Okay, many people say that when switching to the Stillen intake or the Pop-charger they feel a loss of power at low RPMs. Why is this? The only reason I can think of is that the stock airbox provides a higher-pressure environment to draw air from, so in that first push of the throttle, air is more easily forced into the intake. Thoughts?

 

I'm no expert, but my guess would be that when you floor it from a stop, your intake starts to suck in all the hot air thats inside of the engine, rather then the stock air box or cold air intake which sucks the cooler air from outside of the engine, of course once you get moving and into the higher RPMs, this doesn't become an issue anymore and the stillen or jwt wins out over the cold air or stock intakes...at least thats what i'm guessing happens, i took off my stillen to take my car to the dealer and i noticed how it pulls in the lower RPM's.

 

Sorry i ment "under the hood" not in the engine

 

I think this has to do with length of the path that the air travels to the throttle body/engine and its velocity. The longer path generates(?) more velocity versus shorter path of the Stillen/Pop-Charger intake. This philosophy is reversed at higher speed. There was a discussion of this topic on this board and some extensive debate in the maxima club from Yahoo.

 

How does the stock airbox provide a higher pressure enviornment?

ZuM

 

my stock airbox did not make my car feel like there was more torque then my intake or cold air intake but when i went back to intake from cold air intake (because of alot of rain lately but i will soon have the best of both worlds when i do my custom cold ram air intake), i did notice my car felt like it had more torque but not the high end power of my cold air intake.

 

Okay, here's a theory (of course physics was not my strong point). With the stock air box, because of the ram air tubing size, baffle and the distance it has to cover, the air inside the system is travelling faster in order to cover the engines needs. In the Popcharger system, the air would have to accelerate from a much lower speed, causing a 'lag' in the airflow increase. Does this sound retarded?

 

I've dynoed with my HKS (POP) intake and my Poorman's CAI (modified stock airbox). The car makes the same amount of torque from 2200-4400rpms. After that, the POP style intake makes an additional 3-5fwhp and 3-5 fwtq till 5600rpms. Then right 5800rpms, both intake were making the same power and torque.


Dave

 

That's interesting... I wonder why people say that they feel less power down low then? I can't imagine an OSCAI could give that much of a difference (don't flame me 5th gen guys )... could they just be comparing it to the new power up high?

To Zumble:

I think it could be a higher pressure environment because it's sucking in outside air into this sealed box, and when the engine is idle, very little air is used. I admitted from the get-go I have no idea if this is actually true, and it seems that the myth of the Stillen intake is just that, a myth. You can't argue with the dyno.

 

Nah, the engine can easily suck in ALL the air from the airbox at idle. If you have a pop intake. Put your hand over the filter and you can feel how much air it is actually pulling in at idle. Its a lot. I do believe that at idle cooler air is being drawn in though. I would say the cooler air is the reason for the additional torque. The airbox is negative pressure all the time.

ZuM

 

I thought the same thing until I ran my car at the track and street with both the CAI and the underhood style intakes. On the dyno, they show no difference whatsoever. On the street, I "thought" the CAI "felt" faster. On the track, I was sure of it. At least this is true on my car.

I believe the CAI is affected in a positive manner when the car is at speed. With similar 60 fts, my trap speeds were consistently higher (2 mph) with the CAI, and the ET's were consistently lower (more than 0.3 seconds) Those are huge differences.

My best trap speed with the underhood style intake was a little under 94 mph, most were around 93 mph. Thi is about what the car did stock and without the Y-pipe! With the CAI and Y-pipe, it hits mid 95's every time. In cooler weather, it almost touches 97 mph. (96.6-96.9 mph)

 

I definitely agree that the dyno can't show the real power a CAI can make at speed. A stationary car on rollers can't reproduce the CAI's effect even with a big fan in front of it. I don't think the Stillen intake would have a significant difference in airflow from dyno to street though. There's just too much stuff under the hood.

 

There's no reason to imagine, Weasel. Track results have proven the benefits of the OSCAI conversion. Those who have tried it, myself included, enjoy the low-rpm torque provided by the stock airbox coupled with high-rpm performance equivalent to an underhood intake. On a 5th Gen, the only intake system proven to provide better performance than an OSCAI conversion is a Place Racing CAI. At the risk of getting flamed, it's hard to justify an underhood intake on a 5th Gen when the OSCAI conversion is WAY less expensive, just as effective, and won't raise your dealer's eyebrows when you take your car in for warranty service.