Pelican Parts
Parts Catalog Accessories Catalog How To Articles Tech Forums
Call Pelican Parts at 888-280-7799
Shopping Cart Cart | Project List | Order Status | Help



Go Back   Pelican Parts Forums > Porsche Forums > 911 / 930 Turbo & Super Charging Forum


Reply
 
LinkBack Thread Tools Rate Thread
Author
Thread Post New Thread    Reply
Eye of the Toiger
 
matty74's Avatar
 
Join Date: Oct 2005
Location: Sydney, Australia
Posts: 1,204
Garage
Newbie question anyone use a BOV?

Just wondering if anyone uses a Blow off valve on their 911 turbo's?

do we need them and is it a good idea to have one?

Matt
__________________
http://www.aircooled.com.au

1973 911 RSR clone powered by 77 3.0 turbo
Old 03-02-2010, 04:23 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #1 (permalink)
Eye of the Toiger
 
matty74's Avatar
 
Join Date: Oct 2005
Location: Sydney, Australia
Posts: 1,204
Garage
any pics? what type should I get for a single turbo, KKK 7200, running .8 bar, efi on a 3.6, what kinda $$ should I spend?

Matt
__________________
http://www.aircooled.com.au

1973 911 RSR clone powered by 77 3.0 turbo

Last edited by matty74; 03-02-2010 at 05:37 PM..
Old 03-02-2010, 04:48 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #2 (permalink)
E-85 sippin drunk
 
turbobrat930's Avatar
 
Join Date: Jan 2002
Location: Warner Robins, GA
Posts: 1,506
Correct me if I am wrong, but isn't a BOV on a CIS car a bad thing?? You are venting metered air.... In an EFi car, it is not bad as you have the O2 sensor, and the MAP sensor to keep the A/R ratios in check. I would think venting the air after the metering plate would cause a pig rich condition....... Or are we talking such little air that it makes no difference?

A CIS car has a recirculating valve as stock equipment..... which does the same job as a BOV, but it reintroduces the metered air back into the flow instead of venting to atmosphere.....
__________________
Brad...930 gt-1 racecar, increased displacement to 3.6L, JB racing Cylinders, JE 8 to1 pistons, stroked crank, Carrillo rods, extrudehoned 3.2L intake, full bay Bell I/C, GT-2 EVO cams, Rarly8 headers, GTX-35RS turbo, twin plug, P&P heads, Link G4 EFi system, G-50/50 with LTD slip and oil squirters/oil cooler, zork tube, full race coilover system, with carbon fiber body, full cage, E-85 sippin drunk
Old 03-02-2010, 04:56 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #3 (permalink)
E-85 sippin drunk
 
turbobrat930's Avatar
 
Join Date: Jan 2002
Location: Warner Robins, GA
Posts: 1,506
Quote:
Originally Posted by Shadetree930 View Post
May be a semantics issue ..... but anyway, you do want some way to relieve excess boost pressure ...

Blowoff valve - Wikipedia, the free encyclopedia
I agree, compressor surge is a bad thing...... but the 930 does this in stock form, and vents the metered air back in before the turbo...so the air is still metered.
__________________
Brad...930 gt-1 racecar, increased displacement to 3.6L, JB racing Cylinders, JE 8 to1 pistons, stroked crank, Carrillo rods, extrudehoned 3.2L intake, full bay Bell I/C, GT-2 EVO cams, Rarly8 headers, GTX-35RS turbo, twin plug, P&P heads, Link G4 EFi system, G-50/50 with LTD slip and oil squirters/oil cooler, zork tube, full race coilover system, with carbon fiber body, full cage, E-85 sippin drunk
Old 03-02-2010, 05:24 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #4 (permalink)
Registered User
 
mark houghton's Avatar
 
Join Date: Jul 2008
Location: Central Washington State
Posts: 3,776
Quote:
Originally Posted by turbobrat930 View Post
I agree, compressor surge is a bad thing...... but the 930 does this in stock form, and vents the metered air back in before the turbo...so the air is still metered.
You are correct. Venting that already metered air to atmosphere in a CIS fueled system will cause pig rich conditions when shifting. With EFI, not an issue.

