Objective

to increase horsepower and air flow by removing the air silencer, spend as little money as possible and use as many stock components as possible.

Spending one to two hundred plus dollars on a fabricated cold air intake was out of the question (even if one was available).  Plus, I have two kids, a wife who thinks that making the house payment and groceries are important; and besides, IT’S A MINIVAN for crying out loud!!!!

And...

I didn’t want to get too carried away because I know that the folks from TV’s OverHauling are going to hijack my van and stuff a supercharged-hemi in back!  Oh yes.

Vehicle:

2000 Dodge Grand Caravan, 3.3L V6, 93,000 miles

What I could find out

There are not many parts available to hop-up a minivan.

No one makes a cold air intake system for a Dodge minivan.  (Believe me I looked!)

What is an Air Silencer?  How Much Horsepower can be Gained When Removed?

From http://www.njtacc.com/tech/air_silencer.html

Ford, and GM, produced all of their cars with an air silencer.  The manufacturers decided that the average customer wanted a quieter engine, with performance as an expense.  By removing the silencer you will gain a slightly deeper exhaust note. Also, at higher engine RPM, you will hear the vacuum created by the intake system.  You will gain 1-2 hp.  No, not a lot, but the modification is free.

From http://www.netstang.com/moroso_cold_air.htm

When modifying the stock set up, you should always replace the stock paper air filter element with a free flowing reusable filter such as the industry standard "K&N Filtercharger".  In addition, some original non-modified 5.0's and 4.6's may still have the factory installed air intake silencers.  These silencers do nothing for performance but were originally designed with well intentions.

The silencer is a dual purpose device.  It's basic design bottle-necks the air intake charge.  In doing so, it lowers the intake noise for the average consumer and helps keep contaminates such as water, dirt, and snow from prematurely clogging the air filter.  Unfortunately this approach just hurts performance in the process.

Since most Mustang enthusiasts generally like the sound of a "throaty" intake and try to avoid extreme whether conditions at all costs, the silencer should be removed and placed on a shelf in the "non-performance" section of your garage.  Removing it should not hurt emissions or adversely effect the car in any way.  This combined with a free flow filter, is good for about 5 HP or so.  Not bad for a $40 investment and a few minutes of time!

Note: I couldn’t find anything about Dodge air silencers.

According to http://www.allpar.com/mopar/33.html

The 1996-2000, 3.3L, V6 engine, has 158bhp at 4850rpm and 203 lb-ft torque at 3250rpm.

The K&N web site states that their replacement filters are designed to increase horsepower by 2 to 4 percent.  Replacing the OEM air filter with a K&N increases horsepower from 3 to 6hp.

As stated above, removing the air silencer gains another 1 to 2hp.

By replacing both the air filter and air silencer it is “possible” to increase the total horsepower anywhere from 162 to 166hp.

I do not have any scientific proof to confirm any change in horsepower.  But it sounds cool when accelerating hard,

And…

I now have something squealing besides the serpentine belt…the tires!  OK, at least I can get one tire to chirp on wet pavement.

Note

Total build cost does not include:

• Time spent cruising the internet looking for a ready made intake system.
• Time spent cruising the internet looking for ideas for making an intake system.
• Time spent cruising the internet looking for ready made intake parts.
• Time spent cruising auto parts and hardware stores looking for parts.
• Gas.
• Labor.
• Design time.

T-Pipe Fabrication

Heater Hose Fitting Modification

The overall length of the threaded portion of the heater hose fitting (item 5) is approximately 1/2”.  I cut this to about 1/4” long because I didn’t want to interrupt the air flow, but needed  enough length to make up for the curve of the 3” pipe.

Exhaust Pipe Fabrication

The exhaust pipe (item 6) is 3” long.  I determined the length of the pipe by slipping one end into the intake coupler/connector.  It covered approximately 1” of tube.  I doubled that for the other end.  I then measured the distance across the flats of the hex portion (not shown, covered with weld) of (item 5) which measured 7/8”.  I add a little for an even measurement.

The threads of the heater hose fitting (item 5) measured a little less than 13/16” diameter.  A 13/16” diameter hole was machined into the middle of the 3” pipe.  (Item 5) was welded to (item 6).

Remove any weld slag, dirt, oil, contaminates, etc. before installing the T-pipe.  You don’t want any “stuff” getting into your engine.

