Tial wastegate problem

[freeride_ca]

I can't boost past 11 psi? So I took the manual boost controller out and ran the vacuum line from the turbo to the wastegate. I should have been running off wastegate pressure then right? So for me that would have been 20psi. But nope 11 psi and that was all. I then took the vacuum line off and plugged it. I ran the car up to 28 psi before I took my foot off the gas. So to me this means that the problem is in the wastegate. Now is there some way to test it? Is it rebuild able? Please help. It's a tial 38 mm.

 

[wt71gas]

Did you buy it new? If it is 20psi it should have two springs inside so maybe check for that first make sure yo DO have the 20psi springs and also make sure they are not damaged.

 

[oldman]

Did you buy it new? If it is 20psi it should have two springs inside so maybe check for that first make sure yo DO have the 20psi springs and also make sure they are not damaged.

Agreed, sounds like your wastegate is functioning properly and it has an 11 psi (.9bar) spring in it. Which type of MBC and how is it hooked up to the wastegate? It is the MBC spring pressure that determines your boost level, if anything, the problem is associated with your MBC, how it's hooked up OR both.

 

[freeride_ca]

I Have a forge MBC. It's connected By. The vacuum line off of the turbo to the MBC. From the MBC to the wastegate. I tried to dial the boost up via the MBC before I took it out of the mix. Even with it wide open ( all the way +) it was still 11 psi. I had the car running @ 27psi with the MBC set at about half ( 4 clicks). That is why I'm thinking it's something in the waste gate. The waste gate was on the car when I bought it about a year ago. I don't know how old it is.

 

[oldman]

I Have a forge MBC. It's connected By. The vacuum line off of the turbo to the MBC. From the MBC to the wastegate. I tried to dial the boost up via the MBC before I took it out of the mix. Even with it wide open ( all the way +) it was still 11 psi. I had the car running @ 27psi with the MBC set at about half ( 4 clicks). That is why I'm thinking it's something in the waste gate. The waste gate was on the car when I bought it about a year ago. I don't know how old it is.

1. Is the forge mbc a ball & spring or bleeder type MBC? Is "+" CW or CCW?

2. How is it hooked up to the wastegate? There are two ports on the wastegate, side and top ports.

3. First you said you can't get the MBC to boost past 11psi, then you said you were able to run 27psi with the MBC set at half "4 clicks", which is it?

 

[freeride_ca]

1. On the boost controller it's marked "+' and "-" I turned it to the "+"

2. The vacuum line is connected to the side port.

3. The car was running at 27 psi. before this problem started. When I tried to turn up the boost (via the MBC) it made no difference.

 

[oldman]

1. On the boost controller it's marked "+' and "-" I turned it to the "+"

I'm trying to figure out if you have a ball/spring mbc or a bleeder mbc, is "+" CW (Clockwise) or CCW (counter clockwise)?

2. The vacuum line is connected to the side port.

Is the top port vented to the atmosphere?

 

[4SFED_GSX]

Is it rebuild able? Please help. It's a tial 38 mm.

yes they do sell a replacable diaphram for the tial 38mm.

 

[TrboANTsi]

for mbc use the side port on the gate. also to reach higher boost i had to loosen the mbc totally opposite. This is ona joe p. in the past i would turn clock wise to raise boost. but with the tial for some reason i had to turn counter clock to raise boost.

 

[oldman]

The wastegate is not the problem, the problem is whether he truly has 20psi spring in the wastegate. Think about it, if the diaphram is leaking, the boost should increase, not decrease. Solution to your stock 10psi problem is to open the wastegate and verified if in fact you have 20psi springS. My money is on he has a single .9 bar spring in it.

As for the inability to increase boost level, the issue is clearly related to the boost controller or the signal provided to the wastegate. The reason it's important to establish which type of controller is because a bleeder type uses both top and bottom fittings, exactly like hooking up an EBC, a ball and spring type uses only the side fitting while the top fitting is VTA.

 

[4SFED_GSX]

if need be here is where one place you can find the replacement diaphram...

http://shopping.lightningmotorsports.com/customer/product.php?productid=1904

btw, not trying to be a smarty pants but, .9 is 13psi, .8 would be the 11psi.

 

[oldman]

Thank you for the correction.

 

[freeride_ca]

The top port is vented to the atmosphere. I don't know what type of boost controller it is? It was on the car when I bought it. I'm going to open up the waste gate and check the spring? I'll let you know what is in there. Thanx for all the help so far.

 

[freeride_ca]

Okay I opened it up. Every thing looks okay. It has 1 big blue spring inside. So that should be 14psi, Just off the waste gate? So If I'm only hitting 11 psi? I have no idea where to look. Could it be a problem in the turbo itself? Although with the vac line from the turbo pluged it would boost just fine. Do you think I need a new MBC?

 

[oldman]

Just to make sure, test run with the MBC bypassed by connecting the pressure source (hopefully not the BOV line) directly to the side port, expect to see around 14 psi with the blue spring. Another thing to check is the boost gauge and/or the signal going to the boost gauge.

Do you think I need a new MBC?

A problem MBC will make you boost higher, not lower, than the spring pressure. Not being able to raise the boost on the other hand can be a defective MBC. You still have not found out which type of MBC, I can make a pretty accurate guess if you tell me which direction you turn when trying to increase boost.

 

[freeride_ca]

I have it set up direct now. The vac line from the turbo right to the waste gate. So I should be running on waste gate pressure only.

ON the boost controller. "+" is clock wise and "-" is counter clock wise. I noticed that it will stop(close) when turning to the "-". Turning to the "+" it just keep turning forever and does not stop? Is this normal? It does click into position.

 

[oldman]

You have a ball and spring and it sounds like the threads are stripped. Turn the knob all the way in, apply compressor air directly into the inlet and see how much it holds before releasing pressure to the outlet.

 

[freeride_ca]

I tried and it did not hold any thing? There is a small vent hole on the side that would allow air out instantly. It would only hold air if I held my finger over the hole. then not very much.