|
|
|
10-30-2021, 10:01 PM | #1 |
Registered
0
Rep 4
Posts |
Under Boost with New Turbos
Hey All,
I bought a 09 135i about a year and half ago. I knew that the turbos would need to be replaced when I bought it as they had the start of the wastegate rattle issue. Also, it threw the half check engine code for under boost a few times on the freeway. Last winter, I swapped out the turbos for brand new OEM turbos from FCP Euro. However, this did not seem to fix the under boost problem. I have a JB4 tune on the car, and when it is on the 13 psi tune, I cannot get the car to even build up 10psi of boost. It seems to top out at around 7psi. Any ideas on what could be wrong would be greatly appreciated. |
10-31-2021, 02:22 PM | #2 |
Registered
0
Rep 4
Posts |
To follow up with some additional information: I bought a vacuum gauge today and T'd it into the the wastegate actuator vacuum tube (the tube that connects the outputs of the boost solenoids to the turbos). On idle, I pulled 14 in-HG on JB4 60% default wastegate position and 23 in-Hg at 100%. Are these reasonable enough numbers to to determine that the issue is not vacuum related?
Also, here is a JB4 log of a short 3rd gear pull on map 1. It actually never gets past ~7psi despite targeting 13. |
Appreciate
0
|
Post Reply |
Bookmarks |
Tags |
boost, turbos |
|
|