2002 Intake Silencer Removal

[cashmoney]

It won't work. Go to an exhaust shop, give them $20, have them expand the ends.

 

[Oprah]

After a lot of searching for the right size, I ended up at West Marine, found a marine exhaust pipe, basically thick/tough rubber hose that has some metal structure in the walls, and since its for exhaust, you know it can handle the heat. I don't have the part number on hand, but you can go there and ask them for some.

I then drilled a hole in it and fit a plastic fitting for the vacuum hose (that it sounds like an '02 doesnt have?).

All in all, I had it on for a couple days, it made the engine louder, and that was it. It was too loud combined with the deckplate mod, and had some weird resonance. I am thinking one day of blocking off the hole from the deckplate mod and adding in the straight pipe again to see what it sounds like WITH ISR mod and WITHOUT deckplate mod. I do like being able to hear the engine better, because I like to know exactly what it's doing under there without having my eyes glued to the tac.

As most will say on here, both mods are for engine sound. No real performance gains. It may affect your butt-o-meter as far as horsepower though.

Happy modding

 

[MatthewRM18]

Ok, I will just do that and save the trouble. This is why they make a forum, so you don't go out and blow money on something that other people have already figured out! I can't afford to gain any serious horsepower, so the "5-7 dyno claimed" horsepower that comes from these mods is insignificant, my butt-o-meter is all I am really concerned about. Thank you to everyone for the responses.

 

[4-Ripcord]

its not so much power as throttle response. 5 is less than the margin of most dynos anyway so that is a meaningless figure.

 

[MatthewRM18]

Yeah, even with just the deckplate I noticed a bit of pick up, whether it is actually better, or it is all mental from the sound, it works for me. At least it gave me something to tinker with XD

 

[Avwizz]

2.5" emt

I had a piece of 2.5" EMT from a job site that I used for this on my 2000. fits pretty snug then clamped in. there was one vacuum hose that was on the original IRS box and i did drive around with it simply taped off for a while and nothing happened. Then I got a T fitting and plugged it into the top/front of the motor where the vacuum for the 4WD is created and still nothing happened and its like that to this day.

 

[JeepKiller]

It may help, it may not. I did it because I enjoy making my 4Runner my own and I enjoy cheap modding haha. Plus it cleans up your engine bay and provides you with a good bit of extra room.

 

[baja1]

I threw this out before and didn't get an answer, just where does the extra loudness come from? the airbox, the pipe, the throttle body? im curious if the marine exhaust is quieter than a section of metal pipe?
I would do this mod just to free up some room in the engine compartment but im not down with the extra sound.

 

[4-Ripcord]

I threw this out before and didn't get an answer, just where does the extra loudness come from? the airbox, the pipe, the throttle body? im curious if the marine exhaust is quieter than a section of metal pipe?
I would do this mod just to free up some room in the engine compartment but im not down with the extra sound.

We already answered you. The resonating chamber you are removing works similar to how exhaust mufflers work, cancelling out pulses in the air pressure.

You also already said you don't want extra sound so I'm not sure why you are still looking at this mod..

 

[cashmoney]

I'd imagine the marine exhaust is quieter because it's a fibrous//rubber material wrapping the metal pipe and insulating it.

 

[JeepKiller]

I threw this out before and didn't get an answer, just where does the extra loudness come from? the airbox, the pipe, the throttle body? im curious if the marine exhaust is quieter than a section of metal pipe?

I would do this mod just to free up some room in the engine compartment but im not down with the extra sound.

Intake SILENCER removal mod. The giant box that you remove acts kinda like baffles that allow the air to expand and go into different chambers. Almost like a suppressor on a gun. And no... A straight "marine exhaust tube" could in no way be quieter than a rubber tube with giant baffles on it.

 

[jeremyc74]

It's already been said once, but apparently people only hear what they want to hear.

This isn't there for noise.
The minor changes to intake sound levels weren't even a remote consideration for a vehicle like the 4Runner back in the early 90s when this was being designed.

It's there to improve volumetric efficiency. This INCREASES power and efficiency, not the other way around.

What is the Volumetric Efficiency of an IC Engine?

The volumetric efficiency of an IC engine is the ratio of the volume of air fuel mixture (or air) entered into the combustion cylinder to the volume of the cylinder when the piston is at bottom dead center. The volumetric efficiency is directly related to the torque output of the engine. Turbocharged engines can easily achieve a volumetric efficiency over 100%. For naturally aspirated engines, higher volumetric efficiency is achieved by using resonators integrated with the inlet manifold design.



