Long Tube Headers & Check Engine Lights Explained
7/9/12, 03:45 PM
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Long Tube Headers & Check Engine Lights Explained
It has been a long time and I wanted to update everyone who is or may be interested to run long tube headers with cats in place and no check engine light (CEL). The good news is that it can be done but the bad news is that it will be cost prohibitive and I’m not even sure that I could convince Kooks to make additional kits. Also, I would seriously doubt whether traditional O2 “tricks” such as dongles or sparkplug fouler bung extenders would work either. In my view, based on all of the data that we have, the only way that you are going to be able to run long tube headers without a CEL is to programmatically suppress the catalytic efficiency code using and SCT or similar device. Of course, this is not possible for people that want to keep their track key operational.
Unlike 99% of modern fuel injected cars currently on the market, the new Mustangs use true Wideband sensors pre-cats and traditional O2 sensors post-cats. (The other 99% of modern fuel injected cars use O2 sensors pre and post cats.) Our wideband equipped cars (one wideband per cylinder bank) has the capability to do a much better job in controlling a/f ratios at all throttle and load levels. This is why, for example, when you add headers to a Boss 302, no tune is required. The widebands sense the leaner condition and compensate in real time. There are other advantages as well. However, the fact that Ford has widebands upstream of the cats and still O2’s downstream, required that they re-write and “invent” the algorithms used to detect catalytic efficiency. It is after all, a federal requirement in the 1996+ OBDII standard that OEM’s incorporate the on-board capability to detect and report on catalytic efficiency. God forbid that these algorithms didn’t work then 10 years from now a bunch of us could be running around with bad cats and polluting the environment unknowingly. Whether done intentionally or not, Ford’s new “wideband upstream + O2 downstream” test algorithm is very, very tight. This algorithm is tripping the CEL even when we have known-good aftermarket green cats installed. In other words, both Kooks and ourselves believe that a green-cat equipped Boss would pass a CARB sniff test but unfortunately it doesn’t pass the on-board catalytic efficiency test and a CEL is generated.
To the best of my knowledge, all that I am describing here is true not only of the Kooks long tube header solution but also of ANY manufacturer’s long tube header solution. I don’t think any manufacturer offers a catted LT header solution for a Boss that will not throw the CEL using the OEM tunes. (PLEASE correct me publicly if you know otherwise.) In an OEM set-up the OEM exhaust manifolds are very short and this allows the OEM cats to be almost vertical with a relatively large diameter. With LT headers, almost all of the vertical space is consumed by the headers with the collector almost at the intersection of the angled firewall and the floor pan. As such, the cats for a LT set-up need to be horizontal and being horizontal AND under the car requires that their diameter is constrained.
In summary, here are the alternatives available from Kooks. If you decide to go with a Kooks set-up (which we use and highly recommend), I hope you might consider purchasing through us.
1. Boss H-Pipe Off-road (aka no cats)
2. Boss H-Pipe w/cats (would pass a visual but likely fail a sniff test)
3. Boss H-Pipe w /“green” cats – likely to pass both a visual and a sniff test (+$350) over 2) above
4. Boss H-Pipe w/ “ green-green” cats - NO CEL (+$700) over 2) above
Note 1: Option 1-3 will trigger a CEL
Note 2: Option 1-4 alternatively available in an X-Pipe with no side exhaust provision.
Note 3: I have Option 4 on my 2012 Boss and have ~1,000 miles and a full track day and no issues and no CEL
I’m happy to help answer any questions about this info and equally happy to learn of the experiences of others.
Unlike 99% of modern fuel injected cars currently on the market, the new Mustangs use true Wideband sensors pre-cats and traditional O2 sensors post-cats. (The other 99% of modern fuel injected cars use O2 sensors pre and post cats.) Our wideband equipped cars (one wideband per cylinder bank) has the capability to do a much better job in controlling a/f ratios at all throttle and load levels. This is why, for example, when you add headers to a Boss 302, no tune is required. The widebands sense the leaner condition and compensate in real time. There are other advantages as well. However, the fact that Ford has widebands upstream of the cats and still O2’s downstream, required that they re-write and “invent” the algorithms used to detect catalytic efficiency. It is after all, a federal requirement in the 1996+ OBDII standard that OEM’s incorporate the on-board capability to detect and report on catalytic efficiency. God forbid that these algorithms didn’t work then 10 years from now a bunch of us could be running around with bad cats and polluting the environment unknowingly. Whether done intentionally or not, Ford’s new “wideband upstream + O2 downstream” test algorithm is very, very tight. This algorithm is tripping the CEL even when we have known-good aftermarket green cats installed. In other words, both Kooks and ourselves believe that a green-cat equipped Boss would pass a CARB sniff test but unfortunately it doesn’t pass the on-board catalytic efficiency test and a CEL is generated.
To the best of my knowledge, all that I am describing here is true not only of the Kooks long tube header solution but also of ANY manufacturer’s long tube header solution. I don’t think any manufacturer offers a catted LT header solution for a Boss that will not throw the CEL using the OEM tunes. (PLEASE correct me publicly if you know otherwise.) In an OEM set-up the OEM exhaust manifolds are very short and this allows the OEM cats to be almost vertical with a relatively large diameter. With LT headers, almost all of the vertical space is consumed by the headers with the collector almost at the intersection of the angled firewall and the floor pan. As such, the cats for a LT set-up need to be horizontal and being horizontal AND under the car requires that their diameter is constrained.
