i have an k&n cone air filter, but with no intake pipe.
can i just attach it to the stock pipe?
and where would i attach the air sensor, and what would i have to do to it?
also, can anyone give me the dimensions of the stock intake pipe? thanks

 

if you have an 86-88 rx7. you need to buy an adapter to go between the air flow meter and filter. HKS has these for about $20. it holds a filter with a 3" hole. hope yours is...

if you have an 89-91 rx7. the filter will bolt right onto the air flow meter. but requires a filter with a 2.5 or 2.75" hole

 

As scott said, for the s4 you need an adaptor, for the s5's the filter can be bolted right on the air flow sensor.

However, i wanted to add that if you still have an airpump, you'll either need an adaptor with an orifice for the hose for the air pump, or you can get a breather filter for the air pump.

Also, if you don't build a cold air box, or somehow ducting cold air to your intake, you're sort-of counteracting any gain you could get with a higher flowing filter because now you're sucking in hot air which may, under some circumstances cause detonation.

 

What is the breather filter and what is its purpose?

Also is the thick rubber tubing that connectes to the stock air box the hose that leads to the air pump?

 

yep the thick rubber tubing from the airbox is going to the airpump making it so the airpump gets filtered air. the breather filter would be so "clean" air reaches the airpump vs unfiltered air if you got a cone filter of some sort and just disconnected the tube. certain kits, like the Apex'i kit actually have a little piece of rubber hosing and a spot for it on the bracket so you don't need the breather.

 

Thanks. So next question is where can I get one and is there a preferred brand that filters better than another?
Also what alternatives are there to getting a breather filter?

 

You can pick up a "crankcase vent filter" for a few dollars at your local auto parts store. If you need the air pump for emissions, then I suggest using the filter because a replacement air pump is big bucks, and it's not such a great idea to inject dirty air into your car's other components.

Any brand is fine, but here is a link to the K&N crankcase vent filters so you know what to look for.
http://www.knfilters.com/vent.htm

BTW, here is the adapter needed for the 86-88 AFM:
http://66.216.67.51/product.asp?0=214&1=319&3=553

 

Autozone now carries the air flow meter adapter in their rice section.

 

Most of the cheapo Ebay type adapters are not very good. Make sure that it transitions well from round to square. The plastic adapters are not very impressive. I have yet to see anything better than the $20 HKS adapter. Hopefully the Autozone adapter is decent.

See one of my later posts in this thread for examples of what to look for.
https://www.rx7club.com/forum/showth...hreadid=197293

 

i think you can get an adapter on this site for less than 20 bucks...not sure though.

 

I have a 91 NA so I will not need the adapter. I do need my air pump for emissions because I live in the land of smog ***** in CA so I will be searching for a breather filter or a crankcase vent filter.

Thanks evil aviator!