PT Cruiser Forum  
Advertisements
       

Go Back   PT Cruiser Forum > 2.4L Turbo Forums > Turbo Performance

PT Cruiser Forum

Advertisements
Blow off valve - Questions

 
Like Tree5Likes

Reply
 
LinkBack Thread Tools Display Modes
  #11 (permalink)  
Old 27 Mar 2017, 07:20 pm
Cool Cruiser
 
Join Date: May 2016
Posts: 263
Default Re: Blow off valve - Questions

Quote:
Originally Posted by Handy_Cruiser View Post
Re-read my description. The stock bypass valve releases the pressure into the exhaust. The Mopar BOV is a plate that redirects the released pressure in the atmosphere. That's what I said.

On the rest, I agree completely.
Handy, I don't usually get involved in right/wrong discussions, and I usually ask more questions than give answers here in the forum, but saying the "factory" system releases the pressure created by the turbo into the exhaust is incorrect. If you look at the turbo housing itself, you can see where the ports direct the released pressure directly back into the intake side of the turbo, recirculating it back into the turbo and ultimately the intake.

So, you can see how the blue plate reduces pressure, in theory could lower intake air and turbo temps, and sounds cool. Again, the factory setups obviously last many miles, and assigning a number of any kind to prove reduced wear would be difficult.
Handy_Cruiser likes this.
__________________
Reply With Quote
  #12 (permalink)  
Old 27 Mar 2017, 08:16 pm
Handy_Cruiser's Avatar
Obsessed Cruiser
 
Join Date: Oct 2013
Location: Arkansas
Posts: 8,492
Default Re: Blow off valve - Questions

Quote:
Originally Posted by GtPt05 View Post
Handy, I don't usually get involved in right/wrong discussions, and I usually ask more questions than give answers here in the forum, but saying the "factory" system releases the pressure created by the turbo into the exhaust is incorrect. If you look at the turbo housing itself, you can see where the ports direct the released pressure directly back into the intake side of the turbo, recirculating it back into the turbo and ultimately the intake.

So, you can see how the blue plate reduces pressure, in theory could lower intake air and turbo temps, and sounds cool. Again, the factory setups obviously last many miles, and assigning a number of any kind to prove reduced wear would be difficult.
Hah!

Never worry about telling me I'm wrong. Otherwise, how will I learn.

Yes, you are right and I am wrong! It DOES release pressure to the intake side of the turbo. And if that is the case, the pressure there should be lower than or equal to ambient air. Based on this, I don't see any advantage to the Mopar BOV plate unless getting rid of the warmer air does the trick as you've described. I was a big dummy on this one.

Here you can see the edge of the intake port for the bypass valve:


Here you can see the in (crescent hole) and out (round hole) for the valve itself:


And her you can see the port where the pressure is released on the intake side of the turbo:
GtPt05 likes this.
__________________

Last edited by Handy_Cruiser; 27 Mar 2017 at 08:28 pm.
Reply With Quote
  #13 (permalink)  
Old 27 Mar 2017, 09:18 pm
rob302's Avatar
Dedicated Cruiser
 
Join Date: Jul 2016
Location: Darien, IL | Forest Park, IL
Posts: 2,510
Default Re: Blow off valve - Questions

i believe the reason the turbo dumps to the intake from the factory has to do with universal compatibility of the turbo. on my FORD, the air must be reintroduced to the intake tract after the MAF sensor. if the air is vented anywhere else, it creates problems. the MAF sensor measures incoming air. if that air is measured and then not fed through the engine, the computer cannot accurately measure air to calculate fuel, making accurate tuning impossible. on the PT, it uses a MAP not a MAF, so the only benefit with the factory setup is reduced noise... again though the shorter path could (possibly) help vent pressure faster due to a shorter exit path with less piping and bends.
Reply With Quote
  #14 (permalink)  
Old 27 Mar 2017, 10:03 pm
Cool Cruiser
 
Join Date: May 2016
Posts: 263
Default Re: Blow off valve - Questions

Quote:
Originally Posted by rob302 View Post
i believe the reason the turbo dumps to the intake from the factory has to do with universal compatibility of the turbo. on my FORD, the air must be reintroduced to the intake tract after the MAF sensor. if the air is vented anywhere else, it creates problems. the MAF sensor measures incoming air. if that air is measured and then not fed through the engine, the computer cannot accurately measure air to calculate fuel, making accurate tuning impossible. on the PT, it uses a MAP not a MAF, so the only benefit with the factory setup is reduced noise... again though the shorter path could (possibly) help vent pressure faster due to a shorter exit path with less piping and bends.
I believe you are correct... And I'm guessing from your user name and the fact that you have MAF... you have a 5.0 mustang, '89 or later, or a pre '89 that was converted from speed density? I had an '87 LX 5-speed... Loved it! I'd absolutely buy another one in good shape.
rob302 likes this.
__________________
Reply With Quote
  #15 (permalink)  
Old 27 Mar 2017, 11:17 pm
Cool Cruiser
 
Join Date: May 2016
Location: Oswego, IL
Posts: 307
Default Re: Blow off valve - Questions

As for the BOV, Buy it for the noise, and keep telling yourself there is a 1HP benefit. That's how I justify my "performance" modification.
Handy_Cruiser likes this.
__________________
2004 Stage 1 GT Manual, Miles: 84k
Lowered Suspension, Sway bars, sound system W/Mopar Sub, LEDs, Debadged, Hydraulic hood struts, Hybrid BOV.