Installation

No.	Description
1	Air Duct Hose 12” lg.
2	Hose Clamps
3	Heater Hose 17 1/2”lg.
4	Intake Coupler/Connector
5	T-Pipe
6

Install the 2 1/2” end of the intake coupler/connector onto the throttle body.  Snug the clamp.

Install the T-pipe into the 3” end of the intake coupler/connector.  Snug the clamp.

Measure and cut the heater hose to length.  I used 17 1/2 inches.  Press this hose onto the fittings on the valve cover and T-pipe.  The heater hose is now the crankcase vent hose.

Measure and cut the air duct hose at 12 inches.  I tried to make the hose as straight as possible (without bends).  I didn’t want the hose so tight that it would pull loose during operation or loose enough to sag.

Slip both hose clamps onto the air duct hose.

Slip the air duct hose ends onto the T-pipe and air filter box.  Snug the clamps.

Check that everything clears the exhaust and throttle cables, and tighten all the clamps.

You’re ready to Rock and Roll!

Notes and Ideas

From the Internet: Tip For Making a Straight Cut.  To cut hose straight, use a sharp knife, tighten a hose clamp around the hose and use the edge of the clamp as a guide for the knife blade.  Remove the clamp.  Finish the cut by resting the hose firmly on a flat surface.

The T-Pipe

Finding a way to vent the crankcase was a major concern when I removed the air silencer.  I did find a nice T-pipe on the internet for $30.00, but I didn’t want to spend that much.

One thing I had to consider was the weight of the pipe.  Three inch diameter, 14-gage steel pipe weighs 2.586 lbs/ft, whereas the same size aluminum pipe weighs .895 lbs/ft.  What I didn’t want to do was add a support to this piece.  So far, the intake coupler/connector is doing a fine job of supporting T-pipe.  (Weights from Ryerson Steel Stock list.)

What I didn’t take into account was the room the weld was going to take up.  It fits, but if I made another one, I would probably add an extra 1/2”.

I am lucky.  I work at a company that has a fabrication shop.  I was able to have the T-pipe machined and welded.  I had planned on fabricating the T-pipe myself.  Instead of welding the heater hose fitting to the pipe I was going to use JB Weld.

Ideas without the T-Pipe

Instead of fabricating a T, use a straight piece of pipe between the air duct hose and intake coupler/connector and a separate crankcase filter.

Drill a hole in the side of a straight piece of pipe that is slightly smaller than the O.D. of the crank case vent hose.  Jam the end of the hose into the tube.

Don’t use a tube at all.  Clamp the air duct hose directly to the throttle body.  Cut one end air duct hose to fit the small diameter of the throttle body when clamped.  Use a separate crankcase filter.

Other Ideas

I considered using Samco Sport Silicon Hoses and connectors.  Samco makes a variety of hoses that can be custom fitted as needed, but I thought they cost too much for my purpose.

Have a muffler shop bend a piece of exhaust pipe to fit between the throttle body and air filter box.  The reasons I didn’t do this was:

• I wanted to use the stock rubber intake hoses (because they incorporate additional bends to clear the battery and to save money).  But the diameters at the ends of the air filter box and throttle body were too different.  The muffler shop couldn’t enlarge or reduce the ends of the pipe to the sizes needed to fit the stock rubber intake couplings.
• The bend radiuses that the muffler shop told me they had to use were too large for the length of exhaust pipe.

Sure I wanted a cool looking smooth bore intake tube, but it was taking too much time to design, and I really don’t know if I am going to gain that much performance—really…to justify the additional time needed to design an intake tube.

The hardware store has flexible aluminum dryer vent hose.  It looked cool and was half the price of the intake hose I used, but I thought the aluminum had a better chance of getting bent.

It seems that I read that the hot air from the crank case vent would warm-up the cool intake air and cut the horsepower gain.  It probably does.  How much?  I don’t know.  If you are concerned, you might use a separate crankcase filter.

Other Web Sites

http://www.allpar.com/mopar/33.html

Information about Chrysler, Dodge, and Plymouth 3.3, 3.5, 3.8 Liter V-6 Engines.

http://www.karlsnet.com/mopar/crankcase.shtml

Crankcase filter modification and Ram air intake fabrication and installation.

http://www.deyemeracing.com/

After market performance parts for Mopar.

e-mail me at

Good Luck!

- Don Martin