Turbo boost issues

[RXPROJECT]

My 2010 Legacy GT is having a boost issue. When accelerating quickly up to 5000 rpm the engine all of a sudden loses boost and the power drops off.
Any and all ideas will be read.
Thanks

 

[JDK-Michigan]

How many miles are on your GT?

 

[RXPROJECT]

Just 1700 miles on a factory new short block and complete rebuild.

 

[RXPROJECT]

It just started acting like this after 1500 miles.
The engine is in the car pictured.

 

[JDK-Michigan]

It just started acting like this after 1500 miles.
The engine is in the car pictured.

1) Is the Turbo OEM?
2) Vacuum lines leaking?
3) Premium Gas?

I would have said carbon build up, but the engine is basically brand new…

 

[RXPROJECT]

Turbo is new but OEM.
Specifically which vacuum lines are you referring to?
No I have been running regular in the car. It is tuned for stock 265 hp and the engine manual says 87 octane regular gas is good.

 

[RXPROJECT]

I am going to try testing the intake, from turbo inlet to the exhaust for leaks. I want to use some type of smoke to indicate possible leaks. Have been looking at kits for this but will probably make my own system.

Actually, my thoughts have been leaning towards a by pass valve that is weak.

 

[JDK-Michigan]

My thought is running a higher-octane fuel would be my first theory. I know manuals say that 87 octane is ok and the car will run, but getting the peak performance (horsepower and torque) premium fuel is required.

I would try a tank or half a tank to see if that solves the issue.

Vacuum lines would be just to check and make sure they are all secure with no leaks.

Have you run a diagnostic test yet? (Scan Tool)?

 

[JDK-Michigan]

My thought is running a higher-octane fuel would be my first theory. I know manuals say that 87 octane is ok and the car will run, but getting the peak performance (horsepower and torque) premium fuel is required.

I would try a tank or half a tank to see if that solves the issue.

Vacuum lines would be just to check and make sure they are all secure with no leaks.

Have you run a diagnostic test yet? (Scan Tool)?

Also what is the RPM Redline? This is probably governed so it may be slowing you down by preset defaults.

 

[RXPROJECT]

Higher octane is to keep high compression from creating pre-detonation or knock. I have a knock sensor just like stock engine all have these days. The ECU would change the timing and fuel amounts to eliminate knock which can be harmful to engines. It ran great on regular up until 1500 miles, including some real extreme autocross events.

This engine has a multitude of hoses, some are vent hoses, one important one is a vacuum that controls the bypass valve. It is my belief the problem is in the by-pass valve or there may be a pressure leak in the intake, turbo, intercooler or manifold conduits.

The ECU is a Haltech Elite 2500. The car has been hooked up via “remote in” from a Haltech technician. He set all the parameters, including the rev limiter at 6500 rpm.

I wish I knew enough about doing an analysis or a data record with my laptop but at almost 77 I am too late for that dinner call.

 

[RXPROJECT]

I do appreciate any and all suggestions because they get to thinking outside of my box a bit.

 

[JDK-Michigan]

I do appreciate any and all suggestions because they get to thinking outside of my box a bit.

You bet! Let me know what you find out...

 

[RXPROJECT]

I will post it.