TX Tahoe Z71

iTrader: (28)

Would cutting the tail pipe (to maybe an over-axle dump) help or hurt the exhaust drone?

TS77

Ok that would work, but you have to cut a specific amount off. But then again, the exhaust is going to exit closer to the cab, thus being louder if you dont mind.

Ill find the website that talks about shortening the tail pipe. Pretty much it just moves the drone. So instead of droning at 2000 rpms, you can move it to like 4000. I dont know how well this works, because Ive never tried it..

I drew up a little picture. An updated one. I would recommend someone who wants to make it, it make it adjustable so you can fine tune it.

I wanna do this to my friends and play around with it. I just need to get some 2 inch inner diameter pipe and a clamp. Check it out.

skyhighsami

iTrader: (8)

I was seriously thinking about cutting the cats off my truck but didn't want to because it would be so loud and drone so badly. I like the Magnaflow mufflers because they are stright through but they seem to drone alot. I will seriously try this and see what happens.

TS77

Okay i found it...

http://www.autolounge.net/calculator...resonance.html

I mean it makes sense becuase by changing the length, you inhibit the exhaust pipe from being able to create the stable "drone" frequency that resonates inside the cab. I think thats how it works.

With doing the side branch resonator, there is a bell curve effect to the cancellation ability. It works the best right in the middle of the targetted frequency and has a little bit of range, so it doesnt have to be exact, just close enough to the target RPM.

TX Tahoe Z71

iTrader: (28)

So with the calculator on that page, the length to add/remove would be the proper length for the branch resonator? It seems as though they're talking about adding piping to the existing exhaust rather than adding a branch resonator, unless it has the same effect either way.

TS77

Sorry I was talking about the differences between adding/subtracting from the tail pipe length and doing the side branch resonator. It may have confused you.

That link that has the calculator tells you how much to add or subract to the total length of the exhaust pipe to move the drone. The branch resonator is totally different.

You were asking me if changing the length of the overall exhaust pipe length (dump it before the axle) would change anything, and so thats why i posted that link to the calculator.

skyhighsami

iTrader: (8)

I would just like to know how long of one I should put on my truck. I would like to do something to keep the truck as loud as it is now at idle and WOT but when cruising I would like to get the drone out of the system.

TS77

I need to know what RPM the drone is worst in your truck. Also what size engine do you have on it? Maybe take it out for a short drive and get on the freeway or up a slight hill and really try to find the exact RPM. Then I can give you a length that would be good to shoot for.

If you do make it, are you going to try to make it adjustable like the design i drew up? It might be helpful to be able to fine tune it. Every truck is a little different.

Just curious, you have single or dual exhaust?

By the way, thats exactly how my friend's sounds. The same at WOT and idle, but the drone is gone

Stoichiometric

iTrader: (10)

I want to say this is pretty cool what you guys are doing. Thanks for posting up.

My truck has some resonance I would like to get rid of. I have a single 3" with a magnaflow muffler and the most resonance is between 1600-1800, I would say 1700 is the peak.

TS77

I just changed my friends to the adjustable setup i drew and we spent a lot of time tweaking it. We started out at 28" long and went longer and shorter. For his, the perfect length is 27".

The longer the pipe is, the lower the RPM it is going to cancel drone. The shorter the pipe, the higher the RPM it is going to cancel the drone.

So for you Stoichiometric, you would be looking at running a longer pipe since your drone is at a lower RPM.

I really want to pipe a muffler on my truck and do the resonator on mine so that it directly compares to all the trucks we have here. Id imagine its got to be a little different than my friends jeep. The mustang site that this idea came from they were having luck at 24-26" where my friends jeep is the best at 27". Then again it all varies to what engine size and muffler you are running.