For the last week or so i've been having problems with the Tial 44mm wastegate that came on my Buschur FS635 turbo kit. First problem i had was constant overboost, so i changed the vac hoses and even changed my boost source from the turbo to the BOV and still had the same problem (overshooting 30 psi). After that i decided to open the wastegate and check the springs. The wastegate came with 1 big blue and 1 small blue spring and there both brand new. So for s***s and giggles, i pulled out the small spring and just ran the big 1 (13psi spring). Now when i run, i hit 26-27 psi (which is alot better but) i can't increase boost at all from here. I'm in the middle of tuning and need more boost to complete it. I'm starting to think that whatever the problem is, its making me spike to double the spring pressure. I know its an wastegate issue because I ran it str8 to the boost source and the still continues. I have the vac line running from the side port on the Tial and letting the top port vent, so i know its not that. I'm running out of ideas. me out guys.

 

Have you checked your boost controller? By running both that's the highest allowed by that wastegate. I believe if you run the vac line from the Turbo to the bottom port alone you will get spring pressure only.

 

The 2 springs in the wg are 21 psi for the wg. Your wg will not open till 21 lbs for a start. With you taking one out as stated the wg will open at 13 psi wasteing 8 psi of boost. And I agree with the above statement that sounds more like a boost controller problem not a wg problem. An external wg wont have an effect on overboosting being there is nothing for preload holding it back, specially with only 21 psi worth of springs in it to begin with.

 

Just tried running a vac line from my boost source to the Tial again, same thing it just shoots to 26psi. is there anything else i can try?

 

What are you using to control boost?

 

Well yeah like I said its hooked up wrong. The boost source should go to the bottom part of the mbc, the top half should go to the wga.

 

Agreed! I think you have something hooked up wrong, or the boost settings are your boost controller aren't right.

 

I have a Hallman ES. With it hooked up, i've run it both ways with the same results. And even with it off and running a line str8 from the boost source to the wastegate it does the same thing. I still have the 13psi spring in there now and when i ran it I hit 26 pounds. With both springs, it just shoots to 30 and beyond

 

Once you hook the mbc up correctly put that second spring back in your wg. That will keep your wg shut longer allowing the turbo to keep spool instead of blowing it out of the system causeing it to loose power.

 

If you hooked it up the way I suggested and your still getting that problem you have other issues. Do a boost leak test, sounds like you have more problems then you think. The way I said to hook it up is correct and should allow you to control your boost with no issues. Either that or you turned the boost controller the wrong way and its all the way up not down.

 

Quick question, how does a boost leak cause overboost? I had a serious boost leak a few weeks ago and i couldn't get anything 0ver 12psi without it stuttering and bucking every bad. I ran a boost leak test and tightened it up and solved the problem (it was on the UICP) and i didnt see anything else at that time. My question is if its a leak, where would it be that would cause overboost? I'm 100% positive that it's not the mbc because it happens whither its on or not.

 

It would be preturbine leak, maybe a bad gasket or the turbo bolts got loose. It does happen why I suggested it. With the turbo getting hot and cooling off sometimes the bolts will loosen themselves. I already lost a turbo because of that so I always check once a month to make sure turbo to mani bolts are tight.

 

I'ma check them out and report back. Thanx bruh.

 

Glad I can help. I just want to make sure everyting is hooked up correctly

 

I had this issue when I was running WG pressure only. I had a 14# spring in the WG, and somehow I would make 24#s of boost, but it would spool slow. It turned out that there were vacuum lines hooked up incorrectly causing the turbo to lose pressure, making it work harder to build the boost, and thus the WG was not able to regulate the air properly.