Hi guys,
Ive got a 1988 convertible with the 6port, 5-speed.
I wanted to learn a little more about what I can do in terms of Intake mods for my next power modification.
First of all, what kinds of improvements would I get from a custom aluminum intake (from the AFM to the Throttlebody) like the one that Corksport sells? It looks as though I lose all of the vacuum connections, and the inside of the stock tube is pretty smooth already (that hard plastic material).
Second, companies like K&N and Blitz only sell intake kits from infront of the AFM, will the K&N model give me more power since I'm paying so much more?
I picked up a second airbox cover and cut the top off of it so it was still able to clamp the air filter down, so now the air filter is exposed to colder air when I disconnect the headlight fuse and raise it up a little bit. I replaced this set-up back with the stock set-up because I was told it would suck up water when it rains. Is this a good substitute for a cold air kit? I seemed to get little bit better acceleration from 100-150 km/h on the highway with this done but nothing substantial.
LAST point. WeaponR makes that secret weapon air filter that you can attach the ram-air tube to.. I found a way to get that tube to channel air from the front lower grille but when I did some research people reccommended not to do anything with a ram-air set-up since I live in Canada where it snows and rains a lot. Apparently it picks up more moisture?
What's the best set-up for an NA 6-port to make the most power in your experience?
BTW I have some light exhaust mods, with a high-flow cat, and I've gotten rid of the pre-cats. The air pump is still connected.

 

Put the original air box top and snorkel back on. By making a big hole in the top, you're allowing hot radiator air to be sucked in. The stock set up is a true "cold air intake". The area in front of the radiator (where the snorkel goes) is sealed off from the rest of the engine bay, and pulls air up from the bumper cut-out.

All the aftermarket piping available is going to make the problem worse. An open filter sucks in hot air from the bay. You can make an air box to seal it off much like the stock box does, but then you've just wasted a bunch of time/money to do the same thing the stock setup does. For NA cars, the stock box is not restrictive, and will work just fine. It's the turbo cars that suffer from restrictive piping.

The most effective ways to gain power on an NA are through open exhaust systems (header -> presilencer/high flow cat -> good catback), and through tuning a slightly leaner mixture with something like an SAFC and a wideback 02 sensor. Intakes, while it might seem like they do something for you, generally cause the engine to make less power or an insignificant bit more.

 

Okay, thanks.
I'm def. glad I joined since I'm learning more and more every second I'm on here.
When I had the high flow cat and 2.5"" downpipe installed.. I asked about replacing the manifold with RB's headers.. I was told by the "rotary performance" shop in Pickering ON, that I wouldn't like the sound it makes and the power gains aren't worth the money. On the RB site it says a 14hp gain though!! What do you think about the headers?

 

The power gains from a header are considerable. What shop was this?

The important thing with a header is to also use a high quality free flowing stainless packed resonator. This will cut the noise significantly.

 

Aaron Cake,
PM'd you a bunch of info, I don't want to badmouth the shop openly on here.

 

It's not badmouthing if we are just correcting some less then ideal advice. They may have very good reasons for suggesting you stay away from the header. For example, most people don't understand that it makes the car much louder and requires the addition of a good resonator or two to keep the noise down. This adds to the cost on top of the purchase price of the headers.

 

Well i told Mazdee's i was willing to pay for a header setup all the way to the y-pipe and mufflers but they basically said "no dont bother." Dave told me the price to bring the exhaust from California was going to be too expensive. I appreciate him trying to save me money there but since then I've been under the impression that headers weren't worth it.
I've done some thread searches on headers in the NA power section so I understand now, but since I want to put a full exhaust under my car anyways i wasted money on a downpipe and highflow cat, then shortly after a y-pipe. I wish he let me do a full system considering i willing to pay at that point.

 

Don't worry about Dave, he knows me and I would hope knows that I'm not out to badmouth his business.

Shops will have different reasons for making recommendations that us as individuals may not share.

You may be able to see the downpipe and highflow cat. Or, keep the highflow cat and use it with the headers. It will cut power slightly, but the improvement in exhaust smell and noise will be worth it. My opinion on NA rotarys with headers is to sick as many resonators under the car that you can, and stay with a dual exhaust. Resonators don't effect flow much as long as they are flow through (I like the Vibrant brand resonators...all stainless, works well and cheap). The duel exhaust will give you both the muffling and flow.

Dave may have been a bit hesitant on the exhaust due to the effects on the 6 port engine. Remember, you will need to actuate the aux ports with some other method when the exhaust is opened. Most people use the air pump (see FAQ).