I hope this info saves a lot of people time and money.

For as long as i can remember my car has been very sluggish from down low until over 3000rpm. Bad to the point that i didn't use the AC unless i really needed to because of how week my car felt, especially on hot days.
I've had my 03 MCS since brand new. My car is 99% stock except for a Mini Mania crank pulley that was installed to replace a degrading original heavy balancer.

I have over 80000 miles so i assumed the engine was just worn out. I never really worried about the loss of power because i didn't want to start modding the car and risk hurting an already "weakening" engine.
NOT SO!!!!!
I was at my local shop, Presicion Autowerks, and Luis said change the bypass valve, your loosing boost.
I said, ok that's got to help a little.

What i felt after driving the car with a new stock bypass valve is inexplicable with words, however if I had to explain it i would say.....
My car FREAKIN FLIES like a ***** FU.............You son of a b***h.

Not only the power, but my fuel economy went up like 40 miles for the tank, and of-course I'm flooring it whenever its safely possible now.

The difference is so dramatic that I feel everyone should know about this.
I cant imagine how many people are spending alot of money to mod their cars, yet with something so basic as a bypass valve, leaking just a little, its almost entirely negating the natural power of the engine.

I am here by obligating everyone that reads this post to go and have their bypass valves checked or replaced for your own good.
Don't do another mod unless you are absolutely sure you are not loosing boost from your bypass valve.
The valve i had installed is a OEM MINI valve. Nothing else.
I hope to hear some good results from others soon.
Safe Motoring.

 

BPV FTMFW!

 

drfubar, To bad you missed out on all that fun up until now. My 03 has 89,200 and just 2,000 miles ago I replaced the original BPV because it failed. I could tell it was going south because the throttle responce was dropping off. My vacuum / boost gauge confirmed it so I ordered one from Classic, a vendor on this site.
A vacuum / boost gauge is an essential item on a supercharged MINI.

 

Right, now I know. I'm sure there are a lot of people that aren't as "mechanically knowledgeable", and are unaware how essential the BPV is.
After having my car's BPV replaced, for me the difference is almost the equivalent of not having a super charger.

I really want to stress that it made a huge difference for my car.

 

good stuff. I remember pulling my BPV off and doing an adjustment to the little butterfly valve as some light was shining through. How did your BPV go bad?

 

Compared to the new BPV which required a whole lotta pressure to actuate the butterfly, the old BPV was really easy to actuate with my hand.
Also when you would look at the old BPV still installed in the engine, you could clearly see that the "arm" would not rest at the stop.

It's pretty clear that something wore out inside. I've also read that the early BPVs were kind of weak compared to the ones produced later on. I know I've been losing power for a long time.

 

Went with the Detroit Tuned helped ALOOOOOTTT

 

Despite my different mechanics saying it would not make much difference on a 05-06, I think the Detroit Tuned BPV would make a decent improvement.
For a 02-04 its a must DTBPV

 

My 2006 BPV started yo-yoing after about 40,000 miles. So the newer ones eventually crap out also.

MCS + bad BPV = MC

 

hahaha, I thought the same thing. With a bad BPV, it's like there is no supercharger in your engine. It's THAT important.

BTW, Can anybody recommend a boost gauge that doesn't require a mechanic to install ?

 

Easiest solution is to use an OBD-II gauge to display boost (and other things if you like). Just plug into your OBD-II port and done.

Scangauge II is most common and cost effective - but doesn't look like a gauge
http://scangauge.com/
PLX Multi-Gauge with OBD-II is awesome but expensive.
http://www.plxdevices.com/multigauges.html

But lots of people install their own "normal" boost gauges - it's not that hard

 

Scangauge is exactly what I need. Thanks!

 

im happy i came across this thread. my car does feel sluggish until the end of 2nd gear. i've been driving manual for about a year now so i wasnt sure if maybe i was shifting at the wrong times. i want to replace this, i have 60k miles on my 02, so even if this isnt the problem i think it'd be worth it. i have a few questions though.
i saw the DTBPV was about 125$... how much is the OEM one?
is it easy to install?
does anything else need to be replaced when you replace the bpv?
would the DTBPV put anymore strain on the engine and/or require tuning?

im new to all the car stuff. thanks!

 

The OEM is about $85. My mechanic changed it in an hour, however he is a MINI specialist.

I asked him about the Detroit Tuned too, but he said the new OEM BPVs are very tight and dont have the decrease in fuel economy that the DTBPV is said to have.
When the Detroit Tuned came out, they were intended to help fix the yo-yo problem that early R53 ecu software had. Since that's not an issue anymore, I just went with his recommendation and got OEM. I don't know if there is any other purpose for the DTBPV.

Nothing else needs to be replaced. The new BPV will assure you that you're getting all the boost from your supercharger.

 

thanks for the quick response!

 

on my 03 MCS, felt sluggish when i first started driving it also, been driving it for about 6 months now. it was also my first manual car, so i just figured i didnt know how to drive a manual all that well. then i got the hang of it and the car felt really slow, for 163hp, just didnt make sense. found out my BPV spring broke so i switched to the DT BPV, and extremely big difference. now i feel like my car is S/C. its a mod i highly recommend, $200 for part and install, and its amazing the difference it makes. Soon to come with an intake, exhaust, and S/C pulley, so the fun is just starting for me!

 

So, If I have boost guage already, it will clearly show on that if there is anything wrong with my BPV, right?

 

Yep. With a 15% pulley, you should be able to make 14-15psi boost. if the BPV is broken an always open, you'll make almost NO boost. If it's not closing all the way, you'll make partial boost, but won't get close to 15psi.

If the spring is just weak, you'll have to get to high RPMs/load before boost really kicks in, and you'll be unable to hold the boost steady around 7-8psi - it will "yo-yo" up and down as the valve oscillates.

 

i swapped my BPV out when a friend of mine bought a DT BPV for me....i bolted that sucker up(after skinning both of my knuckles and taking extra precaution not to break the plastic tube mounts....it made a huge difference i blipped the throttle and it responded better than before...BPV's are gonna start becoming a recurring mod now that the miles are building on our minis

 

Is there an easy way to measure boost if you don't have a boost gauge or scan gauge? Are there any inexpensive tools out there that can read the boost?

 

cheapo boost gauges are probably the least expensive thing - but require plumbing into the vac lines. Easiest thing is to find someone near you (in a club?) with a ScanGauge or similar OBD-II gauge.

 

Check out Rev, a pretty neat Iphone app. It seems to be a much better justification for $150 than a Scangauge.

http://www.autoblog.com/2009/11/06/s...ata-logging-w/

Here is a bunch of others.

http://images.google.com/imgres?imgu...mzA6PQNMG4_egF

 

I like Rev... but also like to use my iPhone for other things. The "always there, always on" nature of the ScanGauge is why I prefer it - but it's definitely not as pretty or cool as Rev.

 

Are these electronic devices reliable for showing boost? I assume they do it by some calculation on different fuel / air parameters.

 

Much more reliable than most mechanical boost gauges - they display the Manifold Absolute Pressure which is measured directly by the MINI's TMAP sensor and reported by the ECU on the OBD-II bus. Since this value is an absolute pressure (relative to a vacuum), programming in the ScanGauge, Rev, or other device just subtracts an estimate of atmospheric pressure from it to get boost.