[ATLIEN]

I am tuned with MHD but otherwise stock (FMIC has yet to be installed)and all is well, the car runs strong but I have a basic question for you all.

My question is this. When I am at WOT my car pulls strongly but looses boost at the top end. I can vaguely hear the release from the engine bay. There are no issues if I shift early (4k to 6k rpms)and stay in the meat of the power band. Is this a symptom of a boost leak and would an updated charge pipe alleviate this phenomenon?

[Jeff@TopGearSolutions]

Originally Posted by ATLIEN

I am tuned with MHD but otherwise stock (FMIC has yet to be installed)and all is well, the car runs strong but I have a basic question for you all.

My question is this. When I am at WOT my car pulls strongly but looses boost at the top end. I can vaguely hear the release from the engine bay. There are no issues if I shift early (4k to 6k rpms)and stay in the meat of the power band. Is this a symptom of a boost leak and would an updated charge pipe alleviate this phenomenon?

You'd have to log your vehicle to know for sure.

The boost curve normally tapers boost on the top end after 6K so that much is normal. So an average boost might be 16 PSi in the mid range tapering to 12 by red line.

Boost leaks can occur in so many areas it's had to say if and where it is without a proper physical diagnosis of the vehicle.

It could be vaccuum lines, diverter valves, charge pipes, leaks at couplers, boost solenoids, ETC.

This car typically will throw a boost leak code if you do not meet requested target for more then 3 seconds. There is a small margin of error allowable though.

[335NJ]

How many miles on the plugs and coils?

[ATLIEN]

Originally Posted by Jeff@TopGearSolutions

You'd have to log your vehicle to know for sure.

The boost curve normally tapers boost on the top end after 6K so that much is normal. So an average boost might be 16 PSi in the mid range tapering to 12 by red line.

Boost leaks can occur in so many areas it's had to say if and where it is without a proper physical diagnosis of the vehicle.

It could be vaccuum lines, diverter valves, charge pipes, leaks at couplers, boost solenoids, ETC.

This car typically will throw a boost leak code if you do not meet requested target for more then 3 seconds. There is a small margin of error allowable though.

Ok. Good deal on the boost tapering off. I am getting 14 psi so no problems there. Was just wondering if I was missing more at the top of the band. I have some logs that I can post and have no errors or anything like that to speak of.

[ATLIEN]

Originally Posted by 335NJ

How many miles on the plugs and coils?

Plugs have been on the car for about 5k miles and coils are about 2 years old. I've got spare brand new coils so I am always ready to handle a random misfire.

[335NJ]

Originally Posted by ATLIEN

Plugs have been on the car for about 5k miles and coils are about 2 years old. I've got spare brand new coils so I am always ready to handle a random misfire.

I'd suggest getting a log of the issue so everyone can give a reasonable starting point.

[jjbmuu]

There is no issue your car is running fine, it's just the turbo's inability to breath properly at higher rpms with the factory inlet system. Slightly worn out wastegates could be the cause as well. I typically fall a psi or two bellow target depending on the day and I'm fairly certain that is my case on my original 85k mile turbos.

[mike@x-ph.com]

Only way to know for sure is for you to datalog

Car will max max boost in the midrange and then slowly lose boost after 5500 rpm