on my 5.3 I am having issues with controlling boost. I have a 78/75 with a 1.25 exhaust housing, have Holley turbo manifolds with a 60mm wastegate. wastegate came with an 11 and 20 psi spring. I'm shooting roughly for 10 to 15 psi so I put that 11-psi spring and it made up to 16 to 18 psi I have now put in a 5-psi spring and it's still making the same amount boost. I benched test the wastegate and it looks to be working fine. now I know the log manifolds and crossover are not the most efficient and I have the 60mm wastegate at about a 90-degree angle but for it to have a 5-psi spring and still making 16 psi its must not be a boost creep issue. I have the reference line from the turbo to the wastegate. there are 4 bottom ports I know sometimes there are ports for cooling so I'm going to see if maybe I'm running it to the wrong port but other than that I have no clue what else it could it be I'm at the point of thinking of running a second wastegate to see if that will fix my issue. this is my first turbo setup so any input will help.

 

A 60mm wastegate should easily control anything that turbo can throw at it.
I attached pic of how wastegate should be plumbed. The "cooling" ports are usually smaller than the boost reference ports on the wastegates.




If the wastegate is plumbed like pic above AND bench tests good, then the problem lies elsewhere.
My bet is the RED quoted text above...

I chased my wastegate tail for 6 months or more, trying to make a poorly placed wastegate control boost.
I thought I had shared all the info on this site, but cannot find it.

To explain how I 100% FIXED my boost control issues,
I have a thread, with plenty of details & pics linked: DUAL WASTEGATE CONVERSION

In a nutshell, a 90 degree wastegate placement simply doesn't work correctly, and/or consistently. The more prioritized it is in the exhaust flow, the better it will work. I wasted a lot of time trying to make a poorly designed (On3) crossover with wastegate pipe, work. It NEVER worked right, from Day 1.

I had had enough, and removed the complete hot side, modified my crossover, with dual gates, and now can easily make from 3# to 22.5# or so, where it's pretty much done making boost. It'll do it consistently, and rock steady...and no matter if the car is running through a full exhaust, a 3" open cutout/downpipe, or a 4" short downpipe. I've ran it all 3 ways at the track

Obviously, the Holley setup has a completely different crossover style, but there's no reason why the thread link posted above, can't let you see (why & what was happening, and how I fixed it once and for all.

Unfortunately, now my son's car (new build) has the same issue I had. We'll be converting his to dual gates as well.
Overkill? Yes. But the cost of one extra gate, to guarantee solving the problem, was and is, worth it to me.

One of the guys I work with, uses the Holley manifolds and rear crossover and his boost controlling works fine. I texted him asking for a pic or two, so will update if he has any to share.

 

I agree with Rel3rd. I know sometimes we are having to work within the engine/bay confines to plumb the wastegates but this is one of the concessions that has to be made. The wastegate pipes departure angle from the manifold has to be such that it can pressurize the wastegate and have a chance to overpower the wastegate spring. Sure, you can find people that have the wastegate pipe at 90 degrees or nearby variations, but they are 'living' with the resultant behavior rather than having proper control.

 

I have a log manifold, I made sure to mount it right at the curve up to the turbo, so it gets the full shot of exhaust pressure. It's only a 44 MM, but works. Some of those ports have blind holes, kind of storage for the fittings, depending on how you are plumbed, pressure could be holding the gate shut. What happens if spring only, no controller.

 

stupid mistake but it happens - make sure all the ones youre not using are blocked off

 

just so you can see how the wastegate is placed and how I have it plumbed i said there was four lower ports but it theres two on the bottom and two on the top

 

this is how its position and how the wastegate is plumbed. i said there was four lower ports but theres two on the bottom and two above and one at the way top of the gate. the two above are capped off and the one on the way top is venting to atmosphere. im going to log a pull with the wastegate off to to see if it still makes boost. to verify that it is the positioning.

 

you guys are not going to believe this so I took off the wastegate and they forgot to drill the hole where the wastegate pipe welds to the hot side so all that exhaust gas was going straight to the turbo. im glad I had big enough injectors and fuel pump as well as the boost cut because that could have been really bad. i knew this setup would have boost creep issue but not at this level.

 

Geez.. Yes, that's quite an oversight. That couldve been a disaster.

 

I appreciate all the advice! I'll keep all this in mind, hopefully I still don't have a lot of boost creep when I get that fix.
I'll keep you guys updated

 

No doubt.
I thought stuff like that only happened to me, LOL.

 

The one I attached shows pretty clearly it isn't in a good spot. I see you have a lack of space like I do.
If the current wastegate had a "standoff" like my "less than awesome" MSPaint skills are trying to show...(either in RED or YELLOW), it would work fine.



Or...
Similar to this, on the inside or OUTSIDE just before it makes the 90 up to the turbo mounting flange:

 

where you have the red drawing that is where it was supposed to go initially but the 60mm wastegate was too big but we'll see how much creep i have when i get the pipe fixed. ill keep you updated and see if ill need that second wastegate.

 

You may not necessarily "need" 2 gates...just one in a spot that gets better exhaust flow.

Mine is a front facing truck manifold setup, which had a bad spot and had creep from Day 1. Attached a few pics of before and after just to show how it was cured.

Looking forward to update


Original On3 wastegate location, had bad creep as soon as I used cutout and bigger intercooler. Original wastegate standoff Pipe was cut off and welded shut


Prioritized wastegate standoff pipes, welded at outside of each 90 degree headed to turbo


Passenger side gate...had to use a short 90 to relocate gate and give extra needed radiator/intercooler pipe clearance


Driver side gate, simply bolted on with room to spare

 

just a quick update on the 5 psi spring it made 3 psi all the way through so it seems to be working good so far. my thoughts were to install the 11-psi spring back in but I decided to just order a manual boost controller so let's see if I get any creep at higher boost levels.

 

Good deal. Thanks for the update.

 

Hello.Thanks for the photo. I had a turbine breakdown due to pollution. The main thing is to properly and regularly service the engine and monitor the oil pressure. I bought a Ford 6.0 Powerstroke Aftermarket Turbocharger for my car to add power, this is an excellent solution to problems with turbocharging, especially since this turbine is quite easy to install.