now that the ACRX Gen iv headers have been around for a while......

[hightest]

Hi All,
now that the Gen IV ACRX headers have been around for a little while, I was wondering if anyone has been running them without the upgraded Mopar performance ECU?
How have they been on the stock computer for codes?
Thanks in advance!

 

[01sapphirebob]

Watching.....

 

[Moundir]

I have them, no mopar computer = codes!!

 

[ViperGeorge]

I have them, no mopar computer = codes!!

Does that mean that you have the Mopar Controller and you have no codes, or does it mean you do not have the Mopar Controller and do have codes?

 

[TrackAire]

I have them, about 4200 miles on the headers. I've thrown a "cat system efficiency below threshold" code twice. My car has ACRX headers, single metal substrate cat and stock mufflers.

I normally drive the car with minimal "putting around". Drove it to the VOI from the West coast, to the drags, autocrosses, etc., no codes.

Early last summer I took the car out to just drive it on some country roads about 6 miles out of town. On the way back, I got caught in a freak thunderstorm and drove the car back very slowly to keep the tires from throwing up crap all over the just detailed wheels, suspension, etc. Just before home, I threw the code.

On a VCA run to Santa Cruz this summer, tons of slow driving with the wife in the car, driving in stop and go traffic, etc, threw the code just before home after about 5 hours of very mild driving and low revs.

Both codes were thrown in the last 1000 miles of driving. I suspect that aftermarket cats lose efficiency (I don't care who's brand they are, they'll never be as reliable as stock) with age. As the cats get older I'm figuring that the system will throw codes more often. My gut is telling me that aftermarket cats may be a "wear" item if you're not running a Mopar controller.

When I drive alone, I drive much sportier (which probably keeps the cats lit and hot) than I do with the wife in the car on a slow cruise event. I've driven the car about 400 miles since the VCA run to Santa Cruz with no codes.

Cheers,
George

 

[Viper X]

TrackAire,

Try the OE secondary cats next time in place of the aftermarket cats. They seem to flow better, work well and last quite a bit longer than the aftermarket cats...... and sometimes you can pick up a set of "take offs" for quite a bit less $$$$$ than the aftermarket cats.

On subject, one of our So Cal members has had American Racing headers on his 08 for about 6 months now and has not thrown any codes yet ..... but he drives like a maniac most of the time!

Dan

 

[hightest]

TrackAire,

Try the OE secondary cats next time in place of the aftermarket cats. They seem to flow better, work well and last quite a bit longer than the aftermarket cats...... and sometimes you can pick up a set of "take offs" for quite a bit less $$$$$ than the aftermarket cats.

On subject, one of our So Cal members has had American Racing headers on his 08 for about 6 months now and has not thrown any codes yet ..... but he drives like a maniac most of the time!

Dan

Do you think gutting the first set of cats and keeping the original secondary cats in place with the ACRX headers would be feasible?
I don't know how much difference there would be in horsepower, but it sounds like it might be worth a try!

 

[mjorgensen Woodhouse]

Do you think gutting the first set of cats and keeping the original secondary cats in place with the ACRX headers would be feasible?
I don't know how much difference there would be in horsepower, but it sounds like it might be worth a try!

Can't do this as the header systems have 1 set welded to the turnout pipe, you would need to cut up the pipe/cat and just replace it if you want another one in it's place. Either way you end up with just one cat.

 

[Viper X]

Can't do this as the header systems have 1 set welded to the turnout pipe, you would need to cut up the pipe/cat and just replace it if you want another one in it's place. Either way you end up with just one cat.

What Mark said, can't keep the first set of cats with American Racing Headers or any other headers that I know of for Gen IV.

 

[ViperGeorge]

Where do you mount the secondary O2 with American Racing Headers? I had thought that issues with CELs have more to do with placement of O2s. The American Racing headers mount the upstream O2 in the collector don't they? This is supposed to be better than mounting them in one pipe as it gives the O2 better visibility into all cylinders. The downstream O2 is supposed to be mounted after the first cat. The secondary or cleanup cat is not monitored and eliminating it should not cause any issues with CELs.

 

[mjorgensen Woodhouse]

Where do you mount the secondary O2 with American Racing Headers? I had thought that issues with CELs have more to do with placement of O2s. The American Racing headers mount the upstream O2 in the collector don't they? This is supposed to be better than mounting them in one pipe as it gives the O2 better visibility into all cylinders. The downstream O2 is supposed to be mounted after the first cat. The secondary or cleanup cat is not monitored and eliminating it should not cause any issues with CELs.

The CEL's have to do with the fact that the "HF" cats will not get up to an efficient operating temp under less then large loads of spirited driving, so they throw an inefficiency code. The more you run them this way the faster they will foul and and the more codes you will see. The Mopar PCM will eliminate this by not monitoring the back 02's, but the stock PCM does. Some header company's use better cats then others so this process will take longer to come about without the Mopar PCM, but it will happen to all of them eventually.

