Acepted solution for exhaust drone?
 

I've got a pretty open/straight setup after the headers (headers may have the O2 removed I'm not sure yet).

I get a good deal of drone like everyone else with an exhaust like this.

Is there an accepted solution? A crossover/X pipe? Anything else?

you should probably post a pic of what you have under there - caymans typically have a crossover pipe already (one of the easy cayman mods on the stock exhaust for better sound is to shift the joiner pipe on the crossover such that a bit more sound gets out).

what folks do here is use easyseal exhaust clamps to ensure positive seals and most report an improvement. i went straight to easyseal when i put mine in and no drone on full cheap chinese system (catless headers, catless mid pipes, twin can exhaust).

It's basically straight from the headers to the center exit with a ~8" long, slightly larger, "cherry bomb"/"Glass Pack" style "muffler" on each side. I'll try to get a pic tomorrow.

Here are some pics...

http://986forum.com/forums/uploads02...1554223620.jpg



http://986forum.com/forums/uploads02...1554223669.jpg

Also... Why does this forum invert some pics and not others? These pics are perfectly "up side up" even in the previews windows gives in explorer...

Anyway... You get the idea :).

dude, there's barely anything there at all. i'd say the only soln to drone you are going to find is a new exhaust.

some folks have used motorcycle baffles to some success, try a search on this forum for the thread.

Man that must be really loud! :D

It's louder than stock for sure but it's perfectly streetable noise-wise... I mean it gets a little noisy above say 4500 or so but it's not too bad. I've made it through Jerome AZ a few times with no police troubles... Just keep the revs down in town is all.

In any case...


No ideas about possible crossovers or anything?

What causes the drone?

It's trial and error. Start with a crossover pipe, then add baffles if more is needed.

Jerome, that place is incredible. Went 2 years ago, hoping to get back some day. A friend told me there is an annual Vw bus rally there each year. Amazed some can get up there.

It is pretty cool... I "have to" drive through that road/Jerome every Wednesday for work :).

If you are going to try a cross-over pipe, paint the exhaust with a cheap spray paint. Then go run it hard for a few minutes. Look at the spot on the pipes that melted the paint the most, and that is where you should put your cross-over pipe.

And make sure I carry a fire extinguisher on that trip yes? :)


I'll take pics :)

Build a couple of helmholtz resonators and install them in parallel with your cherry bombs. You will be able to tune out what, to you, is the most annoying frequency, and some of those adjacent to that one will diminish or be eliminated.

Sounds like a reasonable idea... I know a couple folks who build exhausts and might be able to lead me in the right direction regarding size/length to tune out that frequency.

I'm assuming it would be a good idea to know what frequency it is...

I'll bet there's a phone app for that :). Assuming it's not so loud it makes the mic clip...

Maybe record the exhaust then import into garage band the use the equalizer will show the wave, might be able to play with the eq and find the frequency.

I was thinking there's likely an app that just listens to the phone mic and just reports the frequency in some way...