so ive been reading around and see people use stock air box and filter for the fact of keeping the fuel air mixture at the appropriate levels who uses an after market intake like k&n and why?
any issues?
ways to prevent the fuel/air mixture from leaning out the fuel?

hope this is a good topic

also which brands are recommended? and are the MAF sensor deleted or what?

 

people use the stock airbox because it keeps the filter cleaner and longer and in fact probably makes as much power as most aftermarket intakes you can find and put into the engine bay.

hot air intakes make more noise and flow better but pulling hotter air the power increase from increased flow is negated from the hotter ambient air it is collecting.

whoever told you it affects the fuel mixture is full up to their neck. you cannot delete the AFM(corrected for you, read as AirFlow Meter) with a stock ECU, only a standalone replacement ECU can omit it.

 

I don't think the intake works like you think it does.
Retaining- or not- the OEM airbox and filter has nothing to do with maintaining the fuel/air mixture, that's what the ECU is for.

 

People use the stock air box because up until 180whp, the engine doesn't need any more airflow. The stock airbox is a pretty good piece, and if one still has the snorkel, keeps the intake air relatively cool. And the intake doesn't affect the AFR. The ECU has more than enough adjustment to manage AFRs with whatever non-forced-induction intake you can come up with. If one does switch to a cone filter, then a heat shield must be installed to keep the engine heat out, as well as fresh air ducted in.

 

If your car is NA, a drop in K&N is the best you are going to do. If turbo, a cone filter, custom TID and heat shield is what you want.

An air filter has absolutely nothing to with fuel/air ratios.

 

Assuming the filter is in the engine bay...

 

yet no one has mentioned yet that the aftermarket intake support is probably the weakest of all areas for these cars.

about the only "kit" i can think of specific for the second gen is the corksport and it is hot garbage. universal kits can be adapted and often are but the filter elements are cheap as all hell with the generic kits. HKS makes a pod filter and HKS a cone filter to clamp to the AFM but does not replace the snorkel piping. there is no true cold air kits that i have ever seen, just honduh fabricated pieces of **** that do nothing but make more noise.

sorry, that sounded biased...

 

I'd accept Karack's "biases" over most peoples "facts" any day.

 

if its turbo, it wont matter, as the air will be just as hot, or "cold" as the IC can make it... are you turbo or n/a?

 

oops i meant K+N also makes a cone filter.


intake temps still play a role in turbo rotaries, the colder you get the air before it goes through the turbo the better still.

that is like saying that turbo rotaries run the same in cold weather as they do on the hottest day of summer, irrelevant of coolant temperatures. ambient temperature drops actually result in more dense air going into the engine, compressed and consequently higher boost levels on cold days. CAI for turbos is almost as beneficial as it is for n/a engines, the drawback is the piping will restrict airflow much more the more power you make without using oversize piping with few bends, an unreasonable task in most cases. but you will notice many drag cars with huge holes cut in the front ends to feed the turbo fresh cool air.

of course the intercooler will be able to exchange the heat better since the air is much cooler passing over the core on cold days but there is always a factor that it is easier to keep cool air cool than it is to cool down scorching hot air with warm air passing over the intercooler already on hot days. the same applies to the cooling system, at a point the engine produces too much heat for the radiator to process, at least with the intake temps you have a little more control over it.

of course i'm not saying it is a huge benefit but we are still talking a % or 2 of max power which is still enough of a difference, in some cases the whole difference of changing out the intake. for turbo 7's the stock airbox begins to hinder power at just above stock levels, the n/a will likely not notice much or any benefits from it's removal.

 

Hotter inlet air will still result in hotter manifold air temperatures even with an intercooler. However, the difference is not nearly as pronounced as it would be on a NA engine.

 

in much fewer words what i meant... lol

 

i knew someone would pick it apart also with a stock top mount you have to remember the heat soak involved. and the all around higher temps the rotaries produce. still waiting to see if OP is turbo or n/a though.

 

yeah i have a 1987 turbo II almost stock has the S5 turbo in it with a jasma cat back exaust top intercooler so one other question that might play into this is the S4 stock pushs roughly 180 HP stock right? well with the S4 motor and S5 turbo does it now push what the S5s do? the 202 HP and does that make a difference for what intake i have? right know i have the stock box.

 

I was going to present the physics equations involved, but I figured that simpler was better in this case, lol.

Your engine will work fine with the stock box. If you want more boost then you can upgrade the TID, and at that point you can add a pod type filter if you wish.
http://fc3spro.com/TECH/MODS/IN/tid.htm

Just a word of warning though, any time you screw with the engine to produce more boost, you need to also make sure that your fuel system can handle the additional fuel requirement. Common basic fuel modifications include installing an Rtek chip that has a fuel cut defenser function, and upgrading or rewiring the fuel pump. Larger fuel injectors are also required at a certain point, and a nice Aeromotive fuel pressure regulator is common.
http://fc3spro.com/TECH/MODS/FUEL/fpump.htm
http://fc3spro.com/TECH/MODS/prefp.htm
http://www.aaroncake.net/RX-7/grounding.htm
http://www.pocketlogger.com/index.php?pid=rtek7

 

forgot to mention the FCD my bad