Detroit Tuned Bypass Valve

Detroit Tuned Bypass Valve

(55 reviews) Write a Review
4.00 LBS
$9.99 (Fixed Shipping Cost)

The Detroit Tuned Bypass Valve is a re-worked new OEM valve that is modified by Detroit Tuned to eliminate the "Yo-Yo" in the MINI Cooper S's, the yo-yo was more prevalent for the early 2002-2004 cars but could happen in any of the years. What is the "Yo-Yo" effect? It's the opening and closing of the valve around 2500 rpm's so that it feels like your stepping on and off the gas, but you're not. So we added a stronger spring to overcome the vacuum condition that it sees so that it will not open as soon or as much.  Our BPV closes at 6" of vacuum, as opposed to the factory value of 0" of vacuum. MINI tired to fix the problem in the 2005-2006 cars with a ECU tweak but it never really worked correctly for a lot of cars. This was the main reason our BPV was created, but there are a lot of benefits, read on!

The DT BPV uses a stiffer return spring, resulting in quicker boost generation, and thus quicker throttle response and transitions. Most cars see about 1psi total more boost @ redline. The butterfly assembly is also adjusted as much as possible to close fully, allowing for maximum boost. This is done by centering of the butterfly door and adjustment of the set screw that sets the openness of the butterfly. Perfect for the aggressive driver or racer. It is possible to see a very minor loss in fuel economy, but you will see a great improvement in throttle resolution and smoothness.

Full how-to instructions (below) and all necessary hardware is included. Easy to install in about an hour. No core charge so there is no need to return your old valve. This part only fits the gen 1 2002-2006/7 Cooper S with the Tritech motor.

Instructions Download


55 Reviews

  • 5

    Posted by CHARLES DUCKWORTH on 9th Aug 2019


  • 5
    2006 mini by pass valve

    Posted by Frank Rufano on 22nd May 2019

    After about a week of daily driving noticed a big difference in performance,and more importantly no EML or engine lights on,goes yo show you u can't go cheap with mini parts,highly reccomend.

  • 4
    Pain in the ass

    Posted by Tommy on 15th May 2019

    The directions are good, but the bypass valve hose on my 05 was hard as a rock. That made it very difficult to get the supercharger intake off. Go ahead and order a new hose with this upgrade. You will take off the inter cooler, reveal the spark plugs, access the fuel injectors, and mess with the intake tube for the air intake, so consider pairing this process with upgrades on any of the above.

  • 5
    Detroit Tuned BPV

    Posted by Michael Rolland on 29th Apr 2019

    Very good purchase make sure you have no vacuum leaks but after that was solved I definitely noticed a better throttle response. Feels like the car woke up feels like she pulls a bit harder! Did notice a little less mpg but very little. Love it! Highly recommend if you have an upgraded SC pulley and the few other bolt ons! Yo-yo is gone!

  • 5
    Works great

    Posted by Nick sampson on 8th Apr 2019

    I've got a 2006 mini cooper s jcw that had a bad "yo yo" effect and boost loss. Buying this bypass valve fixed the issue and restored the lost boost I had.

  • 5
    Cooper S Bypass Valve

    Posted by Ed on 16th Sep 2018

    Beautiful piece of hardware. I will be honest, I noticed (don't know how I missed it the first time I looked) that my old one only had its valve linkage stuck, so I fixed it without having to remove it. But I am keeping this one on my shelf for the next time it fails. This bypass valve arrived quickly, and the finish and construction is "first rate." Also, when you do the math, it is only a few dollars more than one from a salvage yard and this one is reworked and new. Thank you and will be buying from you again.

  • 5

    Posted by KJ ALLARD on 9th Aug 2018


  • 5
    Does its job and then some!

    Posted by Eric on 16th Jun 2018

    I installed this on my 05 Dinan prepped MINI and immediately noticed a difference and the difference was good. My factory valve was still operable when I swapped to Detroit Tuned valve so the differences I noticed aren’t compounded by going from a busted valve to an awesome valve.

    Before installing the new valve I did take the time to examine both side by side and I can say that the Detroit Tuned description is very accurate. Holding both up I could easily see daylight around the butterfly on the factory valve, a lot of it. Just centering the butterfly wouldn’t have made much difference as the gaps still would have been there. Not only Detroit Tuned valve butterfly shut tight, but it seals very well. I tried and couldn’t hardly suck any air through it. The second very noticeable difference is the spring used in each. The factory spring was nothing to write home about. The Detroit Tuned valve is MUCH more stiff.

    I have been running the car for months now with the new valve and here are my observations and results. I don’t see a boost pressure change when I was running out the gears to redline between the two. Where I do see the difference is if I’m just cruising and suddenly hit the throttle, more boost is right there quicker than the factory valve allowed. I really notice it coming out of corners or performing a nice MINI style lane change. I read where others have said that fuel mileage went down after install and my calculations show that is was by about 0.5-0.75 MPG. I find that the temperature affects gas mileage more and I can still hit 32 MPG in the summer like I could with the factory valve so it isn’t enough of a change for me to notice day to day. Besides if gas mileage is that important to you it’s time to sell your MCS and get a Prius.

    In short, the Detroit Tuned bypass valve is way worth the price and an investment I wish I would have made sooner.

  • 5
    Great Product

    Posted by Jonathan Perkins on 16th Mar 2018

    I have 134,000 miles on my 06 MCS and I have been having issues with the "yo-yo" effect while driving, along with the inconsistent throttle response. The spring on my old BPV had absolutely no resistance when I checked it, especially when compared to Detroit Tuned BPV. My throttle response is back and the car doesn't have the annoying "yo-yo" crap like before, Thanks Detroit Tuned for a quality product.