has any one put headers and full catless exhaust and had their z run lean??
and had mad oil consumption and valve noise

 

It's because the car no longer has cats, or atleast I think thats what you mean. The O2 sensor is picking up more O2 from the cats so the ecu re-adjusts the fueling becuase it beleives it's running too rich, thats the what you get for not running cats, a beleive thats how it fans out

 

Your car is breathing better and now as a result the A/F will run lean. Only way to correct that is to go back to the way it was or get a tune.

Secondly, neither of those mods will cause oil consumption or valve noise. It sounds like your engine needs a health check.

 

actually the post cat O2 sensers only tell the ECM that the cats are working , with an O2 cheater of some sort the ECM doesnt know anything is different. Leaning out , probably a little but from what i understand our cars are already run rich from the factory.

 

Even if you get a CEL saying you are lean, you arent "necessarily" running lean...

Often times what is happening is air is being pulled into the exhaust flow stream during the scaveng phase of the exhaust pulse. And if the leak is upstream of any of the O2 sensors, the sensors will see an excess of O2 and tell the ECU your engine is running lean. (even though its not)

Check for leaks and tighten down all the bolts and see what happens.

Tony

 

Curious what year is your car?

 

2006 enthusiast w/ megan headers, megan testpipes, injen catback, and ARC Induction Box

 

won't he lose oil with severe back pressure reduction? that is what I was taught, but I am old and crazy.


just saw you have an 06, that explains it, I can't belive you modded the car without researching it , the 06 oil consumption issue is common knowledge on the net.

 

https://my350z.com/forum/showthread....il+consumption

 

No, headers and exhaust will not cause oil consumption.

Yes, they may cause you to run lean - if you have these mods it's in your best interest to get tuned/reflashed

If your car is N/A, adding headers/exhaust will not make your car run DANGEROUSLY lean, but you will likely not be making optimal power.

 

Headers and exhaust cause excessive oil consumption? Sorry but I don’t get it.

 

I think the 06 is the reason he is bleeding oil, however, the loss of backpressure can contribute. The oil, like most things, will take the path of least resistance....the backpressure normal keeping it from making it's way into the exhaust can be redduced to the point that it ends up taking that path.

 

You might be confusing backpressure with cylinder pressure.

Cylinder pressure keeps the oil down where it should be. Low cylinder pressure may allow some "blow-by" ... I believe low cylinder pressure happens when you rev your engine under zero-load (in neutral), whereas high cylinder pressure occurs when engine is under load... keeping the oil where it should be.

However you seem totally confused because backpressure in the exhaust has nothing to do with this phenomenon.

 

if the car is running lean. Could this cause the car to bog and stutter at certain RPM's? or should the car still run smoothly, just not as *efficiently*?

 

Hmm, agreed with others on the consumption probably not related to the mods and is something you should document and work with a dealership on.

Regarding the lean issue, I'd follow Hydrazine's thinking and look for a leak. Revups tend to compensate quite well for breathing mods.....too well. I know un-tuned my car returned to it's factory rich state real fast after adding my breathing mods. I have no doubt that with a revup you can safely run any/all breathing mods due to the ecu compensation, you just won't get anywhere near the full benefit without a tune.

 

I'd seriously think about getting a tune, whether it be a reflash or a utec. I added headers and high flow cats at the same time and my car ran pretty lean in the midrange at WOT.