Hey guys- just picked up an NA '90 convertible. Down the road I'm planning on doing a full engine rebuild and turbo, but until i get some money saved up I wanted to do a few basic things. First and foremost I was going to put in a cold air intake, ordered a cheap aluminum tube and cone, went to put it in an found the air flow meter... Is there an aftermarket replacement? Or what do you guys recommend? I've been looking online and it seems like everyone just puts a cone on the end of it and calls it a day... Is that the best I'll be able to do without buying a map sensor and a new computer that will work with it?

 

You'll need an AFM adapter. Attach this onto the end of the AFM.



No need for an aftermarket replacement unless you're doing a standalone, where you can delete it.

The only premade CAI is the Mariah Motorsports one:





You can buy the close out assembly here: Mariah Motorsports by Design Energy Inc. RX-7, Rotary, KitCar and Sportscar Specialist

 

Is there any way to delete it or replace it with something that will fit inline with an aluminum tube air intake all the way to the throttle body? It looks like the stock afm is really restrictive so I was hoping to do something else other than work with the stock one...

 

There are cars making 400RWHP with the AFM.

To get rid of the AFM you'll need to buy a standalone like a Haltech, Microtech, Adaptronic, Tech3, etc. Then you can can go to speed density and replace the AFM.

ECUs | Adaptronic
Haltech - Engine Management Systems | Engine Management Systems
Microtech EFI
Electromotive | Electromotive

Just buy the AFM adapter and put the filter on it if you'd like to have a cone filter.

In stock form the stock airbox is just fine.

 

I would not have guessed cars made that much power on the stock intake- I'll just throw a K&N filter in it and call it day then I guess. Any suggestion for other entry level upgrades to make (I'm hoping to get maybe 200 whp out of it for now)? What is the weakest link stock? Exhaust? Ignition? I just want to give it a little more power and better sound for now while I save up for the rebuild.

 

Not with a S5 AFM he won't.

 

I have the cone filter adapter sitting in my garage.

And our cars have a "cold air intake" from factory. Its a ram air style provided you have all the original plastic bits. The S4 box flows better and "Broke_A_Baller" probably has one laying around for you. Tell him I sent you.

 

Oh ****.

My bad! Sorry about that.

Then he just needs to clamp the filter on the end of the AFM. Ez pz.

 

Turbo cars can make that much with the stock AFM.

I use just whatever filters, takes forever to recoupe the money for a K&N. But I've had them before and it's great to not have to replace them.

For a NA RX7 I'd do an exhaust, and if you want power eventually, you may need to look into a rebuild with a streetport, aftermarket intake manifold, aftermarket ECU, lose the exhaust diffusers, and a great tune. Another great modification is gears. But aftermarket RX7 gear sets are very expensive, but very worth it, and can help with the lack of torque that a RX7 has.

Search around here and you'll need many different ways to upgrade your RX7 and enjoy it.

 

Thanks for all the input guys. Like I said I'm just going to put a better filter in the stock intake (I do have all the parts). So with that settled, any suggestions for good mods to start with to up the power a bit and give it a little more aggressive sound? Ignition? Exhaust? (I have a wet shot nitrous kit laying around too but I don't know if that's a good idea to a bone stock car?) I'm super new to this car/rotaries any so input is appreciated!

 

Your gonna play hell to hit 200hp out've a n/a without a deep wallet, just enjoy the car for now, save up for another motor and rebuild, than worry about your HP #'s

 

What is everyone's opinion of nitrous? I only ask because I already have a kit laying around. It's roughly a 65hp wet shot though I can reduce that if necessary... Ok or bad idea? Would I need anything special other than a fuel pump, wideband afr, and adjustable fpr?

 

IMO, save it for your turbo build, i don't see the tension bolts holding up to NOS, just run her how she is, learn the car, and while learning, make a todo list

 

First of all people, the OP has an S5 and that's a totally different animal than the S4 AFM...it doesn't easily work with a S4 airbox.
I'll grant that we have an ambient air intake stock but if you can prove there's an iota of "ram" effect in that setup, I'll eat my filter.

 

I honestly never understood the "ram" part either, the stock setup put the air intake next to the hood latch, which with the hood closed, blocks it off

Even if it didn't, the air still has 3 walls to hit before it even makes its way into the tube connected to the throttle body, if anything, i would think the air would be slowed down with the stock setup, let alone the small amount the stock opening had, unless that was to help speed it up?

Quick batman, to the science chamber!

 

There is an unimpeded path from the nose to the air intake snorkel, even with the hood closed.
It is a reasonable implementation of a fresh air intake given production constraints but there is no pressurization of the airbox at speed, thus, no "ram air".
The engine is relatively free to suck in all the air it wants but I don't believe that any speed actually crams extra air to the throttle body.

 

The important thing is to not rip parts off the car because you think that they are emissions parts that are not needed.

As parts wear out and need to be replaced, this is what I would recommend:
- Drop-in K&N air filter
- Racing Beat catback exhaust
- Koyo radiator
- KYB AGX shock absorbers and Racing Beat springs
- Fumoto oil drain valve (no nipple)
- Anything but the OEM stereo, lol

Do not buy a new computer and MAP sensor. Much like brain surgery, this is not something that can be accomplished by a novice. If you really want a new computer then discuss it with your local professional tuner before you buy anything.

"Ram air" can mean that air is simply rammed into it, it can mean that air is rammed into it causing an air pressure increase, or it can mean a neat looking scoop that serves no function other than to help sell the car. The stock inlet on an RX-7 does not compress the air.

Actually, a centrifugal turbocharger compresses air by slinging the air into the inside wall of the turbocharger. Much like a tomato, fast-moving air compresses when it hits a wall. The higher the speed the more it compresses. Ram air inlets work in a similar manner, but they rely on the vehicle speed as opposed to turbine speed. Obviously, vehicle speed is very low when compared to that of a 150,000 rpm turbine, so actual ram air inlets do not compress the air very much, and at legal highway speeds they are worthless.