LT header and O2 sensor location question - Camaro5 Chevy Camaro Forum / Camaro ZL1, SS and V6 Forums

gearhead440 · 08-01-2010, 05:11 PM

If I understand it correctly, one reason for a CEL when installing LTs is because the front O2 sensor is located far more downstream on the header than on the original exhaust piping. Since it takes longer to heat the front O2 sensor with the header compared to the stock configuration, a code is generated for those O2 sensors. (Please let me know if I misunderstood what I've read on other posts).

On a given LT header of brand "X", if you were to weld in an O2 bung on a header tube at roughly the same proximity as the stock O2 bung and sensor, would you receive this code? When I modified my catalytic convertor inlet piping, I welded a O2 sensor bung into the replacement piping at roughtly the same location as on the stock inlet pipe and it works well and no CEL. The outlet remained stock, just removed rear cat and welding in a pipe, so there was no problems with it, either.

I ask since I would like to install the LT in the future and do not want install a tune to clear the CEL.

Kwaz1335 · 08-01-2010, 05:28 PM

+1

Merc · 08-01-2010, 05:40 PM

That's correct. It can code out low cat effecicenty. That being said i cleared the codes, and it codes now on occaison because of a misfire on cylinder #2 ( backfire).

JANNETTYRACING · 08-01-2010, 08:06 PM

Quote:

Originally Posted by gearhead440

If I understand it correctly, one reason for a CEL when installing LTs is because the front O2 sensor is located far more downstream on the header than on the original exhaust piping. Since it takes longer to heat the front O2 sensor with the header compared to the stock configuration, a code is generated for those O2 sensors. (Please let me know if I misunderstood what I've read on other posts).

On a given LT header of brand "X", if you were to weld in an O2 bung on a header tube at roughly the same proximity as the stock O2 bung and sensor, would you receive this code? When I modified my catalytic convertor inlet piping, I welded a O2 sensor bung into the replacement piping at roughtly the same location as on the stock inlet pipe and it works well and no CEL. The outlet remained stock, just removed rear cat and welding in a pipe, so there was no problems with it, either.

I ask since I would like to install the LT in the future and do not want install a tune to clear the CEL.

The codes are set by the REAR O2 Sensors or CAT MONITORS.

When you move the cats further from the engine, it takes longer for the cats to get up to operating temp.

Also Aftermarket cats have a lower cell count than factory cats this makes them run cooler.

Ted.

gearhead440 · 08-01-2010, 09:22 PM

Ted,
Thanks for chiming in on the subject. I was hoping that you would provide your insight and experience.

If you used a cat with a higher cell count than the typical high flow cat (so it would not be as "cool") and used a high temp coating / header wrap on the cat to retain as much heat as possible, would this be sufficient to preclude the rear O2 sensor code?

SA CHEVY · 08-01-2010, 09:41 PM

Subscribing to this thread. I thought about doing the same thing (welding in an O2 bung in the "stock location" and trying to bypass having to get it tuned so I can retain factory warranty).

csjcsj · 08-01-2010, 10:10 PM

But wodnt he still need to get a tune with LT's because they would cause the car to run lean or rich and he would need to make adjustments to the A/F to even things out. So therefore tune the CEL light out as well. I know with
my LT's my car was really rich.

JANNETTYRACING · 08-02-2010, 08:54 AM

OK,

The Front O2s only watch your A/F ratio and report.

The Rear O2s only watch your Cats and Report.

The Cats must come up to Temp with in a VERY Short period of time, if they don't it sets a CEL.

The Cell count affects how much heat they trap, and the distance they are from the Exhaust Ports.

Low Cell count Flow great but heat slow and vise verse.

Welding bungs, wrapping headers, coating headers will not prevent it only a Tune WILL.

Ted.

RX SS RACERX · 08-02-2010, 10:31 AM

Had same problem with Dynatech LT's,3"high flow cats,FlowMaster American Thunder exhaust. After tune CEL hasn't presented since. (Knock on wood)

gearhead440 · 08-02-2010, 10:33 AM

Thanks again, Ted.

