Hi guys,

I am running a ETS turbo kit with 6057 PTE turbo, 38mm Tial wastegate, Hallman MBC, FMIC, Injen hard pipes and a stock crushed IX Bov. The issue is that most of the time my boost will hold rock steady at 27psi(which is what it is set to) but then one day it will spike to 24psi and drop down to 21psi, and in the next couple of days it automatically goes back to 27psi.

I've done a boost leak test upto 27psi and have no boost leaks. It doesn't matter if I play with the MBC and I've even swapped out the MBC and tested another one but the issue still exists. I've also run the car straight of the Tial wastegate and it holds 14psi rock solid (that is what the spring is rated for)

This used to also happen prior to crushing the Bov, which I thought was the culprit. But now I'm not sure why this happens ever so often.

Please help...

 

outside air temps might be the issue.

 

I'm comparing this in similar temps so that is not the factor.

Ok, I swapped out the stock Bov to a Forge RS and the issue was still present. This has me completely stumped.

And the following day the car is running fine again. I'm out of ideas.

 

Is the MBC exposed to vacume? it should be ran off a line that is positvie pressure only

 

Maybe get a stiffer WG spring? Just throwing that out as it seems you already took the steps:

-Leakdown/Boost Leak test
-BOV
-MBC

Other than that it would have to be your tune...

 

You no you are right. I didn't even think about him targeting boost that is knocking on the door of double the spring pressure. for that boost you def want a closer spring, for instance I run 34psi, and my gat epressure is 22 psi, with the mbc installed and turned all the way down it does 27 psi.

 

Well I've already tested the following..
- Boost leak test - though I hear a very slight hiss towards the back of the TB by the FPR. (I'll further investigate)
- Changed BOVs
- Changed MBCs

I was originally thinking the wastegate could be a factor but when I run it off the wastegate directly the car boosts 14psi solid. And my target boost is 27psi so that should be possible with the spring currently installed.

But the problem is why one day the car boosts fine and the next day it's all messed up. If it's the wastegate it should be acting weird all the time.