What is a "REAL" boost leak test?

[howslowcanyougo]

Been trying trace down a boat load of Boost leaks after I installed a new FMIC and a small 20G.

@ WOT the car sounds like a broken gas main, and gives off a gaint PSHHHHHHHHHHHHHHHHHHHHHHHHHHHHHH, sound like I've never heard before?

Why now, does this thing sound like it's leaking so bad?

And the car actualy fells a bit SLOWER than before?.....:-<

I've found a leaks off the the IC pipe, and the PVC valve and corrected or blocked them off.

The car still won't hold Boost, it leaks out almost as fast as I can pump it in with the compressor?

Cause I'm now finding leaks on biss, injector and TB shaft seals?

I've talked to a local un-named "DSM Guru" and he said that I'm being "anal" by doing the boost leak tests, and that these smaller leaks, like on th TB shaft, biss and injector seals, are too small to even matter, and that the turbo should "make up" for these kind of leaks?

My questions is what is a "REAL" boost leak test?

I've read else where that it should be able to hold it at whatever the amount of LBS od boost, that you plan on Boosting at WOT, and it should hold there for about 30 seconds?

Is this "anal" or not? Are the "smaller leaks" imporatant or not?


Many Thanks in Advance................


Howie

[Shane@DBPerformance]

The BISS and TB shaft are common leaks that often aren't worth fixing, since they are tiny and sometimes hard to fix. You should fix any leaks at the injectors, leaks there can be fixed and they can turn into large leaks quickly.

Are you using an air compressor? It should be able to maintain a decent boost level for a bit, unless it's a small tank.

[Alpine TSi]

Keep in mind with new hard pipes and a bigger turbo you will actually hear the air moving through the IC/pipes and actual spool up. I remember that when I got my car back from QPR last summer and I thought it was a big ass boost leak but was actually the sound of air moving through 2.5 stainless pipes. Later that season we did a boost leak test and only found one at where I blocked off the PCV fitting on the intake manifold.

[howslowcanyougo]

The BISS and TB shaft are common leaks that often aren't worth fixing, since they are tiny and sometimes hard to fix. You should fix any leaks at the injectors, leaks there can be fixed and they can turn into large leaks quickly.

Are you using an air compressor? It should be able to maintain a decent boost level for a bit, unless it's a small tank.

Yep I'm using a compressor. So should the "boost system" HOLD the pressure I'm putting in with the compressor on the Turbo inlet for like 30 seconds or not?

The car does spool ~3600, and hold 20lbs on the gauge to redline?

But I does seem a like fair amout of air is leaking out of the TB Shaft and Biss seals?

Guess I can start with the Injectors first?

Do I need to release the fuel pressure some how before removing the fuel rail to replace the seals? Do I need to buy new insulators as well as the seals?

Any links to a good tech articles or walk throughs for this n00b, who has never installed a fuelrail or injector seals?



TIA......

[howslowcanyougo]

Keep in mind with new hard pipes and a bigger turbo you will actually hear the air moving through the IC/pipes and actual spool up. I remember that when I got my car back from QPR last summer and I thought it was a big ass boost leak but was actually the sound of air moving through 2.5 stainless pipes. Later that season we did a boost leak test and only found one at where I blocked off the PCV fitting on the intake manifold.

Thanks for your input!

If there wasn't a big boost leak "somewhere" I probably shouldn't have a problem with DSMLINK reporting that I'm ok running at a ~18/1 A/F, but when I richen it up to where DSMLINK reports close to 11/1 the car bogs and back fires?

This leads me to believe that the Mas is measuring Air that never makes it to the motor, there by giving the symptom of running ok while that lean?

Does this make sense, or am I way off base?

I'm really trying to diagnose the weak power, strange loud noise and weird DSMLINK reading symtoms to get this car back on base?


TIA.....

[Shane@DBPerformance]

I never tried the pump it up with a bicycle pump or whatever method for checking boost leaks. I can't imagine it works the best or gives you the best idea of how bad a boost leak exactly is without some actual CFM going through the system. Don't expect it to hold perfect pressure though, even with no boost leaks, it will all eventually get out in the motor anyways.

Insulators are the seals. Buy new ones from Mitsu, they get old and hard over time causing leaks. You can try to relieve the pressure one way or anything or just pull the fuel rail off and be ready for fuel. There will be fuel no matter what you do. Just don't drop the 3 black fuel rail spacers, they can get lost in the 2G intake manifold, you might want to tape them to the head before pulling the rail off.

[howslowcanyougo]

I never tried the pump it up with a bicycle pump or whatever method for checking boost leaks. I can't imagine it works the best or gives you the best idea of how bad a boost leak exactly is without some actual CFM going through the system. Don't expect it to hold perfect pressure though, even with no boost leaks, it will all eventually get out in the motor anyways.

Insulators are the seals. Buy new ones from Mitsu, they get old and hard over time causing leaks. You can try to relieve the pressure one way or anything or just pull the fuel rail off and be ready for fuel. There will be fuel no matter what you do. Just don't drop the 3 black fuel rail spacers, they can get lost in the 2G intake manifold, you might want to tape them to the head before pulling the rail off.

Shane, I have a Big tank craftsman compressor, NOT a lame bike pump man!

Thanks again for the good tips!

[Dinkpit]

try soap/water mix, should work at any psi, just watch for the bubbles. :P cheap too, also on ur tb, injectors spray the area with carb cleaner......idle goes up... leak

[howslowcanyougo]

try soap/water mix, should work at any psi, just watch for the bubbles. :P cheap too, also on ur tb, injectors spray the area with carb cleaner......idle goes up... leak

Soapy water is how I found the Injector and Biss leaks, carb cleaner on the injectors is a good idea too!

Thx!

[Shane@DBPerformance]

Shane, I have a Big tank craftsman compressor, NOT a lame bike pump man!

Thanks again for the good tips!

Yea, I read that wrong the first few times.