Mills

iTrader: (1)

Awright, I searched the threads and came up w/about a weeks worth of reading, but can't find a simple answer so here goes. Do any companies make this mod for this car, or is it something y'all usually do yourself? Is there a worthwhile hp improvement? Who makes the best kit? I currently have the Mazdatrix dual RB setup and am looking for something that looks good AND will help breathe better. Right now it has the drop-in K&N filter in there, and if there's something better, I want it...

LongDuck

Here goes: custom cold air intake for the GSL-SE involves getting the Mariah NACA duct headlight lid (or another suitable headlight lid with vent), and some ingenuity.

My custom setup included installation of the Mariah lid, followed by some cutting of the metal that supports the rubber edge lining immediately behind the headlight opening in the hood. Open your hood and look behind the headlight (passenger side) and you'll see what I mean. What you'll have to do is remove the rubber strip that fits on the metal flange, and cut the center section out (about 4" wide). You'll see that the metal flange is flattened in 2 places to allow bolt passages to bolt the thing down. Cut this center channel out between the bolt passages, and then cut the rubber seal to fit on both sides. You're going for an open passage from the headlight lid to the air box - or as close as you can get.

Once you get the passage done, remove your airbox lid from the box, and note that there are 2, 12mm bolts that hold the rubber 'air tube' to the airbox. This rubber tube is oblong shaped (oval cross-section) and makes a 90 degree turn toward the radiator to connect to the extended 'air pipe' in front of the radiator (at the top of the open space). This rubber air tube will be removed, turned 180 degrees and remounted using the existing 12mm bolts - YES, it can be done. The tube will now point AWAY from the radiator, and will be sticking UP and pointing toward the passenger side of the car. Visualize where you'll have to cut this rubber air tube to get it to line up with the passage from above.

Now, using the plastic 'air pipe' that normally runs in front of the radiator on SE's, you'll be using a short length of this pipe (about 5-6") to direct the air from the passage (step 1) to the relocated airbox rubber pipe (step 2). Measure twice and cut once. I ended up cutting it long, and then final finishing it to work well with the installation - there's a lot of tinkering that you're going to need to do to get this to line up correctly, but it's worth it, IMO. I had to create a 'step' on my plastic air pipe to get it to fit where the bolt passages would allow, but also used a thin screw to bolt the new air pipe to the metal flange to keep the air pipe in place at speed and with the hood open. This means that you'll also need to move your radiator overflow bottle closer to the radiator to make room for the air piping. I relocated mine about 5" and it now mounts to the side of the radiator shroud directly behind the passenger side headlight fixture.

The end result of this work (took me about 6 hours, start to finish) was that when you look into the NACA duct on the Mariah lid, you can see the filter element of the K&N. The airflow at speed is going to be 'ramming' through this duct and right on top of the air box filter, allowing for cold, clean air to come in, and without any worries regarding scavenged heat into your intake system. PSI at 60 mph = negligible, but certainly better than in front of the radiator. On my 84SE, which had a longer plastic air pipe in front of the radiator, I've significantly reduced the distance that air must travel to get to the filter, and that alone is worth something to me, plus, this is a unique installation.

Performance should be a bit better, but it's not like adding a turbo or something along those lines. It's a fun and functional project that a pilot and mechanical-minded person like me can appreciate. If you take your time, it works out very well.

E-mail me for pictures, if you're really interested.

1st7heaven

Here is the headlight lid that I make to do that!!

Mills

iTrader: (1)

Nice, thanks for the response!

I was hoping there was a complete kit to do this, being short on time, patience, and tools, but it looks like hard work is required to do it right! That's ok, I'm not afraid of hard work, I'm just not sure I can make it look like a professional job... I'm very interested in seeing pics, especially on another SE. Email me some at greg@militellomotors.com if you can, thanks!

1984special

Does the light still work if you have a NACA duct? What does NACA stand for anyways...

On the 84, can I remove that long air pipe in front of the radiator? Will this be dangerous (like inhaling water)? Will it do any good? Thanks

rich367

Doesn't Mariah still sell the SE ram air kit for their hoods?

jimtesla

Mariah does not make the se ram air kit..............for the headlight duct.......

