low boost on "stock" setup
 

hey,

well.. i used to have a Corksport full 3" and a boost controller, running ~12psi on stock turbo. I sold my Corksport Exhaust, and put the OEM Exhaust-sytem back on, except the Pre-Cat, i Use a 3" to 2,5" downpipe for now.

its a S5 with stock turbo, there is no MAF because of a Standalone ECU,Apexi Filter, the engine is streetported and portmatched.

With the Corksport and w/o Boostcontroller i hit ~10psi. Just changed the exhaus-system.. and i am getting 5psi MAX!! shouldnt i get at least 7psi to stock conditions?? :dunno:

i dont know why my boost is that low..
i also experiance excessive boost-drop at higher RPM (drop beginning at around 6000rpm, 3psi even with the Boostcontroller set up to 12psi!) My wastegate was ported by the previous owner..

please help me out, i am going mad :crzyeye:

check your wastegate actuator. i was experiencing low boost after i rebuilt my turbo. fount out that the wastegate actuator was not reconnected. so exhaust gas was just dumping through it.

if not that. start looking for restrictions in the exhast system. pull off you air filter and spin the turbine with your fingers. GENTLY and WITH THE ENGINE OFF (duh, but i have to make sure i won't get sued)

after all that, or if you've done that... i'm not sure what i can tell you.

TR

Your issue sounds a lot like what i'm dealing with. Wastegate spring is 5.5lbs, so your max boost without the controller on is normal. Most of your choke at high rpm is probably due to that turbo with the restrictive exhaust. The guys that have been around for a while will tell ya that it is a pretty common complaint with a stock turbo setup.

My solution is I am currently fabbing up a custom dual exhaust which should have similar flow to a corksport without being nearly as loud. I will also be using an electronic boost controler rather then the manual controller currently in it.

Hope this helps.

bbrrraaapppp!

S5's have a boost controller. Yours is missing. Thus the 5.5lbs of boost your wastegate spring is set to.

my boost controller is in there, and its working as far as i know, so i dont understand why it goes to 5psi only..

Have you tried turning up your boost controller?

I just did a swap on an S5 JDM TII motor, and i am also getting only 5lbs of boost on a stock setup, where do i adjust the boost controller? or how can i see if the boost controller is missing?

Sorry to bring the thread back from the dead