I am losing boost for some reason and I know all my lines and pipes are tight. It has to be one of the following that I have done. I added a air duct to the turbo for the filter and got the cat welded on. Before i use to run open down pipe and the intake was slapped right on the turbo? My exhaust system tapers down to 2.36" from a 2.5" dp and cat. My PSI spring is set at 7 psi and I would always hit 7 psi. Now i'm only getting 5.8 PSI's So does any of the following mods above affect the boost? thanks.

 

maybe that cat is limiting exhaust flow, or the 2.5 > 2.36 reducer. That could reduce flow. As a quick fix if you don't have a boost controller, the vacuum line that runs from the turbo to the wastegate, run it from the intake manifold to the wastegate. If you have an intercooler, this will compensate for the loss in pressure. Also, make sure you have no exhaust leaks before the turbo (ie wastegate) , or at the exhaust flange on the turbo. If your turbo was originally designed for an internal wastegate, the flange covers that hole, and if any of the bolts are lose on that flange it could cause exhaust to leak out of the internal wastegate hole and you will lose boost.

 

i dont know how it would be limiting boost, but having a cat and having it taper down like that doesnt help the gases flow out any easier. could be related to that, but im not %100

 

i have a revhard kit with a tial wastegate. I checked everything and i'm sure everything is tight. I was wondering to compensate for the lost in boost I'm thinking bout getting a manual boost controller and set it up back to 7 psi. will this mess anything up? But before I do this, Is this normal tho losing a lilttle boost due to the dp being weld to the cat? thanks.

 

if the loss in boost corisponds when you did the ehaust, then yes. it is normal to lose boost when putting any restriction on the flow of the ehaust gases.

it would be ok to put a bc on to compensate for the loss..

 

i c. now i guess its time to search for manual bc's. i was wondering if connecting the vaccum line of the wastegate to the intake manifold instead would be a better idea. Right now its hooked to the turbo.