Single Turbo Setup Can't Reach Wastegate Pressure

[Arrtus]

Hey guys,

I originally had posted this in the N54Tech forum but got little to no help. I'm really stuck on and can't understand what is causing this problem.

This is a brand new DR700 setup and ever since making the swap, I am unable to reach more than ~9 psi (14 psi spring). The car is obviously way underboosting and I have no idea why. All the vacuum lines have been checked and are brand new. I have pressure tested from the turbo output all the way to the charge pipe and have found no issues. I also tested the compressor housing side of the turbo (and intake) and it did not leak whatsoever. I went through all the V-band connections and everything is on correctly and tightened to the max.

Symptoms: The car sounds different. I don't know if it's because of the single turbo but when going on WOT it doesn't sound like it's spooling. It's also very loud, like it just changes sound as soon as it starts building pressure.

With other maps, the wastegate (I think?) starts pulsing and sounding like it's hitting a rev limiter or 2-step while it's on WOT. It's most likely because of the mac that it's switching the air into the wastegate but it's not able to hold pressure or something. With maps aiming at higher PSI, it reaches ~12 PSI. What would cause the wastegate to do this? Can it be defective? It's a turbosmart gen V 45mm. I also checked the wastegate by putting some pressure on it and I can hear it open and closing. The MAC solenoid is also working just fine (which doesn't matter since it's not in use in map 0 and the problem is still there).

Log of a map 0 pull attached. Any advice or suggestions would be really appreciated!

 

[Arrtus]

Did you ever try swapping wastegates with a new one, incase yours was faulty from factory?

I did, although it was with a cheap Amazon one. It didn't make any difference and performed exactly the same. I guess that isn't a good test since the Amazon ones are junk anyway.

 

[NoQuarter]

Dammit... I just read though this for the first time, really engaged and emotionally connected to the players.

Got to page 4 expecting an epic series finale and got ending to Game Of Thrones instead. mfl...

 

[Arrtus]

Dammit... I just read though this for the first time, really engaged and emotionally connected to the players.

Got to page 4 expecting an epic series finale and got ending to Game Of Throans instead. mfl...

LOL! I'm sorry!

The saga continues. I guess it's going to turn into the Walking Dead series now and drag on and on without ending.

 

[NoQuarter]

Ha! Maybe Fast and Furious 12?

 

[fmorelli]

Dammit... I just read though this for the first time, really engaged and emotionally connected to the players.

Got to page 4 expecting an epic series finale and got ending to Game Of Thrones instead. mfl...

Crap. I read this and it caused ME to go back and read the whole thread. I was going to suggest "maybe the spring color rating is not what it actually is..." but you eventually not only covered that but swapped the BOV completely, with same behavior. @martymil dropped off the thread?

 

[Arrtus]

I realize I forgot to update this thread with what I had done because I was posting on bummerboost hoping to get more ideas.

• I eventually dropped the subframe and completely removed the turbo kit as I had ran out of ideas. The only issue I saw was the turbo to header not sitting flush on one side due to warping. I sanded the inner ring down and made sure it would go on correctly. Installed new header manifold gaskets and checked over everything. Turbo had very little in and out play. No up/down play. No oil coming out or anything.
• I also got a custom tune from Twisted just to rule out the tune being a possibility. Replaced all vacuum lines with thicker material ones.
• Ran boost leak tests from output of turbo to the throttle body. Pressurized the system up to 25 PSI and there were no leaks.
• Replaced the throttle body
• Seafoam to check for leaks on hot side, WG did have smoke coming out: https://drive.google.com/file/d/1iC-QtHHO0q1kP3DDpbH3aFRN4ZJgDQw-/view
• Made a boost leak vlog for all my fans:

After all this, there was still no improvement. This is where I am with the car now.

Today I took off the wastegate again for probably the 600th time. The wastegate is definitely leaking at this point and I had been able to hear it leaking on cold starts. I'm chalking it up to the clamp not being able to hold it on as tightly anymore and ordered a new one.

 

[Zulu]

It definitely sounds like you have a boost leak if you're hitting 7 PSI on a 14 PSI spring with 0% duty cycle. Have you already done a boost leak test

Possible... I have done one before. No dice. Unless one of the clamps got loose or something. This BigBoost kit has a poor charge pipe design where the charge pipe inlet/outlet are oval but the supplied couplers and clamps are circular...

Anyways, will be following your thread man. I’m very interested to see what your issue ends up being. Hopefully you’re able to get everything sorted out.

 

[martymil]

I'm still here

 

[fmorelli]

@Arrtus may I ask where you are located?

You have been very thorough. Wondering about other sets of eyes on this, in person.

 

[martymil]

If its not fully sealing than the flange on the exhaust manifold could be ovalized and when he or someone clamped it down could have caused the wastegate to ovalize as well.

Changing the wastegate wont help as it will ovalize the new one too.

This is the only theory I can come up with for the turbo not to reach spring pressure from the info you provided without having the kit in front of me, if i did it wouldn't be hard to as that's what i do best.

The whole system is very basic, there is no magic or wizardry involved, if its not reaching boost its one of three things

leak
turbo
waste gate

Very plain and simple

Get yourself a set of cheap vernier calipers and measure the manifold wastegate flange crisscross.

 

[Cruizinmax]

Crazy this thread is still going without resolution! Something I noticed since your turbo to manifold was leaking so massively, it doesn't look like your turbo to manifold v-band is on all the way/correctly in this photo. Could you describe how you checked the manifold for flatness? Any photos of that mating surface? The turbo should be sitting perfectly flat, with no gap to be felt or rocking if you push the exhaust housing up to the manifold. I'm betting it's still warped and the turbo isn't sealing completely. Could be the same issue with the wastegate as well.

