No, not at all.

 

lol, no.

You're good to go with ART pipes, just don't get the car inspected with them fitted. That's the same for any test pipe.


As for changing the tune whilst you temporarily fit your stock cats, again, no need, just swap them out and your're good to go.


The details other people have gone into are just about the way cali carries out inspection and about the option for changing tunes (if you wanted to) Basically, with uprev and a base model (sans cruise) you would use a laptop to swap the tune over.

But as i said, you don't need to change the tune whilst you run the stock cats for inspection purposes.

 

That sounds much better!

 

If I had to swap out my cats once a year for inspection, the ART pipes are still worth every penny

 

 

 

F2CMaDMaXX I see your a big fan of MD by your signature...

How was the gains with the MREV2? AND if you ever sell that TDX Shockwave, hit me up

 

Haha, yes, i like their products, the independent results, even though i know MD have done the dyno testing to make the products.

I have to own up though, i'm currently awaiting those two products, there was a delay in the fabrication of part of the Shockwave, i'm just waiting to get it all at once.

There will be some gains when i add the MREV2, but not as much as there would be on a revup as i just have the regular DE. I would expect about two thirds the gains i felt after installing the spacer.

I hope that i never have to sell the TDX2, can't wait for it to arrive, i've arranged to borrow a $2k lens for the product/install photos

 

I just got a code after about 150 miles after tdx-2 and art install. I'm going to call tomorrow to see what we can figure out. I think I might have a leak I can't really hear it over the sexy noise.

 

Which model engine do you have?

 

Wouldnt you expect more from the MREV than the Spacer? Thats what I would think, I guess the dyno will show its true colors!

I have the DE engine as well... Cant wait to see the photos. You should also weigh that exhuast prior to install.

What numbers should I hope to see when I tune? I am still using the stock map now. What may any of the think I should gain? I have a CAI, Spacer, Headers, ART Pipes, True dual exhaust.

 

There are already dyno's for the DE showing differences between the stock, MREV2, Spacer and the combo's. Most importantly, showing deltas of each.

Spacer only


MREV2 only


Spacer and MREV2



So for us already having the spacer installed, this is the gains when adding the MREV2. Basically, it gives us a little more power and torque and solidifies the gains from the spacer throughout the range.


Can't tell you on numbers for everything, dyno's are so fickle and aren't good for showing top numbers, only delta changes for parts you add. Also, part power increases don't fully stack, they compound each other, so add together the individual gains and knock a bit off i'd say

I'd also say you can gain that back from the tune itself, how well a car gains on the tune will differ from car to car, from good to great and depending on it's state of tune and how well the mechanicals are.


Finally, and i think this is important to note, it's my favourite part, these are not all peak gains, they're throughout the range, and a lot low down, i love that. 90% of most driving, especially daily driven, will be lower/mid range, so i like getting my gains there

 

I am experiencing the exact same thing. I will have the pause while accelerating every once in a while. My mechanic said that even though the OBDII reader is saying there is a "deficiency in bank 2" the code P0430 means your car thinks your cats are bad, and it is not the sensors fault. It only says bank 2 because bank 2 is the first one that it reads, and if it could, it would read a deficiency in both banks. On my car If you accelerate hard at WOT starting from 1st gear, you will not experience a lag in acceleration and the car feels as if it has more power. Its only during a certain amount of acceleration that the pause occurs. The problem with getting a CEL though is Basically your car can still smell the fumes...(this is what Tony from Motordyne said to me.)

 

I'm about to unplug my rear O2's so they can't be used for long term fuel trimming, i don't care if they read the cats not there, it's the fuelling they switch to that messes things up.

I don't get the codes for the most part, but after loading a fresh rom, everything feels great for a while.

 

I don't have a tune yet, but are you saying that if I unplug the lower o2 sensors from the harness and drive around that way, it will make the car feel better?

 

Well, I don't know if it will populate the long term fuel trims from the widebands, but i'm hoping so. Ideal situation would be getting the sensors back into the main exhaust flow again and disabling the codes for the cats. That just disables the cat codes, not the sensors, so when the ECU wants to get AF info from the 'cat' sensors, it can.

 

If you unplug the o2 sensors from the wiring harness, won't the car read it as the sensors not there? They are unplugged from the car, so basically they are just there to keep exhaust from escaping through the O2 bungs in the test pipes.? ?

 

Correct.

On the 350, the rear o2 sensors seem to have two functions, a primary and a secondary.

The primary, everyone knows, they detect the level of oxygen in the stream and determine if the cats are working ok or not, then flash a light if they're not.

The secondary, most people do not, and most cars do not do this. However, it has been found that 'under certain conditions' (seems to be stoich/cruising) the rear o2 sensors are 'switched' and the AF is read from them, it seems, to assist in setting the long term trims and reading AF during gentle cruise conditions.


Of course, in the case of those using antifowlers, that's going to cause problems some of the time, because of the 'some of the time' part, most people will not even realise


My hope is that with them unplugged there is nothing to read under any condition, the worst they can do is complain about no cat reading, they sure as heck can't rear any AF. I want to fit regular bungs so they can do their secondary function, but until then...

 

So what you are saying is, if I unplug them, the AF will be forced to be read elsewhere, and the slight pause before accelerating will never occur again? Because the slight pause happens only 'some of the time'?

 

I can't say this for 100% certain, what i can tell you is the following:

AF ratio on the 2004.5 and onward, cars, is read by factory wide-bands sensors, instead of the regular O2 sensors that most factory cars use, especially up to that point in time.


Even with the older/simpler O2 sensors, the front or, upstream sensors are the ones responsible for reading AF ratios, they read a certain AF and the figures were used by the ECU to add/remove fuel. The rear were only used to detect a certain range, if the readings were in a certain range, then the cats were deemed ok, if not, they just enabled a dash light, nothing more.


On the 350z, the service manual states that which i just mentioned above, with the exception that, 'under certain conditions, the rear (downstream) sensors are used to calculate AF settings'.

It seems that these 'certain conditions' are during Stoich, cruise conditions with light throttle. What seems to happen, is that instead of just reading the rear sensors and saying yay or nay for the cats, it actually takes the readings and applies them to the fuelling data!


So, turning off the warnings in a tune, means that with hiflow or no cats, the ecu sees a cat problem, but doesn't flag the light on the dash.
The problem comes that the ECU still has the option to take the AF data and make adjustments from it, i believe to the long term trims.



So, disconnecting the rear sensors will do two things; Cause the ECU to not read info about the cat condition, it'll therefore flag a cat problem. Secondly, it will obviously not be able to read fuel conditions, in short, it will actually flag a sensor problem, rather than anything to do with the conditions they're reading.


I do not know how this will affect any long term trimming of the fuel tables, i don't believe it will, but who knows.

So if you're sometimes having a problem going from a cruising condition to accelerating, you're coming off perhaps badly set long term trims (it gets set rich), back onto the 'live' readings from the wide-bands, yes, you could have this problem.

I will be able to disconnect them in the next few weeks.