Ford Focus ST Forum banner

121 - 135 of 135 Posts

·
Registered
Joined
·
3,201 Posts
I think the stock bypass valve on my car was defective or something. I notice the car holding boost for longer with the mountune valve and it peaks higher than it did on the stock valve. I know the gauge isn't terribly accurate but when I noticed it only going to around halfway with stock vs 3/4 with the mountune valve, something was up.
 

·
Registered
Joined
·
3,476 Posts
I think the stock bypass valve on my car was defective or something. I notice the car holding boost for longer with the mountune valve and it peaks higher than it did on the stock valve. I know the gauge isn't terribly accurate but when I noticed it only going to around halfway with stock vs 3/4 with the mountune valve, something was up.
Do you by chance have a datalog before and after?

I understand the Mountune part is a direct replacement, but it may still perform slightly different than OEM. A lot of people say their stock BPV is faulty, but I have not once seen a picture or datalog of an actual faulty unit.

http://www.focusst.org/forum/focus-...ention-focus-st-bypass-valve-information.html
 

·
Registered
Joined
·
3,201 Posts
Do you by chance have a datalog before and after?

I understand the Mountune part is a direct replacement, but it may still perform slightly different than OEM. A lot of people say their stock BPV is faulty, but I have not once seen a picture or datalog of an actual faulty unit.

http://www.focusst.org/forum/focus-...ention-focus-st-bypass-valve-information.html
I don't have a datalog, unfortunately. Just going by what I normally see on my car. I could have the pedal to the floor and maybe see it creep over the 1/2 mark on the boost gauge once in a while. 3/4 is a regular occurrence now, and it holds it for longer. I don't really feel any difference in the butt dyno either. Just thought it was interesting to see, but an actual datalog could confirm or deny - the rubber on the diaphragm seemed very flimsy, and it fell apart when I took it out so I wouldn't be surprised if there was a boost leak.
 

·
Registered
Joined
·
2,085 Posts
I don't have a datalog, unfortunately. Just going by what I normally see on my car. I could have the pedal to the floor and maybe see it creep over the 1/2 mark on the boost gauge once in a while. 3/4 is a regular occurrence now, and it holds it for longer. I don't really feel any difference in the butt dyno either. Just thought it was interesting to see, but an actual datalog could confirm or deny - the rubber on the diaphragm seemed very flimsy, and it fell apart when I took it out so I wouldn't be surprised if there was a boost leak.
The stocker isn't a single piece like the mountune. It does seem pretty cheap though.



If I'm tappin I'm probably lifting.
 

·
Registered
Joined
·
133 Posts
Just installed mine about an hour ago. Gave here a few revs with some built up boost and I noticed a bit of a flutter when coming off boost... everything seemed to be tight, line that connects to it is damn near flush with the unit and its at the preferred 4oclock position..
 

·
Registered
Joined
·
561 Posts
Just installed mine about an hour ago. Gave here a few revs with some built up boost and I noticed a bit of a flutter when coming off boost... everything seemed to be tight, line that connects to it is damn near flush with the unit and its at the preferred 4oclock position..
I think it's normal. You just didn't hear it before??? Same piece same result. Search the forum it's not just this BPV all of them react this way. No problems.
 

·
Registered
Joined
·
133 Posts
I think it's normal. You just didn't hear it before??? Same piece same result. Search the forum it's not just this BPV all of them react this way. No problems.
Idk, im a little weary. I thought I might have heard some before and read that under "normal to light" driving it would flutter and that under full load it was an issue, and never noticed any while I was at 100%.

I also noticed that the motor sounds different today (and I did put about 30 miles on the engine last night after words) and that the car was holding onto rpm's this morning under a cold start. While driving I've also noticed that the boost gauge is showing less boost (all be it that its not that accurate) and that last night it was less, but the car was pulling just as hard (if not maybe harder). It is very cold here in MN and I know that these electronically controlled boost cars run less boost/same power sometimes when the temp drops. My cobalt SS/TC Direct Injection motor did that as well
 

·
Registered
Joined
·
797 Posts
I have the Mountune Recir Valve, there is not change in sound.

