This is probably an old mod, but a few days ago I decided to remove the Power Duct cover from the airbox. A local G owner had told me that when he removed his, the induction noise increased quite a bit. I figured I'd give it a try since I had been craving a little bit more induction noise. Sure enough, with the duct removed, the VQ is noticeably deeper sounding on acceleration. A side effect is the intake whistles a bit more under part-throttle. The whistling is caused by the throttle being hardly opened. I experienced this on my Maxima with a hacked stock airbox. Anyways, I was a bit worried that removing the cover may introduce a bit more hot air and throttle response may be deadened. I'm happy to report that the throttle response appears to be the same. I did some datalogging before and after. Keep in mind that the temps in Kansas City have been hovering in the mid to lower 90s for the last week and a half. Testing was done at night with temps in the 81-83 degree range. Temp wise, the intake air at a stop is about 8 degrees hotter. At a roll, it's the same as it was with the cover on. Intrestingly, I also logged air flow and the numbers are fractionally higher suggesting that the motor might be getting slightly more air. I'm only talking about a 3% improvement though which may or may not be anything. By seat of the pants, the car feels quicker only because of the increased noise. I doubt there is any measureable performance increase though so don't get your hopes up.

 

thanks for the datalogged info as i've wonder if this mod(which i did way back then) had any significant effect......My asusumption about more air into intake is correct according to your findings..3%, not much.....if there's any other surprises that comes up please share!! thanks.......

 

why would infiniti put on something that would hinder power...and also call it a power duct? hmm. does this really do anything?

i understand about removing the resonators, but the power duct? maybe if it were called a "sound reducing duct".

but good work nonetheless. =)

 

Because the overwhelming majority of car owners want their car to be as quiet and smooth as possible, regardless of the make, model, etc...

 

Can you post a DIY or show me a thread that shows how to do this mod. I did a search and couldn't find anything.

Thanks

 

too easy for a DIY.

-open your hood.
-grab a screwdriver and push the center of the 2 studs that hold in the part of your intake that says "power duct"
-use a flathead to pop the 2 studs out. take out power duct.
-andyou're done.

 

Hi,
After reading your post the other day, I popped mine off at lunch. When I drove back to work the engine was noticeably louder. No real perf increase. I made a “new” power duct gasket for my new intake “hole”; I also widened the intake portion just inside the part where the old duct use to connect. So if I want I can snap the duct back on, when going to the dealer ship.

2 Questions:
Assuming the MAF is detecting more airflow, has anyone data logged the a/f mixture, does this mod lean us out a tad?

Can more airflow into the intake box bad be for HP/TQ, assuming I’ve isolated the airflow into the box and kept it away from heat with my homemade gasket?

Thanks for any info you can provide

 

While doing our air intake temp testing (posted, but mostly ignored, on G35Driver) we removed the Power Duct from the stock air case and using the TechTom CMX-100N our observed test results were:

1) No measurable increase in mass air flow sensor voltage. (This voltage signal infers air flow as described in the Nissan/Infiniti service manuals).

2) A 15F+ increase in air inlet temperature at idle and during low speed operation (90F ambient temps).

3) A decrease in the engine's total timing in response to the IAT Sensor's (thermister's) decrease in resistance due to elevated temperatures.

4) Some decrease in low and mid range power. Little or no loss noted at higher rpm levels. Recent dyno tests by well known companies (I promised to keep their names confidential) have confirmed these G-Tech and dyno-butt test results.

 

hey daveO, glad to see you didnt give up on the forums like you were planningthe last time i talked to you. =)

 

Great write up even a nooB like could follow what you were saying.

 

Good info.

 

so its really not that good of an idea, right?

 

now where do we get some useable thermal wrap to wrap up our stillen intake boxes....... home depot doesnt sell the cheap foam stuff anymore

 

One more time. (My apologies to the old timers.)

I use Thermo-Tec Adhesive Backed Heat Barrier. It's $17.88 for a 24 in. x 12 in. piece from Summit Racing. Their part number is THE-13575. It's also available from other companies.

 

I just switched back to the stock box w/ a K&N. I had the stillen box on previously.

I checked out temps using my obd2 scan tool (dyno scan for Palm Pilots). The idle and low speed temps were significantly better with the stock setup.

I miss the sound and top end pull of the stillen, but the stock box has better around town pull and response.

BTW, the stillen "velocity stack" acts like a super heat conductor. That thing was super hot!!!