Needa13b

'86 N/A, (gonna get K&N 3" cone, and any afm adapter i can get my hands on cheap)

I'm gonna home depot this box all the way. And I'm gonna try to keep it sealed so I can use the stock snorkel to suck cool air. But what material reflects heat the best. All the threads seem to mention heat shielding or whatnot.

What is more effective?

-Shielding heat from the outside of the box?
-Insulating the inside?
-Or are they the same thing?

When I think of making a box insulated, I keep getting an image of a house wall. An outside heat reflector, insulation (pink panther), and then an interior wall. Or should i just get some tin and go one layer? I want to keep this box sealed, not by the hood. I want a top that I can feel that I am sealing it when I close it with a snap or screw or something.

One more concern would be with mounting the AFM. Someone had an idea of putting the box right up to the AFM, then mounting the AFM adapter inside the box. I like that idea alot, but then i would need to mount the box somewhere.

I want to keep my home made box right where it is, i'm not gonna cut holes in my car , or fab an air duct from the brake duct.

KillaKitiie

all i can think of is a car windshield shader.they seem to do a good job of keeping the heat out maybe you can find were they sell the material?

Needa13b

I wonder if that could take the heat coming from the exhaust. I don't want to start a fire. I think I want to stay away from soft materials for the outside of the box, just because of fire hazard, unless they are flame retardant or somthing.

niburu

iTrader: (1)

Take a look a Zachs set-up on www.zaxjax.com he did a good job of fabbing one up

Nick86

iTrader: (1)

I think you'll have a hard time making an insulated box that will keep the interior air so much cooler that it will make a huge difference. If the box is sealed properly, it will suck cold air an - and that should be adequate. Don't forget that the air still has to travel up tha t black pipe before it gets to the intake, and unless you insulate that too - having an insulated box seems a bit of a waste.

As for mounting the box - I did the AFM-BOX-AFM ADAPTOR sandwich and it worked really well. There are plenty of threaded holes in that part of the engine bad that will allow you to secure the box to the car. Having it loose doesn't make sense.

Make the box out of metal or fiberglass - I chose metal. It is easy to bend and shape, and sturdy. If you really want an isulated box - you can also make a "Box inside a box" arrangement. In essence the box will have hollow walls that can be filled with either some heat resistant product or left empty. In essence, the "outer" box would act as a heat shield.

My biggest piece of advice is TAKE YOUR TIME! Think the entire thing through and take the time to do it properly.

Evil Aviator

Don't get the cheap adapters that have a poor round-to-square transition that will hurt the airflow. I recommend the HKS or RX7CZ.net adapters.

All you need is something that will keep the hot discharge air from the radiator away from the intake. Even a simple cardboard, plastic, or metal deflector will work. It doesn't need to be a sealed system. This is a road car, not the space shuttle.

Needa13b

My main priorities for the project would be:

1) Keeping the cost down
2) Sucking relatively cool air, as compared to exhaust manifold air, via stock snorkle.

I have stock exhaust, so airflow isn't a huge concern for me. The reason I am making the box is that my stock airbox has half the screws stripped, and one head busted off. Not very handy to easily remove and replace filter as needed. (I have only seen the corner of my filter, car is basically still new to me, i had to pull up the side that i got the screws out of to see filter.)

AFM ADAPTERS

Evil Aviator, you said something about not getting a cheap afm adapter, because of airflow. I just mentioned about having stock exhaust.
-How much is the price difference in AFM Adapters?
-Is it worth the extra money, knowing I don't plan on buying a high flow exhaust or anything?
-Would gutting out the cats be good to do?
-How loud does that make it? (i don't want a loud exhuast)

Nick86, I saw alot of people setups, what kind of tape do they use for heat shielding the black intake tube up to the throttle body?

niburu, Thanks for the link, i'm gonna need some time to check that site out thouroghly.

Thanks for the input and suggestions guys.

