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PTE 5031 boost issue

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jdxnc

10+ Year Contributor
678
924
Sep 15, 2009
Stanstead, Vermont
A friend of mine is having issues with his PTE 5031bb and asked me to ask for help here as he is not good in English.

He has a 93 TSI awd, stock rebuilt 6 bolt, 750cc injectors, front mount, walbro 255, HKS SSQ bov, Evo 3 exhaust manifold with a Tial external waste gate, 3" turbo back exhaust. Tuning with DSMlink V2.

The problem he is having is that he cannot get over 24 psi of boost and I think he said 37lbs/min of air flow. It is the 5031 ball bearing version with internal waste gate, which is welded closed. He says the turbo has no abnormal shaft play. He did a boost leak test and all seemed well except for a slight leak around the compressor housing. He said he removed the compressor housing and placed a very thin bead of silicone on the seal and it seemed to fix it. He has also tried blocking off the Tial external waste gate to see if that solved the problem, but it didn't.

He doesn't know what else could be causing this, as this turbo is obviously capable of more than 24 psi.

Thanks for any help with this.
 
The internal actuator cannot hold the flapper shut under any boost pressure higher than 24psi. This is a common problem on internally-gated turbos. To hold more boost you'll need to go with an external gate, or custom-fab an internal actuator like this:

http://www.dsmtuners.com/forums/tur...oking-strong-internal-wastegate-actuator.html


Are you sure your airflow is calibrated properly? An Evo III 16G generates 35-36lb/min at 17-18psi. If a 50-trim cannot outflow an Evo III 16G at an 8psi higher boost level, something's wrong.
 
... Tial external waste gate... internal waste gate, which is welded closed.

The internal actuator cannot hold the flapper shut under any boost pressure higher than 24psi. This is a common problem on internally-gated turbos. To hold more boost you'll need to go with an external gate

OP, when your friend blocked off the wastegate, did he actually completely remove it and use a blockoff plate?

I can't get more than 24-26psi out of my 5027e through my stock catback, but with my cutout open it pegs my boost gauge at over 32psi. I'm running a recirculated external gate off the o2 housing. Are there any restrictions in his exhaust? Does it neck down anywhere, or have a cat that could be clogged? What turbo was on the car previously, and did he change anything else when this one went on? How did the previous one behave if not?
 
OP, when your friend blocked off the wastegate, did he actually completely remove it and use a blockoff plate?

I can't get more than 24-26psi out of my 5027e through my stock catback, but with my cutout open it pegs my boost gauge at over 32psi. I'm running a recirculated external gate off the o2 housing. Are there any restrictions in his exhaust? Does it neck down anywhere, or have a cat that could be clogged? What turbo was on the car previously, and did he change anything else when this one went on? How did the previous one behave if not?

Yes he used a block off plate. I'm not sure if the exhaust necks down, there is no cat, I'll pose that question to him. Previously the car had an MHI 20G, which I think was fine.

Thanks.
 
I can't be much more help than a comparison. My Journal Bearing 5031 with an internal gate held 27psi and flowed 45 lbs/min through an evo3 O2, RRE DP, and a high flow cat into an Espelier 3" cat back.

That turbo should be capable of much more than he is getting.
 
I am running a 17# spring. I was told this was good to 30 psi at least?
Every turbo and setup is different- wastegate size, turbine wheel size, turbine housing size, and exhaust backpressure all effect how much total boost a certain spring can hold. There is no set number across the board.
 
I have ran it with no boost referance no spike, no taper off just up to 24 and doesnt build any higher. It ran 32 previously with my tubular manifold but it cracked. So I replaced it with a old slowboy cast manifold with external wg flange. I was told by a local shop that there is to much back pressure and not to put another spring in it. It will just create more heat and it will burn up the turbo seals. Is this sound plausable because like you said I was going to just put another spring in it?
 
I was told by a local shop that there is to much back pressure and not to put another spring in it. It will just create more heat and it will burn up the turbo seals.
WTF

News to me.
 
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