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
  #1 (permalink)  
Old 24 Mar 2017, 10:49 am
Fresh Cruiser
 
Join Date: Mar 2017
Posts: 24
Default Blow off valve - Questions

Ok So 90k GT Woodie ( Turbo Autostick )

K&N Box filter is the only modification to the vehicle thus far, I am going to continue going further from least invasive/expensive to start so I am thinking to order the mopar Blow off Valve.

A)

Is the mopar part really necessary considering this is just a piece of billet aluminum?

B) I understand the concept of a BOV and believe that it would benefit ( as insignificant as it may be) the motor/turbo. Plus I get to poof poof around in my woodie so that's a major plus . Are my basic assumptions of this true? and would be worth my time and money to install?


Also any guides on the install.
Reply With Quote
  #2 (permalink)  
Old 24 Mar 2017, 01:00 pm
Handy_Cruiser's Avatar
Obsessed Cruiser
 
Join Date: Oct 2013
Location: Arkansas
Posts: 8,509
Default Re: Blow off valve - Questions

The purpose of the BOV is to quickly release pressure when the throttle butterfly closes. This helps keep from damaging the turbocharger and also prevents pressure spikes in the tubo piping and inner cooler. The PT Cruiser already has a bypass valve on the turbocharger that releases the pressure into the exhaust.

The Mopar BOV uses this same valve but is simply a vented plate that redirects the released pressure to the outside air instead of the exhaust. The exhaust system is usually under some degree of pressure. So there will be some amount of back pressure against the pressure released by the stock bypass valve. The Mopar BOV eliminates that back pressure by venting to outside air. That's it's only advantage. It was designed to be used along with a Stage 1 PCM which increases the boost pressure that needs to be released.

I've never seen any real test information to suggest if the Mopar BOV is really needed with the PT Cruiser Stage 1 PCM or not. And no one has posted anything like this on this forum. The only claims I've found on this and other forums is that on PT's with manual transmissions, it's seems to promote a detectable quickness in engine deceleration while shifting. Other than written recommendations by Chrysler, there's nothing solid on the Mopar BOV specific to the PT that I can find. There's lots of internet-based opinions that many BOV's do very little in general. But it's easy to say something doesn't work without having any proof. And folks on internet forums tend to do this to try and look smart. I pretty well disregard that kind of thing as a form of ignorance.

It should be noted that many aftermarket BOV's are designed to release a much greater volume of air pressure at once. This may have advantages on cars running very large turbochargers. But this doesn't seem to apply to the Mopar BOV for the PT Cruiser running a stock turbocharger. Other than say it was recommended by Chrysler to be used with the Stage 1 kit, all I can say is that the Mopar BOV makes a cool "PISSS" sound and that gets folk's attention. For these reasons alone, I use one and recommend them to everyone with a turbo PT.
__________________

Last edited by Handy_Cruiser; 24 Mar 2017 at 01:11 pm.
Reply With Quote
  #3 (permalink)  
Old 24 Mar 2017, 01:38 pm
Fresh Cruiser
 
Join Date: Mar 2017
Posts: 24
Default Re: Blow off valve - Questions

I found this one on ebay for $34 shippedBP 2003-2007 Chrysler PT Cruiser GT Turbo Blue Turbo Blow Off Valve Plate MOPAR | eBay

Also considering it's a solid piece of Billet I mean. This vs $70 for the mopar do you think it would be better to just get the Mopar? I intend to do a stage one PCM upgrade after I do my timing belt/check compression and bring the car back to as solid as a state before I want to do more performance.
Reply With Quote
  #4 (permalink)  
Old 24 Mar 2017, 02:04 pm
Fk5 Fk5 is offline
Senior Cruiser
 
Join Date: Jul 2011
Location: Cloverly, MD
Posts: 1,394
Default Re: Blow off valve - Questions

Quote:
Originally Posted by Handy_Cruiser View Post
The only claims I've found on this and other forums is that on PT's with manual transmissions, it's seems to promote a detectable quickness in engine deceleration while shifting.
Can you explain this? I know it's not your claim, but I'd never heard that one. FWIW, one of our complaints has always been that the revs seem to hang up a bit when we step on the clutch. Always figured that it was the PCM.
__________________
2003 GT 5 speed
150,000 miles
Reply With Quote
  #5 (permalink)  
Old 24 Mar 2017, 02:53 pm
Handy_Cruiser's Avatar
Obsessed Cruiser
 
Join Date: Oct 2013
Location: Arkansas
Posts: 8,509
Default Re: Blow off valve - Questions

Quote:
Originally Posted by Fk5 View Post
Can you explain this? I know it's not your claim, but I'd never heard that one. FWIW, one of our complaints has always been that the revs seem to hang up a bit when we step on the clutch. Always figured that it was the PCM.
Some folks claim the RPM drop is faster between gears with the Mopar BOV. So they can grab the next gear faster when trying to get gone in a hurry. As you noted, not my claim. I grew up having to sometimes drive big trucks. Mostly with ten and thirteen-speed Road Rangers. So I now try to avoid manual transmissions when I can.
Fk5 likes this.
__________________

Last edited by Handy_Cruiser; 24 Mar 2017 at 02:55 pm.
Reply With Quote
  #6 (permalink)  
Old 24 Mar 2017, 08:15 pm
Cool Cruiser
 