I called last week and they said to keep watching their site as they are going to have something come up soon.........I have the lid,not installed yet, and want a way to seal off my Cone intake setup...

http://www.rx7.com/cgi-local/1catalo...cat=6&part=110

I have the Bonez Intake see the above link....................I noticed a big difference after switching over to this........My next step is the complete RB exaust.......

rich367

Isn't the hood just a bolt-on? Slap the ram air kit on and you're done.

LongDuck

The light still works fine, and when you put the headlights up, the NACA duct is on the backside of the lid, thereby killing the ram air effect. This is, however, nice to have, since it prevents rainwater from being forced into the duct when it rains and gathering on the air filter element. Water here will cause it to flow less air.

When driving on the freeway, at speed, I have the driving lights on (custom airdam mod) and don't use the main headlights during the daytime. At night, I don't drive that fast, since I can't see that far, anyway.

I'll try to take some pictures tomorrow and will attempt to e-mail these to you. The mod is worthwhile, since it gets cooler air to the intake - here in 115 degree (F) heat in AZ, that can make a very big difference in engine temperatures and performance.

MRGSL-SE

hey LD... have you solve that problem you had... about the injectors or your GSL-SE idles funky... or something???

Manntis

Air intake has nothing to do with a ducted headlamp lid. Air can just as easily be drawn in from in front of the radiator which is cool, clean air. Any dirt or dust particles stay under the bumper level while only the air rises. 'Drawing through' a high mounted duct, if it works, would also draw in dust and rain - but then what if your headlamps are in the up position?

KYPREO

plus they look **** and create more drag.
you could create a similar ram effect having the air from in front of the radiator if your cold air duct features a flouted mouth and the correctly sized piping (ie not too large in diameter).

PaulFitzwarryne

The reality is there is minimal horsepower increase gained from a 'cold' air intake on a NA engine.

The air is sucked into the carb at a high rate from air flowing into the engine bay. Even after passing through the radiator, there is minimal difference in temperature between external air and engine bay air. Certainly insufficient to have a measurable impact on power.

Using a digital gauge I could not find a temperature difference even with the car stopped when the fan was
working.

The intake forward of the radiator may look cool, but there is no cooi in the impact!

The impact of an intercooler on a turbo engine is significant due to the increase in charge air temperature with increased pressure. But this does not occur on a NA engine.

KYPREO

Couple of observations:

It does make a difference when heak soak would normally have set in. If you run a NA engine on a dyno for long enough, the readings will get lower and lower for a reason. From this point of view, it makes performane more consistent if anything - especially on hot days after driving for a while.

How come your temperature guage didn't read a difference from one side of the radiator to the other? My hand reads a big difference! Maybe your radiator isn't dissipating heat. when my thermo fan kicks in, the temperature drop in the cold air ducting can be literally felt. You're measuring the termperature with the bonnet closed or open? Of course when its open, heat soak will be reduced greatly.

With the bonnet closed, the radiator isn't the only source, nor the major source of heat - how about the extractors, the engine etc?

The horsepower increase isn't phenomenal or anything on a NA engine but it is there - it is noticeable - just as driving on a cold night is faster than a hot day. That needs to be qualified with a few remarks: you need a decent filter to flow the amount of air, you need to have an engine that wants to flow more, you need to tune the engine for the colder air including a tad more advance which you can then squeeze out safely.

The principle on turbo and Na engines is the same: cold air is denser than warm, and therefore more oxygen by volume. Similarly, colder combustion temperatures leave less chance of detonation than warmer ones, so more advanced timing can be dialled in. It is just more noticeable when the pressure of the air of the intake is well above atmospheric.

Mills

iTrader: (1)

I mentioned I have a header system, but I left the air pump and emissions intact. Should I remove these and get the "race" intake? Or should I leave the air pump in and get the "street" intake?

My header has the 6-port actuator and oxygen sensor, is removing the emissions even a good idea w/this setup? What can I do to increase the horsepower and still keep a nice idle?

Another question: will doing any of this stuff make the car much louder? I kind of like the way it sounds now, not too loud...

