Recirculating a blow-through system? - Ford Focus Forum, Ford Focus ST Forum, Ford Focus RS Forum
Ford Focus Forum
HomeContact UsAbout UsGalleryDiscussion ForumsMarketplace


Go Back   Ford Focus Forum, Ford Focus ST Forum, Ford Focus RS Forum > Ford Focus Tech Discussions > General Forced Induction

General Forced Induction The place to chat about turbochargers, superchargers nitrous systems and custom engine fabrications.

Search This Forum | Image Search | Advanced Search    
Ford Focus Tire & Wheels FocusFanatics Merchandise

Reply
 
Thread Tools Display Modes
Old 08-16-2013, 05:06 PM   #1
svtf1417
MOAR BEWST!!!!
 
svtf1417's Avatar
 
Join Date: Aug 2008
Fan#: 58428
Location: Canton, MI
What I Drive: 2001 ZTS, 2002 SVTF Turbocharged

Posts: 1,527
FF Reputation: 6 svtf1417 Good Standing Member
Buy-Sell-Trade Rating: (6)
Recirculating a blow-through system?

Is anyone using a blow through setup, and recirculating their BOV? If I wanted to would I vent it to pre-turbo? I discovered the other day either my BOV is faulty, where my BOV is in relation to my MAF is no good, or I need to recirculate my BOV.

Backround story. Ive been having the HARDEST time getting my car to return to idle without stalling. Tom and I have been working on in for the past 2 months now. It would even stall revving it in the driveway. Anyways I noticed my BOV wasnt shutting very smoothly (brand new TiAL) so I unhooked it and plugged the vacuum line. It revved without stalling, and I could drive it around without stalling anymore.

Anyone else every experience these problems? Heres my setup




__________________
[#1417] 2002 Sonic Blue SVT Focus
Born on June 25, 2002

2001 Silver ZTS Sedan - "Ol' Reliable"
svtf1417 is offline  
    Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
Old 08-16-2013, 05:23 PM   #2
Timmeh!
aka The Wizard
 
Timmeh!'s Avatar
 
Join Date: Sep 2005
Fan#: 27514
Location: Pinckney, MI
What I Drive: '91 Miata, '82 Benz 300TD

Posts: 8,939
Points 22,215, Level 92
Points: 22,215, Level: 92 Points: 22,215, Level: 92 Points: 22,215, Level: 92
Level Up 87% Completed
Level up: 87% Level up: 87% Level up: 87%
Forum Activity 1%
Activity: 1% Activity: 1% Activity: 1%
FF Reputation: 9 Timmeh! Good Standing Member
Buy-Sell-Trade Rating: (6)
BOV should be farther upstream from what I can tell. what do you mean by it's "not shutting smoothly"?

BOV -> MAF should be at least 6" (IIRC... and more is always better tbh)... plus that coupler doesn't look good for flow. the MAF relies on laminar (straight and even) flow to get an accurate reading... dumping a bunch of air out sideways just before it makes it not happy.

can you get a MAF/tube that matches the charge pipe diameter? cause that will help.


my 6" estimation is corroborated here: http://www.performancetrucks.net/for...cement-500925/


proof i read too much of everything on the internet. I've built 0 boosted cars but I can identify 1 for sure and 1 potential problem here.

if your were recircing it'd be a diverter not a BOV (i know some can do both, it's not necessary when the valve is pre-MAF)


little info from Wikipedia

Quote:
The type of flow occurring in a fluid in a channel is important in fluid dynamics problems. The dimensionless Reynolds number is an important parameter in the equations that describe whether flow conditions lead to laminar or turbulent flow. In the case of flow through a straight pipe with a circular cross-section, at a Reynolds number below the critical value of approximately 2040 fluid motion will ultimately be laminar, whereas at larger Reynolds number the flow can be turbulent. The Reynolds number delimiting laminar and turbulent flow depends on the particular flow geometry, and moreover, the transition from laminar flow to turbulence can be sensitive to disturbance levels and imperfections present in a given configuration.
When I look at your maf sitting between couplers... I keep seeing those words in bold jump out at me. Now under normal operation they may be (and it sounds like they are) fine. but once the BOV opens you're changing the whole game because the air pre-maf is now more turbulent, causing the MAF to read wrong (probably low, i doubt it would read high in that case, but i don't play with MAFs much) and your car to do funny things. (I.E. too low of a fuel... runs lean... stalls.

http://www.engineeringtoolbox.com/re...ber-d_237.html

^^ you can calculate the reynold's number there... not sure how applicable it is in this exact instance. I don't have my aero books on my desk at work (or on my normal desk at home, they're at my mom's) but when I get them I'll try to have a gander and figure it out.

^^^ those are the wrong formulas... I'll try to find the ones I/you need.
__________________
Otto - 82 Benz Turbo Diesel Wagon - cruiser
Mara - 97 BMW M3 - fun fun fun
CATIA is a dirty tramp, until you figure out its sweet spots, and how to make it moan. Then its easy as apple pie on a fall afternoon.