Join Date: May 2016
Posts: 263
Default Re: Blow off valve - Questions

Handy's response is pretty accurate, except the fact that it releases the hot compressed air into the atmosphere instead of back into the intake system (not the exhaust). So, it does a few things... relieves pressure, stops hot air from recirculating, and sounds cool! How much damage does it reduce? That would be difficult to prove, but in theory, it is doing something right? So you can feel all warm inside knowing that, regardless of how much or little it's doing. And it sounds cool! One bolt requires a little patience to install, otherwise it's pretty straight forward. Did I mention it sounds cool??? This combined with an open cone air filter produces some cool sounds with windows down in the summer. Put it on, you'll like it.
__________________
Reply With Quote
  #7 (permalink)  
Old 27 Mar 2017, 01:59 pm
Fk5 Fk5 is offline
Senior Cruiser
 
Join Date: Jul 2011
Location: Cloverly, MD
Posts: 1,394
Default Re: Blow off valve - Questions

Quote:
Originally Posted by GtPt05 View Post
Handy's response is pretty accurate, except the fact that it releases the hot compressed air into the atmosphere instead of back into the intake system (not the exhaust). So, it does a few things... relieves pressure, stops hot air from recirculating, and sounds cool! How much damage does it reduce? That would be difficult to prove, but in theory, it is doing something right? So you can feel all warm inside knowing that, regardless of how much or little it's doing. And it sounds cool! One bolt requires a little patience to install, otherwise it's pretty straight forward. Did I mention it sounds cool??? This combined with an open cone air filter produces some cool sounds with windows down in the summer. Put it on, you'll like it.
What damage does it reduce? What pressure does it relieve? Don't these cars have BOV's? They just don't vent to atmosphere. I was just trying to figure out why an aftermarket/Mopar piece would let revs drop quicker during shifts.
__________________
2003 GT 5 speed
150,000 miles
Reply With Quote
  #8 (permalink)  
Old 27 Mar 2017, 02:29 pm
Fresh Cruiser
 
Join Date: Feb 2017
Location: Central PA
Posts: 14
Default Re: Blow off valve - Questions

Quote:
Originally Posted by Salderosa54 View Post
I found this one on ebay for $34 shippedBP 2003-2007 Chrysler PT Cruiser GT Turbo Blue Turbo Blow Off Valve Plate MOPAR | eBay

Also considering it's a solid piece of Billet I mean. This vs $70 for the mopar do you think it would be better to just get the Mopar? I intend to do a stage one PCM upgrade after I do my timing belt/check compression and bring the car back to as solid as a state before I want to do more performance.
I just installed that same BOV on mine. Pretty easy to install, 3 bolts. I put mine on with the turbo off the engine because it arrived while I was half way through a head swap. Pretty nice unit that makes a fun noise
Reply With Quote
  #9 (permalink)  
Old 27 Mar 2017, 03:06 pm
Handy_Cruiser's Avatar
Obsessed Cruiser
 
Join Date: Oct 2013
Location: Arkansas
Posts: 8,509
Default Re: Blow off valve - Questions

Quote:
Originally Posted by GtPt05 View Post
Handy's response is pretty accurate, except the fact that it releases the hot compressed air into the atmosphere instead of back into the intake system (not the exhaust). So, it does a few things... relieves pressure, stops hot air from recirculating, and sounds cool! How much damage does it reduce? That would be difficult to prove, but in theory, it is doing something right? So you can feel all warm inside knowing that, regardless of how much or little it's doing. And it sounds cool! One bolt requires a little patience to install, otherwise it's pretty straight forward. Did I mention it sounds cool??? This combined with an open cone air filter produces some cool sounds with windows down in the summer. Put it on, you'll like it.
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.
__________________
Reply With Quote
  #10 (permalink)  
Old 27 Mar 2017, 04:10 pm
rob302's Avatar
Dedicated Cruiser
 
Join Date: Jul 2016
Location: Darien, IL | Forest Park, IL
Posts: 2,515
Default Re: Blow off valve - Questions

Quote:
Originally Posted by Fk5 View Post
What damage does it reduce? What pressure does it relieve? Don't these cars have BOV's? They just don't vent to atmosphere. I was just trying to figure out why an aftermarket/Mopar piece would let revs drop quicker during shifts.
It may vent quicker due to the shorter, lower pressure path the air takes to vent. Since it vents faster, less pressurized air would squeeze through the IAC when the throttle body slams shut. Idle air valves move slow, so i think this could be plausible.

Instant idle adjustments are done with timing. I never realized how much timing is used in idle adjustment before i dove head first into tuning. I think the factory pt programming is sub par in the idle programming department. Even my NA PT had an annoyingly lethargic idle drop if the AC was on.


for reduced the reduced damage part.. picture you're flooring it winding out 3rd, making max boost.. you take your foot off the gas and the throttle closes. a build up of pressure can cause the impeller to touch the turbo housing. . suddenly all that pressure has nowhere to go but right back at the impeller. i've shimmed the impeller on my supercharger to make more boost. it used to have 0.020" clearance, i have it shimmed down to 0.008(two sheets of paper). i can imagine an impeller closing a tiny gap like that with a sudden high pressure blast, no?

Last edited by rob302; 27 Mar 2017 at 05:36 pm.
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 10:30 pm.




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