let me start off by saying- i full understand how a supercharger and an engine work, and how they work together.

i'm looking for information specific to the mini though.

does anyone have any diagrams or information regarding the mini's setup, with detailed information on things like the BPV. (which i understand plays a large part in everything)

 

for what its worth, i started reading the "yo-yo chronicles"...

i just dont have it in me to read something starting back in 2004 to figure out how the BPV works and such.

i have that little 3000rpm hiccup, and from what i've read the DTBPV will fix it.

i kinda want to know WHY this is all happening and how.

 

Here is a quick MS paint diagram I went and did. The bypass valve works on a vacuum. When the throttle is closed it is held open by the vacuum bypassing (more like re-feeding) the supercharger. When the vacuum goes a away a spring inside the valve closes it creating boost in the intake manifold. The DTBPV replaces that spring with a stronger one.

 

The short answer to "why" if you in fact are having yo-yo symptoms...the spring in your current BPV isn't strong enough to close and hold closed the butterfly in the valve. That's the theory, anyway.

As you know already, as long as the engine is running the SC is spinning...the BPV is open because there is vacuum present. When the vacuum drops(engine under load) the spring closes the valve, and boost is created.

Hook up a vacuum/boost gauge to your engine, and you will be able to see(in comparison to throttle position) where each occurs.

EDIT: nice diagram Some Guy, very accurate.

 

 

Curses... I missed this thread earlier. Although I don't have time to make a proper diagram tonight.

 

The most common BPV failure is due to a broken spring.


Three versions of the MINI BPV, the oldest on the left with the notorious thin & brittle spring, slight change in the middle, and the newest on the right.

 

K-Huevo, when were these changes made (built dates)?
And how does the "latest" compare to the Detroit Tuned valve? Thanks!

 

Sorry, I don’t have build dates. The first model was in use until at least 5/2003, the second version has different screws, same body (casting), same spring, in use during early model 2004; the latest (start date unknown, 2005 for sure) has a different body, stop limiter, and spring. The DT BPV has a much stiffer spring, all version’s butterfly plates can be adjusted by the user, the DT’s is pre-adjusted.

 

Great; thanks! That's accurate enough.

 

awesome. thank you.

awesome x2. thank you.

 

what's the deal with the BPV collection? Use it to impress the ladies?

Matt

 

I was wondering about that too.

 

on my car... I have only had the stocker that I modded myself, and now have a second one on the shelf for when this one fails... But then, I'm married and don't have to show off a huge collection of BPVs on date-night!

Matt