Did you hollow out all the cats or just the 2 rear ones? I was thinking about doing the 2 rears but still wanna pass inspection. and X2 to flowmaster drone, have a 40 series on my 4.7 dakota, notttt fun to drive on a hangover morning.. just bought a magnaflow 14" 2.5 si/so from summit, so pumped

 

Just switched from flows after 12 years of having them on my truck. I have the 14" SI/DO and I love it. Power gain like crazy. You'll see!!!!

 

I did all 4 cats, but we don't have an inspection here in Alabama, so no worries for me. There are only 2 things I don't like about it. It now has that "uncleaned exhaust" smell, which basically smells like gas, and it makes a "whooossh" sound under acceleration which I suspect is coming from the B-Pipe now that its more like an expansion chamber than a pipe...lol

 

:readclose

If you did all 4 cats, you just "F"ed your self. Your truck needs to be fixed by a "professional". Bring your checkbook.
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Oh and Deerslayer, do you guys have cows with deer horns up there or what? LOL

 

LOL Thanks man!!! He was a giant buck. Shot him with my bow in 07' and he scored 165 3/8 and dressed 241#. My biggest ever!!!! He was in FEB. 08' bowhunting world magazine. I'm still on cloud 9

 

notsureifserious.jpg


Could you be a bit more specific other than I just F'd myself? lol Im not a professional by any means, but Im pretty sure I can fix anything on my truck that requires a wrench.

 

The short story is, you need a cat between the a/f sensor and the heated oxygen sensor. The second set of cats on 4x4 can be removed. The heated oxygen sensor monitors the exhaust gases and when the voltage goes off scale in the ECU mapping, the ECU will recalibrate the A/F mixture. The results are richer AFR at idle instead of 14.7 AFR target it will drop and it will run rich through the RPM’s . Power loss, gummed up valves, carbon build up, raw fuel entering motor oil and so on, will be inevitable.
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I have the same magnaflow too and love it, you can usually get a used one on ebay or cragislist. I wanted a valid warranty so I got it here. Magnaflow 49175. Also some of the forum sponsors selling magnaflow usually have a sale going on. Either way its a great cat, sounds great, and very easy to install."idhitit2:

 

Well, telling the entire internet community that you gutted all the catalytic converters on your truck just about voids your insurance claim when your truck lights itself on fire! :huh:

Oh, and it also opens you up for a federal lawsuit since tampering with them, and admitting it, is a federal offense...

Good luck... You'd better hope your fuel lines never spring a leak and all your components can withstand the intense heat generated by your exhaust now...

 

Yeah your truck is boned if anything happens. If you get pulled over, well it was nice knowing you.

 

You guys got it all wrong. Getting caught with all the cats gutted is an offense.... talking about it is not. If by the time they check he has real cats on it then he can just say he made the story up to talk smack on the net :bangit: Better get on that!

 

True.... and to the OP, there are plenty of Hi-flo cats available out there. I would highly recommend you look into incorporating them into your exhaust system... at least one on each pipe. They're not expensive... not like factory replacement cats... Your truck will thank you for it.

 

I thought this thread was about former pets. :teethmast

 

Yeah you might want to put some high flow cats back on for the motor to be happy .. I wouldn't worry about the law thing go over to the Diesel forums they have Cat Delete " test pipes " and pass inspections all the time..

 

I do appreciate the comments and concerns, although some were a little harsh... But I do take them in the spirit they were intended. Just out of curiosity, what do the guys who run long tube headers do about the sensors? Doesn't the long tube header eliminate the front cat?

 

Sorry for the harshness.
The smart ones put a set of high flow cats in, the others use a simulator which stops the codes but doesn’t allow the full puritanical of the ECU to learn, “some loss of power”.
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I believe they run emmulators to get the correct AFR

 

What Thrust T is saying is not the first time I have heard the exact same information and the first time was from someone who knows alot more about the electronics in these trucks than I ever will. I tend to trust the guys that are truly "IN THE KNOW" around these sites and take the others with a grain of salt.

 

^^^ I get that...but the FSM says otherwise.

"Under normal conditions", the secondary O2 is not used for A/F monitoring, see here:

So while I may not be directly "in the know" (haven't done my own logs)...all the data I do have available says that if you have functioning primary O2's...the secondary ones are for backup and/or diagnostic purposes.

If that's not the case, post up a log, or maybe link me to another thread where it shows otherwise.

...and I'm not trying to argue here, just trying to make sure the info we're all putting out there is correct.

- Brian

 

Thrust is right to a degree, it will run more rich and get worse fuel mileage however it is not gonna run rich enough to wash out cylinders and gum up the top end. I have done this mod to numerous vehicles and being a service manager at a big dealership I have tested it and no it doesn't destroy your motor. It will simply move you 14.7:1 A/F ratio down to maybe 12.5:1 at best which anybody that knows anything can tell you that isn't gonna hurt a thing. I have friends running F/I cars running 9.5:1 A/F and not washing out cylinders. But to regain your fuel mileage I suggest getting 2 sets of 18mm spark plug anti-foulers and drill out one to 1/2" and screw it into the other and insert that into the pipe and screw the secondary o2 sensor into that and voila it is fixed. I have done it many times and it restricts enough flow to the sensor that it reads almost perfect and makes your truck run right.

