Parts Catalog Accessories Catalog Tech Info Tech Forums
 
  Search our site:    
 Cart  | Project List | Order Status | Help    



Go Back   Pelican Parts Technical BBS > 1- Porsche Technical Forums > 911 / 930 Turbo & Super Charging Forum

Reply
 
LinkBack Thread Tools Rate Thread
Author
Thread Post New Thread    Reply
wcc wcc is offline
Registered User
 
wcc's Avatar
 
Join Date: Aug 2005
Location: Michigan
Posts: 3,333
930 Pop off Valve

Should our 930 cars have pop off valves installed? I know it's common for SCs to have them and haven't heard talk about this for a 930. I wouldn't think it's needed cause our air intake system is different being a turbo, but I'm not sure. So it a good idea to install one? Or is it not needed?

I was helping a friend with his SC and it back fired and I now know what you guys are saying about it blowing up the air box. He has a pop off valve installed, but if he didn't it wouldn't have been pretty.
__________________
Bill
Old 03-04-2007, 05:50 AM
  Pelican Parts Technical Article Directory    Reply With Quote #1 (permalink)
Crotchety Old Bastard
 
RarlyL8's Avatar
 
Join Date: Jan 2000
Location: Huntsville, AL
Posts: 12,690
Garage
930s don't have an air box.
Any belching through the intake will have to go through the turbo as well which dampens the effect.
__________________
RarlyL8 Motorsports / M&K Exhaust - 911/930 Exhaust Systems, Turbos, TiAL, CIS Mods/Rebuilds
'78 911SC Widebody, 930 engine, 915 Tranny, K27, SC Cams, RL8 Headers & GT3 Muffler. 350whp @ 0.75bar
Brian B. (256)536-9977 Service@MKExhaust Brian@RarlyL8
Old 03-04-2007, 06:35 AM
  Pelican Parts Technical Article Directory    Reply With Quote #2 (permalink)
wcc wcc is offline
Registered User
 
wcc's Avatar
 
Join Date: Aug 2005
Location: Michigan
Posts: 3,333
That's good to know. I didn't think a pop off valve was as important on a 930 like it is on a SC.

As for the 'air box', I always called it that. What is it called then? Air cleaner housing? Isn't that like the you say tomayto and I say tomoto thing? Not trying to be a smart alec, just curious.

Not a great pic, but that's all I could find on the computer without taking new ones....
__________________
Bill
Old 03-04-2007, 07:34 AM
  Pelican Parts Technical Article Directory    Reply With Quote #3 (permalink)
Registered User
 
Join Date: Dec 2006
Location: Winston-Salem, NC
Posts: 72
Re: 930 Pop off Valve

Quote:
Originally posted by wcc
Should our 930 cars have pop off valves installed? ...
I had a diverter valve installed to avoid build up of back pressure and to maintain boost in between shifts.

No diverter valve means the backpressure caused by the throttle closing has nowhere to go but backwards through the turbocharger's compressor, slowing it down and slowly damaging the turbocharger.

Maybe someone more knowledgable can list other benefits as well.

The parts cost me about $200 and the job seemed fairly straight forward with the biggest thing being the welding of a 25mm port onto the Intercooler. While I did not do the job myself, I probably could have with the exception of the weld job.
The rubber elbow from the airflow sensor housing had to be changed as well to accomodate the installation of the diverter valve.



Please feel free to PM me if you want references.
__________________
Olli Selander

1989 930 - 3.5l - M48 - G64/51

Last edited by oms930; 03-04-2007 at 10:49 AM..
Old 03-04-2007, 10:18 AM
  Pelican Parts Technical Article Directory    Reply With Quote #4 (permalink)
Crotchety Old Bastard
 
RarlyL8's Avatar
 
Join Date: Jan 2000
Location: Huntsville, AL
Posts: 12,690
Garage
The configuration of the SC air box is not the same as for a 930. The SC has the throttle body and the air flow meter in the same housing. The 930 air flow meter or plate has the air filter housing sitting on top of it (your green arrow) while the intercooler sits atop the throttle body.

The stock 930 BOV serves the same function as the 965 style diverter valve. Niether are present in a normally aspirated engine.
__________________
RarlyL8 Motorsports / M&K Exhaust - 911/930 Exhaust Systems, Turbos, TiAL, CIS Mods/Rebuilds
'78 911SC Widebody, 930 engine, 915 Tranny, K27, SC Cams, RL8 Headers & GT3 Muffler. 350whp @ 0.75bar
Brian B. (256)536-9977 Service@MKExhaust Brian@RarlyL8
Old 03-04-2007, 06:23 PM
  Pelican Parts Technical Article Directory    Reply With Quote #5 (permalink)
Registered User
 
beepbeep's Avatar
 
Join Date: Jun 2001
Location: Sweden
Posts: 5,464
You don't need pop-off valve (as in SC) as backfire is very unlikely to happend due to very long path air has to take.

Also, engine already has BOV installed in it's original conception (the thing that clonks when you flip the throttle) so installing a plastic one is waste of time.
__________________
Thank you for your time,
Old 03-04-2007, 11:07 PM
  Pelican Parts Technical Article Directory    Reply With Quote #6 (permalink)
wcc wcc is offline
Registered User
 
wcc's Avatar
 
Join Date: Aug 2005
Location: Michigan
Posts: 3,333
This is all good info! Thanks guys. I haven't had the car for two years yet and haven't really had any 'under the hood' time. So I'm still learning on how everything works.
__________________
Bill
Old 03-05-2007, 04:15 AM
  Pelican Parts Technical Article Directory    Reply With Quote #7 (permalink)
Reply

Thread Tools
Rate This Thread
Rate This Thread:

 


All times are GMT -8. The time now is 12:39 AM.


 
Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2016, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2016 Pelican Parts - 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.