Cold air intake vs short ram?????

[93HondaSI]

Cold Air Pros: Cold air means more power
Cold Air Cons:Possible engine damage.
Short Ram Pros:Better throttle response
Short Ram Cons:Warmer are means loss of power

[8695Beaters]

You forgot CAI is more expensive than short ram. Short ram is also lighter. I like everything to be compact in my engine bay, so I use short rams. I'm also cheap.

[splink48]

also...the gains aren't really significant b/w the two. I built my last cai setup, it cost a dollar or so more because I needed one more coupler.

[8695Beaters]

Well it depends. On a turbo or SC car, the colder the air coming, the more power you will make. It's an interesting phenomenon, if you measure the air that goes into a turbo system with the air that comes out, warmer intake air actually raises the temperature of the compressed air a higher proportion. A hypothetical situatiuon would be your turbo sucks in 50 degree air, and spits out 200 degree air. So if it inhales 70 degree air, it should expel 220 degree air, right? Well it turns out that the compressed air coming out is actually hotter than that. And it depends on the compressor efficiency (which for turbos is actually kinda low), so it may very well end up being 250 degrees when it leaves the turbo.

Unfortunately, intercooler piping is much more important than a CAI, so a good deal of turbo cars use short rams. Also, turbos hate water and sucking in any will do major damage to them. And splink is right, on an NA car, the difference is minimal. My Integra will actually run the 1/4 mile faster, on a hot day, because the track and tires are stickier than on a cold day. I get a better launch, which negates the 2 hp loss I have from the hotter ambient air.

[splink48]

I guess that goes along the same guidelines as starting with cold water vs warm if you're going to boil it. It's a more dramatic change that gains momentum (the change) quicker.

[Konger75]

I just picked up my 09 honda fit sport this weekend. I’m not familiar with the earlier models, but the 09 fits’ actually have a modified ram air intake. There is a duct that is mounted on the hood that forces air in at the grill and shoots is back to the air intake. However the intake/filter box makes about 4 different 90 turns before it gets to the engine. It will be nice once someone makes a short ram intake for it, except there might be some issues with the location of the mass airflow sensor.

Also to give a scientific view about intake temp and exhaust temp that 8695Beaters posted. The 50 in 200 out 70 in 220 out equation is not correct. In a heat exchanger like a furnace that is true, but in an engine it is actually opposite. 50 degree air would technically make your exhaust hotter, especially in a turbo. At 50 degrees the oxygen is more compact. The higher concentration of oxygen will cause a more complete reaction when burnt with the fuel. This creates more energy, which we see ass HP and torque, and more energy means more heat. Also compressing gases creates heat, just like decompressing gases make things cold. Like when you spray an aerosol can for an extended period of time, it gets colder. Anyway, the more condense 50 degree air will create more heat when compressed because it has a higher density. The only reason you don’t notice the hotter exhaust at a lower temperature is because the cooling system also runs more efficiently at lower temps thus counter acting the increase in heat.

Lastly there is one thing that hasn’t been mentioned about CAIS. The metal piping connecting the filter to the intake manifold is metal and is located in the “hot” engine compartment. The metal piping will get hot and will still heat up the air in your CAI before it gets to the engine. I still say that a short ram intake is better, especially if you can feed outside air to the filter inside the engine compartment, i.e. – ram air, scoop, cowl. I’ve seen some dyno charts showing that short rams produce more power. Also, I was looking at the dyno chart for the CAI from AEM for a Honda fit. Anyone else notice that it actually lowers your HP. The only real HP gain was at top RPM, and you rarely ever drive a car at 6600 RPMs. For it to be of any benefit it needs to increase the HP throughout the whole power band. Like I said before, it’s like drinking from a longer straw. It only makes the engine work harder.

[8695Beaters]

I haven't had thermo yet and it's been 2 years since I read the article about turbos and heat exchange. Thanks for correcting me, I'm a bit fuzzy on things. I'll try to find it again to clear that all up.

[2000-honda-civic-LX]

i was woundering if it was possible to have both the cold air inake and the short ram intake in my 2000 honda civic LX

[8695Beaters]

Not as a bolt in. If you cut a duct into your fender, you can divert cold air onto your air filter, but it's not worth the work. Depending on where your intake is, you can get both, but on most Hondas, the intake manifold is against the firewall, so you need a long intake just to get to the engine. On the other hand, any K-Series car can not have a true CAI because there is simply no room to put the filter in a cold air inlet. You would need either very small piping (bad) or cut a hole in the bumper or fender to divert cold air onto the filter (lots of work, and very ugly). The intake on my SR20 is sort of a cold air short ram because it picks up air that goes around the radiator (and is thus cold), but the piping is only about a foot long before it goes into the turbo. I still end up with heat soak because the intercooler hot pipe runs right next to the air filter.

[ghost_xero]

wait a second here, i cut the stock hose of my air intake and fitted a cone filter on it , and it does its job.... the stock hose is like....2 1/2 feet long, i cut it to about 1 foot long and fitted the filter on and presto i had a cai, plus hydro lock is impossible, and the stock thick rubber hose doesnt get nearly as hot as a cai metal pipe would......if u wanna be cheap like me....modify what u have!