Best steps to take for cleaner revs, better throttle reponse?
 

Had my fc vert for a few months now, want to start replacing things and getting the 30 year old parts updated properly. Did the brakes, rotors, vacuum lines were all done shortly after purchasing the car, and I am putting on a new fuel filter later this week. Just wondering, outside of getting a k&n filter to replace the stock one, what should I be looking into first to get better reactions from putting my foot on the gas pedal? It's a convertible and I'm not doing a motor swap anytime soon so I don't expect it to be much faster, but I want to be able to feel when it's getting gas, if that makes sense. Getting the exhaust redone by a shop soon, nothing aftermarket I don't think, just a replacement system.

You make a K&N sound like a universally accepted performance upgrade, which, imo, it is not.
If you have the full stock intake, a regular ole Wix filter from Rock Auto (at @ $7.50) is the best deal going. You can replace it 8 times for the cost of one K&N and you don't have to pretend you didn't throw it in the dishwasher like everybody else.

Your vert is the heaviest of the already underpowered NAs, it'll never be a neck snapper without serious work. Probably the simplest change would be a 4.30 diff from a S5 GTUs, which would increase accel at the cost of some top end.

Doesnt hurt to check the throttle cable adjustment. These cars are old and cables will stretch over a long period of time, making sure you have minimal slack in the cable could even give you a few ponies if the throttle body isnt being fully opened.

Best steps to take for cleaner revs, better throttle reponse?
 

Make sure your 5th/6th ports are working too

Not really true on the K@N filter. In the 7 years I have owned my car, I have only cleaned it twice. The first time was right after I bought the car because it was all caked with dirt and hadn't been cleaned for 60k miles. The second time I cleaned it was a month ago because it hadn't been cleaned in 20k miles and would have been okay because it wasn't caked but I cleaned it anyway.

Paper filters will last 3-5k miles on a good day. In Texas, the air pollution is so bad, a paper filter will be black and nuked after about 3k miles. Thank the coal industry and their coal fired powerplants and the garbage incinerator in midlothian.

Shit you not, if I dont wash my car every week, I get a black dust all over my white paint. Never knew what it was until a chemical engineer friend of mine pointed out that it was industrial fallout and coal dust from power plants. Eeeew like a B.

And how would you explain the paper filter being "nuked" in 3k miles and the K&N being "okay" after 20k?
My explanation would be that the filter element of a K&N is so porous that after the oil starts to dry, the particles that are clogging the paper filter just pass right through the K&N.

I've just asked my friends and they've all said outside of a complete redux of my intake, throttle body, etc it would be a nice reasonably priced upgrade to the stock intake, I'm pretty new to anything under the hood working on my cars so I'm taking it as its given to me haha. I do live in Arizona and it's smoggy as hell, and I think the user above (I'm on mobile so sorry I don't have names and the formatting is shit) may be right, I need to tighten my e brake cable as well so I'll have to check that out. Does the fuel filter being gunked up have any effect on this? I'm guessing the one on it hasn't been replaced and is the 27 year old filter it shipped with, I'm about to change it. My reason for asking is it misfires at idle, and the plugs and wires were all replaced shortly before I purchased the car, so I'm trying to find out what's going on.

When it comes to the easy stuff- fluids, filters, basic maintenance items- don't even think about it, just replace 'em.
Don't forget there are TWO fuel filters, the big one in the bay and the sock on the bottom of the pump (in the tank).

About the air filter:
I'm not sure what your friends consider a "complete redux" of the intake but here's an idea...if a K&N is supposed to be an upgrade, that presupposes that the stock filter is an impediment, does it not?
So, pull the filter out and drive without it- see if removing the supposed "restriction" of the stock filter makes the slightest amount of difference. If you think it does (and I'd be skeptical), consider this: you've gone from the theoretical worst case scenario (at least according to the collective wisdom) to the best, from the stock filter to absolutely no filter at all.
Now, think back to that desperately hoped for and maybe fractionally perceptible power increase you felt and cut it in half because putting in the K&N is going to reintroduce some restriction back into the equation.
Given that a Wix paper filter is $7.25 and the K&N is $65 I question not only the efficacy but the "reasonable price" of the swap.

This is probably just me being stupid not knowing anything about cars but taking the filter out completely sounds like a good way to get all kinds of shit into my motor.

Thanks for the heads up about the filters, but is there a word for that pump filter? When I ordered the bay one from autozone they didn't ask which one, they just showed me what was available, and I'm guessing they aren't the same kind of filter.

@iduley what do you mean 5th/6th ports?

@ibeljin thank you I was just wondering about that and I saw your post, first thing tomorrow morning, could make a world of difference.

Rock Auto calls it the "fuel pump strainer" and has seven versions, from $2 to $11.

If you avoid sandstorms, driving filterless for 15 minutes won't hurt anything.

Good to know, and I'll try it out in a few hours, been up researching suspension, will update zzzz

Sort of.

The paper filter does by far have superior filtration as it picks up the teeny tiny stuff. I won't deny that.

It's not that I'm on some anti-K&N jeremiad here, I've certainly used them...in fact, one year we had sponsorship for one of our supersport bikes.

Here's the thing though:
Unless you religiously follow their cleaning and oiling protocols, it's a worse filter than the fractionally priced paper part and I'll guarantee that 99% of street people (especially those with stock airboxes) don't follow the instructions.

