I've heard about the positive effects, but what are the negative effects if any? Is it bad for the car in the long run?

 

I don't know if it was my imagination or not. After I installed the Injen CAI, it seemed that I lost a little torque down low , especially from a start. It came back after my NISMO exhaust though.

 

VQ is right- as long as you don't plan on driving your Z through 2 feet of standing water, you're A-OK

 

Understand the water issue....but what about snow and ice? such as a Boston winter? thanks

 

would 2 feet of running water make a differance?

 

You telling me the intake sits TWO FEET above the ground? lol

Uhhh no... if the water is high enough to hit the filter you WILL injest it. The oils on the filter help repel to a point, but alas water will still penetrate.

 

Two of the G owners one being me have experienced problems with the Injen CAI. When we drive at speeds above 65mph and disengage the clutch, the revs would drop to about 500, then it would jump back up to around 1200, then drop again with a fluctuating pattern. It seems that the engine is struggling to idle when the car is moving very fast and the clutch disengaged. At times the engine would even stall and we lose power steering.

Now heres my theory of what's happening.
My theory is not that the engine is getting too much air, but the engine is not getting enough air. Heres my thinking:
-When you disengage the clutch, the throttle body is pretty much closed with a very small opening, it lets in just enough air to let the engine idle at around 600 rpm's.
-The location of the Injen filter allows the filter to get direct air flow entering from the front of the car. There is no obstructions to deflect the air.
-WHen you're driving 65+ mph, the air enters the front bumper and hits the filter directly, causing the bernoulli effect. When the velocity of air increases, the pressure decreases. So the pressure around the filter is very very low.
-So when you're driving above a certain speed, and let off the throttle when the car is in neutral, there just isn't enough vacuum inside the CAI to allow the engine to get enough air.

I'm going to install an Injen heat sheild/deflector to try to obstruct the airflow and see if it helps. Also, it'll protect the filter from mud/dirt/etc... because the oncoming air doesn't hit the filter directly.

Has any of you Z guys experienced this? would you mind doing a test on a freeway by disengaging your clutch while above 70mph and let the revs drop down to idle. Help would be appreciated.

I know the Z CAI from Injen comes with some sort of a heat sheild or deflector. Where exactly does that sheild go?

Also, I know the filter for the Z's CAI sits right infront of the radiator. The radiator acts like a wind deflector screen on a convertable. Which slows down the incoming air. Our G intakes however, sits in the corner of the bumper and there is nothing behind the filter so the air has a free flow right around the filter.

 

You just have to run into enough water to suck it into the lowered CAI intake. I depends on your speed, the depth of the water and the location and protection afforded the CAI intake. The filter might stop a little mist, but hitting into more than a few inches of water at a high enough speed could be enough. If water reaches the engine, it flashes to steam and expands with substantial force typically damaging internals and basically the engine is junk. Its not just a stall and wait til it drys out!

It looks cool and maybe you get a few more hp, but is it worth the risk. If your Z is for weekends and the track, ther's not much risk. But, if its a daily driver, the risk is much greater. Some of the CAI manufacturers make a valve that closes to stop water intake, check that out at least.

Look at the intake on the Z now. How much colder will air be from a lowered intake??

I'm in the process of hooking my intake up to my air conditioner, its safer.

 

to hydrolock your engine you pretty much need to submerge your intake or you'll stall before any damage is done. Again, this won't happen unless you're an idiot (or there's a flashflood).

 

Exactly!
Yes, for water to completely submerge the entire filter and induce hydrolock you would need about 2 feet of water (maybe 18"). Even if the very bottom was in water this would not induce hydro lock- the entire filter would have to be submerged- There is simply not enough pressure to be concerned about rain, splashes etc being pulled all the way up into the engine. If this was the case you'd be hearing about it.

 

Yes, for water to completely submerge the entire filter and induce hydrolock you would need about 2 feet of water (maybe 18").

so i guess my episode with my first Miata where I drove it into 3 feet of standing water would be out of the question? (Car came out fine -- long story short I would have been trapped between two exits on the 101 freeway for 48 hours until the water went down, IF the car hadn't been washed away completely. I figured it was worth a try.)

It's pretty troubling to see driftwood floating in front of your headlights, by the way...

-- Mark

 

by using a CAI you're getting more airflow and this causes less back pressure through the exhaust as it is pushed more. A decrease in backpressure decreases low end torque, BUT increases high end HP. it's all about sacrifices, but I prefer high end HP.

 

Explain this one to me?!?!?

More air plus potentially more fuel (gotta have both to make power) nets higher cylinder pressure (more gas) leads to MORE gasi n the exhaust, leads to LESS back pressure?!?! If anything it will lead to more back pressure (small amounts). The cai typically has 2 things going for it, cooler air, and a straighter path to the TB = higher speed and mass of air. Exhaust is typically not effected greatly and if anything sees more volume of gases due to more air being taken it. A CAI will not reduce pumping losses in the exhaust.

One reason you might be losing low end is that in the lower RPM's air VELOCITY is more important to making torque than air MASS. So the wide diamaeter piping flows more air but at a slower speed thus reducing cylinder filling and sacrificing torque.

Ben