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*****
Join Date: Apr 2006
Location: Charleston, SC
Posts: 2,359
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CO% on 911 SC - Should it be adjusted for street and track days?
I was wondering if the CO should be adjusted for track days.
Is this a good idea or bad idea? If it makes sense to adjust the CO, what should it be for street driving and what should it be for track days? Right now mine is set at 2% and was thinking 3% would be better at the track.
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82 911SC Coupe Chiffon / Chocolate 9.5 JEs, 964 Cams, SSIs, Dansk Exhaust, CIS (SOLD) |
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09-18-2008, 01:06 PM
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RETIRED
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Rich is good....lean is bad......
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1983/3.6, backdate to long hood 2012 ML350 3.0 Turbo Diesel |
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09-18-2008, 04:47 PM
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Designer King
Join Date: Mar 2004
Location: Toronto, ON Canada
Posts: 5,499
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I know JW has recommended 3.5% for these cars. It corresponds to about 13.2:1 A/F ratio. I remember seeing specs for 911s in pre CAT days, like my original '77 engine, and they recommended a max of 3.5%.
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Paul Yellow 77 Sunroof Coupe/cork interior; 3.2L SS '80 engine/10.3:1/No O2; Carrera Tensioners; 11 Blade Fan; Turbo tie rods; Bilstein B6; 28 tube Cooler; SSI, Dansk; MSD/Blaster; 16x7" Fuchs/205/50 Firestone Firehawk Indy 500s; PCA/UCR, MID9 Never leave well enough alone |
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09-18-2008, 07:06 PM
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*****
Join Date: Apr 2006
Location: Charleston, SC
Posts: 2,359
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Here is a good source for converting CO% to air/fuel ratios:
http://www.perfectpower.com/technical_info/afr.asp 2% CO = 13.77 AFR 3% CO = 13.38 AFR 3.5% CO = 13.20 AFR
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82 911SC Coupe Chiffon / Chocolate 9.5 JEs, 964 Cams, SSIs, Dansk Exhaust, CIS (SOLD) |
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09-19-2008, 06:07 AM
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Registered
Join Date: Oct 2004
Location: San Luis Obispo, CA
Posts: 320
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What is considered the "ideal" a/f ratio for max performance without risking an excessively lean condition?
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356robo 70 T Targa Looking for a 2.2,2.4, or 89 coupe |
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09-19-2008, 08:43 AM
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Designer King
Join Date: Mar 2004
Location: Toronto, ON Canada
Posts: 5,499
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How about 13.2:1 @ WOT?
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Paul Yellow 77 Sunroof Coupe/cork interior; 3.2L SS '80 engine/10.3:1/No O2; Carrera Tensioners; 11 Blade Fan; Turbo tie rods; Bilstein B6; 28 tube Cooler; SSI, Dansk; MSD/Blaster; 16x7" Fuchs/205/50 Firestone Firehawk Indy 500s; PCA/UCR, MID9 Never leave well enough alone |
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09-19-2008, 11:48 AM
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Registered
Join Date: Jan 2003
Location: Algonquin, Illinois
Posts: 696
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You need to talk to Souk, the CIS Jedi master...
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PCA-Chicago Region-DE Tech Coordinator-Retired PCA-Chicago Region GingerMan DE Co-Chair-Retired 1987 Cab-under construction-Sold pending pickup 1986 911- Race/DE car-Sold |
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09-19-2008, 05:02 PM
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Da cab
