anyone know if this is all i need http://weapon-r.com/english/index.ph...oducts_id=5845

it comes with a filter as well

they also have one for 90 - 92 models but i dont think it will work


87 na

 

Yeah, that's it. You AFM is square and that adaptor plate allows you to clamp a round filter to it. Too bad you cant use an S5 AFM (or as far as I know) since it is less restrictive and already round.

 

It's not less restrictive.

 

so what do i do with the air pump hose

 

why buy that for $68 when you get the same on ebay for $8. Go buy the drop-in filter for the stock box and gain more instead of lose power from sucking in hot air

 

my car has a little breather connected to the air pump. its tough to see but heres a pic

 

While they make some decent pipes for other vehicle models, that RX-7 AFM adapter isn't the best design, and foam filters are generally considered slightly inferior to the pleated mesh types like K&N, Apexi, etc.

If your NA engine is generally in stock condition, a simple K&N drop-in will work just fine. If you have a highly-modified engine, then you may want to piece together your own kit if you like making things yourself. As stated earlier in this thread, you would need to make some custom ducting panels to keep the hot radiator discharge air from getting sucked into the intake... this goes for making your own kit as well as buying the kit in your link. Some of the pricier kits on the market come with ducting.

Buy a "crankcase vent" filter from your local auto shop.
http://www.knfilters.com/vent.htm

Because a lot of those Ebay kits have cheap plastic AFM adapters and there have been reports of reversion waves (mostly in turbocharged cars) ripping up the filters and the resulting pieces getting ingested into the engine.

 

Why on earth is the stock intake snorkel still in place?

 

i put it on there to get more cold air to the intake. behind the headlight theres not much break in the frame for air to get thru.

 

Then you shall be sorely disappointed.
The only reason any air flows through that snorkel (when connected to the stock airbox) is that the engine pulls it in.
Absent the suckage* of the stock sealed intake, no air is being "forced" through that tube to feed your cone filter.


*Genuine JDM technical terminology.

 

It hides the ugly fan shroud.

 

What if you design the intake box to have a hole for that snorkel? Will it have the suction effect then or will it still be useless?

 

^ +1

 

The box would have to be air tight, and connected only to the snorkel and engine. Which, in turn you would get something similar to the stock setup.

 

well im going to leave it on because i got it for free off my parts car, and no one looks at my engine bay. AND it doesnt weigh a damn thing so i dont care. its a nother path for the air to travel imo so its staying.

 

The stock cold air snorkel is a great way to get cold air into an airbox.

The Mazda airbox is the problem with the intake system. It flows rather poorly (AutoSpeed ahs run some tests and finds it to be very crappy).

As soon as I have forum vendor status, I will be releasing the first fully bolt on cold air system for the S4 NA using a new airbox, cone filter, and other stuff. I'm already treading the fine line between following and breaking forum rules without vendor status, so I can't say much more.

 

awesome, i'm very interested. if that happens soon then let me know

 

the only thing i can see whrong with the stock intake is the inlet for the AFM. other than that, it seems to be a perfectly good piece of kit.

 

Yeah I have yet to see an intake kit which has exception function, and bought the K&N for the mean time till I find something that isn't useless.
The air box is definitely key though otherwise your sucking in ambient heat and loosing power compared to the stock box. Some have built a few which look great, but I will be interested to see more future plans for a good intake kit for the FC.

 

In true AutoSpeed fashion, they performed that test on a flow bench rather than on a dyno using the respective stock engines. While this method is great for comparing components for a given application, it does not take into account that a "restrictive" filter box may work just fine on a 146-160bhp 13B engine even though it may choke out an 800bhp 5.7L V8. In similar fashion, they could have performed a test on the stock Mazda RX-7 brakes and shown that they are totally inadequate for a school bus.

Additionally, the RX-7 box rated in the middle of the pack once they removed the dirty filter and compared it to the other filterless boxes.

While a custom intake could help performance (more so with 13B engines producing in excess of 200bhp) I just don't want the stock NA owners out there thinking that there is something horribly wrong with their stock intake system just because of some ghetto test on the internet.

 

i <3 my stock intake.... just as much as i <3 my rb header... just as much as i <3 my evo 8 turbo sitting in my living room.

i got to the point that i dont think there is much to do on a n/a besides exhaust work

then its all for ***** and giggles.

on btw, the webber out flows the stock air box, so maybe you guys may be interested in a carb conversion.

i miss my carbbed 7... that thing runs like a beast.

 

I agree. While I do believe if you are going to modify/upgrade something you should do it right, for a stock N/A application the stock box does just fine.

 

True enough. On a stock NA I expect the gains to be minimal. I'm currently just trying to find a stock NA to use as a dyno mule as to get some actual numbers.

As soon as I've done with the jigging on the S4 NA box, S4 TII is the next step.

 

Aaron, what exactly makes the stock air box flow poorly? I have been contemplating modifying the stock box to get it to flow better. I want to keep the factory looks.

 

This is speculation on my part, but here goes:

1. The plastic "ribs" that come down from the lid seriously block airflow.

2. The narrow AFM input that squeezes down right at the cold air source.

This is based upon watching the dirt pattern form on the stock filters. It only forms right at the cold air input in about a 6 square inch area. I have inferred from this that the majority of the filter is not seeing much flow.