Anyone thought of a tunable bypass valve that is either electrically driven or has replaceable springs for different types of driving? I would honestly be very interested in an electrically driven valve that can be tuned for different throttle angles.

I just bought a used bypass valve to take a look at and see if something can be designed to convert or replace the unit with that will provide the desired results. I am looking for increased fuel economy without overall loss of power. Of course loss of power at cruise is expected with the valve open but that is also what I am trying to do to drop the fuel pulse widths. I have ALTA 15% underdrive pulley (which I love!) but have lost a little fuel economy which I expected but am looking for a way to get back and maybe increase the efficiency.

ALTA and other tuners, this is a chance for a new product!

I drive long distances (100 mile trips twice a week) and would like to get near cooper gas mileage with my '06 S and still be able to switch back to beast mode for screwing around. I am a college student who wishes he had the fuel economy of a cooper and the go power of an S all in one (but cant afford 2 cars or to upgrade to the 07+ S model) So my hunt begins to squeeze every bit of fuel economy out of my S without sacrificing my ability to make it truly an S again.

While a supercharger upgrade would be awesome, no twin screw type manufacturers make a charger that is small enough for the MINI or are stupidly pricey. So I want a better way to bypass the supercharger.

Anyone interested? Thoughts opinions?

Thank you all

 

 

You could actually achieve this using the OEM (or DT) bypass valve, and just control how much vacuum it receives. Maintaining the OEM vacuum source will yield OEM behavior. Providing high vacuum all the time will keep the valve open all the time - more cooper-like performance. Providing lower vacuum will yield a valve that is closed much of the time - under boost more of the time. Turning off vacuum will yield an always-closed valve (poor economy, maximum boost all the time).

Various ways you could rig this with alternate vacuum sources, manual valves, solenoids, whatever floats your boat... I'm not aware of anyone who has tried it... but it's a cool concept...

Some of these conditions might throw a code.

 

That is tons of help! I never thought about using a solenoid to switch it! great idea! wouldnt be hard to do either! 3 position switch. closed (pressurized) normal (free flowing) and open (vacuum applied) I am curious what the parameters are for setting the codes. Anyone care to chime in? I do not have a scanner yet but am looking into getting one in the near future. I would tune it myself if I had the software but obviously dont...

 

Not sure what you're asking regarding "setting codes"...

In general, if the car senses that it's making significantly less boost than it expects under a given load and RPM and throttle opening, it can throw a corresponding code. Won't hurt anything... but you'll have to clear the code to get rid of the service engine soon light.

You don't have to pressurize the BPV to close it. Just open it to atmospheric pressure. It will only open under vacuum.

Tuning MINIs is non-trivial compared to many other cars.

 

I have noticed the ease of tuning from the readings on here. Quite a nice feature. I am really curious what the threshold of the sensor data is that will trigger the derate strategy. I am used to this on Ford Diesels. We have specific numbers that will trigger certain codes. I am looking for these on the MINI. That way I can keep it within those numbers so that tuning is not needed.

The biggest time I notice the loss of fuel economy is hill climbs. The engine makes more than enough power with a partial boost but with my underdrive pulley the boost comes in so soon that it is almost impossible to stay out of it. If I can partially open the bypass valve to create a controlled boost leak then hopefully I can increase the economy tremendously! also no more yoyo you know?

 

How is tuning a MINI non trivial... I fail to see how it is different from any other SC I4, the same rules apply...

I think the only people who really know the parameters are BMW and people who have the software to read the ECU, and in the later case maybe just through trial and error.

You might have to experiment a bit. A 3 way valve tied into the line would serve as a way to close it whenever you want. Of course because vacuum goes away when you add throttle opening whenever you want is trickier.

 

Here is my attempt at using a needle valve to control the rate of closing of the BPV. I am using the vacuum gain system (VGS) routing of vac lines. The set-up is still on my car, but I leave the valve open all the time.

https://www.northamericanmotoring.co...g-the-vgs.html

 

Absolutely genius! That is what I was looking for! I am thinking about an electronically adjustable unit but for all intensive purposes I will likely experiment with a manual valve first. That is awesome! I have not tried the VGS idea yet however have pondered it. With your needle valve idea I may likely be trying it though. Thank you inimmini!

May I ask, you said you can close the valve to keep the vacuum in and the boost at zero; at what point, typically, does the check engine light set when this is done? Can you more or less drive around with light throttle and it will stay off or will it throw even at light throttle inputs with no boost? I will likely be trying this this weekend but figured Id try and get a heads up. Thanks

 

To tell you the truth, I only drove a few minutes with the valve fully closed (zero boost is not much fun). But, no CEL in that time period. I really don't think it will throw a CEL with the valve closed because there is no loss of vacuum (or boost) in that situation.

 

inimmini this setup is awesome! I have a very small leak releasing the vacuum when the valve is shut but will be trying a few things. I also went to the hobby store and found that i can make a remotely adjustable valve system for about $30 give or take. I will update this with my findings as things progress.

 

The VGS mod mainly serves two purposes. Primarily, it is an alternative to those that have the "yo-yo" effect. I never really had it. I chose to use the mod because I like the instant-on boost effect when I floor it. There is no lag in the valve only being partly open or closed. This does require some getting used to (i.e. relearn your driving style).

The 1.6L engine in the MCS is fairly efficient as it stands. If you are not in boost, you're not going to get any more efficient. Even under low boost conditions, the supercharger adds to efficiency by creating a more complete air/fuel charge in the cylinders (i.e. volumetric efficiency easily reaches 100% and higher, while a naturally aspirated engine typically only reaches about 80%).

