Boost leak? Exhaust leak? Need some opinions

[aruth55]

School me on this please as I need the information, call me an idiot if you have to, I won’t be offended because I would understand lol, but here’s what I’m currently dealing with. I have a rebuilt C39 hybrid turbo with an external wastegate setup using a Tial 38mm with 14.50psi springs. Now with that aside, we have been tuning the car with Adam at tune+ which has been a great experience, he has confirmed everything we have on is setup correctly, but that we are experiencing either an exhaust or boost leak. We were told this by Adam, “ we are at 72% WGDC and only seeing a max of 23.27psi. The higher we can go before the boost control solenoid maxes out is 85%. So another 13% of WGDC, but unfortunately your translation is not 1:1 for psi. If you have a base spring of 14.50psi, 72% WGDC should be netting us 25-26psi.” With background information aside, let me disclose this. We used fuel lines, yes fuel lines, as vacuum lines on the car because we read that it is okay to do on many forums. I have now done more research after experiencing issues telling people that is not okay to do. So first what is it? Okay or not? At start up I am seeing AFR get to 15 and then regulate itself down to high 14’s. It remains at high 14’s while cruising as well as at idle and fuel MPG is bad (I assume adding fuel for a vacuum leak). Fuel MPG goes up with driving, and while under boost the car actually runs rich (I read is symptomatic of a vacuum leak as well). When I let off the throttle with AFR at 14 while cruising it drops to 12 or 13 first before going up to the high numbers it does for fuel economy. I am not experiencing any knock whatsoever. I hear a slight squeaking noise in the engine bay as well during idle at times, which when I open the hood to check it out, goes away completely instantly. Could this be air leaking? I have ordered silicon vacuum lines through stratified so we are going to replace them regardless with those, but is this our problem? If not car is being taken to a shop for full fuel and boost leak testing, but would like all of your two cents on this. Thanks!

 

[aruth55]

Oh yeah, and if it passes those tests Adam told us it would be the turbo failing, which we are obviously hoping it’s not that! We haven’t found any evidence of that so we’re hoping it’s just a leak of some sort somewhere.

 

[TyphoonFiST]

Need to do a Boost leak test or a smoke test to
Reveal any boost or vacuum leaks. Its what I would do!

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[aruth55]

Need to do a Boost leak test or a smoke test to
Reveal any boost or vacuum leaks. Its what I would do!

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You’re right that’s likely what we’re going to end up doing regardless! We saw slightly more boost by fixing that exhaust leak with the v band so I figured that had fixed it and we just needed a revision, but after sending the logs got this info back. Thanks for helping me all over typhoon!


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[slopoke]

It might be more of an exhaust leak. Did you remove the exhaust manifold? If so, did you install a new gasket? Did you replace the fire ring gasket at the exhaust manifold flange to turbo? For a boost leak, read the link below. It's how I did my own boost leak tester.


I just read your post about the V band clamp, so disregard the part of fire ring at the manifold/turbo connection. I however will say this. When I installed my GTX2860, the turbo flange was really easy to partly come out of the clamp. I had to remove and reinstall my turbo, because of a leak at the turbo clamp. When I put it back in the second time, when installing, I had to keep constant pressure on the turbo, forcing it towards the manifold, during the time I was clocking the turbo into position.

In the aviation industry, we use a lot of V band clamps on pneumatic plumbing. Usually we coat the edges where it will slip into the clamp, anti seize works good in this instance. The next thing we do is tap on the clamp around the entire circumference then torque the clamp bolt. We alternate tapping and torquing til the bolt will not turn while torquing with a torque wrench at the specified torque. This helps seat the clamp fully with the flanges.



https://www.fiestastforum.com/threads/diy-boost-tester.17541/

 

[aruth55]

It might be more of an exhaust leak. Did you remove the exhaust manifold? If so, did you install a new gasket? Did you replace the fire ring gasket at the exhaust manifold flange to turbo? For a boost leak, read the link below. It's how I did my own boost leak tester.

https://www.fiestastforum.com/threads/diy-boost-tester.17541/

Yes we replaced all gaskets when we did the swap because we did swap the exhaust manifold for a stock manifold set up for the external waste gate. We don’t see any soot around the manifold to cylinder heads or manifold to turbo and we torqued everything to spec, it’s been driven about 3k on this setup now so I figure we would see some signs around those areas if we had a leak. I’m also not smelling any exhaust in the engine bay since we fixed the leaky v band on the wastegate to manifold and that is when we checked the other connections for soot about a week ago. Also I am using a whoosh turbo inlet and we used gasket maker to create a gasket there as well which looks to be sealing well also. Thank you for your two cents!


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[slopoke]

Yes we replaced all gaskets when we did the swap because we did swap the exhaust manifold for a stock manifold set up for the external waste gate. We don’t see any soot around the manifold to cylinder heads or manifold to turbo and we torqued everything to spec, it’s been driven about 3k on this setup now so I figure we would see some signs around those areas if we had a leak. I’m also not smelling any exhaust in the engine bay since we fixed the leaky v band on the wastegate to manifold and that is when we checked the other connections for soot about a week ago. Also I am using a whoosh turbo inlet and we used gasket maker to create a gasket there as well which looks to be sealing well also. Thank you for your two cents!


