Cold Air Intakes (CAI) Mythbusted MCM Video

[svard75]

We've had so many forum discussions on the pros and cons of adding a CAI to a car and the majority of us, from what I recall, were leaning towards the factory air box vs CAI, including myself. I was confident that Nissan had engineered the best solution for our cars... but have they?

Have a watch and perhaps this may change your mind.

[youtube]http://m.youtube.com/watch?v=xwNtjKT_1c ... e=youtu.be[/youtube]

[Larz]

First, I have to say that I really enjoy these two. I have been watching them forever. Second, it proves what I have always said:

1) If you're going for looks, or sound - it's a pricey mod but it will look good in your engine bay. (but how many of us open our bonnets to show peeps our intake on a regular basis? Who is going to see it in there?)

2) If you're going for more hp - it's a total waste of money for a gain of "maybe" 5hp and only at the top end, plus you could be endangering your engine with the oil based pod filter and fibers gumming up the works.

3) If you want more hp, buy an M45 / M56 model or get an up-rev tune with or without the CAI.

In other videos, they have proven that, although OEM intakes look cheap and simple, they really do have lots of engineering in their design to max out the power of the engine.

[Ilya]

Or 4) Buy an M45/M56 and get an UpRev tune and get even more goodness. . That's my plan.

[svard75]

Larz, I believe they did see very minor increases in the low end as well. What turns me off CAI is actually having to remove the fender wheel liner to install and clean the filter and for a car like ours having a loud engine just sounds too ricey.

I totally agree if you or anyone wants gobs of power an m56 is the way to go. I really like the way an m56 sounds without mufflers. Reminds me on the audi S4

[CPJ LB]

From my recent experience of having installed the Injen CAI (having driven with it for approx 1000 miles), here are some perspectives (rating of 1 to 5, with '5' being the best vs. stock)

1. Looks/style: 5
2. Sound: 4
3. Performance: ~ 2.5
4. Cost: 3
5. Installation: 3

Keep in mind, I did not have my car re-tuned after installing the CAI so I do not have any dyno numbers of any possible gains or losses. I recently removed the CAI and re-installed the stock airbox along with the Ztube in order to drive my car in wet weather. I'll probably install the CAI back on in the spring and get a comparison on the dyno.

The install of the Injen CAI is pretty straight forward and I did not need to go thru the fender liner. The filter cone (non-oil contained) sat right next to my driver-side fog light (where I have custom mesh lower grilles for my 08 bumper swap)... definitely getting cold air...I'd park the car after a drive and pop the hood to feel the intake tubing and it was not hot.

My impression about re-installing the stock airbox in terms of performance, I do feel a difference in the overall power band. it was more consistent compared to the CAI. The bottom end with the CAI felt a little sluggish unless you have the RPM's above 2100, then from there it feels great.... I relate that to not having the car tuned since my Uprev tunes were tailored to a different set up.

Similarly, in my younger days, I ran a CAI in a BMW where I did an engine swap in my 1993 BMW e36 (325i) by adding an '95 M3 e36 engine. In addition, I had the Dinan CAI installed (similar to my current Injen CAI, where the filter cone sat below in the front bumper area) and prior to having the car tuned, it felt sluggish until I got on the pedal and then it pulled. Once the car was tuned, I noticed the difference almost immediately - in every range of the power band.

In my opinion, "just" adding a CAI to an otherwise stock set up will only yield some good 'growl/noise' under acceleration. The ECU will make adjustments accordingly. However, if one were to have more performance mods and install a CAI and get the car tuned, I think the gains would be overall positive. I'm really curious to get my car to post some numbers with/without the CAI and stock air box....I think the VQ35DE engine is really sensitive to specific mods.... The mods that I've done since picking up my M in 2010 have been documented and I've posted some numbers accordingly, so I'm looking forward to do the same with the CAI vs stock airbox...more to come. But in the meantime, when I have the polished CAI installed, it looks really good when my car is parked

[svard75]

Nice writeup. One thing comes to mind about loosing low end. Our factory setup is also resonance tuned. Noises in the intake can actually have a detrimental effect on airflow, so removing all resonance components from the intake could be just enough to loose the torque. The cai that you add just changes the powerband due to resonance. Real interesting stuff.
http://www.autospies.com/news/Engine-Tu ... t-1-47183/.

[veery]

CPJ LB, where on the car did you fasten the tab on the outside of the lower Injen pipe?

[CPJ LB]

Nice writeup. One thing comes to mind about loosing low end. Our factory setup is also resonance tuned. Noises in the intake can actually have a detrimental effect on airflow, so removing all resonance components from the intake could be just enough to loose the torque. The cai that you add just changes the powerband due to resonance. Real interesting stuff.
http://www.autospies.com/news/Engine-Tu ... t-1-47183/.

Thanks!! You are correct...it's amazing how something as simple as 'noise' can change things up

CPJ LB, where on the car did you fasten the tab on the outside of the lower Injen pipe?

it'll be to the right of two holes -- where the two long lower tabs (from underneath the OE airbox) are inserted to the frame rail. There should be an open hole where the Injen supplied screw w/padding -- the vibramount -- that can be mounted to. it sits horizontal to the frame rail .... I'll check and see if I have some pix of that area, but if I remember, there should be a picture of the location in the owner manual.



[veery]

Thanks for that. I plan to get longer!!!

This forum ROCKS!

[CPJ LB]

You're welcome

...I also added a 4" piece of rubber hose (sliced along the length) to the frame rail where the lower intake tube will 'butt up against'. This helps protect the intake tube from being scratched when the motor moves also serves as an anti vibration.

[svard75]

I'm actually thinking of going back to the stock tube since it had a resonance chamber built-in just for the heck of things. Anyone want to buy the Stillen Z-Tube off me? Send me a PM.

[veery]

You're welcome

...I also added a 4" piece of rubber hose (sliced along the length) to the frame rail where the lower intake tube will 'butt up against'. This helps protect the intake tube from being scratched when the motor moves also serves as an anti vibration.

I think that's a great idea. One reason I didn't pursue the long solution and ended up with a short ram is because of the way the pipe was rubbing against metal. I suppose thermotech wrapped would prevent that chafing as well.