Last night, I decided to put the OEM intake tube back because I wanted to see how much of my car's noise was coming from the intake mods and my exhaust mods. I got the car fully warmed and did some normal driving and then started getting on it pretty hard. Things I noticed right way:

1) The intake is pretty quiet above 5000rpms. Where it use to wail and resonate a bit, it's now smooth and probably over 50% quieter.

2) The motor feels smoother above 5000rpms

3) The motor feels punicher, less peaky, and sure feels like it pulls harder at most any rpm, especially WOT from 4000rpms to 6600rpms.

4) 5AT shifts feel more direct under 50%+ throttle

Even though everything is much quieter above 4000rpms, the car sure feels like it's stronger. Nothing earth shattering, but the motor feels "fuller". It's hard to explain and I'm a bit confused now. Are the resonators on the OEM G-tube simply noise resonators or are they Hemholtz-style resonators that actually improve the intake pulse and possibly power?

Years ago when I had my modded 96 Maxima, I tried every intake setup under the sun. The OEM Maxima intake tract had a resonator box between the MAF and intake manifold, much like the G's. It turns out that resonator box was in fact a Hemholtz resonator and was responsible for legit power. Remove it and you nueter power from 3500-5500rpms by about 7whp. Also, removing it deadened throttle response a bit and hurt the surge of power just after a shift. Taking it off did make the intake much louder though and that's what most people wanted. It turns out the best setup for that car was to simply mod the stock airbox slightly and leave the rest of the intake alone. I always ran better times with that intake setup, even though the induction noise wasn't as sexy. I swear I'm feeling the same thing with my G.

My G's current intake work includes a slightly enlarged PowerDuct, Revup airbox, and MD spacer. Is it possible that the G's convulated intake tract is really designed to deliver both power and noise reduction? The Z's intake tract is a bit different than ours obviously. It doesn't have the over radiator snorkel, the under airbox resonator, or the resonated intake tube. The intake tract simply has a large opening at the front of the airbox and pulls from an area between the forward lip of the hood and radiator support and the piping is smooth. We know the Z ECU has different tuning. Is it possible the tuning between our ECU and Z is more elaborate than we think and that the G's intake tract is ideal for this car?

I know the Z-tube doesn't add power, but is it possible that using it might actually hurt power on the G? Granted it was about 75 degrees last night when I was racing around, but I did have a fully topped off tank. I was running around this morning when it was 80 and the car felt the same as last night. We'll see how it run this afternoon when it's 90.

I've read numerous posts in the past of people saying they noticed some reduced torque when installing the Z-tube. I can't say that I remember that, but I do remember the increase in induction sound and noisy always seems to feel like you're going faster. Who knows.

 

I would suspect that it is for noise reduction alone. If it actually made a significant difference, nissan would have used the design on the 350z as well. If it was something you could actually "feel" in terms of added hp, then that would have to be in the 10hp+ range, which would be pretty unlikely. Try getting some earplugs and driving around with both intakes installed and see if you can tell the difference

 

I'm just wondering if the G's long and resonated intake tract setup performs just as well as the Z's straight and non-resonated setup and that the G's resonators infact help this system to perform and that removing some of these resonators has a deterimental effect on it's performance. It's just a thought. I'm going to run it this way for a full tank of fuel and then swap back. I'm also going to grab to MAF readings before and after.

 

Did you happen to disconnect and reconnected the battery for this swap? It could be an ECU resetting or rebooting itself that gives it an extra initial kick.

I've noticed this slight increase in power whenever i disconnect and reconnect whenever I'm working on anything in the engine. Then it just goes back to normal, or I just get use to it again.

 

i'll try it out at the track tonight along with some other things and see what happens.

Too bad the DA will be about 1500 tonight because of the humidity

 

That's a very interesting synopsis there. I have been thinking about restoring my intake to the stock airbox as well.

 

Dave,

Are the resonators on the G kind of similair to the ones on the maxima or completely different? Just curious.

 

I can't see it helping that much (ie.. perhaps by "storing" an extra amount of air) given the way the oem resonator is designed. The path of the air is pretty angled to me (ie.. alot of 90 degree or worse angles)

 

subscribing

 

I'll do 3 runs with the g-tube and 3 runs with the z-tube with a 10 minute cool-downs between runs and 20-30mins between switching tubes.

My 60ft is consistent at this track 1.9-2.1 so it should be a good test hopefully.

Anything else to try or do?

 

You rock. I don't have anything else suggest trying.

I'll dig up pictures of the Maxima resonator box.

How do you like that Edge TC? How does it effect daily driving, MPG, launch, TCM conflicts?, etc. I don't think I ever saw a writeup.

 

Dave, I hate to tell you this but...."It's all in your head!" Unless the z-tube you were using was metal then you're suffering from heat soak even at 75 degrees since the under hood temp is 20+ degrees higher. I've been using the plastic composite z-tube for 5 years and don't have major heat issues but the temp change is noticeable winter vs summer. My G seems to run it's best below 60 degrees where second gear scratch is common without much crowding....
Gary

 

I never did one on the convertor it's been on my car for about 4yrs with no problems.

My TC is my stock one modified by edge racing. l like it you can't even tell that it is there.

Check this out.

http://blog.autospeed.com/2003/11/30...-into-intakes/

 

Helmholtz resonator theory

http://www.dinamoto.it/DINAMOTO/on-l...suonatore.html

Take notice of the power curve with and without the Helmholtz resonator. That's pretty much what we saw with the Maxima's with and without the resonator in place.

 

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