Last edited by Timmeh!; 08-16-2013 at 05:35 PM. Reason: I have edited this WAYYYYYYYYY too many times already. I think I hit all the bases though.
Timmeh! is offline  
    Reply With Quote Quick reply to this message
Old 08-16-2013, 05:46 PM   #3
PumkinSvt
Focus Fanatic
 
PumkinSvt's Avatar
 
Join Date: Apr 2007
Fan#: 46561
Location: SoCal, CA
What I Drive: 10 Forte DD,Comp SVTF, 14 Fiesta ST

Posts: 7,498
Points 16,375, Level 82
Points: 16,375, Level: 82 Points: 16,375, Level: 82 Points: 16,375, Level: 82
Level Up 5% Completed
Level up: 5% Level up: 5% Level up: 5%
Forum Activity 0%
Activity: 0% Activity: 0% Activity: 0%
FF Reputation: 28 PumkinSvt Great Standing Member
Buy-Sell-Trade Rating: (33)
move the BOV closer to the intercooler. And what spring do you have in that BOV?

That could be your problem.
__________________


HKS||Garrett||TopSpeed||Tial||Massive||
PumkinSvt is offline  
    Reply With Quote Quick reply to this message
Old 08-16-2013, 11:03 PM   #4
tcorbs
Focus Jr. Enthusiast
 
Join Date: Jan 2013
Fan#: 108172
Location: new boston, NH
What I Drive: 2001 greenzx3

Posts: 42
FF Reputation: 1 tcorbs Good Standing Member
Buy-Sell-Trade Rating: (0)
Post

Quote:
Originally Posted by svtf1417 View Post
Is anyone using a blow through setup, and recirculating their BOV? If I wanted to would I vent it to pre-turbo? I discovered the other day either my BOV is faulty, where my BOV is in relation to my MAF is no good, or I need to recirculate my BOV.

Backround story. Ive been having the HARDEST time getting my car to return to idle without stalling. Tom and I have been working on in for the past 2 months now. It would even stall revving it in the driveway. Anyways I noticed my BOV wasnt shutting very smoothly (brand new TiAL) so I unhooked it and plugged the vacuum line. It revved without stalling, and I could drive it around without stalling anymore.

Anyone else every experience these problems? Heres my setup

my blow off valve is located right to the drivers side of my intercooler behind my bumper, i have a greddy bov works just fine and its also down streem from the maf away from motor
__________________
2001 turbo zx3, h&r cup kit, eagle gt's, bbs rims, forged lower end, focus sport head package.
tcorbs is offline  
    Reply With Quote Quick reply to this message
Old 08-16-2013, 11:30 PM   #5
Turbo Turtle
Fins Up!
 
Turbo Turtle's Avatar
 
Join Date: Mar 2006
Fan#: 32772
Location: Calera, AL
What I Drive: Miata, STi, GSXR1k

Posts: 4,747
Points 20,705, Level 90
Points: 20,705, Level: 90 Points: 20,705, Level: 90 Points: 20,705, Level: 90
Level Up 72% Completed
Level up: 72% Level up: 72% Level up: 72%
Forum Activity 0%
Activity: 0% Activity: 0% Activity: 0%
FF Reputation: 54 Turbo Turtle Excellent Standing Member
Buy-Sell-Trade Rating: (25)
your set up will be fine with atmospheric vent, just move the bov further from the maf. the bov you choose is up to you. any will work on a blow through maf set up. you can recirc if you want really doesnt matter. charge piping being smaller than maf housing will not hurt any thing either.

Tim
__________________
Turbo Turtle Garage
Mig and Tig fabrication, engine building


facebook.com/TurboTurtleGarage
TurboTurtleFab@gmail.com
Turbo Turtle is offline  
    Reply With Quote Quick reply to this message
Old 08-17-2013, 02:41 AM   #6
kwg2371
Focus Addict
 
kwg2371's Avatar
 
Join Date: Jan 2011
Fan#: 82857
Location: springfield, IL
What I Drive: 03 screming yellow SVT #1841

Posts: 1,250
Points 3,766, Level 38
Points: 3,766, Level: 38 Points: 3,766, Level: 38 Points: 3,766, Level: 38
Level Up 78% Completed
Level up: 78% Level up: 78% Level up: 78%
Forum Activity 2%
Activity: 2% Activity: 2% Activity: 2%
FF Reputation: 3 kwg2371 Good Standing Member
Buy-Sell-Trade Rating: (5)
Quote:
Originally Posted by Turbo Turtle View Post
your set up will be fine with atmospheric vent, just move the bov further from the maf. the bov you choose is up to you. any will work on a blow through maf set up. you can recirc if you want really doesnt matter. charge piping being smaller than maf housing will not hurt any thing either.

