no boost control with 38 mm tial wastegate.

[Saff71]

Hello everyone. I'm hoping someone can help me with this problem. I am using an 11.6 lbs. Spring combo in my 38 mm tial wastegate with an FP green turbo and unable to get less than 24 lbs of boost even with the waste gate plumbed directly to turbo pressure side. Can someone explain what may be going on here? Wanting to adjust to 18lbs for now. Please help...

 

[gofer]

Did you install the springs correctly in the Tial wastegate?

What port (top or bottom) on the wastegate is the vacuum line connected to that comes from the compressor housing?

 

[Saff71]

I plumbed into one of the bottom three air ports and plugged the other two air ports.

And I left the top two ports and all water ports open.

 

[gofer]

I plumbed into one of the bottom three air ports and plugged the other two air ports.

There are (2) bottom AIR ports and (2) top AIR ports.

You run the line to (1) of the bottom AIR ports and plug the other then you leave the top (2) AIR ports open to atmosphere.

 

[Saff71]

Pretty sure I installed the springs correctly but I will pull it tomorrow and double check that. Here is a pic of what I have.

I could swear I have three bottom air ports. But either way its plumbed into one of them and the others are plugged. Top 2 air ports are left open. I appreciate the response Gofer. I sure would love to get this resolved.

 

[gofer]

Pretty sure I installed the springs correctly but I will pull it tomorrow and double check that. Here is a pic of what I have.

I could swear I have three bottom air ports. But either way its plumbed into one of them and the others are plugged. Top 2 air ports are left open. I appreciate the response Gofer. I sure would love to get this resolved.

I just ask if they're installed correctly because a local who was wanting me to tune their car also had over boost issues. Their spring pressure was 12psi and they couldn't hit less than 28psi and the issue was the springs. All he did was open the wastegate, reseat the springs and make sure they were installed correctly and not binding and after he installed everything it held spring pressure just fine.

 

[Saff71]

That may very well be the problem Gofer. Man I sure hope that's it. Its the only thing that makes any sense. I'll be checking that first thing in the morning. Thanks for the help man.

 

[gofer]

While you've got the wastegate off be sure that the other lower port marked AIR is actually plugged and not leaking.

 

[Saff71]

10/4 man will do thanks again.

 

[Saff71]

OK, I have a boost control issue. I have a 9 lbs spring in my 38 mm tial wastegate. With the waste gate plumed directly to the pressure side of the turbo I get 20+ pounds of boost. Shouldn't I see something near spring pressure, about 9 or 10 lbs? I had a spring combo of 11.6 lbs and was seeing 24 lbs+! So I put this single 9 lbs spring in the gate and I'm now seeing 20+ pounds! Any ideas what could be wrong?

 

[clipto]

I would try another springs but most likely your boost creeping past the spring pressure causing your boost to be higher especially if your running a larger turbo.

 

[jed344]

I find it hard to be leave that he is boost creeping with a external gate.. Is your waste gate on the manifold or o2 housing? Have you tried taking the waste gate off and using a air compressor to push air to the nipple and see exactly at what psi the gate is opening.

 

[Saff71]

Waste gate is on o2 housing. That's a good idea, I will try blowing air through the nipple to see what pressure it opens at. I also noticed that the motor spooled slightly slower with the lighter spring in the waste gate also. Wondering if its starting to blead off earlyer with the lighter spring. Im running an FP Green turbo.

 

[rEclipserGST]

Waste gate is on o2 housing. That's a good idea, I will try blowing air through the nipple to see what pressure it opens at. I also noticed that the motor spooled slightly slower with the lighter spring in the waste gate also. Wondering if its starting to blead off earlyer with the lighter spring. Im running an FP Green turbo.

Why don't you just save time & just remove all lines from the wastegate & drive the car? That wastegate will open at spring pressure.

The issue you were seeing before is mixing up lines to the WG, making it open later. Which looks to be double the spring installed in the WG.

It happened to me until I figured out how to plum the vacuum lines correctly.

 

[Saff71]

Yea but if I do that then it will not have the pressure from the turbo to assist in over coming the spring pressure and acctualy open later than it is now. Correct?

 

[jed344]

I would just check and see at what psi it is opening i am running a frank 3 20g with a tial F 38 on o2 housing with a 12lb spring and i have never ever had it creep not even at just spring pressure.

 

[Saff71]

Yea that's what I am going to do next.
Quick question, i just want to make sure that I am correct here. The pressure side of the turbo helps the waste gate valve overcome the set spring pressure and lift the gate's valve upward in turn bypassing exhaust gases around and away from the hot side of the turbo causing the turbo decrease in rpm/ boost. If this is correct then putting let's say 20 psi to the bottom side air port with the other two air ports closed should tell me if it is opening at 20 psi or whatever boost I want to check for. Man if testing the gate this way says that it (IS) opening at 20 psi but when I make a pull my guage says 25 psi+ then what?

Yea that's what I am going to do next.
Quick question, i just want to make sure that I am correct here. The pressure side of the turbo helps the waste gate valve overcome the set spring pressure and lift the gate's valve upward in turn bypassing exhaust gases around and away from the hot side of the turbo causing the turbo decrease in rpm/ boost. If this is correct then putting let's say 20 psi to the bottom side air port with the other two air ports closed should tell me if it is opening at 20 psi or whatever boost I want to check for. Man if testing the gate this way says that it (IS) opening at 20 psi but when I make a pull my guage says 25 psi+ then what?

 

[Saff71]

Well I tested the waste gate with new hallman pro boost conttoller and twenty psi with the 9 lbs. Spring in the waste gate. 20 psi on the bench and it opens fine. It starts to open at around 13 psi. I also replaced my unmoded 1g Bov with a recirculated forge motorsports Bov with the yellow 16-23 psi spring plus two of the shims. I'm going to make a few pulls today to check the boost. Thanks everyone.

 

[Saff71]

Well yesterday I did a couple of pulls. I am seeing about 15 psi now but I'm not sure what rpm I was at I did not take a data log. Maybe it will creep up a tad if I would have stayed into it a little longer. I was probably around 6,000 or so rpm. Before the boost would creep up as I got up to and over 7,000 rpm so I guess I still have to test it again. Only thing is the rest of my Megan racing exhaust ( cat back) is still on back order from extreme psi. So to many pulls and my neibors will lynch me soon. does anybody think having only a three inch down pipe and test pipe with no other exhaust as of yet could be causing creep?