87_rocket

I recently purchased a 1987 base N/A and i've been wanting to get a new intake system. I heard that using a K&N intake filter with a prelude intake system can produce nice results. What year prelude systems work best? I just wanted to know what will give me the most "bang for the buck" and im anxious to get my hands on that nice, stock 13B engine. Thanks

TurboIIGuy

LOL!!!
What the hell is this about Prelude intake??
I've been into Rotaries for almost 10 years now and never heard that....
I was just at sevenstock last saturday and didn't see one intake on any FC that was for a damn prelude.
Ok first of all the stock intake is fine considering that when you swap to a pipe with a cone intake filter you are now sucking in hot engine bay air as opposed to the cold air the stock intake.
It's a non turbo. All you need is exahust, headers, and a K&N stock drop in filter. Unless you swap to a carburator there isn't much to do to a N/A FC without some porting and an ECU swap and new injectors.
Actually I would swap to a carb if you want to see some real improvements in performance. Other than that leave it fairly stock if its a daily driver on a budget.
that's my 2 cents.

Jwowl

there is actually a writeup on another rx7 forum of how to modify a prelude intake setup for the rx.. I seem to recall it being for a specific setup, however... can't quite remember where I saw it though...

jono20

A 92 prelude CAI off of eBay, if cut in the correct place, will create 2 pieces. One in an S shape, to replace the stock black tubing, and another long piece with a 90 degree bend at the top, to go after the MAF, and down through the floor (washer bottle location) and into the wheel well, where the air pump muffler is.

Ive heard about it many time sand ive only been banging a rotary for a few months :P

the cheapest I found was 38 bucks USD shipped to Canada. Do an eBay search on "92 prelude intake", find the cheapest. Theyre all basically the same.

Id also reccomend investing in some heat wrap, or at least ceramic paint. The piping is aluminum, and will get HOT!

jono20

here you go.









a "pre-cut" version is also available for a few dollars more.

TurboIIGuy

you all realize that putting a longer intake than stock on any car will usually show on a dyno as having lowered it's top end hp numbers right?!?! Not significantly but still there.
You also realize that swapping from stock intake to an aftermarket like the ones in the pictures on a car that has a stock setup will yield no actual gains on a dyno other than looking ricer.........
There is a reason you won't find a rotary shop selling something like this......It's pointless, that's why.

JUST GO TURBO!!!!!!
Bolt on a stock TII setup to your motor.

Sideways7

iTrader: (7)

I think its a bit more complicated than that.

jono20

I think this went a little off topic. COlder air yields more power.

Jager

iTrader: (10)

Denser air will yield the good stuff, but you're right :O!

jono20

yeah, colder = denser :P

fcdrifter13

well back to topic then I have heard of this also. A couple of ppl i know have done it tand they use there butt dyno and its seems to work pretty well.

But on the topic of length It is a win lose situation unless you cut a hole in your hood much like a GTR. The length does effect power on the top end but you must also consider that even though a shorter style intake would be good for just like dyno runs and max HP for short periods of time were heat is not a figure the short ram would be better.

But at speed the length of the intake tube is almost negated by the fact (if the system is a true cold air drawing air from outside the car) cold air is being pushed into the intake. Thus making more power on a course.

I guess you could put it like this short ramrag race Dyno and short sprints
CAI: circuit racing and daily driving

The reason that I put daily driving in there is because that is were most of drive our cars. And a coldair charge gives better gas milage and reduces air intake temps while intraffic

but hey I dont know ****. Just my .02

j200pruf

iTrader: (4)

If you go this way I would suggest making a new air box around the filter that brings in cold air from the out side. Not doing this will just have the new higher flowing intake sucking in hot engine bay air which isn't the best of things for performance.

jono20

this design put the filter underneath the "floor" of the engine bay, in the wheel well, alongsie the air pump muffler. it is sepereated by body width metal from the engine bay, sucking air in from the brake cooler ducts

j200pruf

iTrader: (4)

Sweet didn't know that, makes it a lot easier, i'd be scared to drive it like that where I live, we get a **** load of rain.

RandomHero

iTrader: (2)

Dude, this guy is talkin about intake and everyone seemed to get off topic. If you want an upgraded intake on the cheap side, just get the bonez cone filter from rotary performance. Its about $50 and its washable just like a k&n. The benefit of a hard pipe going to the throttle body is prolly minimal. If you want a cold air, there isnt much room behind or under the headlights anyway becuase the pop up motors are in the way. But all that fabrication wouldnt yeild much of a power gain anyway.

uRizen

iTrader: (2)

Rotaries aren't that easy to hydrolock. That's where I'm putting my filter using the prelude intake method.

The worst part it having to do away with your washer bottle. If you have the cold start assist tank still sitting in the driver's rear corner of the bay you can always rip the CSA system out and convert that tank to washer fluid with some new wiring.

jono20

rain is a lot heavier than air. The chances of it travelling UP HILL, around the bend, through the AFM, and up into the TB is very minimal unles the whole car was submerged. and even if you did get water in the engine, its not going to hurt it. its filtered, plus water is regularily injected into some rotaries to rid them of carbon build up.


@SGPguy, cold air vs hot engine bay air is very different. a true cold air intake with heat wrapped / ceramic painted piping will yield a noticible difference

88IntegraLS

If you mean the runners that go from the dynamic chamber after the throttle body to the ports, you are right. If you mean the tube that goes from the cone filter to the throttle body, you are incorrect, tuned runner lengths and the resultant timed resonances which return before ports close to ram a bit more air in the port only happens with tuned runners. Changing the lengths of them will affect the power curve, changing the length of the cone filter tube won't, as long as it produces no more / less intake restriction and / or heat soaking.

On the subject of heat soaking............

Avoid those shiny metal intakes unless you can live with losing a small percentage of your engine's potential power. Having a bare metal pipe sitting in the hottest part of the engine bay (over the exhaust manifold) defeats the purpose of having a cold air intake.

Back when I was experimenting with cold air / ram air systems for the NA FC, I used the stock rubber intake tube and still ran 14's. Later, I installed a metal pipe sans the airflow meter and didn't really feel much difference, although the pipe got really hot after a drive; metal conducts heat and has a high capacity to store it.

[/grumpy rant]

reatrdedspleen

what if you built a heatshield just below the metal intake pipeing?might make the engine bay look a little cleaner too?

88IntegraLS

I dunno, adding more weight and complexity only to make up for the original pipe material's poor thermal qualities doesn't jive with the "keep it simple" approach, but it's not my car.

reatrdedspleen

lol, cmon you never though of making like a rat maze inside the engine bay?

Havnt you seen new cars dude? the more complex the better it must be!

mali_FC

lol.....

Just make sure to cover the bottom when you finish with the installation. It will guide the air better towards the intake....