Exhaust elbow sealing techniques?

[1QUICK85]

I have tried to get the thing to seal a couple of different times. Then I figured screw it, the puck is sealing perfect. But, does the seal of the exhaust elbow cause problems once the puck opens??
Just got my RJC boost controller hooked up. The car feels ten times better getting into boost. It hits 15lbs. of boost then settles right away at 13lbs. for the rest of the test run. So, could that be the exhaust elbow not sealed properly? Its the only exhaust leak I can hear. I did put JB weld on it a month ago to make sure the leaking wasn't causing my boost issue at the time. The JB weld sealed it up nice and quiet, but that wasn't the issue.(stock adj. wastegate was bad) So, the JB weld flaked right off after a week or so of driving I was thinking of JB welding it and seeing if that is the culprit for the drop in boost. I know JB welding it sounds stupid but it was a good trial and error. :redface:
How is everyone sealing theirs up......just metal on metal? May I have to get the elbow or turbo resurfaced??
I could just turn the boost up to 17lbs. and then let it settle in a 15lbs., but I just want to be able to run at a constant level. Especially on 93 octane.
TIA, Nick.

 

[Jerryl]

I have tried to get the thing to seal a couple of different times. Then I figured screw it, the puck is sealing perfect. But, does the seal of the exhaust elbow cause problems once the puck opens??
Just got my RJC boost controller hooked up. The car feels ten times better getting into boost. It hits 15lbs. of boost then settles right away at 13lbs. for the rest of the test run. So, could that be the exhaust elbow not sealed properly? Its the only exhaust leak I can hear. I did put JB weld on it a month ago to make sure the leaking wasn't causing my boost issue at the time. The JB weld sealed it up nice and quiet, but that wasn't the issue.(stock adj. wastegate was bad) So, the JB weld flaked right off after a week or so of driving I was thinking of JB welding it and seeing if that is the culprit for the drop in boost. I know JB welding it sounds stupid but it was a good trial and error. :redface:
How is everyone sealing theirs up......just metal on metal? May I have to get the elbow or turbo resurfaced??
I could just turn the boost up to 17lbs. and then let it settle in a 15lbs., but I just want to be able to run at a constant level. Especially on 93 octane.
TIA, Nick.

JB weld is rated to 500F
Key is "Flat surfaces" with about a 16-32 finish or better.
There is also a graphite gasket available from a vendor (TA performance?? ..... CRS) Search for tubo gasket in the general section.

 

[1QUICK85]

I know its only rated at 500 degree.........it was just a test.

Do you think that it could cause a slight drop in boost once the desired boost level is made? The small exhaust leak doesn't bother me that much, unless its causing the drop in boost. Thanks Jerryl.

-Nick.

 

[Jerryl]

..... Do you think that it could cause a slight drop in boost once the desired boost level is made? The small exhaust leak doesn't bother me that much, unless its causing the drop in boost. Thanks Jerryl.

I am no expert but here are my thoughts;
Actually, I believe the leak after the WG would result in a boost spike, since in essence you are "reducing the back pressure" with the leak. Now, as the volume of the exhaust increases, the % of leakage would diminish resulting in a drop in boost.

A drop in boost at higher RPM/load (in this very theoretical scenario) would indicate that the exhaust is restrictive, thus reducing flow, and limiting boost.

 

[cool 84]

What type of boost controller are you using? I have found when using a bleeder valve my boost will spike and then settle back down. I try and get the base wastegate setting pretty close to where I want the boost to be and then fine tune with the bleeder. Even without a bleeder it sometimes will do that.

With stock boost control it's supposed to spike and then come back down.

 

[Jerryl]

I know you already knew there is no gasket on a stock set-up, but here is a good thread.
http://www.turbobuick.com/forums/showthread.php?t=152319

 

[1QUICK85]

Its a RJC boost controller. I will try setting it for 17#.....so I can have my 15#'s once its settled. -Nick.