Cold Air Intake

So I've been lurking on this site for about six months, including the three months since I bought the Jimny.
The site has given me the information to replace the front speakers, put in rear speakers, fit a standard DIN stereo, and install sound insulation.

So I thought I might contribute something back.

So every new car has a cold air intake, even a 1982 car I owned had a one. 4WD's don't so they don't suck in a lot of dirt and water. I'm not talking about the road racers with the aluminium pipes, silicon elbows and pod filters, just pulling fresh air in from outside.
So normally the fix is a snorkel, but they have some downsides.

• They cost a couple of hundred dollars
• You have to drill holes in the guards
• It's permanent, you can't back out
• There's lots of discussion about the benefit of the cool air being offset or negated by the extra long intake runner.

So the perfect cold air intake should be short, straight, and located in a high wind pressure area.
This mod is cheap, not permanent, and can be removed in a minute when going off road.

Parts

• 50 mm Flexible Rubber Pipe Coupling, from a hardware store
• Radiator hose from a large six or eight cylinder engine

For those in Australia or New Zealand, I used a Ford Falcon (XC,,XE,XF) six cylinder bottom radiator hose from super cheap. If you use the Falcon hose rip out the anti-collapse spring.

For those who can't access it I have the dimensions so you can find something similar

Below is the plan image of the coupling and hose. If using the Falcon hose you need to cut about 20 to 25 mm off the end that fits on the inner guard. If you can't get a neat trim don't worry the cut is hidden.



Below is an elevation of the hose. Note it drops about 200mm, this will stop rain running in to the air box.



Loosen the screws on the flexible rubber pipe coupling

Fit the radiator hose into the flexible rubber pipe coupling, then tighten the screw. Just a gentle couple of twists. When the CAI is fitted it will just sit by it's self, we are just sealing against air leaks.

Slip the hose end into the spot next to the radiator and front guard, then lower down the end to connect to the side guard air intake.

Give the screw a couple of gentle turns, not so tight you break the original air pipe.



If done right it will sit in the spot by it's self, and can be removed in a few seconds.





Here you can see the positive air pressure from around the grill next to the radiator



Seat of the pants-dyno tells me it's a little better at 100KPH. There is a hill near me where if I attack it at 70KPH in forth by the time I hit the top it's struggling and dropped to 60. It now pulls up the hill much better. (not like a sports car, just not as asthmatic)

Total cost was $25.00 AUD, and about 15 minutes work

Nice contribution, I for one thank you. I love cheap useful mods like this especially with pics. I need to look under my hood to orient myself now.

Just resuscitating a zombie thread.
The seat of the pants dyno says it's a tiny bit better, but it could be a placebo effect hopping I haven't wasted $25

The only way to really tell is an actual dyno, or fuel economy.

The dyno would be more than the cost of the modification, and not really interested in redlining, under full load a new engine.

This leaves economy. This is hard to judge as the car only has a few thousand kilometres and we are changing season, so I'm using the air conditioning more.

Recently got a chance for a long highway run, normally I'd take the wife's Holden (Chevrolet) Craptiva diesel for more comfort.

So the numbers are
Speed = sat on exactly 100 kph / 60mph
Fuel = 95 RON as per fuel cap recommendation
Air Pressure = 23 psi front, 26 psi rear
People = one occupant
Ambient temp = mid 20 c
Engine state = just over 5000 km
Windows = up, no air conditioning running
Modifications = only the CAI, and about 20 kg of extra sound proofing

Distance Travelled in Kilometres 273.7
Type Number of Litres Used 17.43
Result in Kilometres per litre 15.70
Result in miles per gallon 44.37
Result in litres per 100 kilometres 6.36

OK so not magic compared to a normal 1.3 car, but it has the aerodynamics of a barn, and underneath is real steel, not sticky tape and paper mache.

I think I've managed ROI for the $25

After reading this thread I did something similar SEE HERE

You could use a scan tool to measure the difference between Intake Air Temperature and ambient before or after, if the difference is less then you get a power increase which is inversely proportional to the decrease in temperature measured in degrees kelvin. The length of the pipe makes no real difference as its before both the throttle body and the plenum.

Thanks for the pictures. Very useful!