 

I guest, I’m just a newbie here and don’t know anything about the Titan. Ok, no problem. Good luck.

 

C'mon, man...if were wrong, then tell us why.

Discussions like this are good, everyone learns.

Like I said:

If that's not the case, post up a log, or maybe link me to another thread where it shows otherwise.

...and I'm not trying to argue here, just trying to make sure the info we're all putting out there is correct.

If not, then fine...we'll just go along assuming you're actually a newb. :huh: Otherwise, share the wealth (of info)!

:kiss: - Brian

 

Damned Newbs! :bang: They're everywhere! :eeeek:

 

Im glad this got everybody talking. What I honestly want to know from Thrust (no bashing, serious question)....what exactly is different about the Titan truck that makes it react this way to O2 readings (after-cat)......or does every vehicle react the way you speak of?

I previously owned an EVO and ran a 3" TBE with no cats, but did have a simulator installed. I never got any engine codes, and I had it dyno tuned by Dynoflash, and nothing to the effect of what you are bringing up was ever said by anybody. (365whp and 397tq FTW)

 

I don’t know if every vehicle reacts the same way. I do know the Titan reacts this way

Clear all codes and reset the learned fuel, pull the heated oxygen sensors out and let them hang for a day or two. Don’t unplug them just let hang. On a cold start the heated oxygen sensors will report in a data log as .32 volts. If you check the voltage at the sensor you will find that it’s not .32 volts but .01 volts, why .01 volts? Because, they’re not screwed into the exhaust system. The ECU receives the real time voltage and overrides and reports .32 volts, this is due to the engine and exhaust not up to its operating temps. After they warm up the ECU will start to report real time voltage. Yes .01 volts and you do know why now. After a day or two of this depending on how many miles you drive the check engine light will come on. Check the codes you will find a 1273 and 1283 code, look them up and see that it’s an Air fuel ratio bank 1 and 2 “LEAN CONDITION” now run a data log. At idle the AFR will be 13.5 or lower and at W.O.T. the AFR will drop down and flat line 10.95:1, 0 volts. Why is it a LEAN CONDITION code if the AFR is rich? Why would the A/F sensor give a code if you haven’t touched it? The ECU was unable bring the heated oxygen sensor voltage up past .32 volts, by adding more fuel it’s still at .01 volts. Now, if you have a FFV (Flex Fuel Vehicle) the ideal air to fuel ratio for gas is 14.7:1. The air fuel ratio for ethanol is 9:1 and when in a 10% blend yields an air fuel ratio of 14.1:1 (BTW. E85 is around 9.7:1) The ECU will recalibrate the ethanol percentage, setting it to a higher percentage,and adding more fuel as well.
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If you happen to run the truck like this for 500-1000 miles, change the oil, and send some of the old oil to Blackstone Labs have it checked, it may surprise you on the other comments I made.
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BTW you won’t find this in the Nissan Service Manual.
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So a heated oxygen sensor only checks the three way catalyst? Hmmm the nonbelievers are welcome to try it out.
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I do know the Titan reacts this way...

Cool, thanks for posting.

Clearly, you've done this...logged it...and the ECU doesn't like it (with the sensors left hanging).

But what happens if you just don;t have cats? If the sensor isn't screwed in, I don't think it's grounded (electrically).

And if they are reading lean all the time (just hanging there in regular air), it might make sense for the ECU to richen things up like you said...but what if they're output just matches the primary O2's?

So if you have it screwed in, and up to temp...does it act the same way?

There's gotta be someone with LT's who just put the secondary O2's back in somewhere like the B-pipes...what happens in that case?

I guess it could be the same, has anyone logged that?

- Brian

 

Gutted cats= Sorry MPG's and loss of TQ. Sorry not for me!!!! I agree with Thrust T. Just my opinion

 

man these newbs.... full of fail.....

 

Dunno if that was directed towards me, I have to assume it was...but I am no "newb".

What I am...is someone who has been doing this kinda stuff for a LONG time, and active on forums like this for long enough, that I find A LOT of people, like yourself...who blindly believe the "facts" as presented by people who regurgitate information.

I asked some concise questions above...not 'newbish' kinda stuff, but questions about what I believe to be a flawed test (secondary O2's hanging is NOT the same as having them installed, but with no primary cat).

SO, while Thrust_Titan may be 100% correct that the ECU will act the way he said when the secondary O2's are effectively out of the loop...that is NOT the same situation as when the cat is gutted.

Or maybe it is, and that's why I asked.

