Hi everyone,
So my mini has had the yoyo effect ever since I've owned it and I finally got around to changing the bpv. I ordered a Detroit tuned bpv and removed the stock one and replaced it with the new one. After I put everything back together making sure to plug in every line I started my car and it freaked out. The supercharger immediately started to whine like I had the pedal all the way down and after a second or two the engine would shake and act like it was going to stall. I looked again to make sure nothing was out of place and started the car which then did the same thing again. Is there something I'm missing? I don't think I broke anything while installing the new bpv. Tomorrow morning I'm going to reinstall the old one and see if it freaks out again but I wanted to get insight from you guys.

Thanks,
Roo

 

Sounds like you have a vacuum leak or intake leak. Check the boots on the intercooler, especially check the bottom of the boots with a mirror. I am confident you will find something loose if you keep looking.

 

Like David said, the bypass valve I found to be a pain to swap out, could be it didn't seat properly when reinstalled. Or the intercooler boots are folded over and leaking.

 

I checked the seals on everything and took off the throttle body and bpv along with the small side supercharger horn then put everything back together and still had the same issue. It could only be something with the intake/air system because it was working earlier yesterday. My guess is when I pushed the supercharger intake duct to pull off the bpv it loosened the other side of the duct causing the leak. I'll take a look at and see what I can do.

 

So turns out it was the intake duct. It came loose on the supercharger side and was causing a major air leak. After putting that back together and installing the new BPV the mini runs like a dream again and there is no yoyo to be found.

 

Awesome. Glad you tracked it down

 

Hey Roo92,


how do you like the Detroit tuned BPV? ive been thinking about getting one here soon but I haven't found enough info from people to see if I should hold off and buy something else or if its a great mod


thanks in advance

 

I actually ended up selling my mini and have regretted it ever since. To answer your question though, I wish I would have changed to the Detroit tuned bpv much sooner. My r53 had the yo-yo really bad and when I changed to the DT bpv it completely fixed the issue. It was like a night and day difference. As for the "power gains" you do notice a small bit more power down low because the bpv is supposed to start building boost faster because of the stiffer spring iirc. If your mini has the yo-yo problem you could just replace the bpv with a new oem bpv but my reasoning for going with DT's was that it didn't cost that much more than a genuine mini bpv and I wanted the extra power that supposedly came with it.