In summary, here are the alternatives available from Kooks. If you decide to go with a Kooks set-up (which we use and highly recommend), I hope you might consider purchasing through us.
1. Boss H-Pipe Off-road (aka no cats)
2. Boss H-Pipe w/cats (would pass a visual but likely fail a sniff test)
3. Boss H-Pipe w /“green” cats – likely to pass both a visual and a sniff test (+$350) over 2) above
4. Boss H-Pipe w/ “ green-green” cats - NO CEL (+$700) over 2) above
Note 1: Option 1-3 will trigger a CEL
Note 2: Option 1-4 alternatively available in an X-Pipe with no side exhaust provision.
Note 3: I have Option 4 on my 2012 Boss and have ~1,000 miles and a full track day and no issues and no CEL
I’m happy to help answer any questions about this info and equally happy to learn of the experiences of others.
Last edited by nota4re; 7/9/12 at 03:46 PM.
7/9/12, 04:40 PM
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Kendall
I have American Racing Headers and the American Racing 3" x pipe with cats and have no CEL.
My car has a Steeda CAI and Brenspeed tune both of which were on the car before the headers. When I was installing the headers I asked Brenspeed if I had to update the tune, the answer was no it's good to go. I have run the car for 7000 miles and have had no codes cause a CEL or been stored in memory. I honestly don't know if the secondary o2 sensors are turned off but wouldn't think Brenspeed does that on all tunes automatically, maybe they do. Is there a way to read if they are off with the SCT tuner? I have to do a state inspection in October and don't want a headache.
PS my car is a 2011 GT.
Steve
I have American Racing Headers and the American Racing 3" x pipe with cats and have no CEL.
My car has a Steeda CAI and Brenspeed tune both of which were on the car before the headers. When I was installing the headers I asked Brenspeed if I had to update the tune, the answer was no it's good to go. I have run the car for 7000 miles and have had no codes cause a CEL or been stored in memory. I honestly don't know if the secondary o2 sensors are turned off but wouldn't think Brenspeed does that on all tunes automatically, maybe they do. Is there a way to read if they are off with the SCT tuner? I have to do a state inspection in October and don't want a headache.
PS my car is a 2011 GT.
Steve
7/9/12, 05:10 PM
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Kendall
I have American Racing Headers and the American Racing 3" x pipe with cats and have no CEL.
My car has a Steeda CAI and Brenspeed tune both of which were on the car before the headers. When I was installing the headers I asked Brenspeed if I had to update the tune, the answer was no it's good to go. I have run the car for 7000 miles and have had no codes cause a CEL or been stored in memory. I honestly don't know if the secondary o2 sensors are turned off but wouldn't think Brenspeed does that on all tunes automatically, maybe they do. Is there a way to read if they are off with the SCT tuner? I have to do a state inspection in October and don't want a headache.
PS my car is a 2011 GT.
Steve
I have American Racing Headers and the American Racing 3" x pipe with cats and have no CEL.
My car has a Steeda CAI and Brenspeed tune both of which were on the car before the headers. When I was installing the headers I asked Brenspeed if I had to update the tune, the answer was no it's good to go. I have run the car for 7000 miles and have had no codes cause a CEL or been stored in memory. I honestly don't know if the secondary o2 sensors are turned off but wouldn't think Brenspeed does that on all tunes automatically, maybe they do. Is there a way to read if they are off with the SCT tuner? I have to do a state inspection in October and don't want a headache.
PS my car is a 2011 GT.
Steve
Last edited by 2006mach1; 7/9/12 at 05:18 PM.
7/9/12, 05:13 PM
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Hi Steve,
You should be able to put a OBD code tester on your car and check to see what, if any codes are present. If no "catalytic efficiency" codes are present, you are probably OK. I don't have any first hand experience with the GT but Kook's told me that their single green cat set-up works fine in a GT and that's why they were initially very surprised that it did NOT work in the Boss set-up. You may be OK.
You should be able to put a OBD code tester on your car and check to see what, if any codes are present. If no "catalytic efficiency" codes are present, you are probably OK. I don't have any first hand experience with the GT but Kook's told me that their single green cat set-up works fine in a GT and that's why they were initially very surprised that it did NOT work in the Boss set-up. You may be OK.
7/9/12, 05:47 PM
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Just checked with my SCT programmer and don't have any codes present but I can't find a screen to check on rear O2 readiness. A link to the correct tool to view that status would be appreciated.
Steve
Steve
7/9/12, 06:46 PM
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Do the Boss 302 H-Pipe with the green green cats bolt up to your factory mufflers? Looking at what you have said the green green cats option id the only one that would retain your side pipe and still you would still not throw a code correct?
7/9/12, 07:23 PM
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you cant check or modify the rear 02 now because the epa came down on the tuners about that.
the only way to change it is through the cmr or similar software that the tuners purchase from diablo or sct ect..
you will need a scanner to check the car to see if she is sitting in the rear 02 ready state or not ready state
the only way to change it is through the cmr or similar software that the tuners purchase from diablo or sct ect..
you will need a scanner to check the car to see if she is sitting in the rear 02 ready state or not ready state
7/9/12, 08:07 PM
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Do the Boss 302 H-Pipe with the green green cats bolt up to your factory mufflers? Looking at what you have said the green green cats option id the only one that would retain your side pipe and still you would still not throw a code correct?
7/9/12, 08:26 PM
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