As for climbing hills, in my experience, if I am driving under 55 MPH, it's efficient to just downshift to 5th or 4th gear. This does increase the RPMs, but boost is not as high, and this does cut down on fuel usage. Above 55 MPH, the boost level is not affected as much by downshifting.

In lots of stop-and-go traffic, you might get 26-28 MPG. With a combination of stop-and-go and highway driving, you can get 28-30 MPG. All highway driving should be no less than 32 MPG. Drafting, driving above 75 MPH, coming under boost conditions more often, and living in a hilly or mountainous area will have additional impacts.

Sad to say, there really is no in-between. If you want power, keep your Cooper S. If you want fuel economy, get a regular Cooper.

 

I am afraid to say that my testing has already shown vast improvements by sticking open the bypass valve. The problem as you stated is using the throttle. With the current setup, the instant vacuum goes away the valve closes and boost comes on strong. Boost = more air which requires more fuel. The extra boost is not needed during cruising.

You are correct, the engine is very efficient... on its own. With the supercharger added and pumping air in at a consistent rate every time the valve closes, it becomes far less efficient. While a turbo works in a similar way, the big difference is a turbo is much more efficient than a roots type supercharger, like the one on the mini, at producing boost. This allows the turbo cars to consistently get much better mileage. If the BPV could be electronically controlled to match the throttle angle and input, the supercharged engine would likely be equally as efficient. Once again, the problem lies in the BPV.

What I have discovered is, (and I am likely not the first) that if the BPV is opened, the engine will consume much less air which results in much less fuel under light throttle conditions allowing the hills and imperfections in the road to not require as much fuel to navigate over.

What I am going to do is create a way to remotely open the BPV from inside the car. By combining this with the fun of the VGS, there will be a dual benefit to the system. Almost like the sport button on the current MINIs. Once I have everything figured out and have some consistent data (like I said I have just figured it out and already noticed a vast improvement but have not tested very long) I will share how to make this simple contraption in conjunction with the brilliant VGS.

The whole purpose of this endeavor is to allow the R53 MINI owners to enjoy the benefits of natural aspiration (MPG) along with the smile invoking sound and boost of the supercharger. I think I will call it "Cooper mode"

 

If I am not mistaken, a needle valve will just slow down the vacuum, but it will reach the same pressure eventually. You need either some sort of pressure regulator, or just close it. It may have the effect you want for x amount of time, but it is basically just closed so much you might as well close all the way. You may be able to just delay the opening to a point where you like it though.

A faucet turned to a slow stream will still fill a balloon and burst it, just more slowly.

 

[quote=HRM;3138849]If I am not mistaken, a needle valve will just slow down the vacuum, but it will reach the same pressure eventually. quote]

Right, that was my intention in playing around with the valve. Just to slow the closing & opening response a bit. As others have said, the VGS gives abrupt transitions.

 

I agree with the efficiency of a turbo. It's the best power adder that does not rob the engine of horse power.

If you are really going to pursue an adjustable BPV, I tend to believe most MINI drivers won't want to do it manually. There are going to be certain driving conditions that will make you want to change the "mode" at a point you won't be able to respond quick enough, similar to fumbling with a cell phone. Having said that, you will need a separate electrical actuator that is tied into the MAP sensors. It's open/closed position will have to be graphed into the ECU based on how quickly the driver presses the accelerator. This can require a complete reprogramming of the ECU, which is most likely only possible by BMW engineers.

I found this thread. It might help shed some light on the topic: http://www.eng-tips.com/viewthread.c...=233418&page=1.

 

Great information. Many good points. I do plan to eventually capitalize on all of them. As of right now I am working with a concept to provide basic adjustability to the bypass valve operation. The goal is to be able to remotely control the bypass valve for cruising conditions. Eventually I would like to create a computer/circuit controlled bypass valve.

Currently I have discovered that using a one way check valve in the vacuum line to the bypass valve will keep it fully open all the time. The main point of the one way check valve is to allow a continuous vacuum to be pulled on the valve despite some inevitable bleed-off. This is ideal for cruise conditions. The trouble with it is the valve is always open bypassing the supercharger. So using inimmini's idea to put a valve in the line for adjustability, I put the valve in parallel with the one way check valve so that when the valve is closed, a continuous vacuum source will pull the valve open. Then the valve can be opened to adjust the vacuum when not in cruise. This will then be remotely adjustable using a small electric motor and gear set which I will begin developing soon and put a rocker switch inside the cabin to adjust the valve. This will be a simple do it yourself project and possibly something that could be packaged and sold if people show enough interest.

The eventual goal will be to create a completely servo actuated bypass valve using the signal from the accelerator pedal position sensor to control it. This could then be taken a number of ways. For the average user, I could make multiple adjustments for different driving styles that would rely on the base computer program to compensate for the changes.

For the more advanced level, I would like to have the vehicle tuned to specific bypass functions. This may involve multiple maps or make one very large map. This will take a lot of R&D work. Like I have stated before, this is the eventual goal and may be months away depending on my funds for R&D.

As I said previously, for now I am just creating a way to make a cruise mode for maximum MPGs with the minimum modifications to the car.

I have the whole concept laid out with goals for the final products as well as the R&D that needs to be completed to make this feasible. I am not looking to make any money from this whole project. My goal is to create a system that can allow the R53 MINIs to get similar (or better) mileage than the turbo cars while keeping the wine and making it cost effective.

I greatly appreciate all input on the idea as the more troubles that can be brought to light now, the more I can anticipate in the final design. Thanks

 

any follow up reporting since some time has passed?
Did you do further R&D>?
were your ideas feasible and in the long run are your goas the same and are you still persevering this?

 

One of our local club guys, Mugami, and I talked briefly about this topic a couple of weeks ago. If memory serves, he's actually done this mod before. You might want to send him a PM to find out more details. Also mention this thread so he can comment.