 

[ViperGeorge]

The CEL's have to do with the fact that the "HF" cats will not get up to an efficient operating temp under less then large loads of spirited driving, so they throw an inefficiency code. The more you run them this way the faster they will foul and and the more codes you will see. The Mopar PCM will eliminate this by not monitoring the back 02's, but the stock PCM does. Some header company's use better cats then others so this process will take longer to come about without the Mopar PCM, but it will happen to all of them eventually.

Thanks. Is it possible to cut out the HF cat that comes with the header and replace it with an OEM unit? Would that then eliminate the CEL issue?

 

[mjorgensen Woodhouse]

Thanks. Is it possible to cut out the HF cat that comes with the header and replace it with an OEM unit? Would that then eliminate the CEL issue?

You could, but would take some precision welding to get everything to line up properly, and to answer the other part NO, you need both factory cats in place to be efficient enough for the stock PCM to not throw a code, sorry.

 

[ViperGeorge]

You could, but would take some precision welding to get everything to line up properly, and to answer the other part NO, you need both factory cats in place to be efficient enough for the stock PCM to not throw a code, sorry.

How does the PCM know that the second (cleanup) cat is even in place? Isn't the downstream O2 sensor between the primary and secondary cats? I always thought that the downstream O2 is what the PCM used to determine cat efficiency by comparing voltages between upstream and downstream sensors. What if you mounted an OEM secondary cat after the header's cat and relocated the downstream O2 to after the secondary cat? Do you think that could work?

 

[mjorgensen Woodhouse]

How does the PCM know that the second (cleanup) cat is even in place? Isn't the downstream O2 sensor between the primary and secondary cats? I always thought that the downstream O2 is what the PCM used to determine cat efficiency by comparing voltages between upstream and downstream sensors. What if you mounted an OEM secondary cat after the header's cat and relocated the downstream O2 to after the secondary cat? Do you think that could work?

It doesn't know, it is just the efficiency it needs to show proper function. This is also dictated as to placement of the rear 02 sensors, and they are after the cats. If you just added one after the header cat it would be too far away from the heads and the heat needed to work. There is no easy way around this, just get the Mopar PCM if you want a code free experience.

 

[hightest]

What about the spark plug anti fouler trick?
Wouldn't this be enough to trick the pcm, or do you feel that this would just be a temporary solution also?

 

[mjorgensen Woodhouse]

There is no tricking the Gen4 PCM...

 

[Viper X]

There is no tricking the Gen4 PCM...

Not even with 02 sensor simulators? Used on the track of course.

 

[Dan Cragin]

O2 Simms can eliminate the light, but the computer will never pass a downstream O2 Monitor test or Cat test. Wont ever pass smog.

 

[mjorgensen Woodhouse]

+1 ^^^^ Thanks Dan

 

[Viper X]

O2 Simms can eliminate the light, but the computer will never pass a downstream O2 Monitor test or Cat test. Wont ever pass smog.

Good to know it will eliminate the light.

So, if it eliminates the light, will it "show proper function" and allow the car to run OK?

 

[Moundir]

Does that mean that you have the Mopar Controller and you have no codes, or does it mean you do not have the Mopar Controller and do have codes?

I have the mopar computer and no codes! I swapped out the mopar for stock computer to pass the emissions test and threw a code right away.. I tried keeping the rpms high but a cop pulled up right next to at a light lol...

 

[ViperGeorge]

I have the mopar computer and no codes! I swapped out the mopar for stock computer to pass the emissions test and threw a code right away.. I tried keeping the rpms high but a cop pulled up right next to at a light lol...

well that sux.

 

[Viperless]

What about the spark plug anti fouler trick?
Wouldn't this be enough to trick the pcm, or do you feel that this would just be a temporary solution also?

Worked for me.

 

[Hoodoo Man]

Spark plug anti fouler also worked for me on my 2010 ACR. But I also have M@M headers.

 

[Viper X]

Mopar race controller = no CE lights related to headers as Mark says.

12K miles, no codes in 09 ACR.

 

[Westxsrt10]

Mopar race controller = no CE lights related to headers as Mark says.

12K miles, no codes in 09 ACR.

What is the answer when you have to smog test in Ca.? Mopar controller = failed smog test.
Some of us just want the cel to be off for smog in states with no tailpipe testing.


08 Viper...Belanger full exhaust

 

[Viper X]

What is the answer when you have to smog test in Ca.? Mopar controller = failed smog test.
Some of us just want the cel to be off for smog in states with no tailpipe testing.


08 Viper...Belanger full exhaust

I haven't smogged my 09 ACR yet as in CA, you don't have to "smog test" for five years, so not a big deal until then.

I'll likely re-install the OE computer and drive it aggressively before I take it in for smog.

If it fails, I may have to have it "repaired".

Dan