Evil Aviator

Even with a cone filter modification, the exhaust manifold heat isn't significant unless you are a police officer who sits in the car all day with the engine running and the car parked. The RX-7 comes with a stock CAI, unlike some of the Hondas that have the intake mounted in such a manner that it sucks in air off the engine/header. Note that the Honda propaganda doesn't always apply to the RX-7.

Best airflow: HKS, $60 plus shipping:
http://www.rx7store.net/index.asp?Pa...ROD&ProdID=553

Next best airflow, $30 shipped:
http://rx7cz.net/shop/

Cheap Ebay kits with crummy airflow, not worth bothering with (the filters are lousy, too):

Notice how the airflow is abruptly interrupted by the square part of the plate.
http://cgi.ebay.com/ebaymotors/ws/eB...sPageName=WDVW

This one doesn't have a plate, but it may as well because the square afm inlet is going to cause the same restriction as soon as the air passes through the completely round hole.
http://cgi.ebay.com/ebaymotors/ws/eB...sPageName=WDVW

Nick86

iTrader: (1)

HOLY ****!!!!!

I bought that exact same adaptor from them for $20 not even 2 years ago! I guess HKS has raised their prices!


As for the heat tape, I honestly haven't seen anyone use it on the intake tube, so I don't know what they would use. I think it would be a waste of time however. Just make a nice CAI that gets ample cold air and you'll be alright.


Here's my setup - look on page 5 for all the pics.
https://www.rx7club.com/showthread.p...light=cold+Air

Needa13b

Nick86, I noticed on your setup that your AFM is mounted upside down from stock. Does that affect anything, since the metering device moves horizontal to the ground? I would assume that if you mounted it 90 degrees from stock, gravity would affect the device and you would get inaccurate AFM readings.

What filter are you using. I was looking at K&N filters at Advance Auto, it looks like those just slip over the adapter without any kind of fastening. Is that right or do I need to fabricate some kind of zip tie deal?

Let me see if I understand how your setup works. Fresh, cool air is pushed up through your duct and supplys your filter with air. So there is no suctioning of anykind. Your box just blocks engine bay air, and keeps the cooler air around the filter. (nice looking box by the way)

Evil Aviator, so that transition from circle to square is really important, given my application of the adaptor,(i.e., just a replacement for crapped out stock box)? I suppose it would be worth it just cause I love my car.

Nick86

iTrader: (1)

That is correct. If the AFM is mounted horizantal to the ground (upside down or right side up) it will function as normal. Mount it at 90 degrees and there can be problems. Some people will tell you that theirs was mounted like that and it was fine, others will tell you their car wouldn't even start with the AFM on the side. Personally, I believe that having it at 90 degrees is bad. From what I read (and I did a lot of searching) and my experience - upside down is A-OK.



It is a universal K&N Filter. I got it at a speed shop - I'll see if I still have the box so I can give you the K&N part number. It slides over the adaptor but is held in place with a T-Clamp. (In those pics it is a hose clamp) The Hose clamp (worm gear style) worked just fine - but I like the look of the T-clamp better. You need something to hold it there, and seal the filter to the adaptor. My filter came with this clamp, so I'm sure that many of the kits do.



That's basically it, yes. I have since installed some weather stripping on the hood to seal the warm air out, but there is no actual suction or vacuum in the box caused by the engine's intake suction. What I've done is simply brought in cold air and kept out warm air - that way the filter is only taking in cold air. Obviously when the car is stationary the ambient temps in the box increase, but the box it's self does a good job of shielding the heat.



Thanks, a lot of people like my box....

Evil Aviator

It appears that way. The HKS adapter has been $20 for many years, and now everybody is selling it for about $60. It seems like a lot of money for a small piece of cast aluminum, even if it is designed well. I would imagine that the CZ adapter will become more popular now.

I think its worth paying for the better adapter.

If money is a problem, then just get the CZ adapter for $30 shipped. You can also keep an eye on 86-88 RX-7 owners on this forum who are converting to a standalone EMS and are willing to sell their HKS or CZ adapter for cheap. Also note that a real K&N filter lasts 10 years or 1,000,000 miles, so it is actually less expensive than paper filters in the long run.