Quote:
Originally Posted by fstrnldr
i find it interesting that a Nissan engineer would refer to it as a plastic intake manifold when every technical document i have read from Nissan regarding the intake refers to it as a nylon piece. Before someone points out that nylon IS plastic, i know this, however nylon is far stronger (especially the blend used in the auto industry) than your standard piece of plastic, and Nissan seem to go out of their way to point this out.
As far as GTM going far above 4 psi on the stock intake, don't forget GReddy, and i believe AAM have as well. i haven't heard of a failure yet, and the G37's have been boosted for a couple of years now. You can also look at other non Nissan vehicles that use the same Dupont technology for intakes as well as charge piping on a variety of factory engines, including turbo diesel engines.
Basically for anyone other than bullitt, and maybe a couple other insane folks looking for that kind of HP. i'm sure the factory nylon intake will not have issues. High boost, and high hp may be a different story.
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Technically, the intake manifolds are made out of a material called Polyamide 6. You are correct that it does fall into the nylon family however you are not taking a look at the most important aspect of this material...What is its intention and how was it engineered?
Polyamide 6 is a very versatile material and can be used in many applications, for example. It is also the same material used in radiators. However, radiators actually use a material designated PA66-GF30 which is a stronger material due to the addition of the 30% glass fiber construction. Radiators use this material because they see....pressure....as well as heat. To stand up to the pressure the radiators use internal and external ribs to prevent cracking. For reference sake...research Nissan Titan radiator crack...The Nissan 370Z intake manifold is constructed out of PA6-GF30. This material is good for high temperature working conditions but is not intended to see very much pressure.
So we've answered the first question, what is its intention? Well, the intake manifold is intended to see high temperatures obviously in its environment directly above the engine. But, on a naturally aspirated engine it is not intended to see pressure. Which is why NISSAN told us the intake manifold was not intended to see more than 4 psi.
The other thing to consider is the engineering that goes into something. Just because you take a material that has the properties you're looking for does not mean it is 100% perfect for the job if it was not designed to do that job. What I mean by that is, take a piece of wood...That wood might have great strength at 1 inch thick. But, if you introduce pressure to that weight then the 1" thickness is no longer sufficient. Now you need to add internal ribbing or other support structures to hold it up. It's the same principle for an intake manifold, or radiator, or anything else...
NISSAN engineer's developed the factory intake manifold to work in an NA environment...Which is exactly what it does, and it does a great job at that. They did not intend for that manifold to see boost.
Yes, there are other appliations that are using these materials for intakes or other pressurized systems, however they are designed that way from the factory, from the beginning. The engineer developing that part is making sure that it can stand up to the task of seeing that heat and pressure. The Nissan 370Z came from the factory N/A so NISSAN chose the best material for the job.
I'm sure by now you have done the research to see that the Titan radiator's have a high failure rate. Some people can go 10-15K on one...Others are getting over 100K on their radiator...My radiator blew out at 35K. I'm not saying that the minute someone introduces boost to their car that their intake manifold is going to explode into a million pieces. I am merely passing on information that we have received from NISSAN that they are concerned about these manifolds seeing over 4 psi for long term durability.
P.S.- I know I'm not going to sway the opinion of someone who introduced himself to Josh at our open house event as "the guy who talks #### on the STILLEN supercharger." This information is for everyone with an open mind...