Just wondering what the pros and cons are of the standard Nissan OEM air filter set up verses the aftermarket pod filters that many people run?
I think its just easier to install and remove a pod filter over the stock panel filters. Thats the only real reason i switch to a pod filter. It was also standard on the usdm 25 anniversary stillen models.
Re: Pros & Cons The purpose of an air filtration system is to prevent dirt from entering the engine. An OEM system is about as good as it gets. A pod filter is supposed to give "free horsepower" by improving airflow to the engine. The only way it can achieve this is by reducing the filtration efficiency, thereby permitting more dirt to enter the engine.
When installing a pod the idea is to get more surface area filteration. Not sure if this would be true for a single pod with the y piece still fitted. Best results you would get dual pod setup. More surface area at the same filteration levels would move more air? Assuming there is no bottle necks in pipe work etc.
and if you've ever seen an unmolested stock airbox system, there is about another meter of small diameter intake piping that draws air in from under the headlights back to the panel filters. THIS would be the main reason why it is better to move to a pod.
Any other ideas for airbox setups? Anti? Thanks guys, that pretty much clears up that question. I was thinking of going back to the OEM set up but MORE pipe work is the last thing a TTZX needs. Any other ideas for airbox setups? Anti? I'll be disappointed if you don't throw your hat in the ring here.
The Stock airbox is OK provided you rip the ducting out from under the guards and then cut the sides out of the airbox where the air entry is. Then its quite free flowing.. No defects either http://www.aus300zx.com/forum/showthread.php?t=278073&highlight=airbox
Power wise......keeping in mind this ISN'T a Zed and is a single pod setup..... [yt]PAIxeQUSg-Q[/yt] https://www.youtube.com/watch?v=PAIxeQUSg-Q In short they test several pod filters and there was no noticeable HP gain at all. IN fact, in some cases there was a loss. HOWEVER.....many would also argue that a POD is just 1 piece of the puzzle. You need a POD, Exhaust upgrade, AND....a TUNE to suit the mods. At the end of the day, ,many people like the induction noise a pod offers, and it's easy to clean/change. meh.
Here's something to consider regarding a stock Z32 engine. The VG30DE engine is 2960cc. The redline is 7000 rpm. When we don't have the airflow numbers, we can use the general rule of 2.5 times the horsepower of the engine to get an approximate amount of air required. If we want to calculate the CFM (Cubic Feet per Minute) for a 4 cycle motor we can multiply the cubic inch displacement of the engine by the maximum rpm (Revolutions Per Minute) and divide the result by 3456. Then we multiply the results by the volumetric efficiency of the motor. The volumetric efficiency is a factor determined by the efficiency of the turbo, the electronic control systems, the type of fuel injection and the variation of valve timing or opening. A carburated engine normally has a volumetric efficiency of 0.70 to 0.80, but the electronics can raise this figure as high as 2.0. A diesel engine (2 cycle or 4 cycle) normally has a volumetric efficiency of 0.90. A turbo can raise the volumetric efficiency to between 1.5 and 3.0. If you don't know this value for your turbo, it is best to use 3.0. Capacity - 2960cc RPM - 7000 VE - 3.0 The Turbo engine will require 732 Cubic Feet per Minute (CFM), or 20,720 litres per minute of air. If you have an NA, you can forget about a pod filter, because the NA won't have the VE of a turbo engine. Using the above figures but replacing the VE figure of 3.0 with 2.0 equates to an air flow of 293 CFM or 8,288 litres per minute.
Re: THAT'S STOCK Stock at 8000 rpm & 30 psi boost? What's the volumetric efficiency figure used in the tables?
I didn't really have much of an opinion on this but since you asked, here's some general information on turbo intakes you can use to make up your own mind. Turbos are pressure multipliers. The rate at which they multiply pressure depends on the air pressure at the turbo inlet. Not factoring temperature, at sea level this is one atmosphere (1 BAR, 14.7 PSI) of pressure. Slightly less in reality as the turbo is "sucking", but in an ideal world close to. For an example, assuming a perfect 14.7 PSI at the turbo inlet (impossible), and you've set your turbo out to output 29.4 PSI (two atmospheres; 2:1 pressure ratio as it's called) 14.7 x 2 = 29.4 PSI The more restrictive an inlet pipe to a turbo is, the lower the air pressure before the turbo and the lower the boost level output at a result. Every bend in the intake pipe lowers the pressure before the turbo to some degree, as does a restrictive air filter. Another example, with a restrictive intake pipe: 13.7 x 2 = 27.4 PSI So your turbo will be working just as hard, and giving you less as it does. This is why people boost higher with the same controller settings after fitting up a Selin kit. How big an air filter has to be can actually be checked too... It factors in surface area, how much CFM it must flow, the density of the filter, etc etc etc. More is not always better but it certainly doesn't help... Been a while since I read up about this stuff so check out these links for more http://www.turbobygarrett.com/turbobygarrett/air_filter http://www.turbobygarrett.com/turbobygarrett/pressure_ratio