You buy it because it's a more durable unit when you're pushing more boost.
 

·
Registered
Joined
·
561 Posts
Pull the passenger front tire and get back in there. Reinstall and double check all hoses. I too was a little freaked out by the fluttering noise from venting at partial boost/throttle but there were no problems holding boost or noise at WOT. @work0039
 

·
Registered
Joined
·
133 Posts
Pull the passenger front tire and get back in there. Reinstall and double check all hoses. I too was a little freaked out by the fluttering noise from venting at partial boost/throttle but there were no problems holding boost or noise at WOT. @work0039
After some looking around I guess its normal with these things. Tunes eliminate that, however i have the FRPP recalibration. So lets just let it rip i suppose.
 

·
Registered
Joined
·
62 Posts
Only thought would be maybe it doesn't release under lighter boost since its made to hold up to high boost applications. The valve staying closed under very low boost (1/2%) should be fine. Could also be hearing the waste gate if you have an open filter on your intake. A more tech savvy car person can clarify any confusion I'm having.
 

·
Registered
Joined
·
3,265 Posts
Do we have the specs of how much PSI the Mountune Recirc Valve can legitimately handle?
 

·
Registered
Joined
·
1 Posts
We are glad you like and thanks for posting the photos.
We designed this part originally for the Focus RS and RS 500. It was part of our MR375 package so it will handle significant flow.
Fortunately, the C346ST uses the BorgWarner turbo with mechanical recirculation valve so this part was compatible.
I will talk to engineering and see if there are any specific ratings.

As a side note, our new lower IC pipe upgrade helps turbo response and is an easy install once you are underneath the car.
We will be adding a kit with favorable pricing to the website that includes the pipe and bypass valve later today.

Lower Intercooler Pipe Upgrade, Focus St 2013-18 Intercooler Hard Pipe Upgrade Focus St


Ken.
We are glad you like and thanks for posting the photos.
We designed this part originally for the Focus RS and RS 500. It was part of our MR375 package so it will handle significant flow.
Fortunately, the C346ST uses the BorgWarner turbo with mechanical recirculation valve so this part was compatible.
I will talk to engineering and see if there are any specific ratings.

As a side note, our new lower IC pipe upgrade helps turbo response and is an easy install once you are underneath the car.
We will be adding a kit with favorable pricing to the website that includes the pipe and bypass valve later today.

Lower Intercooler Pipe Upgrade, Focus St 2013-18 Intercooler Hard Pipe Upgrade Focus St


Ken.
Hi Ken I've been told you are the guy to ask I know this has been asked many times but really confused. I'm fitting a mountune recirc valve on my st250 mk3 uk modle and I'm really confused with the orientation of the valve some are saying 7 o'clock some say 5 o'clock. And I'm not sure which can you help
 

·
Super Moderator
Joined
·
9,232 Posts
Hi Ken I've been told you are the guy to ask I know this has been asked many times but really confused. I'm fitting a mountune recirc valve on my st250 mk3 uk modle and I'm really confused with the orientation of the valve some are saying 7 o'clock some say 5 o'clock. And I'm not sure which can you help
Looks like Ken has not been active since March of 2016. According to Mountune's installation guide, 5:00 position.
 
  • Like
Reactions: rambleon84

·
Premium Member
Joined
·
2,327 Posts
Hi Ken I've been told you are the guy to ask I know this has been asked many times but really confused. I'm fitting a mountune recirc valve on my st250 mk3 uk modle and I'm really confused with the orientation of the valve some are saying 7 o'clock some say 5 o'clock. And I'm not sure which can you help
Yup 5 o’clock:

Sorry I realize this is 3 days ago on a zombie revival, but it’s here, for posterity and a belated Easter
 
121 - 135 of 135 Posts
Top