With that said, many of us are using the updated BOV's in place of the recirculation valve that comes stock with CIS 930's, but we're still plumbing the boost air charge back to the front of the turbo so as not to generate the pig richies.
__________________
Mark H. 1987 930, GP White, Wevo shifter, Borla exhaust, stock everything else. The result of a massive Pelicanite good will fire recovery effort. Truely an open book, ready for the slippery slopes to modification.
Old 03-02-2010, 06:25 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #5 (permalink)
Turbo Hooligan
 
Join Date: Sep 2007
Location: Greensboro NC
Posts: 1,246
I vent to atmosphere on CIS, I've been doing so since 2002. so you get a little more flamage, and some excess fuel to cool off the heads. meh, not bad things if you ask me.
__________________
www.d-zug.com
blog.d-zug.com

All these guys do is drive too fast, work on cars, chase ******* and drink.. really no fun at all...
Old 03-02-2010, 06:37 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #6 (permalink)
 
beancounter
 
jwasbury's Avatar
 
Join Date: Jan 2008
Location: Weehawken, NJ
Posts: 3,383
^^^Ahh. The "secret" of Pete's decel flames finally revealed!
__________________
Jacob
Current: 1983 911 GT4 Race Car / 1999 Spec Miata / 2000 MB SL500 / 1998 MB E300TD / 1998 BMW R1100RT / 2016 KTM Duke 690
Past: 2009 997 Turbo Cab / 1979 930
Old 03-02-2010, 06:47 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #7 (permalink)
E-85 sippin drunk
 
turbobrat930's Avatar
 
Join Date: Jan 2002
Location: Warner Robins, GA
Posts: 1,506
Ahhh, ok, I guess it is not that big of an issue then.... Coo, well BOV away then!! LOL
__________________
Brad...930 gt-1 racecar, increased displacement to 3.6L, JB racing Cylinders, JE 8 to1 pistons, stroked crank, Carrillo rods, extrudehoned 3.2L intake, full bay Bell I/C, GT-2 EVO cams, Rarly8 headers, GTX-35RS turbo, twin plug, P&P heads, Link G4 EFi system, G-50/50 with LTD slip and oil squirters/oil cooler, zork tube, full race coilover system, with carbon fiber body, full cage, E-85 sippin drunk
Old 03-02-2010, 06:49 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #8 (permalink)
Eye of the Toiger
 
matty74's Avatar
 
Join Date: Oct 2005
Location: Sydney, Australia
Posts: 1,204
Garage
Quote:
Originally Posted by jwasbury View Post
^^^Ahh. The "secret" of Pete's decel flames finally revealed!
whats the trick to getting decel flames on EFI?
__________________
http://www.aircooled.com.au

1973 911 RSR clone powered by 77 3.0 turbo
Old 03-02-2010, 07:44 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #9 (permalink)
Turbofrog
 
smurfbus's Avatar
 
Join Date: Aug 2009
Location: Europe
Posts: 1,423
add fuel on decel or just vent your BOV to atmo and maybe retard the timing too on decel. Have an extra rear valence/bumper as a spare.

Last edited by smurfbus; 03-02-2010 at 10:44 PM..
Old 03-02-2010, 08:24 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #10 (permalink)
Large Member
 
krasuskyp's Avatar
 
Join Date: Nov 2001
Location: top of 3rd
Posts: 4,141
Garage
Quote:
Originally Posted by pkracer21j View Post
I vent to atmosphere on CIS, I've been doing so since 2002. so you get a little more flamage, and some excess fuel to cool off the heads. meh, not bad things if you ask me.
^troof^

and the sounds added to his already fantabular repetoir of audible awesomeness are to addictively *behold*!!!

schweeetahhh!!!

8-)

There certainly is _A_LOT_ goin on back thar... good thing

cause

there most certainly isn't much going on

UP thar (driver's seat, upstairs)

of course I mean... when I was havin at it... yeah that's it

heh heh heh
__________________
Paul... CT | '87 930 | '07 //S6 v10 JNR | '98 ///M3 vert |
past:

| '01 ///M5 | '96 993 C2 cab | '05 S600 Sport - biturbo V12@Just Not Right 495rwhp / 612rwtq |
| '58 TR3A | '01 //S8 | '95 //S6 6gang | '88 ///M5 | '87 190E 2.3-16 |
Old 03-02-2010, 08:32 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #11 (permalink)
Happiest when Tinkering
 
gsmith660's Avatar
 
Join Date: Jun 2007
Location: Missouri
Posts: 4,175
I think I am going to use this one

__________________
" Porsche there is no substitute" I always liked that saying. Air cooled is the only way to go!
76 911 C.R.A.P. Gruppe #2 BIG time TURBO C.R.A.P. Bitz EFI/EDIS Now MegaSquirt 3
76 Blazer also restored by me
Old 03-03-2010, 03:37 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #12 (permalink)
Registered User
 
Join Date: Jan 2004
Location: Sacramento
Posts: 7,269
Matt,

A K27-7200 on a 3.6 with C2 cams or better and EFI is not a good fit and may not even be able to hold .8 bar to red line. You are talking about a motor that has 450hp+ potential and putting a sub 400hp turbo on it. It can support up to a max in some cases to 425hp but not efficiently.

