I've been considering the Detroit Tuned Bypass Valve.
What's the difference between the DT Bypass Valve and the Stock Bypass Valve?
Is it just the heavier spring? Or are there some other differences?

 

Heavier spring and the valve is adjusted to fully close. The stock BPV does not fully close causing a loss in boost. It's well worth the money.

 

Some valves are misaligned from the factory but not all. There are differing opinions on whether to replace this as a preventative measure or wait till something goes wrong. Lots of folks have no problems with the stock one.

 

I've been having a mild yo-yo for a while now.
Then since a couple of weeks ago when I accelerate hard and hit the higher rpms the car will abruptly drop to low rpm and will not allow me to increase speed over approximately 5mph or so.
I can switch the car off and back on and drive at somewhat normal speeds as long as I don't push it hard into the higher rpms.
Check engine light is on and acceleration is not what it should be.
I am getting an error code P1688

 

I believe that code has to do with the throttle. It may be a BV problem or a boost leak.

 

I want to check for air leaks before I order the DT BV but I'm not sure of all of the locations to check.
I have been trying to find some pictures or a really clear explanation of where to find all of the hose connections.

I'll probably replace the bypass valve anyway.

 

mostly all push in hose ends . so you could use propane or starter fluid to check gaskets and hose ends . if rpms change from the leak pulling in fuel then there's your leak . see if bpv is in fact not stuck open . there's a black rod actuated by the diaphram . just see if it slides back and forth . listen for sucking sound from diaphram . kinda doubt it's stuck open as usually they stick closed and you get really rough idle .that code is throttle says electronic throttle control monitor level 2/3 mass air flow calculation . so either too much air or not enough ?

 

just a thought but are you overboosting? nm that would be manifold pressure . so your air is def off . dont forget to clean the throttle body well .

 

I just replaced mine with a stock valve. I did adjust it to full closed and what a difference from the old one. Never had a yo-yo but mine would for a lack of words hold boost. Now everything is A ok

 

I've seen the install instructions from Detroit Tuned and it looks like something I could do myself.

I've also read that it could be a MAP sensor.

I'd like to try some of the things herbie said but I don't know how to do that stuff without some detailed instructions and pictures.

 

you can get propane from any home depot etc. ask for the tip too and striker to light it . case you wanna melt some heat shrink some day. anyhow just point the tip (not lit) at all the gasket surfaces with the propane cracked open to where you can hear it . this is with car running. if you get a noticeable change in rpm's then look there for your leak . map sensor would've put up a different code i think . some guys here are pushing alot of boost and can tell you. do a search on over boost. dont think that's your issue . as far as the dtbpv ; i put mine back on due to my oem crapping out and i can say the boost is abrupt but much better so go for it .

 

Thanks for the tip.
I emailed DT about my problem but I'm still waiting for a reply.
Sounds like I might as well get it though.
Is there any discount through NAM?

 

Just a thought, but you might want to check the vacuum hose on the by-pass valve to see if it is still connected. Your car will run really bad if its not. The by-pass valve is just to the left of the throttle valve, betweeen the two manifolds. The vacuum hose connects to the barb on the left side of the valve. (left is as your looking at your engine from the front) The other end of the hose could also be pulled off the other end. under the manifold just to the left of the intercooler.

Good Luck

P.S. I've used the Detroit Tuned By-pass Valve for a couple of years. It makes a nice boost to the mid-range but may also effect your gas mileage by one or two Mpg.

 

"I just replaced mine with a stock valve. I did adjust it to full closed and what a difference from the old one. Never had a yo-yo but mine would for a lack of words hold boost. Now everything is A ok"

How did you adjust it?

 

How did you adjust it?

It has a set screw that controls how far it can close- Pretty easy adjustment

 

also the two screws holding the butterfly on can be loosened to allow adjustment . just look to eliminate daylight . use locktight to snug them back up /.

 

I'm planning to order and install the DT bypass valve but my wife was in a fairly bad accident in my niece's Honda so I haven't really had any time for the MINI since my last post.

I also received a pm from timmyz1963 that he had the exact same symptoms from a Crank Pulley gone bad.
Here is his topic on that: https://www.northamericanmotoring.co...-gone-bad.html

I suppose that it is worth checking the crank pulley.
But since I was already having the yo-yo for some time before this happened I'm betting on the bypass valve.

 

I am either going crazy, just imagining things or fixed something I am unaware of.

After I changed my radiator fluid (using a shopvac to suction everything out and then refilling with distilled H2o and vacuuming it out again --did this 3 times), I have not felt any hesitation or jerkyness @3000rpm/70mph.

I noticed some tan colored residue on the inside wall of my coolant tank while I cleaned it out though.

It usually happened (and it was very prominent - - so prominent my girlfriend commented on it) while driving an incline and now.....it doesn't.

Like I said....I am either going crazy, just imagining things or fixed something I am unaware of.

 

I finally got the DT bypass valve installed.
While I had everything apart I also cleaned my intercooler with acetone and my throttle body with valvoline throttle body cleaner and a microfiber cloth.
All of my problems with the engine seem to be fixed and I seem to have a bit more power than before. At least it feels that way to me.
DT bypass valve is a great product and highly recommended.

 

The DT BPV works on Turbos or Superchargers? Does it decrease MPG?

 

SC cars only.

Thus the 1st gen thread.........

 

Sorry to dig up an old thread........but yes, when I stalled my DT BPV I saw a loss of around 1-2mpg. They even tell you that on their website. The spring in is is stiffer, so it comes onto boost sooner. So at part throttle where you may not have been into the boost with the stock BPV, you now may have a few pounds of boost.....using more fuel.

It fixed my yo-to problem, so that's good. I wish someone made an adjustable BPV that you could soften up the spring in for better MPG. Either way, at WOT you are going to get full boost.....the spring just determines how soon it comes on.

 

It is my understanding that the DT Bypass valve was devised to fix the yo-yo problem. When I asked Chad if I should install one on my 06 he told me he wouldn't bother.

 

I had problems with my stock BPV....that's the only reason I put in a DT BPV. If I had to do it again, I would probably just install a stock BPV.....I didn't really have a yo-yo problem before. The DT DBV works great, but I don't like that it eat up 1-2 MPG

 

Just the advice I was looking for. My '06 R52 Yo-yo's a bit after slowing from Hwy speed and then speeding back up under medium throttle. Then smooths out. Otherwise driveability is good overall with good WOT power. I have the DT unit, but am not sure whether the downside is worth the possible benefit. RMW dyno-tuned at about 200 WHP (est 225 crank HP) with only external mods and cat-back exhaust - no engine or injector work. Everything is stock otherwise.

Talked to Chad at DT who said to go ahead and install, but I am afraid of that stiffer spring. Chad said not that much stiffer and won't be a problem. Some tuners, including Jan RMW aren't recommending this, or are just neutral on the issue.

Your opinion?

Thanks.