How the Resonator can improve Volumetric Efficiency
•In an IC engine, air or the air-fuel mixture is sucked inside the cylinder while the piston is moving toward bottom dead centre (BDC).
•As the filling process progresses, the charge air gains more and more momentum, so the speed of the charge air increases gradually.
• As soon as the piston reaches BDC, suddenly the inlet valve closes. But, the air in the intake manifold still has a substantial amount of velocity (or dynamic pressure).
•Eventually, the flowing charge air hits the closed valve, and the pressure of the charge air at the vicinity of the valve increases. The pressure wave bounces back and starts moving toward the opposite direction.
•If a resonator is attached with the inlet manifold, then it will act like a spring to the just-created pressure wave.
•The frequency of the resonator determines the speed at which the pressure wave will proceed again toward the inlet valve.
•If the frequency of the resonator and the speed of the engine (which determines the interval between the opening and closing of the inlet valve) are properly tuned, the pressure wave will hit the inlet valve again at the time when the inlet valve is open. This phenomenon will cause a rush of charge air into the cylinder. The charge air will be forced into the cylinder, causing the increase in volumetric efficiency.
• The point to be noted here is that you will get maximum benefits of increased volumetric efficiency only if the engine running frequency and the resonator frequency are properly tuned. That means you can get maximum benefit only for a particular engine operating speed with a fixed frequency resonator.
•For selecting a resonator, the engine operating speed, intake manifold design, and volume of the intake manifold need to be considered. Roughly, the resonator frequency is kept around double the engine frequency in order to get the benefit of the volumetric efficiency increment.

Volumetric Efficiency and Helmholtz Resonators in an Air Intake in an IC Engine

 

[Oprah]

I'd imagine the marine exhaust is quieter because it's a fibrous//rubber material wrapping the metal pipe and insulating it.

I haven't heard anyone else's using a different pipe material, but the marine exhaust piping was definitely too loud for me.

 

[cashmoney]

I was grasping at straws.

 

[Oprah]

It's already been said once, but apparently people only hear what they want to hear.

This isn't there for noise.
The minor changes to intake sound levels weren't even a remote consideration for a vehicle like the 4Runner back in the early 90s when this was being designed.

It's there to improve volumetric efficiency. This INCREASES power and efficiency, not the other way around.





Volumetric Efficiency and Helmholtz Resonators in an Air Intake in an IC Engine

You sound smart. I like you. What say you about the deckplate mod?

 

[jeremyc74]

You sound smart. I like you. What say you about the deckplate mod?

:brushteeth:

I think it might be worth a couple of HP under certain circumstances, like when you're moving and at high RPM, but I think it's probably going to result in a loss of power under a lot of circumstances because the inlet air temps are going to rise. There are dynos out there for supercharged vehicles where it shows a little gain (5-7Hp I think) but the ones on NA vehicles I've seen are within the noise range of the dyno.

I've said it in other threads, but it's worth repeating. The engineers don't just leave free HP on the table. If making the opening to the air box a little larger would have added HP, they would have done that. There's just no reason not to.

 

[Oprah]

:brushteeth:

I think it might be worth a couple of HP under certain circumstances, like when you're moving and at high RPM, but I think it's probably going to result in a loss of power under a lot of circumstances because the inlet air temps are going to rise. There are dynos out there for supercharged vehicles where it shows a little gain (5-7Hp I think) but the ones on NA vehicles I've seen are within the noise range of the dyno.

I've said it in other threads, but it's worth repeating. The engineers don't just leave free HP on the table. If making the opening to the air box a little larger would have added HP, they would have done that. There's just no reason not to.

Interesting, I've been under the impression that when the air is allowed to move faster, it actually cools down (I thought to be one of the basic ideas behind cold air intakes that allow faster airflow). Is the air not moving faster, or is that assumption incorrect?

 

[Skinfaxi]

Pretty sure this was discussed recently and turned into a nightmare thread. There are several conflicting statements, pick your favorite:

1. Toyota didn't care about induction noise of SUVs in the 90s, it's obviously there for power.

2. Toyota wouldn't spend that much money on design & tooling for a 3hp power gain, it's obviously there to control noise.

3. Engineers don't leave free power on the table, ever. It's obviously there for power.

4. It's a power robbing noise killer and should be eliminated at all costs.

5. It's there exclusively to start internet arguments between people without engineering & physics degrees.




Ask yourself, do racecars have intake resonators?

 

[Nunyabiz]

I have been using the AiRaid Jr kit for about 2 years and regardless what anyone believes or what Toyota claims it works better than the stock tube with silencer.
Combining the better air flow IN with the better air flow OUT of both the Airaid Intake and a freer flowing Muffler I gained about a solid 2MPG better MPG on the highway.
Very little difference in city except that it just "feels" better, you can tell the engine is breathing better and the throttle response is way better.

The only time it sounds louder is when you are giving it quite a bit of gas.

On my one cross country trip of 7700 miles it virtually paid for itself in gas savings.

 

[jeremyc74]

Ask yourself, do racecars have intake resonators?

Apples and oranges. How often is a racecar loping along at 2000RPM?