HOMEMADE Cold Air Induction.. dimensions.... options..... how much??

[PrOxLaMuS©]

After searching the archives for my quest to make a HOMEMADE cold air intake... I concluded the following:

Get a 90* Bent Mendral Bent tube with 3" inlet and 3" outlet

Get a K&N Cone Filter with a 3" inlet

SO I started looking around for mendral bent tubing.... yeh... really hard..

so I came across this website JCWhitney.com and I found 2 that closely matched my needs :

*90 Mandel-Bent Aluminized Tubing, (A/B)=12, ©=6", ID=2-7/8" OD=3" $20.99

http://www.jcwhitney.com/webapp/wcs/stores/servlet/ProductDisplay?catalogId=10101&storeId=10101&langId=-1&productId=219788&mediaCode=ZX&appId=384383

*Swaged (Expanded) End 90 Mandel-Bent Aluminized Tubing, (A/B)=14", ©=6", ID=3", OD=3" $22.99

http://www.jcwhitney.com/webapp/wcs/stores/servlet/ProductDisplay?catalogId=10101&storeId=10101&langId=-1&productId=219803&mediaCode=ZX&appId=384177

Now my question is.... What does (expanded) mean>?

The first pipe has an inlet of 2-7/8" and an outlet of 3"

will this work???

or should I get the inlet and outlet of 3" like the 2nd pipe?

And this filter??

http://www.jegs.com//cgi-bin/ncommerce3/ProductDisplay?prrfnbr=4969&prmenbr=361

Total Cost : $69.98 plus shipping so about $80.00 to the front door plus install.

Or.. should I just go with MSA http://www.zcarparts.com/store/merchant.mvc?Screen=PROD&Product_Code=11-2931&Category_Code=PFFC12

Total: $124.95 plus shipping so about $135.00

Hmm.. what do you guys think....

[PUSHER]

I've heard you dont really gain much from those set ups, slightly better throttle response and about 2 hp max rpm. Dunno, would probally save the 125 for a rainy day.

[Ed]

That Aluminized tubing is very common for exhaust systems. Go to any muffler shop and they should be able to bend you a custom tube.

[PrOxLaMuS©]

for how much though??

it's only 22$ and shipping to my front door?! Wouldn't this be cheaper and better?

[Ed]

Not sure, most places have some kind of minimum charge for the hour. But you figure after an hour of bending and stuff you will have a pretty nice fitting tube.

[TomoHawk]

When you plan the tube, make sure the inlet is someplace where you get COLD AIR, like NOT behind the radiator. Most cars get the cold air from inside the fender or behind the headlights, so keep that in mind.

Don't go to "just any" muffler shop!

You need to find a muffler shop that can bend the tubing with a mandrel bender; most use a crush-bender, which puts constriction on the bend, and it looks crappy.

Then the exhaust guy could bend the tube to fit under the hood & around any stuff to go where it should.

[ecp48]

PrOxLaMuS©

In answer to your question, swaged or expanded means the 3" id was expanded to be a slip fit over the end of a 3" Tube.

Your local muffler shop will not produce a "mandrel bent" tube. They slightly collapse the tube, creating a smaller ID in the bend.

Yeh, the intake by itself may only produce a couple of HP, but when combined with headers and other changes the result is much greater. As someone has quoted many times on this site, "the internal combustion engine" is nothing but a large air pump. Getting the air in is only half the battle. However, as restrictive as the stock intake is, any improvement is a plus. I noticed the difference on my 78 280 and the addition of a new header was an even bigger plus! The exhaust on the 77 and 78 is real restrictive (area between the manifold and the main exhaust, 2 into 1). Much more so than my previous 75 280.

ecp48

[speedyblue]

The 280zx parts car I've got had a pod filter infront of the radiator, piped to the (now empty) air box with 2.5 inch PVC pipe. Cheap to get any bends you need. But doesn't look as good. Do a neat job and it won' be too bad though.

As for size, what size is your exhaust? Remember this air in your exhaust is way hotter, hence greater volume flowing through the pipe, but it is forced through also. There is also the theory off air speed charging through your carbies.

But I would work out the equivalent area of the carby inlets and use a single pipe of the same area. Cant go wrong there.

Area = pi x R^2, or Area = pi x (D^2)/4

In the end, unless you do something really wrong, or your current filter is really bad, the gain won't be enough to feel. But you will have fun fitting it.

[sblake01]

Originally posted by speedyblue

But I would work out the equivalent area of the carby inlets and use a single pipe of the same area. Cant go wrong there.

He has fuel injection.

[TomoHawk]

So then would you calculate the size of the tube to go with the area of the exhaust port(s)?

You gotta avoid constrictions for free flow.

[panchovisa]

Tomohawk,

why size the total intake to the exhaust port/header primary diameter (times 6)? Why not the area of the tail pipe outlet (times 1)? Six exhaust ports have much greater area than one tail pipe, and exhaust ports are used only 1/6th as much as tail pipe.

If intake area should equal exhaust area than why are intake valves always bigger than exhaust valves? Air+fuel in/ combustion by products out, right?

Got you guys thinking now????????

[PrOxLaMuS©]

Here's the crapper...

My engine only has 110,000 miles and I do have a set of headers (not yet installed) and I want to make this Cold Air Intake.

Only problem is I want a TURBO.. so it wouldnt be a good idea to put on the headers and exhuast if I will replacing it with a 3" later when I get my L28eT.

But i figured until then... CAI would be ok.

BTW did anyone notice a difference in the SOUND of their engine with CAI? I have seen Honda's with an ALL stock exhuast setup, and they plugged in CAI and the car sounded deeper and throatier.

Do Z's do that?