 

[shushikiary]

I was driving my self crazy with similar issues and eventually got 2 things figured out to get it fixed.

1. My turbo smart waste gate was not fully closing because it was striking the manifold split for my twin scroll... obviously I don't think you have that problem. I fixed it by grinding down the center split just a little bit so the waste gate could fully close.

2. TURBO INLET. How is your turbo inlet setup? Everyone seems to be making the same assumption they did on mine, that you just slapped a straight filter to the inlet of the turbo. I did not, I have some tubing that runs to two cone filters in a high pressure zone in the bumper. THIS was my problem. When ever I would build boost pressure the inlet tubing would collapse and the turbo then had a massive restriction on its inlet. I put solid aluminum tubing inside the silicone tubing to prevent the collapsing and it fixed the problem.

I haven't seen anyone mention #2 above to you... I don't know your exact setup, but something to think about.

 

[Steve135i]

Hi i also have a dr700 kit. When you took your manifold off did tou inspect it really well? I saw a pic of a totally cracked one, and i had mine out for an engine swap at the time and inspected it and a nice crack was forming. These are stainless steel they did not purge the welds and you can see the stainless tube seams if you look inside the manifold holes. I had the crack in mine ground out and re welded on the outside and inside. But the tubes are too far back, cant reach them to do anything about them.

 

[Steve135i]

Forgot to mention, less than 200 miles on that manifold

 

[SLOWESTN54]

Forgot to mention, less than 200 miles on that manifold

Is their possibly a way to have the manifold replaced under warranty? Or is their no warranty? Also aren't a lot of people having issues with these manifolds cracking?

 

[Steve135i]

Is their possibly a way to have the manifold replaced under warranty? Or is their no warranty? Also aren't a lot of people having issues with these manifolds cracking?

Yes doc race is aware of the problem and is supposedly making a cast manifold to replace the welded one on future kits. They offered for me to send it back to get a new one. But i found it on the day i was putting in a new engine and couldnt wait for shipping across the country. So i have a great welder close to my house, and just went and got it welded in an hour. And they even offered me to pay for the welding.They definitely will stand behind it and do the right thing. I just didnt have time to send it back. I did let him know my engine will be coming back out in a couple months for a built one, and he told me he will take care of it when that happens.

 

[shushikiary]

What's interesting to me about those welds is it looks like it was stick welded. The inside was for sure ground down after the weld.

I'd bet the manifold is 304 stainless, or maybe 409 (but I hope not) so I bet they used a 308L rod.

 

[Arrtus]

Wow, didn't realize there were so many replies!

***OKAY FINAL UPDATE HOPEFULLY!***

My car had been leaking massively from around the wastegate flange. I figured this was the problem the past couple weeks and tried everything to get a better seal. I seafoamed again and noticed more and more amounts of smoke coming out. I could (what I thought) feel exhaust coming out from the flange when putting my hand there.

Today, I took off everything and saw that the MANIFOLD WELD IS CRACKED. Just like @Steve135i posted! I find it comical that I find the failure today, come to update this thread and see you had mentioned it lol.

I am so disappointed in this whole kit, you guys have no idea. My car has been in my garage for the past 4+ months over this same issue that I have completely had enough of.

I emailed DocRace today and hoping they can make it right. I honestly don't even think I want the bottom mount kit anymore. I will most likely sell it after it has been fixed and go with something else because this is going to be the 2nd time I have to drop the subframe and probably the 50th time that I have taken the car apart. I've spent a ton of money fixing anything and everything and for it to come to this type of failure seems like the cherry on top for me.

Video of crack: https://drive.google.com/file/d/1EmUkh5wrzE9XpaSxOmLVR_PpzbnSm_0S/view?usp=sharing

Seafoam leak: https://drive.google.com/file/d/1z8GDHcrqNskTpV8p1J1kMmxxNWE2cj2K/view?usp=sharing

 

[Steve135i]

Sorry i wish i saw this earlier. I could have saved you alot of BS. I also had underboost issues and whoosh sound when in full boost. I checked my wastegate, did a boost leak test. Heard it coming out from below wastegate. Realized i left 1 compressor housing bolt just hand tight. I fixed that and never got to check if it was the problem. Because i also decided to change motor mounts and my jack pad slipped off and the jack cracked my oil pan. So i was replacing it and saw the copper flakes in the pan. So i took everything out and bought a new engine. A couple days later i saw that video of a cracked manifold. You are the 4th person i know of with a cracked dr700 manifold

 

[Arrtus]

Sorry i wish i saw this earlier. I could have saved you alot of BS. I also had underboost issues and whoosh sound when in full boost. I checked my wastegate, did a boost leak test. Heard it coming out from below wastegate. Realized i left 1 compressor housing bolt just hand tight. I fixed that and never got to check if it was the problem. Because i also decided to change motor mounts and my jack pad slipped off and the jack cracked my oil pan. So i was replacing it and saw the copper flakes in the pan. So i took everything out and bought a new engine. A couple days later i saw that video of a cracked manifold. You are the 4th person i know of with a cracked dr700 manifold

No need to be sorry! Thank you very much for posting on here. It's good to know that the issue has been brought to DocRace's attention and that I'm not the only one in this situation.

Just wish I saw the crack the first time I took the kit off but it definitely wasn't as bad, otherwise I would have noticed. I will say, I remember seeing hair-like lines in the manifold but I thought that was normal. Maybe the metals were expanding and contracting when hot/cold and worse under boost which made it difficult to see it until it got as bad as it is now.

I'm hoping that they can redo all the welds. I'd hate to have one weld get fixed, reinstall the kit, and then have another weld break. Don't even want to think about that.