What is the "resonator" for ?

[Richardv]

Hi,

I ride an ST 2013. There is a resonator in front of the air box intake. What is its purpose? Can I remove it to improve air flow? I would prefer to stick to the original air box with a K&N filter, because I am seriously thinking to get a cat delete..... but also, I would like to get better air flow to cool down the engine/SM5 tranny.

And, YES, I did get the heat recall done. (i.e. 2014 air intake panel) . Also, I know about the JT air filter mod, but I don't want to go that route with a fuel chip and O2 sensor problems, if I also get the cat delete.

Thanks in advance for your inplut/ explainations.

[SNOOPY]

I removed the whole air intake whatever crapola. Man what a difference. So much more room for airflow. I did do the JT airfilter and Akrowhatever muffler thingy and the bike/trike whatever has been great for 3 years.

Back to your question, I think the resonator only improves sound and mileage. It could be removed and blocked off, but with the trouble I would just remove it.

I have no chip or tune and the bike runs great with the JT filter and muffler.

I think there are 5 different answers to your question, and that is mine and what I did.

[Peter Aawen]

Those 'resonators' & big bulgy bits in long air intake tracts are usually there to 'tune' the length/ volume of the air intake in order to remove dead spots in the revs or improve the fuel economy or power/torque curve of the engine!! The manufacturers have generally spent millions of dollars on research & testing to work out how to get the desired results from the engine/air intake/filter housings, & you mucking around with that generally won't end up making things much better!! They do usually have a reason to be there, & simply tossing those & leaving the rest of the plumbing alone or just blanking the resonators off is not generally such a great idea!!

So if you want it gone, I wouldn't just remove or blank off the resonator - if you do that it's pretty likely that you'll have some degradation of your power/torque & revs, & even if you also replace the filter with a free-er flowing unit in the original but now degraded air intake tract/filter housing it isn't likely to make the degradation all that much better!! So if you want to lose the resonator, bite the bullet & toss the whole air intake/filter housing & replace it with one of the 'known improvement' filter housings & replacement filters like JT's replacement! That way, you are far less likely to create issues for yourself/your engine even if there are some recognised/potential issues down track, it is still far more likely to give you the improvements that come from improving the air flow into the engine than mucking around with the extensively researched & designed original!

Besides, there are many like Snoopy who have fitted those JT filters or the Kewl Metal versions who have later or also done the cat elimination thing who haven't ended up with any significant other issues - most get away with it, only some have further issues, don't you feel just a little lucky?!

[pegasus1300]

I also would like to add JT's air filter arrangement but I also like the quietness of my RT. How much intake roar did you experience and did you wish you'd left well enough alone?

[SNOOPY]

Those 'resonators' & big bulgy bits in long air intake tracts are usually there to 'tune' the length/ volume of the air intake in order to remove dead spots in the revs or improve the fuel economy or power/torque curve of the engine!! The manufacturers have generally spent millions of dollars on research & testing to work out how to get the desired results from the engine/air intake/filter housings, & you mucking around with that generally won't end up making things much better!! They do usually have a reason to be there, & simply tossing those & leaving the rest of the plumbing alone or just blanking the resonators off is not generally such a great idea!!

So if you want it gone, I wouldn't just remove or blank off the resonator - if you do that it's pretty likely that you'll have some degradation of your power/torque & revs, & even if you also replace the filter with a free-er flowing unit in the original but now degraded air intake tract/filter housing it isn't likely to make the degradation all that much better!! So if you want to lose the resonator, bite the bullet & toss the whole air intake/filter housing & replace it with one of the 'known improvement' filter housings & replacement filters like JT's replacement! That way, you are far less likely to create issues for yourself/your engine even if there are some recognised/potential issues down track, it is still far more likely to give you the improvements that come from improving the air flow into the engine than mucking around with the extensively researched & designed original!

Besides, there are many like Snoopy who have fitted those JT filters or the Kewl Metal versions who have later or also done the cat elimination thing who haven't ended up with any significant other issues - most get away with it, only some have further issues, don't you feel just a little lucky?!

....and sometimes people (usually engineers), overthink things and in reality they work out great for years and years.

.

[SNOOPY]

....and sometimes people (usually engineers), overthink things and in reality they work out great for years and years.

.

And I say this with an air/fuel meter on my bike and years of experience in modding vehicles...just sayin'

[Chupaca]

I have an RS sm5 with the JT filter, K&N cleaner and a foam wrap to tone down the airflow noise, along with a Yoshimura R77 pipe. I also have a turbofan direct to the air cleaner. I do not have any fuel mixture control or modified o2 senors and the spyder performs very well.
Now if you have the 998 twin and like the quiet of the RT or in general then add a K&N filter to the stock box. I love the sound but it is noise if you get on the gas. It is a choice and you have to say to yourself....do I really need more

[SNOOPY]

Most often, the engineering for tuned length intakes deals with the intake design downstream of the throttle plate or slide. Those dimensions are very critical.

Upstream of the throttle plate does have merit and requires some consideration but in overall simple terms, this area tends to employ methods and design to quiet down induction air noise, provide a quality airflow path to the throttle body inlet, and, done correctly, have a still air plenum when needed to help provide throttle response.

Possibly, one of the most important aspects in designing an airbox system is how effectively it delivers intake that is not heated.

Many considerations, how the engineer determines priorities shows in the design. I suggest Spyders tend to focus on a quieter design of an intake that results in other compromises.

I was just going to say that.


lol

[Machinegunner]

Years back, when the crotch rockets first arrived many tuners took off the air box because they knew it was no good. Turns out the air box made a stable and even source of air for all the carbs or injectors. With out the air box, each carb had it's own air supply, which wasn't always the same. With carburetors there was a reverse pulse in the intake that was called stand off. The results of this was air and fuel flowing backwards out of the intake thereby leaning the mixture. The air box captured this stand off and kept the mixture correct. This is not as serious with fuel injection, but is still present. Without the air box, this reverse pulse is lost, thereby losing power and increasing intake noise.

[bluestratos]

The resonator acts like a muffler for the intake, without it the sound of the intake is very loud and annoying to me. It did not change the power or cooling on my 2011 RT. It does make access easier with out it and it is tricky to get in in and out but I have done it several times so it is doable.

[robmorg]

I also would like to add JT's air filter arrangement but I also like the quietness of my RT. How much intake roar did you experience and did you wish you'd left well enough alone?

i don't have a direct answer for you, but there was an awful lot of forum discussion on this very subject back in 2014-2015 before the major heat recall came out for the 2013 RT that Spring. The idea of adding the JT filter then was to allow more room under the cowling for air to flow around the engine. As part of that mod, the resonator, etc. was all eliminated. There was a lot of additional noise, and at one point JT came out with a foam "muffler" to wrap around the air filter which helped cut down some of the noise. That had varying reports of success. I remember one fellow saying that he installed JT's system and then de-installed it, putting back the air box and resonator, because the noise was just too annoying for him. You might do some thread searching on JT's air mod, and probably find a lot of information.

I never went this route, because I didn't want all the extra noise. Also, as some others have alluded to here, I didn't think it should be necessary to completely re-engineer the air intake system in order to cool down the engine. I did get a deeper exhaust rumble when I removed the cat, but that wasn't too much louder and it was a pleasant sound, IMO. I did that because it reduced a lot of heat on the engine and the fuel tank - especially since the cat was located directly below the tank.

[pegasus1300]

I am not really interested in more power,just ease of access for spark plug/wire changes and valve adjustments. If the noise is objectionable I will leave it alone and deal with removing the air cleaner package.