Tim
this^^^^^^^^^^^^^
__________________
HatchNation #36
FF 13 best audio
FF 13 3rd place best in class SVT
FFW 13 best focus
FFW 13-14 best in class SVT
kwg2371 is offline  
    Reply With Quote Quick reply to this message
Old 08-17-2013, 09:14 AM   #7
svtf1417
MOAR BEWST!!!!
 
svtf1417's Avatar
 
Join Date: Aug 2008
Fan#: 58428
Location: Canton, MI
What I Drive: 2001 ZTS, 2002 SVTF Turbocharged

Posts: 1,527
FF Reputation: 6 svtf1417 Good Standing Member
Buy-Sell-Trade Rating: (6)
Thanks everyone!! Now I just need to find someone with a tig welder, and see if my guy will re-powdercoat my pipes after I ruin them lol
__________________
[#1417] 2002 Sonic Blue SVT Focus
Born on June 25, 2002

2001 Silver ZTS Sedan - "Ol' Reliable"
svtf1417 is offline  
    Reply With Quote Quick reply to this message
Old 08-17-2013, 09:30 AM   #8
1turbofocus
FF Affiliate
 
1turbofocus's Avatar
 
Join Date: Oct 2003
Fan#: 1123
Location: Belmont, NC
What I Drive: 2000 ZX3 / 2002 SVT Turbocharged

Posts: 22,205
Points 51,320, Level 100
Points: 51,320, Level: 100 Points: 51,320, Level: 100 Points: 51,320, Level: 100
Level Up 0% Completed
Level up: 0% Level up: 0% Level up: 0%
Forum Activity 32%
Activity: 32% Activity: 32% Activity: 32%
FF Reputation: 154 1turbofocus Excellent Standing Member 1turbofocus Excellent Standing Member
Buy-Sell-Trade Rating: (28)
I would loose the tial bov , I dont like tial and never did , if you bov is sticking like you said it was where you can see it close in steps then there is something wrong with it

You should see the bov snap open and snap closed , with it off you shouldnt be able to move the plunger when trying to push it in

You are a little close to the MAF but I am not 100% that being close is your problem

Tom
__________________
Focus-Power: Your #1 Source for Ford Focus Speed, Tuning & Performance!

Customer Support
AIM: hpdyno
Email: hpdyno@aol.com
Phone: 704-249-3745
Site: focus-power.com

Elder 1turbofocus
1turbofocus is offline  
    Reply With Quote Quick reply to this message
Old 08-17-2013, 10:49 AM   #9
svtf1417
MOAR BEWST!!!!
 
svtf1417's Avatar
 
Join Date: Aug 2008
Fan#: 58428
Location: Canton, MI
What I Drive: 2001 ZTS, 2002 SVTF Turbocharged

Posts: 1,527
FF Reputation: 6 svtf1417 Good Standing Member
Buy-Sell-Trade Rating: (6)
Quote:
Originally Posted by 1turbofocus View Post

You are a little close to the MAF but I am not 100% that being close is your problem

Tom
I'm taking it to them Tuesday morning it's under warranty. If anything is wrong they'll fix it or replace it on the spot. I'm not 100% either, I believe its a combination of things. Also, your guys are the ones who put that bov openning there.
__________________
[#1417] 2002 Sonic Blue SVT Focus
Born on June 25, 2002

2001 Silver ZTS Sedan - "Ol' Reliable"
svtf1417 is offline  
    Reply With Quote Quick reply to this message
Old 08-17-2013, 02:00 PM   #10
1turbofocus
FF Affiliate
 
1turbofocus's Avatar
 
Join Date: Oct 2003
Fan#: 1123
Location: Belmont, NC
What I Drive: 2000 ZX3 / 2002 SVT Turbocharged

Posts: 22,205
Points 51,320, Level 100
Points: 51,320, Level: 100 Points: 51,320, Level: 100 Points: 51,320, Level: 100
Level Up 0% Completed
Level up: 0% Level up: 0% Level up: 0%
Forum Activity 32%
Activity: 32% Activity: 32% Activity: 32%
FF Reputation: 154 1turbofocus Excellent Standing Member 1turbofocus Excellent Standing Member
Buy-Sell-Trade Rating: (28)
I put it there on all my kits , I know my piping when I see it lol

Tom
__________________
Focus-Power: Your #1 Source for Ford Focus Speed, Tuning & Performance!

Customer Support
AIM: hpdyno
Email: hpdyno@aol.com
Phone: 704-249-3745
Site: focus-power.com

Elder 1turbofocus
1turbofocus is offline  
    Reply With Quote Quick reply to this message
Reply

Bookmarks & Social Networks

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Ford Focus Forum, Ford Focus ST Forum, Ford Focus RS Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.



Thread Tools
Display Modes

Posting Rules
You may post new threads
You may 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

Forum Jump


All times are GMT -5. The time now is 07:21 PM.


Copyright 2002-2014 FocusFanatics.com. All Rights Reserved : Privacy Policy : Advertise Information

Focus Fanatics Ford Focus Forum offers many fun ways for you to engage with other Ford Focus Owners from across the world. Whether it be about the aftermarket performance modifications, technical how-to's, European tuned suspension or awesome fuel economy similar to the Audi S3, Ford Fusion and Acura TLX. You can find all Ford Focus and Focus ST related information here. Join our Ford Focus discussion forums and chat with local Focus enthusiasts in your area. Challenger Hellcat - Charger Hellcat