To get flames you need fuel. CIS keeps sending fuel on overrun but EFI mostly dose not. You would have to program in fuel on overrun as noted above.

Venting to atmosphere with EFI probably will not do any thing unless you are doing a blow through system and put the BOV after the AFM / MAF.

Mostly making this a goal is not a sign of a good EFI build, will not add any HP, and make for early turbo ware.

There is an anti lag strategy that plays with timing and sends fuel to the turbo and turns it into a turbine bit that eats turbos.
Old 03-03-2010, 07:35 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #13 (permalink)
Eye of the Toiger
 
matty74's Avatar
 
Join Date: Oct 2005
Location: Sydney, Australia
Posts: 1,204
Garage
911st - your talking sence and i apprciate the advice, I was going to use the 7200 because I had one available, I may as well bite the bullet and get a K27 HF thats what Brian recommended.
__________________
http://www.aircooled.com.au

1973 911 RSR clone powered by 77 3.0 turbo
Old 03-03-2010, 01:38 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #14 (permalink)
Turbofrog
 
smurfbus's Avatar
 
Join Date: Aug 2009
Location: Europe
Posts: 1,423
Quote:
Originally Posted by 911st View Post
CIS keeps sending fuel on overrun but EFI mostly dose not.
Air metering is the key here even with EFI.
Old 03-03-2010, 08:18 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #15 (permalink)
Registered User
 
Join Date: Jan 2004
Location: Sacramento
Posts: 7,269
Yes but it depends.

Where is the BOV. If it is a C2 style blow through conversion the BOV is usually before the AFM and no effect.

If it is a 993 based conversion it should be converted to a suck through to protect the MAS wire. So the BOV should be after the metering function. However, these cars have TPS, when the TPS signal's low throttle angle at an elevated RPM fuel it usually cuts back fuel based on the cell value.

With a stand alone EFI, most turbo's are MAP sensing after the throttle body so the BOV is not going to be able to be located where it can effect AFR's. However, fuel can be programed where ever or how ever you want it.

On an MFI or CIS car the popping and flames are kind of part of the ambiance. Doing this on an EFI car for the effect is as the potential expense of premature turbo ware.

Last edited by 911st; 03-04-2010 at 07:46 AM..
Old 03-04-2010, 07:43 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #16 (permalink)
Turbo Hooligan
 
Join Date: Sep 2007
Location: Greensboro NC
Posts: 1,246
Turbos are wear items.
__________________
www.d-zug.com
blog.d-zug.com

All these guys do is drive too fast, work on cars, chase ******* and drink.. really no fun at all...
Old 03-04-2010, 04:39 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #17 (permalink)
Registered User
 
Cobalt's Avatar
 
Join Date: May 2004
Location: New Jersey
Posts: 1,218
Garage
Billet BOV on 94 turbo

__________________
Anthony PCA affiliate '77 member '83 '90 3.8 RS tribute, '93 964 C2, '93 928 GTS 5 speed, '94 Turbo 3.6, M '15 Boxster GTS18 Macan GTS
Gone worth mentioning '71 E '79 SC, '79 built to '74 3.0 RS tribute (2390 # 270 hp), '80 928 euro 5 speed, '74 2.0l 914, '89 944 S2,'04 Cayenne TT '14 boxster, '14 Cayenne GTS many others
Old 03-11-2010, 08:40 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #18 (permalink)
 
Reply

Thread Tools
Rate This Thread
Rate This Thread:

 


All times are GMT -8. The time now is 05:27 AM.


 
Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2018, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2018 Pelican Parts, LLC - Posts may be archived for display on the Pelican Parts Website -    DMCA Registered Agent Contact Page
 

DTO Garage Plus vBulletin Plugins by Drive Thru Online, Inc.