I'm willing to give someone else the benefit of the doubt until shown otherwise. So far, no one has given ANY data...just conjecture.

...

So if there's any "fail" here, it's on you...for jumping on the bandwagon and not adding anything useful to the thread.

- Brian

 

I also thought the secondary o2 sensors were just for diagnostics (checking the efficiency of the cats).

What would be the point of altering the AFR from the secondary o2 sensor readings instead of just using the primary o2 sensor readings? Not to mention, if your cat goes bad (which is a definite possibility over time), the readings will obviously be off for the second sensors - then the AFR is changed when it doesn't need to be? It doesn't make sense.

 

Why you are resisting the fact that technology is advancing and you are behind the times.

You’re claiming that I maybe wrong or at least implying some doubt. Well that’s fine with me, but the damage of passing on outdated info hurts everyone else.

You claimed the second set of sensors are for diagnostic purpose ONLY, useless for A/F monitoring and will not influence the tuning. I clearly provided firsthand knowledge showing a step by step procedure for doing a simple test to show how the heated oxygen sensors can change the AFR and I also provided data that supports the procedure. If you have the burning desire to understand more, you will need to catch up by testing it for yourself. It appears your ego has been hurt and your attempt to build it back up is blocking your ability to understand this logically. For you to make a statement like “If the sensor isn't screwed in, I don't think it's grounded (electrically).” Is a perfect example that you are either lazy or you need help with your ability to use and understand the Nissan Service Manual. With all those years of experiences I would think that it’s ego building and laziness.
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When everything is operating correctly and under normal conditions there is no need for the ECU to make any additional adjustments to the AFR from the secondary sensor. I’m not saying that there isn’t fine tuning going on. That never stops. Under abnormal conditions like for instance a faulty AFR sensor or an ethanol mix additional adjustments would be necessary. The ECU is programmed to perform many checks and balances to insure proper operation and safety procedures to avoid catastrophic failure.
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Why you are resisting the fact that technology is advancing and you are behind the times.

You’re claiming that I maybe wrong or at least implying some doubt. Well that’s fine with me, but the damage of passing on outdated info hurts everyone else.

That's EXACTLY what I'm getting at...I think that your test is NOT the same as gutting your cats (what this thread is actually about!!!).

Letting the sensor hang in open air...OF COURSE it's gonna read full-on lean (if and when the secondary O2 is referenced), and richen things up.

So if it reads full lean (atmosphere), then yeah..it'll run super rich, as you claimed.

So I'll concede that you are 100% correct given the scenario you described (sensors hanging). I never said you were wrong about that.

What I said was that when the sensor is installed, but there's no cat in front of it...then it's NOT going to do what you said, and you've shown NO evidence otherwise.

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....and I have to laugh - "I'm resisting technology and behind the times." Rather than answer the question I posed, you go for "look everyone, he doesn't understand the technology here".

You claimed the second set of sensors are for diagnostic purpose ONLY, useless for A/F monitoring and will not influence the tuning. I clearly provided firsthand knowledge showing a step by step procedure for doing a simple test to show how the heated oxygen sensors can change the AFR and I also provided data that supports the procedure. If you have the burning desire to understand more, you will need to catch up by testing it for yourself. It appears your ego has been hurt and your attempt to build it back up is blocking your ability to understand this logically. For you to make a statement like “If the sensor isn't screwed in, I don't think it's grounded (electrically).” Is a perfect example that you are either lazy or you need help with your ability to use and understand the Nissan Service Manual. With all those years of experiences I would think that it’s ego building and laziness.

There's no ego attached to my post. I could care less if I turn out to be wrong. However, I'm not.

Lets clear up a few things.

I can read an FSM, just like you. Yes, I was lazy in not checking to see if the sensor ground was the exhaust. That does not make my argument any less valid...ad I'll repeat it here, so it doesn't get ignored again:

Letting the secondary O2 sensors hang in open air is NOT the same as having them in place, but with no cat before them.


That's my whole argument, and you have yet to prove ANYTHING with respect to that.

And to prove my ability to read an FSM, here's yet ANOTHER piece of evidence that under NORMAL CONDITIONS, the secondary O2's are ignored:

Do you see the 2nd O2's listed there as a possible cause for a overly rich condition? No.

When everything is operating correctly and under normal conditions there is no need for the ECU to make any additional adjustments to the AFR from the secondary sensor. I’m not saying that there isn’t fine tuning going on. That never stops. Under abnormal conditions like for instance a faulty AFR sensor or an ethanol mix additional adjustments would be necessary. The ECU is programmed to perform many checks and balances to insure proper operation and safety procedures to avoid catastrophic failure...

...and here, you agree COMPLETELY with my argument!

...

I'll be glad to discuss this as long as you like, no ego involved...and I'd appreciate if you kept it on topic, rather than playing amateur-psych and deciding for everyone that I'm "behind the times" (whatever that has to do with this argument????).


- Brian