Manntis

since yours is an SE, ignore all the stuff about carbureators. The stock intake is actually a sort of cold intake already, just a bit restricted. Dropping in a K&N filter designed to fit the stock airbox will help. Not huge gains, but a bit more throttle response.

Mills

iTrader: (1)

Thanks, Manntis, but I've already done that. What I'm wondering is if putting a less restrictive intake would be even better

Manntis

in theory, yes, but you'll notice the tapered hose, the extension to in front of the radiator, etc. that Mazda already thoughtfully included. My only complaint is the shape of the air box. Why not have a rising pipe and cone filter instead if air blowing across a horizintal filter, then 90 degrees down and through it, then 90 degrees again...

jimtesla

Keep checking the mariah site........They have a guy I spoke with there that has an SE.......and he has forwarded lots of complaints from owners that they have no set up for our model..........That is why I went the Bonez intake set up.......I just need a heat shield to help on hotter days........With the NACA duct and a heat shield.....and the stock cold air tube on my 85 SE it should be a decent set up....Maybe even a third area to look at would be to fabricate an additional area to suck air from.........say the side via under the fender?

I am sure that when I move up to a full exaust I will really notice a difference in power.......but with this as my only performance mod.........It sounds stupid but I do notice a difference with a cone set up versus the stock box.......

Manntis

the full exhaist makes a huge difference, but since you're in SoCal it won't pass smog. Nice neighborhood, that Simi Valley... Fulla cops and **** stars all at the same time

jimtesla

Your right......

My neighbor is cop...........has a stupid acura integra.....
White color like mine.......He found a Possom in has back yard and tried to shoot it up.....Thought it was dead.....
Next day tried to pick it up by the tail to throw it away......Jumped a mile high........Dick..........

I have found out that we have certain areas that for a price will take care of the smog thing

Simi Valley has only one topless bar......Snookies.........They will not alow anything else............As far as **** stars go.....
I dont know of many..........But we do have the market on blondes and screamers........

Im the only Se in the City...That I know of..........

mcgarret

Yeah, I ripped that stupid looking plastic intake tube out. It draws air from behind the battery, not really efficient. It now draws the road draft from front bumper opening.

PaulFitzwarryne

Kypreo- There is about 3000cfm passing through the engine bay of which 300-400cfm goes into the carb. The amount of heat generated from the engine is insufficient to heat this significantly. I was measuring with the bonnet closed as the car was going 100kph!

If you look at intercooler design theory you will see the temperature drop required to increase power by 1%, that level of reduction does not occur on a NA.

The problem with the hand test is windspeed chill factor. A domestic electric fan works on the same principle.

If you look at a series of engine bay pictures of 12A racing set-ups, the standard approach is a Weber IDA carb with a top mounted filter or open trumpets. There is no attempt to use a 'cold' air intake because it has no impact compared with the large quantity of air moving through the engine bay.

KYPREO

OK cool...thats a little more interesting data you've got there. I own a street car though and I rarely spend time over 100kph - what is the flow at the front air dam compared to the engine bay at 60kph for example.

I've seen various racing setups - and you're right - most of the IDA setups I've seen have no air box. Some do however. I've also seen one of the most powerful BPs in the world (over 300rwhp on DynoDynamics@12,000rpm) which uses an EFI quad throttle body setup, and it does use an air box setup sitting over the intake trumpet and being fed with a ram setup.

I'm sure we'd both like to see the differences of measured intake air temperature at the manifold, cos that is where a difference, if any, will be felt. That is something for someone with an injected NA setup to check out.

EDITED for left out words

PaulFitzwarryne

Kypreo- will ask one of my CSIRO friends to devise a method of measuring temperature at the manifold.

Following your post to another thread on getting into the 14 second 1/4, what modificatons do you have? Your figure for the 12AT is the second series which went into the RX-7 The quoted figure of 165hp is JIS, thereis no official SAE data. This would be about 136-138 SAE, supported by the 1/4 time of 15.4seconds compared with the heavier gsl-se time.

Like you I am a member of AusRotary, spending much of my time in Australia.