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
Registered
 
Join Date: Jun 2009
Posts: 745
About to readjust CO can i use a afr tool?

Hi guys getting mixed responses from my web search . I need to adjust my CC to 3%
Can i use a afr tool to do it using the conversion tables on the net?
Was told the numbers do not really correlate . Is this true?
Thanks
Erick

Old 10-01-2012, 01:13 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #1 (permalink)
Registered
 
Join Date: Jul 2003
Location: Back in B'ham, AL
Posts: 3,459
Unusual inquiry having 374 posts in Pelican... lots of info in the turbo forum. Do a search here and you'll be amaze of the results.
Old 10-01-2012, 06:16 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #2 (permalink)
Registered
 
9dreizig's Avatar
 
Join Date: Jul 2005
Location: Reno, NV
Posts: 5,941
Send a message via AIM to 9dreizig
Miguel woke up on the wrong side of the bed today
but he's right do a search..
I do remember someone publishing a AFR to CO conversion chart ..
__________________
"Todd"
98 Tahoe ,2007 Saturn Vue
86 930 black and stock, 80 930 blue tracdog
91 Spec Miata (yeah I race a chick car)
"life"ll kill ya" Warren Zevon
Old 10-01-2012, 06:36 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #3 (permalink)
Registered
 
mark houghton's Avatar
 
Join Date: Jul 2008
Location: Central Washington State
Posts: 4,398
Adjusting to 3% is all fine and dandy, but if you're trying to pass an emissions test then that will be way too rich. It's not a "magic number", but rather dependent upon your car's build and general state of tune as to how well it will idle at 3%. Lacking any hard data (such as an emissions exhaust sniffer or an AFR gauge) then let your ear tell you how she's idling as you adjust the mixture screw.
I idle at about 13.8 to 14.0 which my car seems to like. Been a long time and many adjustments since I "sniffed" with my old Gunson Gas Tester, but I seem to remember something in the neighborhood of 2.0 to 2.5% CO works well for my car.
__________________
Mark H. 1987 930, GP White, Wevo shifter, Borla exhaust, B&B intercooler, stock 3LDZ.
Old 10-01-2012, 06:43 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #4 (permalink)
Registered
 
mark houghton's Avatar
 
Join Date: Jul 2008
Location: Central Washington State
Posts: 4,398
Adjusting to 3% is all fine and dandy, but if you're trying to pass an emissions test then that will be way too rich. It's not a "magic number", but rather dependent upon your car's build and general state of tune as to how well it will idle at 3%. Lacking any hard data (such as an emissions exhaust sniffer or an AFR gauge) then let your ear tell you how she's idling as you adjust the mixture screw.
I idle at about 13.8 to 14.0 which my car seems to like. Been a long time and many adjustments since I "sniffed" with my old Gunson Gas Tester, but I seem to remember something in the neighborhood of 2.0 to 2.5% CO works well for my car.
__________________
Mark H. 1987 930, GP White, Wevo shifter, Borla exhaust, B&B intercooler, stock 3LDZ.
Old 10-01-2012, 06:44 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #5 (permalink)
Crotchety Old Bastard
 
RarlyL8's Avatar
 
Join Date: Jan 2000
Location: Huntsville, AL
Posts: 15,005
Garage
3%CO is a sweet spot for performance but can vary. Typically 13.5:AFR at idle is the same sweet spot.
__________________
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 10-02-2012, 03:33 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #6 (permalink)
 
Registered
 
totle's Avatar
 
Join Date: Oct 2008
Location: Norway / Miami
Posts: 1,390
Garage
Here is the table
__________________
Trond R.
1979 930: Garret GT35r turbo, EFI, carerra intake, Link EMS, custom GT2 cams, 98mm JE P/C, 964 crank (stroker), custom valves & ported (XtremeCylinderHeads) etc..etc..
1972 914-6 GT replica project
1986 944 Turbo
Old 10-02-2012, 10:25 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #7 (permalink)
Registered
 
boosted 89's Avatar
 
Join Date: Nov 2009
Location: Ontario Canada
Posts: 134
Garage
Quote:
Originally Posted by RarlyL8 View Post
3%CO is a sweet spot for performance but can vary. Typically 13.5:AFR at idle is the same sweet spot.
Brian

Will setting your co level to 3% ish area affect WUR operation at higher boost levels. I only ask thinking that my WUR is in need of a rebuild because of the low AFR readings I'm getting at WOT(mid 9's). I'm not sure of the correlation between having the CO level set rich and the operation of the WUR under boost at WOT. I hope I don't sound like a dumba$$ but is the effect of setting the CO level high to have the car running a little richer under higher boost pressure? Would this be something you do even with an adjustable WUR?

Chris

Old 10-03-2012, 05:50 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #8 (permalink)
Reply

Thread Tools
Rate This Thread
Rate This Thread:

 


All times are GMT -8. The time now is 01:10 PM.


 
Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2025, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2025 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.