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I updated my previous post with new information.

 

[aruth55]

It might be more of an exhaust leak. Did you remove the exhaust manifold? If so, did you install a new gasket? Did you replace the fire ring gasket at the exhaust manifold flange to turbo? For a boost leak, read the link below. It's how I did my own boost leak tester.


I just read your post about the V band clamp, so disregard the part of fire ring at the manifold/turbo connection. I however will say this. When I installed my GTX2860, the turbo flange was really easy to partly come out of the clamp. I had to remove and reinstall my turbo, because of a leak at the turbo clamp. When I put it back in the second time, when installing, I had to keep constant pressure on the turbo, forcing it towards the manifold, during the time I was clocking the turbo into position.

In the aviation industry, we use a lot of V band clamps on pneumatic plumbing. Usually we coat the edges where it will slip into the clamp, anti seize works good in this instance. The next thing we do is tap on the clamp around the entire circumference then torque the clamp bolt. We alternate tapping and torquing til the bolt will not turn while torquing with a torque wrench at the specified torque. This helps seat the clamp fully with the flanges.



https://www.fiestastforum.com/threads/diy-boost-tester.17541/

Okay that makes sense, that could be it right there. The only places we have v bands though are where the wastegate connects to the top of the manifold, and where the dump pipe connects to the wastegate. The turbo connects without a v band normally the same as a stock turbo connects. I included a picture of the hardware we are dealing with off the car on install day so you guys can see my connection types right there.

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[draxxus131]

Does that turbo blanket even fit that small frame turbo? If so which brand is it?

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[aruth55]

Does that turbo blanket even fit that small frame turbo? If so which brand is it?

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It was actually used and it broke before we ever got to use it, so I’m not sure. It was custom made for the C39 and I suppose other stock frame turbos by sour skittle I believe.


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[TyphoonFiST]

That thing has a screamer pipe!?!?!

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[aruth55]

That thing has a screamer pipe!?!?!

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Oh yeah she’s got a screamer pipe alright! Lol when she’s running right I’ll get a video on here for you guys. She’s going in tomorrow for a boost leak and smoke test at 12:30pm at APM tuning.


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[TyphoonFiST]

Oh yeah she’s got a screamer pipe alright! Lol when she’s running right I’ll get a video on here for you guys. She’s going in tomorrow for a boost leak and smoke test at 12:30pm at APM tuning.


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I got me one too with my not yet installed DHM360R Kit! I'd love to hear yours though!

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[gtx3076]

I got me one too with my not yet installed DHM360R Kit! I'd love to hear yours though!

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When it's only on spring pressure it just sounds like an open exhaust, and is just loud, but the flutter once it's tuned it sounds awesome. Very unique to turbo cars.

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[aruth55]

Just got the tests done. Looks like I need a new GFB dv+ I currently have the VTA version and it’s leaking. Getting some leaking from the dump pipe as well so looks like I need a new diaphragm for the waste gate. Could be worse! $50 and $130 fix and the tests were only $120!


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[Alkoran]

Just got the tests done. Looks like I need a new GFB dv+ I currently have the VTA version and it’s leaking. Getting some leaking from the dump pipe as well so looks like I need a new diaphragm for the waste gate. Could be worse! $50 and $130 fix and the tests were only $120!


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Before buying a new GFB unit, I'd open up the one you currently have and inspect it to see if there's any visible cause, either with the oring that seals on the turbo housing or the silicon part of the piston. I'd also contact GFB about this issue to see if they already had any similar issue with other customers.

 

[aruth55]

Before buying a new GFB unit, I'd open up the one you currently have and inspect it to see if there's any visible cause, either with the oring that seals on the turbo housing or the silicon part of the piston. I'd also contact GFB about this issue to see if they already had any similar issue with other customers.

I’ve had a lot of people tell me GFB is a bad company in general and some Subaru blow off valves they make come leaking from the factory. I’ll probably get this one now as a cheap fix but change brands eventually. The smoke test looks like it’s leaking from where it vents to atmosphere from the video. I have the video if you guys would like me to post.


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[Alkoran]

I’ve had a lot of people tell me GFB is a bad company in general and some Subaru blow off valves they make come leaking from the factory. I’ll probably get this one now as a cheap fix but change brands eventually. The smoke test looks like it’s leaking from where it vents to atmosphere from the video. I have the video if you guys would like me to post.


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Yeah that'd be cool, I'm curious about it, since I have yet to install mine, it could help me if I get the same issue.

 

[aruth55]

Yeah that'd be cool, I'm curious about it, since I have yet to install mine, it could help me if I get the same issue.

We actually had it off the other week and were oiling it up because I’ve read they can get stuck and they recommend you do that every 10k when I thought that could be my problem and there was no physical damage or anything looking like it was wrong with it. So I’m not sure if you’d be able to know without a smoke test like I got unfortunately.


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[Alkoran]

We actually had it off the other week and were oiling it up because I’ve read they can get stuck and they recommend you do that every 10k when I thought that could be my problem and there was no physical damage or anything looking like it was wrong with it. So I’m not sure if you’d be able to know without a smoke test like I got unfortunately.


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About that smoke test; was it simply hooking the smoke machine to the intake (pre or post turbo) and was it also pressurized?