Hi, am new to BMW have tended in the past to buy Jap or smaller german cars, the family came along so now i have become the owner of a 535d i brought the car knowing the small turbo was not actuating (with money off, never pay the asking price ) been reading into these for a while so roughly knew what i was looking for as i didnt want to get stuck in whilst clueless. so first things first it must be a Vac Hose as no oil burning, leaking etc..... so new vac hose from the vacuum box to the vacuum converter for the small turbo actuator.....turbo working
however i ran a test on an Iphone related app because the car felt sluggish at top end boost compared to when it was broken!!
Small turbo working - 300bhp @0.58Gs of accel
small turbo Vac Disconected - 329bhp - 0.92Gs of accel ( accuracy of figures not important, it was a controlled test (conditions for both were the same) so i know theres a difference)
im just wondering if anyone else has experienced this im thinking maybe the vac hose from small to big turbo actuator as when the big turbo was boosting alone (ie. small turbo actuator not opening) the boost was almost breath taking @3000-4750 now it almost flattens out just after 4000rpm