider MBC operating range. Of course that's just my experience, and yours may differ.