How Close Does the O2 Sensor Really Need to Be?
Thread Starter
Le Mans Master
Joined: Oct 2000
Posts: 8,897
Likes: 1,353
From: Santa Ana CA
How Close Does the O2 Sensor Really Need to Be?
While a portion of the exhaust system is out of my '64, I thought about having an O2 bung welded into the "H-pipe" crossover. (Obviously no cats.) I figured here, it would see both banks simultaneously without disturbing the exhaust flow so much. On my car this is just infront of the rear axle either just before or after the mufflers.
Is this too far from the hot exhaust stream to be an effective point to measure O2?
Thanks
Is this too far from the hot exhaust stream to be an effective point to measure O2?
Thanks
Le Mans Master
Joined: Oct 2002
Posts: 7,098
Likes: 378
From: Las Vegas - Just stop perpetuating myths please.
Sensor heating is more important than location.
I know you've seen the smog test station sample at the end of your exh pipe. The difference is that some O2 sensors are self heating and some are not. But as a general rule the closer to the exh port the better. And for the serious tuner an O2 sensor in each exh port header pipe right at head is best (yes a sensor for each cyl).
U need to find out if your sensor is self heating or heated by the exh. I think the 3 wire sensors are self heated and location less critical. 2 wire sensors need to at least be in the header collector or closer.
Hope this helps.
cardo0
U need to find out if your sensor is self heating or heated by the exh. I think the 3 wire sensors are self heated and location less critical. 2 wire sensors need to at least be in the header collector or closer.
Hope this helps.
cardo0
Thread Starter
Le Mans Master
Joined: Oct 2000
Posts: 8,897
Likes: 1,353
From: Santa Ana CA
Actually, Innovate's web site notes that placing the bung too close to teh engine results in too hot a mixture that cannot be read.
Melting Slicks
Joined: Jun 2000
Posts: 3,215
Likes: 6
From: Tampa Florida
Well the standard for those sensors seem to be in the first 1/3 of after header exhaust. If that is not convenient there doesn't seem to be too many standards...ie I've used the tail pipe probe at the dyno and it worked fine although folks will argue that the 'transitory' time will cause issues with synching the AFR with a particular RPM point.
If it was an EFI control..then putting it at the tail end of the pipe would more than likely cause problems with being too cold and when the engine goes into O2 sensing mode.
I mounted mine in the collector and has no issues-coated headers too.
One other comment is putting it in the h pipe makes sense, but not heard of anyone doing that...wonder if there is enough 'gas passing' to read accurately-I don't know.
If it was an EFI control..then putting it at the tail end of the pipe would more than likely cause problems with being too cold and when the engine goes into O2 sensing mode.
I mounted mine in the collector and has no issues-coated headers too.
One other comment is putting it in the h pipe makes sense, but not heard of anyone doing that...wonder if there is enough 'gas passing' to read accurately-I don't know.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)
Joe Kucinski
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!
Verdad Gallardo
Top 10 Corvettes Coming to Mecum Indy 2026!
Brett Foote
Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!
Michael S. Palmer
10 Revolutionary 'Corvette Firsts' Most People Don't Know
Joe Kucinski
5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2
Michael S. Palmer
2027 Corvette vs The World: Every C8 vs Its Closest Competitor
Joe Kucinski
10 Most Common Corvette Problems of the Last 20 Years!
Joe Kucinski
