Upon the advice of the tuner that if one buys stage 5 software set at 8000 rpm along with the proper hardware, one should use it, i decide to heed his words. So...taking off from a stop other day, I wind out 2nd gear to 7500 rpm, the engine shuts out and the service engine soon light flashes on. One of those moments we don't look forward to, but i take deep breaths, maintain calm, no four letter words. I pull into a parking lot and check the OBD codes while the heart is pounding and the mind is having flashbacks of a previously blown engine. I get codes 0563 and 1688. Both have to do with aire intake and boost. I switch off the service engine soon light, and the car starts fine. Being a little cautious now, it is noticed the car is only making about 5 pounds of boost. At 1st i thought it was the AGS system, but everything appears intact and i don't hear any leaks. I ask Peter and he fervently defends the efficacy of the AGS when properly installed. In speaking with the local mini tech, he tells me the car probably need a new bypass valve. He says winding it up probably blew the valve. So i take it in and yes, the valve is blown. He shows me how the little black piece on the valve is moving back and forth and says it should be in a fixed position. Though its a warrantied part, the tech tells me its a problem and some minis may be losing power because this thing can slowly malfunction. So boost can be greatly affected, but if you don't have a boost guage, it would be hard to tell. The tech tells me that he has brought this problem to the attention of a number of tuners because he sees it as a major weakness in the car. But no one has yet to address it with an aftermarket fix... a bigger more efficient valve. Can anyone comment on this.

 

Not to be a butt head but try the big search button and check out detroit tuned on the vedor list. They have a tuned valve.

 

The Detroit Tuned valve is not a replacement for the stock one. It is a stock one with a stiffer spring that prevents the valve from opening completely. At least that's my understanding from what's been posted here and on their site. If your valve is physically broken, I don't see why the DT one would be any stronger.

 

So, is it possible to use an aftermarket valve of any type that might replace this. Like convert a vale on a turbo to use on the supercharger? Maybe the spring is the weak point and Detroit tuned fix is all that is needed. But the tech said a bigger valve would probably keep this thing from blowing under intense use and highly modded applications.

 

The BPV is probably not the weak point at 7500 rpm. My bet is that the engineers @ BMW knew that your valve train would begin to do funky things way up there, like valve float.

Unless you have your head gussied up with HD valve springs (or double valve springs maybe?) and a higher lift/duration cam, I'd stick with a 7200 rpm redline, and simply tune an OEM BPV as desribed elsewhere on this site (i.e. adjust the stop screw and center the disc inside the bore of the BPV body).

Marty

 

In this case, valve float is not the problem. This car is fitted with solid tappets. This head has been designed specifically for this. I think a valve replacement is in order. We just need a better valve.

 

You may want to plumb in a high quality bypass valve like an HKS. Also, unless you are really worried about fuel economy, you could just remove the BPV entirely and plug the lines. You'll feel engine braking more suddenly, but a BPV isn't mandatory on a vehicle where the throttle is upstream from the supercharger.

 

If the butterfly valve itself had failed, the parts would have gotten sucked into the SC or the Engine.

It sounds like what let go is the control of the bypass valve, the Diaphram which moves the valve based on vacumm or boost, or perhaps part of the linkage. Try the "ryphix" tie down and see if the car works right. Plug the "sense line" and tie the "little black thing" in the closed position.

J. D.

 

The tech said it was the diaphragm that failed. Can you explain what you mean by tying it down with ryphix?

 

There is a 30 page thread, about "the yo-yo chronicles.

Some where in there is a set of photographs of how to tie the bypass valve down. (Ryephix1) It also describes a few disadvantages to doing this.

So Ryan came out with a bypass with a stronger spring, but the original diagphram so solve that problem. (Ryephix2)

Since you already know it is a bad diagphram, you should just fix it. You cold drive the car around for a while by just tying the valve shut.

Good luck

JD