Cold Air Intakes - do they really work?

[chinadan]

My understanding of a CAI is that is is supposed to suck in ambient, cooler air and provide a shorter path/bigger diameter for easy flow and hopefully more power.

The original air intake on a Versa/Tiida already is a CAI - the opening is in front of the car, behind the grill. At speed, I assume the intake air to be outside temp.

As long as the inlet area of the snorkle is bigger than the inlet area of the engine (where the CAI connects), air volume flow (high rpm) should be sufficient.

A filter is a resistor and restricts air flow. A larger filter (as in an OEM-sized filter) should provide less resistance compared to a smaller CAI filter.

The length of a pipe certainly creates resistance losses, especially when the air speed is too high and turbulent streaming occurs. Not sure what the imapct is but it would only be felt at high RPM.

So far, a lot of assumptions...but:

The original design of the air intake is a resonance air box (notice the 2 chambers to the left and right of the inlet?). Resonance air boxes are tuned to provide easy air flow right where the engine hits its torque dip, thus boosting the output of the engine in that narrow area.

When reading the marketing literature of CAI manufacturers, they usually mention that the colder air is the main reason for ower gain, followed by an unrestricted airflow. I have not found any mention of the resonance tuning of these pipes.

Does anybody here have some info on that?

From my own experience I can say that my Simota air box does little more than providing nice sound. Low-rpm torque is certainly diminshed and my automatic trasnmission downshifts at highway speed at 4,000 rpm with the slightes touch of the gas pedal - redlining the engine. The original intake was no problem and I'll revert this weekend.

Comments and corrections welcome!

[Concord]

a CAI on a stock Versa will do nothing, nada, zero for performance.

Actually I've used numerous CAI's on 300 HP motors and the only performance increase from a CAI is at very high RPM's. Save your money unless you like the sound.

[bulld0g]

a CAI on a stock Versa will do nothing, nada, zero for performance.

Actually I've used numerous CAI's on 300 HP motors and the only performance increase from a CAI is at very high RPM's. Save your money unless you like the sound.

I would have to say you are incorrect on this for the Versa....I have dyno numbers that say otherwise....and anyone that has one on there V can tell you the same...

[chinadan]

Concord-

that's what I figured. I just switched back to the original intake and will monitor fuel efficiency as well as performance impact, especially low-rpm torque and hig-speed downshifting.

As I have just added a catback exhaust the sound is just fine...:-)

When comparing the 1.6l air box with the US 1.8l air-box, the US resonance chamber is like 4x larger - almost the size of the coolant reservoir.

I noticed on the 1.6l intake that there is a penny-sized hole on the underside of the intake...presumably to add high-rmp airflow or to drain water...either way, that can't be good on a tuned system. Can anybody confirm this on the US version?

Looking over AEM's website they have the V2 CAI, according to them tuned to perfection. At least they acknowledge the need for resonance-tuning....

I just wish they had a dyno in my area...

Cheers!

[chinadan]

Seems to work. Problem for me is taht in China there are only 1.6l engines and purpose-designed CAI such as Fujita or AEM are not available.

My Simota CAI is essentially a 90deg elbow bend with a straight tube ending up in the same spot as the original intake. It has a chinzy plastic faux-carbon scoop and the bottom half even has a cutout for the radiator cap to fit in. Good to know that when the car overheats it will spray hot oolant straight on the air filter...

I am on my way to Shanghai to see the impact on the high-speed downshifting on my AT Tiida on the freeway.

Any idea where I could find a 1.6l specific CAI?

[Demonspawn]

fuel economy is subjective with CAI you have to stay out of the gas pedal to get better MPG i was alsmost to 32 mpg avg before CAI but i get avg 31 mpg with CAI 10500 on OD

but there is a definite performance increase with CAI but still not a hot rod but a nice increase

[Nismo V]

Chinadan seems the experience you have had using your own Short Ram Air Intake has left you a little unsure of the benefits of a cold air intake, a Cold Air Intake usually under optimum circumstances can give you gains upwards of 5-10% of actual hp under throttle, which can be a overall good benefit comapred to a stock airbox. Concord claims to have experience with 300 Hp vehicles but that said he should also know that a 5-10% gain is a great performance addition given the low cost. There are not many street legal aftermarket mods that can be done at home with little mechanical knowledge that could produce as much in the area of performance, also if your driving a 300hp + performance vehicle it would be very loud in the cockpit anyways so the intake would be a minimal noise issue. To gain high performance output would be a more costly and time consuming project .. this Impul Supercharger however would give you a nice boost in pperformance if you have the extra cash

[versaspeed.com]

Every bit helps, and the CAI do improve the throttle response on the Versa and was the first thing I noticed when I put mine on. Intake and Exhaust is the first places to start for improvement on any car.