I've fucked around with my intake a lot and came to realize that as I tried to compare my latest mod to stock, it was easier to tell if I'd made it worse instead of better.
Even with the latest, most radical iteration, I doubt anyone familiar with RXs would notice much difference (although my ego would like to think they would...), so the whole idea of boosting performance merely by dropping in a different air filter strikes me as farfetched.

especially when the filter is sized for a ~200hp engine, and its installed on a 160hp engine

The thing for me that made the most noticeable difference from stock was when I replaced the stock exhaust manifold and cats to a header/pre silencer setup. After that I went to a K&N style cone filter. The butt dyno agrees with other posters. Not a very, if noticeable difference. Next was replacing the stock mufflers with an HKS sport system(now long discontinued so Racing Beat is a good choice). To make power the first place to start is a freer flowing exhaust than stock.

I never said that there was a performance increase, and I too from working in the field, have almost never seen a properly serviced K@N filter. They almost always have been washed and not re-oiled.

The fact is, when you get the K@N service kit, it will service the filter properly ONE time. If you clean and oil the filter the way you are supposed to, you will have no left over cleaner or spray oil from the can.

I prefer the K@N on a serviceability standpoint, not a higher performance or filtration ability standpoint. First, any paper filter will be far superior in filtration ability than the K@N just from design. Oiled gauze filters filtration ability goes up as they catch more crap whereas a paper filter does its best from the beginning to the end, there is no denying it.

What I am trying to say is, my promotion of the K@N filter is just for serviceability and time, not superior filtration or some magical 10 horsepower. No, I don't like replacing my air filter every oil change so spending 60 bucks plus 2 recharge kits set me back $90 but I would have spent a little bit more time and money dealing with the paper filters in the long term.

and just for the hell of it...

Filtration Testing for Amsoil, K&N, Napa, Jackson Racing, Baldwin, and Mazda air filters on a Miata

I know...it was the OP's friends who claimed that.
OK, here's where your logic eludes me.
You admit the K&N is an inferior filter but somehow still insist it's overall easier to deal with than a paper filter. If a paper filter only lasts the length of an oil change (so, 3k miles?), wouldn't the K&N require servicing at that same interval?

A paper filter is at it's very best when brand new, from that point on it's filtering capabilities remain constant but it's ability to flow air degrades.
A K&N filters best when fresh but it's airflow increases as the oil dries away and it stops trapping debris.
Seems to me that if you think the paper filter is toast at 3k miles, then you should also think the K&N needs servicing at that same interval and there's no way that's "easier" than just dropping in a new paper element and being done.

I live in Denver, which is a pretty dirty environment particulate wise, and my air filters last way longer than 3k miles in daily driving duty.

Sorry if I'm way off guys, everything I know I've learned over the past few months, and I haven't done much (not for lack of trying)

I can't find the point where I can re tension the throttle cable, there is a bar bent at 2 places attached and it leads down below the motor between it and the belly pan, so I don't know if I should start removing things without seeing it done first. Also couldn't do the fuel filter because it's between what I think is the crossmember below the transmission, and that's the only place I could get a jack under the car, not a lot of space to work with ATM. All in all not a very successful day.

My thinking with a new intake was the stock one just looks so restricted, couldn't imagine a cone style intake not being better in some way.

As an amendment to my previous recommendation:
If you believe the stock airbox/snorkle/filter is too restrictive, pull it all off and slip some nylon over the AFM snout and drive without ANY "restriction" at all...see if you notice a difference.

Here's a hint, you won't.

The rest of your post almost scares me.
The throttle cable is about a foot long, comes through the firewall next to the brake booster and goes right to the back side of the throttle body.
I think you're looking at the OMP rod at the front of the engine.

The main fuel filter is no where near the trans crossmember, it's right at the mouth of the transmission tunnel, below the brake booster. If you don't have power steering or AC, it can be changed from the top of the car.

I concur. Maybe I should but I have never adjusted my throttle cable. Only time I've touched it was to disconnect it to pull the motor.

Oh that was dumb of me, I didn't realize it goes out and around to the back, I was able to mess with it a bit and tighten it :D did it a little too much though I think, need to loosen it again. I have to put pressure behind the gas pedal to get it to release all the way, else it idles at 1050 rather than 800.

I can see the fuel filter underneath the booster but I have both power steering and A/C so I can't get to it without removing whatever that metal plate is that goes across the car beneath the trans. I'm a big guy, one of my smaller friends MIGHT be able to do it without removing anything. Should I wait until I'm low on gas to do it or can I just pinch the lines shut while I swap filters?

the transmission mount? no....... get your tubby ass under there and do it.

and you relieve the pressure by removing the egi and or comp fuse and start the car until it dies.

I'm 6'2", not fat, sheesh! I don't have access to a jack that can get high enough for me to get completely under it right now. Not sure how to do either of the things you said, but I guess I'll have to find out.

I have one similar to this: 1.5 Ton Compact Aluminum Racing Floor Jack with Rapid Pump®

You can get the smaller all steel ones cheaper but they are heavier, or you can pay a little more for one that will do 2 or 2.5 tons. The aluminum ones are nice cause the are lighter and easy to carry around. Also get some jack stands and you'll be set.
As to the fuel. Start the car then disconnect the fuel pump's power. Either by unplugging it( connector is under the carpet in the hatch), unplugging the relay which I think is under the dash or pulling the fuse if it has one for just fuel( I can't remember). Let run till it dies and most of the pressure will be gone.

make sure you disconnect the battery, the fuel filter is close enough to the positive terminal, that i have a funny story about a guy bringing an FC to the dealership for a fuel filter change and them setting it on fire, and fixing it while he was in the waiting room