What were the Nissan engineers thinking?
 

I'm thinking about installing a set of the Z1 silicone side PCV breather hoses. These are the relatively short hoses that are fitted with a restrictor and attach to the post-MAF intake tubes. After looking at the hoses, it strikes me that they are a lot simpler in design than the complex baffle arrangements that come from the factory. Does anyone know what the Nissan engineers were thinking? What is gained by having the multiple baffles? Are they meant to reduce noise … catch debris … whatever??? I can't help but think that the engineers had some purpose in mind … which also makes me think that something may be missing from the Z1 hoses. Any thoughts? Also, has anyone had any issues with the Z1 hoses after installation? They certainly look to be durable and easy to install. I've also heard that the factory baffle arrangements have snapped on occasion … which is another reason I'm leaning toward the Z1 hoses. Problem is that I just have a nagging feeling that the engineers were onto something, but it escapes me what it is. Again, any thoughts?

If you're talking about the accordion part, it's because the engine moves, the air boxes don't.
If you're saying the boxes, that's to catch debris and shít/oil

Yeah, pretty much what DE said.

Let me say though, car manufacturers spend million upon millions of dollars to create all the parts that make up a vehicle. I believe strongly that part of that research is in developing parts that are "manufactured to fail" in order to secure future profits from parts. For instance, these accordion style intake hoses satisfy the notion that the part has to be flexible to allow for engine movement, but at the same time is manufactured with weak spots due to its inherent design. These flex points become weak and crack, forcing the need for a repair, rendering the need for a (usually) dealer only part, therefore hitting their intended goal of securing future service work. Can't forget that manufacturers make large amounts of their profits through parts sales. I've replace SO MANY of these hoses at my shop it's silly. Actually have an Accord here now awaiting the delivery of the intake hose from the dealer.

IIRC, those are to tune the intake ducts and reduce pulsations in the air flow. Same basic principle as partially closing your windows to eliminate thrumming in the cabin. But my memory ain't what it used to be, so that take with a grain of salt; check the FSM for more info. Going by my past experience with gas flow measurement, I'd guess they don't do much until you reach higher flows.

The manufacturer only makes money on the production and original sale (to a dealership or distributor) of a car and off franchise rights to their dealerships. They also make money from selling parts to dealerships which in turn sell them to customers. Dealerships make money in car sales, service hours, and parts but none of those profits directly go to the manufacturer.

Poor choice of words, I meant profits from the sale of the parts from the service, not the service itself. My fault.

I completely disagree about engineering things to fail. That is false. No company would do that simply to increase repairs and such. That would only hurt their name. Every now and then there is simply a quality issue or material issue, like you probably experienced. Engineers do make mistakes too when it comes to how much abuse a part will take.

However, there are companies that do some slightly sketchy things to increase profit. Take for example: Apple. They release an Iphone 5 that is superior to their iphone 4. they have the technology and ability to release an Iphone 5s, but they wait until about a year or so later to release it, so that all of the people who own the 5 will want to upgrade and purchase a new one.

You can disagree all you want, and I have no qualms with that, except that your disagreement is based on principle and not reality. Now I'll save the long story about recyclable parts, government regulations and their impact on the auto industry and the evolution of cars. You mistake the "engineered to fail" idea as present situation, when in fact the results of this take time before they come to fruition, long after the car has undergone the scrutiny of reviews and testing and not existing in a way to affect new car sales or company reputation. I'm could say, "trust me, I've been in a family of, and am myself, mechanics and dealership operators for a long time," but I'm not, because until you experience the situation first hand and have access to kind of information we do, I can understand your skepticism.

http://img.photobucket.com/albums/v2...psacadca58.png

lol.

Parts wear, if its a common issue they issue a recall which ends up costing much more $$. Unless you're saying that they engineer these parts so that they are "just bad enough" and does not warrant a full recall that would cost the automotive manufacture millions of dollars. Lets pick for example the current key turning off fiasco that GM is having, do you think that was intentionally engineered that way and they just got caught?

To design a part to fail is unethical and to be an engineer working on that part and knowingly release it could come back to that individual who was responsible for its design.

When you install your Z1 post-MAF intake tube, you'll understand my Nissan used an accordion design -- it's simply easier to maneuver (ergo install) in the engine bay.

The stiff smooth design of the Z1 tube is a bit of a bitch to install, but it's worth the effort. Hint loosen the bolt on the air intake box as it allows easier installation.

Well, yes and no. I'm not talking about the factory accordion intakes … I've already replaced those with the Z1 silicone post MAF tubes. I'm talking about the PCV "baffle box-tubing" arrangements that run off the side of the intake tubes toward the rocker cover. They're a rather intricate and complex design that some engineer must have spent several days thinking about. I'm not sure why such a complex design is needed compared to the Z1 PCV breather hose set which consists of short 1/2" hoses fitted with restrictors that attach to the post-MAF tube. I'm just wondering why the factory arrangements are so intricate, what with the baffle boxes and all. I can't imagine that there isn't some purpose to the design. I guess I'd also be interested in knowing whether folks who have installed the Z1 breather hoses have had any issues with them. Thanks again for any input.

Yeah, I agree … the Z1 post-MAF tubes were a bi*ch to install. However, I'm talking about the PCV breather hoses that run off the side of the tubes.

From what I've seen and been told is that the little boxes are sometimes for catching slight traces of oil/water vapor because some of the boxes have foam filters in them. But the Z, IIRC only has the box on one side, the passenger side. Their also designed to reduce resonance from the valve train coming through the intake that is a side effect of the PCV/breather system.

Just poor design but not intended to fail. Just like any part that breaks down easy with our Z's.

I 100% agree. Just look at our CSCs... ugh.