DUE TO LOW STOCK OF OLD UNITS I AM FORCED TO ADD A REFUNDABLE AMOUNT OF £30 TO THE LISTING SO PLEASE RETURN YOUR OLD ONES OR BUY AN OLD ONE TO SEND
The ROOSTER Bypass Valve is a re-worked OEM component that is modified to provide much crisper throttle response by eliminating the "Yo-Yo" in the MINI Cooper S's. The yo-yo was more common for the early 2002-2004 cars happens in any of the years especially as the springs are now 10 years old or more .
"Yo-Yo" effect you ask ? It's the opening and closing of the valve around 2500 rpm so that it feels like your stepping on and off the throttle pedal which you're not. So we added a new 1.6mm stainless spring to overcome the vacuum condition that it sees, so that it will not open as soon or as much. The OEM BPV spring is 1.78N/mm and we have replaced that with a 2.31N/mm up rated one. BMW tried to fix the problem in the 2005-2006 cars with a ECU tweak but it never really worked correctly for a lot of cars and like I mentioned before that's 10 years ago!
The ROOSTER BPV uses the stiffer return spring, resulting in quicker boost generation, and thus quicker throttle response Most cars will see about 1psi total more boost @ redline due to not just the spring but the following modifications carried out on reassembly. The butterfly valve is also adjusted as much as possible to close fully, allowing for maximum boost. This is done by centering of the butterfly after choosing the best fit from my supplies and adjustment of the set screw that sets the 'open' idle position of the butterfly - I either replace the idle screw or machine the cam stop to sit lower. Perfect for the driver who doesn't want to wait for the throttle to kick in or track users wanting to control the car better with the right foot - a must for fwd cars! This was done on my UK Time Attack Mini in 2010. Throttle response is KING . It is possible to see a very minor loss in fuel economy.
Easy to install in about an hour or two. This part only fits the gen 1 2002-2006/7 Cooper S with the Tritech engines not the turbo charged R56 cars and later.
Instructions included - garages charge around £50 to fit I am told
Contact me if you have any questions
This item can is used on the Mazda MX5 and the classic mini when they use the Eaton M45 supercharger