Duke · 08-03-2010, 10:41 AM

There are several threads about the JBA and Solo high flow cats for the stock exhaust manifold setup. The testimony so far is that they don't throw codes. The Solo is 200 cell and I think the JBA is also.

This would imply that the thrown codes are indeed caused by the cat position rather than the cell count.

gearhead440 · 08-03-2010, 01:14 PM

The SOLO and JBA cats are roughly in the same location as stock and so are the 02 sensor locations. The SOLOs also use an extender for the rear 02 sensor.

LT headers, compared to the stock manifold and cat assembly, place the 02 sensor locations and cat at a different location than stock.

I used the SOLO pictures as a template when I modified my cats and also retained the 02 sensors and cat in the stock location.

SA CHEVY · 08-03-2010, 01:20 PM

So still questioning here is it possible to bypass getting a tune or no? The information in front of me is saying two different things.

gearhead440 · 08-03-2010, 02:27 PM

SA Chevy,
If you run LT headers you will require a tune, no bypassing it as I had hoped.

However, if you use stock exhaust manifolds or shorty headers with a cat configuration like SOLO or JBA, you should not need a tune.

08-01-2010, 05:11 PM	#1
gearhead440 Drives: Yellow 2SS, 6 speed manual Join Date: Jan 2010 Location: Concord, NC Posts: 218	LT header and O2 sensor location question If I understand it correctly, one reason for a CEL when installing LTs is because the front O2 sensor is located far more downstream on the header than on the original exhaust piping. Since it takes longer to heat the front O2 sensor with the header compared to the stock configuration, a code is generated for those O2 sensors. (Please let me know if I misunderstood what I've read on other posts). On a given LT header of brand "X", if you were to weld in an O2 bung on a header tube at roughly the same proximity as the stock O2 bung and sensor, would you receive this code? When I modified my catalytic convertor inlet piping, I welded a O2 sensor bung into the replacement piping at roughtly the same location as on the stock inlet pipe and it works well and no CEL. The outlet remained stock, just removed rear cat and welding in a pipe, so there was no problems with it, either. I ask since I would like to install the LT in the future and do not want install a tune to clear the CEL. __________________ Hers & His

08-01-2010, 09:22 PM	#5
gearhead440 Drives: Yellow 2SS, 6 speed manual Join Date: Jan 2010 Location: Concord, NC Posts: 218	Ted, Thanks for chiming in on the subject. I was hoping that you would provide your insight and experience. If you used a cat with a higher cell count than the typical high flow cat (so it would not be as "cool") and used a high temp coating / header wrap on the cat to retain as much heat as possible, would this be sufficient to preclude the rear O2 sensor code? __________________ Hers & His

08-01-2010, 09:41 PM	#6
SA CHEVY "HILLARY" Drives: "HILLARY" :D Join Date: Mar 2010 Location: Bakersfield Posts: 1,922 View My Garage	Subscribing to this thread. I thought about doing the same thing (welding in an O2 bung in the "stock location" and trying to bypass having to get it tuned so I can retain factory warranty). __________________ 2010 Camaro SS2 L99 Aircharger, Straightpiped, DT long tubes, Dyno tune by Cal Speed 384 HP & 392 Ft/Lbs. 13.203 @ 107.13 mph at Camaro5FestII

08-01-2010, 10:10 PM	#7
csjcsj Drives: 2010 Camaro SS/RS 6spd Join Date: Sep 2009 Location: Jefferson, Ga Posts: 4,399 View My Garage	But wodnt he still need to get a tune with LT's because they would cause the car to run lean or rich and he would need to make adjustments to the A/F to even things out. So therefore tune the CEL light out as well. I know with my LT's my car was really rich. __________________