[Demonspawn]

yea even with a CVT i noticed the improvment and can get a decent burn out sometimes that suprises me!not a hot rod but a fun feeling!

[Wings]

Just remember it may increase 5% to 10% but it may not be an increase in the peak HP and torque. Say peak HP is 6000 RPM I know that's close but not accurate. The 10% HP increase may be at 3400 RPM. It's not false advertising but it is misinterpreted by many. They do help HP and Torque and if you drive it real easy will greatly help your MPG.

[bladesbravo]

How does the CAI sound on a CVT engine? I could only think of it as a car scared to shift out of 1st gear.

[#1Tango]

a CAI on a stock Versa will do nothing, nada, zero for performance.

Actually I've used numerous CAI's on 300 HP motors and the only performance increase from a CAI is at very high RPM's. Save your money unless you like the sound.

have you put a cai in a versa???? i noticed a significant difference compared to stock. i even got my car dyno'd w. a custom cat-back.

[Kolk1]

When I had my turbo Laser on the dyno, I did a stock dyno Vs Stock with K&N cone filter, Peak HP was identical, BUT the top end hp didnt fall off like the stock filter, and even though peak hp was at 4800, I had less drop off and by 7,000 rpms, I was at over 10whp more compared to stock.

[Red Devil]

I don't know if I'd call 4hp a "significant gain".

[dl56zza]

I thought that the resonance boxes in the oringinal versa intake were only to muffle the sound of the air flow at high RPM, so I removed them on my 2007 versa SL thinking that they would create turbulence thus slowing the air flow. After reading your post, I will reinstall my boxes. To any one who has added after market CAI, where is the cone shaped filter positioned? I have seen engine compartment images but I can only guess that the CAI terminates in the driver's side wheel well. If this is so, how is the filter protected from dust and rain water kicked up by the left front wheel?

[Rockhound]

I don't know if I'd call 4hp a "significant gain".

Yeah, that's definitely a case of diminishing returns.

[xtwoonamatchx]

the end of the intake with the filter ends right behind the driver side fog light, there is the wheel well liner, and other panels that keep it covered, if you take out the drivers fog light you can touch the filter.

[shiryu0]

i checked the filter on our Versa not that long ago, weve had it for about 10 months, the first thing i put was a CAI on it........the stock air intake is a joke.......

the filter on the CAI was clean, and i live in the desert, the cabin air filter on the other hand looked like crap

[Shad0wXCalibur]

i checked the filter on our Versa not that long ago, weve had it for about 10 months, the first thing i put was a CAI on it........the stock air intake is a joke.......

the filter on the CAI was clean, and i live in the desert, the cabin air filter on the other hand looked like crap

Stock air intakes are designed to let in the least amount of dirt possible and be as quiet as possible. CAIs do neither. Now if Nissan riced out their econoboxes from the factory, there wouldn't be much of a hobby of modding cars, would there?

And I speak from experience. I had a CAI on my Versa for a short time. Why a short time? Because yes, it does add a little power but not enough to go "Wow, this was worth the big chunk of change I just let go!" on top of it not sounding great except when you rev it in park. When stepping on it, the little engine just sounds kind of... rough. And for whatever reason, my gas pedal vibrated with it on and it annoyed the hell out of me. I wasn't the only one with that problem. And lastly, they do let in more dirt making your oil dirty faster and it would be annoying to clean whereas the stock filter is about the easiest thing to change out.

[BlueMango]

Stock air intakes are designed to let in the least amount of dirt possible and be as quiet as possible. CAIs do neither.

The stock air boxes are extremely restrictive. They collect more dirt because they line up along the top of the grille, they let in all of the road, dust, bugs, etc. They also run your air right over the top of the engine and then keep it there for a little bit running it through the air box before it goes into your engine.

The CAI is positioned so that it is taking in air from a lower area that is slightly protected from so much road crap. The AEM filter has been proven to have a 99% filtration rate in FINE dust testing. That means it keeps things out of your engine that are as small as one micron. It actually keeps your engine cleaner!

[steelcityversa]

Have you (or anyone else) had your engine light go on as a result of the CAI?If so, how did you fix it? Mine came on about 400km after I installed it and has been on for a week now.

[ADOversa]

Have you (or anyone else) had your engine light go on as a result of the CAI?If so, how did you fix it? Mine came on about 400km after I installed it and has been on for a week now.

I really have nothing useful to add, but its cool to see another person from the area on here!

[steelcityversa]

I really have nothing useful to add, but its cool to see another person from the area on here!

What do you think our chances are of starting a Jeep-esque wave when we drive by each other in our Versas?I try all the time to get a wave back from other V drivers. People look at me like I'm a lunatic.