05' N/A Automatic Red PT Mileage:121k (Died summer 2017)
Reply With Quote
  #16 (permalink)  
Old 28 Mar 2017, 07:43 am
Senior Cruiser
 
Join Date: Sep 2002
Location: Just south of the Mason/Dixon line
Posts: 1,714
Default Re: Blow off valve - Questions

Quote:
Originally Posted by Handy_Cruiser View Post
Re-read my description. The stock bypass valve releases the pressure into the exhaust. The Mopar BOV is a plate that redirects the released pressure in the atmosphere. That's what I said.

On the rest, I agree completely.
I've been out of the game for some time but IIRC, the factory recirculating valve directs hot air back into the INTAKE flow not exhaust. Also IIRC, there was some concern early on about that redirected HOT air being mixed into the cool intake air.

EDIT: I should have read the entire thread first before posting
__________________
.....................................
'03 GT base w/175k and a 2 speed autostick (read: trans is shot) and powered by a hybrid MOPAR S3 with DSP untuned
1st Forward Motion E1 powered PTGT w/Psi-Fi Power pack fuel tuner back in '07
FS: '03 GT Elec Blue w/rear suicide doors or '03 auto PCM, S3 turbofold, WGA, 3.5" o2 & 3" DP - make offer

Last edited by OurPTGT; 28 Mar 2017 at 07:46 am. Reason: didn't read entire thread before posting my opinion
Reply With Quote
  #17 (permalink)  
Old 28 Mar 2017, 09:08 am
Cool Cruiser
 
Join Date: May 2016
Location: Oswego, IL
Posts: 307
Default Re: Blow off valve - Questions

As for the turbo, I thought there was a pressure relief on both sides of the turbo. One on the boosted intake that vents back into the intake to control boost pressure, and one on the exhaust side to relief back pressure.

Exhaust gases should not be relieved into the intake except in the case of EGR. The hot burnt gases are not the best thing to be venting into the intake.
__________________
2004 Stage 1 GT Manual, Miles: 84k
Lowered Suspension, Sway bars, sound system W/Mopar Sub, LEDs, Debadged, Hydraulic hood struts, Hybrid BOV.

05' N/A Automatic Red PT Mileage:121k (Died summer 2017)
Reply With Quote
  #18 (permalink)  
Old 28 Mar 2017, 10:10 am
Cool Cruiser
 
Join Date: May 2016
Posts: 263
Default Re: Blow off valve - Questions

Quote:
Originally Posted by UnitD77 View Post
As for the turbo, I thought there was a pressure relief on both sides of the turbo. One on the boosted intake that vents back into the intake to control boost pressure, and one on the exhaust side to relief back pressure.

Exhaust gases should not be relieved into the intake except in the case of EGR. The hot burnt gases are not the best thing to be venting into the intake.

On the exhaust side, you have the gate in the manifold to redirect exhaust flow. On the intake side you have the pressure relief valve that circulates the already compressed clean air back into the incoming side of the turbo, which is where the hot air comes into play. At no point does exhaust get vented into the intake. The BOV just eliminates the hot air from going through the turbo again, and ultimately into the engine.
__________________
Reply With Quote
  #19 (permalink)  
Old 28 Mar 2017, 11:09 am
Fresh Cruiser
 
Join Date: Mar 2017
Posts: 24
Default Re: Blow off valve - Questions

So...after carefully reviewing all of the input laid forth. I've made a conclusion based of the advice, experience, and opinions given.


PSSSHT PSSSHT it is.
Reply With Quote
  #20 (permalink)  
Old 28 Mar 2017, 11:15 am
Cool Cruiser
 
Join Date: May 2016
Posts: 263
Default Re: Blow off valve - Questions

Quote:
Originally Posted by Salderosa54 View Post
So...after carefully reviewing all of the input laid forth. I've made a conclusion based of the advice, experience, and opinions given.


PSSSHT PSSSHT it is.

Hahaha.... Indeed!
__________________
Reply With Quote
Reply


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
blow off valve SuperGirl Tech & Performance Forum 24 25 Apr 2013 08:57 pm
Blow off valve. Turboguy85 Turbo Performance 6 03 Feb 2012 12:49 pm
blow off valve question reaper121 General Turbo Discussions 5 21 Feb 2009 05:12 pm
what is a blow off valve careyk General PT Cruiser Discussions 3 17 Apr 2008 02:23 pm
Stock blow off valve DMW General Turbo Discussions 8 12 May 2005 07:08 pm


All times are GMT -5. The time now is 05:05 am.




Powered by vBulletin® Version 3.8.2
Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.
LinkBacks Enabled by vBSEO 3.6.0 PL2 © 2011, Crawlability, Inc.
vB.Sponsors