08-02-2010, 08:54 AM	#8
JANNETTYRACING Drives: BLUE CAMARO ZL1 1LE M6 Join Date: Jun 2009 Location: ON THE DYNO WATERBURY CT. Posts: 15,418	OK, The Front O2s only watch your A/F ratio and report. The Rear O2s only watch your Cats and Report. The Cats must come up to Temp with in a VERY Short period of time, if they don't it sets a CEL. The Cell count affects how much heat they trap, and the distance they are from the Exhaust Ports. Low Cell count Flow great but heat slow and vise verse. Welding bungs, wrapping headers, coating headers will not prevent it only a Tune WILL. Ted. __________________ www.jannettyracing.com Celebrating 39 years Performance parts, Installation, Fabrication, Dyno tuning, Remote custom tuning, and alignments. 203-753-7223 Waterbury CT. 06705 email tedj@jannettyracing.com

08-01-2010, 05:28 PM	#2
Kwaz1335 The Kwaz Drives: Black 2010 Camaro 2SS/RS Join Date: Mar 2009 Location: Long Island NY Posts: 259 View My Garage	+1 __________________ Ordered:3/13/09 1100: 3/13/09 3300: 5/12/09 Picked up and brought home 6/26/2009 2010 Black on Black SS/RS Camaro Silver stripe package Ground effects package 6 Speed Manual Transmission with Hurst short throw, Magnuson Supercharger, SLP loudmouth 1 kit.

08-01-2010, 05:40 PM	#3
Merc In The Circle Drives: 2010 Camaro 2SSRS IOM M6 Join Date: May 2009 Location: Abbotsford BC Canada Posts: 11,310	That's correct. It can code out low cat effecicenty. That being said i cleared the codes, and it codes now on occaison because of a misfire on cylinder #2 ( backfire).

08-02-2010, 10:31 AM	#9
RX SS RACERX Drives: 2010 2SS/RS RJT Join Date: Jun 2010 Location: MOUNTAIN MARYLAND Posts: 279	Had same problem with Dynatech LT's,3"high flow cats,FlowMaster American Thunder exhaust. After tune CEL hasn't presented since. (Knock on wood)

08-02-2010, 10:33 AM	#10
gearhead440 Drives: Yellow 2SS, 6 speed manual Join Date: Jan 2010 Location: Concord, NC Posts: 218	Thanks again, Ted. __________________ Hers & His

08-03-2010, 10:41 AM	#11
Duke Drives: 2010 Red SS/RS Join Date: Jul 2009 Location: Lake Jackson, TX Posts: 476	There are several threads about the JBA and Solo high flow cats for the stock exhaust manifold setup. The testimony so far is that they don't throw codes. The Solo is 200 cell and I think the JBA is also. This would imply that the thrown codes are indeed caused by the cat position rather than the cell count.

08-03-2010, 01:14 PM	#12
gearhead440 Drives: Yellow 2SS, 6 speed manual Join Date: Jan 2010 Location: Concord, NC Posts: 218	The SOLO and JBA cats are roughly in the same location as stock and so are the 02 sensor locations. The SOLOs also use an extender for the rear 02 sensor. LT headers, compared to the stock manifold and cat assembly, place the 02 sensor locations and cat at a different location than stock. I used the SOLO pictures as a template when I modified my cats and also retained the 02 sensors and cat in the stock location. Attached Images __________________ Hers & His

08-03-2010, 01:20 PM	#13
SA CHEVY "HILLARY" Drives: "HILLARY" :D Join Date: Mar 2010 Location: Bakersfield Posts: 1,922 View My Garage	So still questioning here is it possible to bypass getting a tune or no? The information in front of me is saying two different things.

08-03-2010, 02:27 PM	#14
gearhead440 Drives: Yellow 2SS, 6 speed manual Join Date: Jan 2010 Location: Concord, NC Posts: 218	SA Chevy, If you run LT headers you will require a tune, no bypassing it as I had hoped. However, if you use stock exhaust manifolds or shorty headers with a cat configuration like SOLO or JBA, you should not need a tune. __________________ Hers & His