Turbo spooling but not boosting

[sillylepricon37]

Big 16g Turbo- Spools but does not boost. It will idle forever and be fine...we pull the car out of the garage and take it around the block for 5 min and pull back into the garage. pop the hood. the turbo is glowing red. after only 5 minutes. it will spool. you can hear it. but it will not boost the car. and the blow off valve is not releasing air. no matter where you tune the bov. spent 2 hours tuning it and it still sounds the same every time. oil lines and coolant lines are hooked up correctly. has minor minor shaft play.



tell me what you think. but how much money should i get back from the guy who sold me the turbo.??

 

[Slightlystoopod]

Not an expert.. but

Throttle body stuck? not letting the boost pressure into the intake manifold?

 

[LiquidX]

I just had a nice long informative post and I hit the back button on my mouse. Here is another go...


As mentioned already, do a through boost leak test using soapy water and looking for bubbles. Start at the throttle body and spray everything that sees positive and negative air pressure. Fix all leaks and re test at the turbo. You should test at least 10 psi higher than what you are currently running.

Next look for any exhaust leaks pre turbine, checking gasket seals for black soot. Missing nuts on the exhaust manifold can cause a leak. Also check for cracks in the manifold as well.

Next, test the wastegate actuator with air pressure to ensure it opens up at the correct pressure in a nice smooth action. Remove the actuator arm from the wastegate flapper pin and see if the flapper opens and closes smoothly. Verify that the flapper is fully seated with the actuator arm attached.

Double check your timing both mechanical and ignition (if you have a 1g adjustable CAS).

Lastly, if all else fails, it's possible you have cracks around the flapper that is causing pre turbine exhaust to bypass the turbo and causing the issue.


On a side note, it would have been a good idea to start boosting after the first heat cycle/oil change.

As for the other question pertaining to the boost source, you tap as close to the compressor as you are going for accuracy and responsiveness with your boost signal. Further away from the source the slower the response is.

Yes, post IC may be more accurate to what the gauge is saying at the time it opens, however, you have xx amount of CFM already in the pipes pre IC that is now un accounted for making it's way to the motor i.e. boost spike.

Closer to the source, faster the actuator opens when the proper PSI opens it which means more stable/accurate boosting.

 

[Mr PopUps]

On a side note, it would have been a good idea to start boosting after the first heat cycle/oil change.

I strongly disagree, break it in like you will drive it. You think dragsters wait till they hit 500 miles? Yea i went to the other end of the spectrum, but im sorry the idea of a break in period is bosh. The rings will either seat or not, and its best to make them seat under pressure (boost pressure, they are already under pressure from your comp ratio). Ive done a few like this and never had anything but good results.

If you dont believe me look up motoman break in, or here i did it for you.

 

[Psyclone]

I just had a nice long informative post and I hit the back button on my mouse. Here is another go...


As mentioned already, do a through boost leak test using soapy water and looking for bubbles. Start at the throttle body and spray everything that sees positive and negative air pressure. Fix all leaks and re test at the turbo. You should test at least 10 psi higher than what you are currently running.

Next look for any exhaust leaks pre turbine, checking gasket seals for black soot. Missing nuts on the exhaust manifold can cause a leak. Also check for cracks in the manifold as well.

Next, test the wastegate actuator with air pressure to ensure it opens up at the correct pressure in a nice smooth action. Remove the actuator arm from the wastegate flapper pin and see if the flapper opens and closes smoothly. Verify that the flapper is fully seated with the actuator arm attached.

Double check your timing both mechanical and ignition (if you have a 1g adjustable CAS).

Lastly, if all else fails, it's possible you have cracks around the flapper that is causing pre turbine exhaust to bypass the turbo and causing the issue.


On a side note, it would have been a good idea to start boosting after the first heat cycle/oil change.

As for the other question pertaining to the boost source, you tap as close to the compressor as you are going for accuracy and responsiveness with your boost signal. Further away from the source the slower the response is.

Yes, post IC may be more accurate to what the gauge is saying at the time it opens, however, you have xx amount of CFM already in the pipes pre IC that is now un accounted for making it's way to the motor i.e. boost spike.

Closer to the source, faster the actuator opens when the proper PSI opens it which means more stable/accurate boosting.

+1 well thought out and logical procedure for finding the problem. Thou I am curious, why a exhaust leak pre turbine would cause an extreme temp problem in the turbo.

 

[LiquidX]

I strongly disagree, break it in like you will drive it. You think dragsters wait till they hit 500 miles? Yea i went to the other end of the spectrum, but im sorry the idea of a break in period is bosh. The rings will either seat or not, and its best to make them seat under pressure (boost pressure, they are already under pressure from your comp ratio). Ive done a few like this and never had anything but good results.

If you dont believe me look up motoman break in, or here i did it for you.

I don't know why you are disagreeing with me as I said what you just said.

+1 well thought out and logical procedure for finding the problem. Thou I am curious, why a exhaust leak pre turbine would cause an extreme temp problem in the turbo.

A temperature problem?

 

[Psyclone]

A temperature problem?

the red hot, light your cig off the manifold issue. Its my understanding that this does occur from time to time while running it hard, but not after 5 minutes of run time. Still new to this car, please correct me if I am mistaken.