It's an oring seal at that connection. Older ones had a square style oring, but the newer ones have a traditional round hydraulic o-ring. It needs to be there or you will lose lots of boost and your truck will be smoky and higher EGT's.

www.cncfab.us

 

Got it - thanks Corey!

Fingers crossed the boost leak is gone after putting it all back together.

 

I use a very small dab of rtv to hold the o-ring in place. I've screwed up a time or two and pinched it.

 

Boost leak wasn't resolved.

Removed the y-plenum to replace the o-ring and take a look at the condition of the plenum (wanted to compare to my other truck), and while I had everything apart, I noticed some pretty deep gouging to the turbo outlet.

I didn't install the turbo (I wish I did, though, as I've uncovered a lot of work that was done that I'm not happy with), so I have no how it happened...

Since a new o-ring and a new outlet clamp didn't solve the leak, is the gouging on the outlet the likely culprit?

I've attached some pictures of the gouging - kinda hard to see it in photos, but it's pretty significant.

 

The o-ring sitting in the groove should be protruding about 1/16" out past those gouges so they shouldn't be affecting anything

 

Got it.

I'm glad that's not the culprit - would be an expensive issue to deal with, but now I'm back at square 1 trying to figure out why there's a leak.

 

So how or why are you convinced you have a boost leak? How did you determine that?

 

I initially suspected it because of high EGT's (truck can hardly make it up a hill) and black smoke.

I made a boost leak detector and sprayed everything down with soapy water. I found leaks from several places, but the turbo outlet/plenum connection is the only one I can't solve. Truck still has high EGT's and makes a lot of black smoke. I can use it for around town errands, but it's basically useless for anything that involves hills - EGT's climb past 1200F almost immediately on any type of climb.

 

Are you absolutely positive you have no exhaust leaks between the exhaust manifolds and the turbo? How much boost are you seeing? What rpm's are you turning climbing these hills? Doe's it sound like the turbo is spooling like it should? Who's tunes are you using? The 66/88mm inlets on these aftermarket turbos have a tendency to cause smoky exhaust unless you turn constant higher rpm's. Are you lining up and tightening the turbo V clamp (and is it the right one) before tightening the clamps on the intake plenum boots? What ratio turbo exhaust housing are you using?

 

No leaks that I am aware of. I haven't actually tested this, but I've gone under the truck to check the connection between the manifolds/up-pipes, and there is absolutely no soot or signs of a leak. Same with the up-pipe/turbo connection; completely soot free.

RPMs: Doesn't matter how high I run the RPMs - EGT's still climb past 1200F nearly immediately. I downshift coming into hills, am forced to back off the throttle to control EGT's, continue downshifting, and eventually have to pull off the highway to let people pass. Smoke diminishes at higher RPMs, but EGT's are still high.

Current tunes are by Full Force (not sure who actually writes their tunes). I'm going to try other, but it seems futile to do before getting this last boost leak resolved.

Yes, tightening the v-clamp before tightening plenum boots. As far as lining up the v-clamp... not sure exactly what its orientation is supposed to be, but I am making sure the outlet/plenum are lined up before tightening. The clamp is new, but I am open to buying another; any recommendations?

Unsure of what ratio exhaust housing, as I unfortunately wasn't the person who installed it. How do I figure this out? And what is recommended?

Thanks for all the help!

This^^^^

And a plugged air filter. The 6637's are common to be restrictive and actually have caused quite a few turbo failures.

The filter is new, but I was not aware of this issue with the 6637. What filter do you recommend?

Also - do you have recommendations for a good performance shop for the 7.3 in Southwest Colorado/4 Corners region? I'm getting to the point where I'm considering paying someone to deal with this for me. I'm willing to travel a reasonable distance.

The truck was a bit gutless when it was stock, but at least it was drivable. I have enough work to do on my F250 and my 87 Suburban... At this point, I wish I had just left the F350 stock. :doh:

 

This^^^^

And a plugged air filter. The 6637's are common to be restrictive and actually have caused quite a few turbo failures.

 

Corey@cncfab or riffraff diesel are great sources for parts. Might talk to Jodi at dp tuners. Great wealth of info and I like his tune's. If you where able to get over to Page Az I could help you but you are talking about two hours from four corners. When egt's climb where do they want to level out at? Only time I've known the 6637/2818 filter to have issues is when it was abused. You didn't say how much boost you are making. The exhaust housing ratio should be on the housing, example, 1.15 stock, doesn't spool well until about 2200 rpm's. 1.0, which a lot of people with the 1.15 switch to so it will build boost sooner usually about 1200 rpm's. .84 which is stock on the superduty 7.3.
Also want to add, running larger than stock injectors without an intercooler especially with the heat you see where you live is not a good ideal.

 

The fine folks from KC are sending me some new o-rings - we'll see if that helps.

I'll report back on the exhaust housing and boost numbers. Gonna take the truck out today. Sounds like a new exhaust housing may be in order - higher boost and lower RPM's sounds good.

The EGT's don't seem to want to level out. They'll just keep climbing past 1200 pretty quick, but I never let them get far past that.

I'll contact Jodi and see if he has any thoughts.

Regarding an intercooler: I'm going back an forth between the 7.3 or 6.0 intercooler; any thoughts?

If you want to stay with the 6637 style, then I highly recommend this one.

https://www.cncfab.us/shop/afe-power-air-filter-21-90058/

As for a complete intake kit, this is what I recommend.

https://www.cncfab.us/shop/s-b-filters-cold-air-intake-kit-94-97-7-3l-cleanable-filter-75-5027/

Great - thank you. I'll get on ordered up soon.

 

Most of us go with the 7.3 all aluminum cooler and stay away from the 7.3 and 6.0 coolers with the plastic end caps

 

Curious what gauges you have and where is the sensor tapped into?