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Series 8 FD Second Turbo Boosting Issue

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Having a slight issue with the activation of the secondary turbo and any information would be greatly appreciated, it's actually pretty hard to find info on the series 8 in English.

So basically, The car operates like an absolute gem, omegle appvalley https://192168ll.onl/ no heating issues, fantastic compression etc It's a very healthy car.The issue is that the second turbo doesn't always come online, once 4500rpm comes around there is no activation of the 2nd turbo. Especially after a long drive in low rpm.

The motor takes longer to pass through the rev range and it feels more like something is "blocked" and a couple pumps of the accelerator solves the problem and we're back at full power. Almost like a solenoid sticking or incorrect pressure sensing?

I plan on going through to replace ratnest hoses and inspect the solenoids - of which I am highly suspicious of being the culprit because the 2nd turbo works wonderfully (when it works) it's getting it to activate which is the issue.

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First of all check the 2 pressure tanks (black plastic tanks in around the engine) one of these stores pressure and the other stores a vacuum. If these are leaking it will cause an issue for you. Also there is 1 way check valves that lead in or out of these that are prone to failing. Older model FDs had what we affectionately called the "rats nest". This was a bunch of solenoids with a spaghetti load of vacuum hoses that controlled the actuators for the turbos. On later models like yours this was replace with a black box with all the workings hidden away inside. It's possible that one of these solenoids is on the way out. Most people replace this entire box (Quite expensive) but some have had some luck in stripping this down.


Start with the tanks and check valves then go from there.

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