Hey guys, so originally i had a full mandrel bent 3 inch hks hi power exhaust on my car. And i sold it cause i ****ing hated the drone but LOVED the wot sound.

now i have a custom done exhaust with dual top speed mufflers.

Still i have horrible drone, after looking around i noticed that alot of the supra exhaust seem to come with a sort of chambered muffler or resonator midway through the piping

as seen here http://www.360tuners.com/93-98toyota...FSXZQgodGiAAzw

my question is what do they use? a chambered muffler? or a resonator? definetely going to do this so i can have more of a "throaty" sound with less drone. More 350z ish you know??

 

No way to know what is in that exhaust without cutting it open.

Mufflers do not eliminate drone, they muffle sound (although some have an included resonator). Drone is resonance, to eliminate resonance you need a resonator, now that doesn't mean go buy what is sold as a resonator these days. As the resonators you'll find are really just inline mufflers.

What you want is a quarter wave resonator, or a Hemholtz resonator. The latter being more complicated and thus you'll probably go with a quarter wave resonator.

To calculate the length of the resonator you use the following formula which will give you the length of the resonator in meters.


like my paint skills?

The speed of sound is dependent on exhaust temperature.

Let me know if you have any questions.

 

Your only solution to your drone is this:


That's my car, no more drone. You can keep your loud exhuaust without power loss and have a quiet cabin at cruising speeds. Google "Side branch resonator". Only downside to this is that it's done by trial and error but it costs less than $200 at a reputable muffler shop.

 

i put a cherry bomb on my midpipe and it helped a million, still a slight drone, almost unnoticeable. still sounds good just no rattleing and shaking i didnt want to spend the time trying to figure out what the previous post shows

 

Side branch resonator = Quarter Wave Resonator, but it isn't trial and error if you follow the formula and gather the requisite information.

You'll need to get the rpm of the drone and the temperature of the exhaust. Use the temp to get the speed of sound at that temp and plug the info into the formula.

Alternatively you could get a chromatic meter (possibly available as an app for your phone, but I provide no guarantee of accuracy) and just divide the frequency of the drone by 4 and you'll have the resonator length.

 

Well as well as drone i feel like the sound needs to be improved, i wonder if a chambered muffler or something midway would help cause these topspeed mufflers are straight through

 

sj408, let me know if u find a solution to this problem. i had a 3 inch straight thru mandrel install a month ago, the drone was just too much and i ended up cutting off the cat back and put the stock system back in. there was no room to add side branch resonators according to my muffler shop. The 3 inch was deep and i like it but the drone was just insane, setting off every car alarm in my neighborboud wasnt fun.

oh ya, stock 1j in sc3 in norcal. ;/

 

its a resonator they put in the middle.