Most common reason for lost boost

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Wld87GN

Active Member
Joined
Feb 21, 2013
Messages
235
So I noticed the last few times I have had my car out that hate boost has dropped down to the point it doesn't want to make boost over 12-13#

After researching this pretty extensively, I am of the opinion that I have a bad waste gate actuator... This is my assumption since the is no other evidence to support this and it appears stock (despite my previous thought it was aftermarket).

It simply looks like a stock unit that was modified, and not very well.

So my question is this... Is there a way to tell it is the actuator that is causing the loss of boost?
 
If the actuator diaphragm were to fail, you would overboost to the point of destruction.

If it happened on it's own without changing anything my guess is the DS header crack has grown past the tipping point.
 
If the actuator diaphragm were to fail, you would overboost to the point of destruction.

If it happened on it's own without changing anything my guess is the DS header crack has grown past the tipping point.
How do I determine a DS header crack?
 
If you've never welded the DS header, it's cracked.

get a piece of toilet paper and tape it to the end of a stick. Then the car is idling cold (the fan's off), put the tissue down where the Y is. The leak should blow the chitwipe all over the place.

When you get it welded make sure to tell the welder that it's 304 stainless so they use the right wire. If you put a triangular gusset in the 'V' it'll help the weld last.

Also, bolt it to an old head or have him clam the hell out of the header to a welding table to keep the flange from warping.
 
If you've never welded the DS header, it's cracked.

get a piece of toilet paper and tape it to the end of a stick. Then the car is idling cold (the fan's off), put the tissue down where the Y is. The leak should blow the chitwipe all over the place.

When you get it welded make sure to tell the welder that it's 304 stainless so they use the right wire. If you put a triangular gusset in the 'V' it'll help the weld last.

Also, bolt it to an old head or have him clam the hell out of the header to a welding table to keep the flange from warping.

I like simple instructions... Okay, so is there a particular area they typically crack?
 
Yep, right where the rear tube merges with the front two.

Once at the track I had the wastegate maxxxed out and couldn't get more than 13#... I yanked a spring off the screen door at the snack shack to fortify the wastegate and same thing... Couldn't even see or hear the crack until I pulled the header.

It's such a common problem that EVERY header cracks in that spot. It's no big deal.
 
Yep, right where the rear tube merges with the front two.

Once at the track I had the wastegate maxxxed out and couldn't get more than 13#... I yanked a spring off the screen door at the snack shack to fortify the wastegate and same thing... Couldn't even see or hear the crack until I pulled the header.

It's such a common problem that EVERY header cracks in that spot. It's no big deal.
Awesome... Thank you for the help.
 
another test is the smoke test. Get some top engine cleaner that smokes like a freight train. You might find other problems too.
 
I found a crack on the underside of the of the header that looks like the header itself cracked off of the weld line
 
disconnect the battery and pull it out. you just found a shitload of missing horsepower.


(It comes out the top BTW)
 
1149033_10151778220037417_1959025993_n.jpg


Just so you can see what I saw... This is taken from under the car
 
Yep. That little crack can vent enough pressure to kill your boost. That's not as common a place to crack as the Y where the first two tubes connect to the rear. You'll probably find one there too when you get the header out.

it can also suck fresh air and make your O2 think you're running lean. Are your BLMs high at idle and light cruise?
 
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