Can't control boost, how do you check Tial 40mm external wastegate

[OkieRichard]

Boost shoots up as high as it wants and I would like to know how I can check my wastegate to see if it is the problem. I swear I've searched and have been reading all kinds of miscellaneous stuff for about an hour now. If you could explain how to do it like I'm a 12 year old, that would be nice too!

 

[andy4g63]

WG is a simple device: It consists of few thing:
-body- lower/upper
-valve/piston
-diaphragm
-spring
-seal around valve/piston

Basically the WG has inlet and outlet on its lower part. Inlet is where is attached to the exh.manifold, or O2 housing. Outlet is where the dump tube is...
Once you remove the bolts there is/are spring/s Each one of the springs have a different load/boost/ settings. They are small and large springs. If your boost source is connected directly to the WG, your boost should equate to the rating of the spring /s combo..The load for the different springs, depends of the size of WG.
Under the springs is the diaphragm. It is a piece of orange/high-temp/ silicone with metal attachment to it. Its job is to prevent the air to go up in the WG and leak. If it is broken, or cracked, needs to be replaced. It is however attached to the valve with 4 allen bolts. If you replace it, put BLUE LOCKTITE on the threads.
And last is the valve seal. It is a metal ring, that helps the valve to seal, when in closed position.

Here is how it works...

Air/boost/ is coming from compressor side of the turbo to the WG. It might be connected to BC/boost controller/, before that. After the turbo reaches the pre-set bost level/or spring rate/ the air is directed on the side port of the WG, putting that prssure on the spring and eventually blowing it open. That means, that the valve in the WG has lifted and this time the hot exhaust gases are forced/diverted away, before they reach the turbine wheel. This is how boost is controlled via external WG. If you need anything more visit the TIAL site.

 

[silvreclips]

To test it just hook a compressor directly to the wastegate and apply 15-20psi and it should open. If the wastegate opens fine then you may want to add the boost controller and retest everything to make sure it still opens.

 

[95'RS-T]

^ has it right but what port are you running your mbc on top or bottom?

Edit: top or side port?

 

[andy4g63]

Acyually, the right way to test the WG is to apply the air on top/is opposite on the how hooked up to the turbo/.

To the OP, there also may another reason, that you can't control boost:If you aare getting the WG fed off O2 the hole may not be big enough/needs porting.

 

[OkieRichard]

When I apply pressure through the nipple should I hear a clicking or something? I only have one nipple on the wastegate and it is on the side, could I just move it to the top to test it? I will have to find an air compressor somewhere so I can test this. Right now I'm not even running a boost controller because I'm trying to figure out how this works. The current configuration is straight from wastegate side nipple to turbo compressor nipple. As for the setup for my electronic maft boost solenoid(which is not connected right now) I have installed it the way the maft solenoid diagram says. Tials website says to hook up the wastegate another way but I don't have a second nipple to install it the way that they say. As for the wastegates location, it is in fact coming off the O2 housing but I had FP prepare the turbo for the setup... so I would hope that the hole would be big enough. Here are the diagrams for the electronic boost controllers:

Maft's setup
http://www.fullthrottletech.com/attachment.php?attachmentid=258&d=1149733519

Tial's setup
http://www.tialmedia.com/documents/w3_tial_wginstall.pdf

 

[andy4g63]

Move the nipple to the top and test it. If it leaks, you would hear it. All this info I got from Tial. I spent countles hours trying to cure my boost creep, changing springs several times, changing diaphragm, chaging lines to and from WG, everything... Just call Tial tomorrow, ask fro tech. support and please confirm, if what I said is correct.

Sounds to me, like I said: your hole, where the exhaust diverts to WG is too small.

 

[rEclipserGST]

Just got my Tial 38mm wg in the mail from a tuner. I have a Blitz ebc, and I've searched. Most people are using an mbc whether going external or not. My question is do I need the top port connected to anything? Because the used one I bought, does not have the top air fitting. Just making sure I dont need anything else befor I do this 14b swap & going external all in one motion.

Thanks for any help or info in advance.