intake resonator
 

ok so last week while i was putting on my new bumper, i thought it would be ok to take off my resonator. i was down there anyways so why not right? well all in all it was a success besides the part that im starting to lose my fe! :thumbdown: i thought that restriction was the enemy of fe? i had the idea that the more free flowing the intake and exhaust the better the fe and power would be!? check out my garage and let me know what you guys think. im going to keep it on for a while just to see what happens. :confused:

If you remove intake resonator you will lose low-end torque. Another words your car will lose power in low RPMs. I've done it and that's what happend to me.

Not sure exactly what you mean by "resonator."

Most modern cars have an intake "resonator" that looks like tubes folded over themselves. In some cars they're metal, I think in newer ones they're plastic.

They function to increase the intake charge pressure by acoustic resonance ... in the 4 cylinder cars I've owned, they kick in at 2,500 RPM or so, and their peak function corresponds with the peak torque.

I wouldn't recommend that you remove it. You're probably better off changing your driving technique.

Might have something to do with intake velocity.

yea i kinda felt that.

exactly that. its the tube/box that goes from the intake filter to the wheel well and into the engine bay. i guess its kind of like a wai in a way. i am going to try and be a little more conservative with my driving with the intake resonator off to see what i can get from it. if i like it it will stay off if not then i will definitely put it back on.

You've noticed the loss in power.


BTW, would the FI be mapped to include the resonator? Is it possible that you're now running at a non-optimal fuel/air ratio?

Keep us posted on any FE changes.

lol yea i noticed the difference big time in taking off the resonator. especially in first gear trying to take off! :thumbdown:

thats what i was thinking and i talked to one of my car guys tuner (helped tune the first honda into the 10.5 sec mark in my town :eek: ) and he said that by removing the ecu fuse it will reset the af map? i tried but saw no real difference? i want to buy a VAFC or a NEO to tune it and lean it up a little. but we'll see.

What part of fluid dynamics don't you understand? Wouldn't it be cool if there was a way to make it so the air going in to the engine kept up it's momentum so the engine didn't have to work as hard to pull fresh air in? oh wait! they already did that and you removed that part! that piece of the air intake was there to help your car run better, sure you might be able to baby it to get your lost mileage back, and strips some weight out of the car so you don't notice the lack of power but why?

Paralysis induced by overanalysis.

Hmmm, just thinking about intake resonator type devices... I wonder if it's possible to make one that takes up the momentum of high speed intake air, at higher RPM, say 5000 or so and gives it "somewhere to go" such that you can run much weaker intake valve springs and not get valve float...

You could easily make one for 5,000 RPM. The ones on cars now are made to coincide with a particular RPM (peak HP, I think).

As for the valve spring thing, I don't think so. The resonator acts to push an acoustic pressure wave into the intake valve when it opens.

But if you can set it up such that the pressure wave is negative at valve closing time....

You lose volumetric efficiency and you burn more gas.

Which is exactly the opposite of what it is designed for, which is that it's resonant frequency is the same as a particular frequency of valve openings.

Kind of backwards, right?

Well yes, but you also have to have a negative wave at some point, I'm just wondering if it can be synched slightly off to help snap the valve shut, rather than at some point after valve closing, or during valve opening.

Would totally depend on the duration though, obviously it would come naturally with 180* duration at the point of resonance. However you might be working with 2nd or 3rd harmonics to fit it in the duration otherwise.

Well, since the waves are probably very close to SHM, I can't see how you could have them both push air in and simultaneously pull it out.

From a friend who designed them, the resonators are only good for about 10hp or so, so I can't imagine there would be enough force/power to help shut the valves when compared to the spring rates of the valve springs.

Possibly not, but if there's 1 oz more on one side of a seesaw, it still stays tipped, the same as if it had 10lb on it.

The resonance pushes AND pulls though, it's all in the timing, it doesn't push and pull at the same instant, it pushes then half a wavelength later pulls back, by the time the air is springing back though, the valve is closed so it doesn't matter... but if there was an advantage to timing it to pull at the last instant before closing, to help weaker springs overcome the inertia of the valvetrain....

ok so as you guys know i took out the resonator and to my surprise i actually have been getting the same, or better fe readings! is this typical?

Come to think of it, if it was in the bumper area it was just a silencer type. These actually kill some intake velocity because they work on the destructive interference principle.

Silencer or intake pulse tuner, I don't know which but my car has a big resonator on the intake pipe, I was thinking of half filling it with water to make the intake air more humid. Just to see what'd happen.

Mark you might suck the water in and liquid lock your engine. Happens around here a lot in floods. Did one 300ZX Twin Turbo that bent the rods amost 90 degrees.

regards
gary

wow im a hyper miler now! im trying to get ahold of one of my old friends that has a d15b for sale, the vtec-e model. im going to need to get my hands on an ecu as well though. well see how it goes!