What % of you do/don't have catalytic converters? and drone follow up...

[final5-0]

From everything I've seen about high flow cats ............

You would only pick up two or three rwhp if you went off road.

You see peeps talk about a noticable gain by going to OR pipe.

Of course they do .............

That oem 4 cat pipe is really restrictive ..........
even all the more so if a lotta miles has been put on it.

Grady

 

[Cwalk]

No Cat BBK X-pipe, flowtech shorties, and flowmaster's.

 

[MI95Cobra]

custom built offroad x-pipe, no cats, flowmasters pro-dumped looking for headers....

 

[95strokerPSU]

Custom H-pipe with hallowed out cats and flowmaster cat-back. Drones at 2k but my cruising RPM is 2500-3000 on the street with the 4.10 gears. I don't do any highway driving.

 

[Pokageek]

I have no drone BUT, I still have the stock cat back. Didn't Ford kill drone by using different length mufflers?

I was thinking of actually trying this...but will that mean unequal backpressure? Mess up the engine? I am not sure I want to pay $100 for another flowmaster to find out. Anyone want to try it?

Oh, yeah and some of ypou posted but did not say whether your combo drones.

 

[igotyofire]

i think ur basing drone off the mid pipe rather then the mufflers which is where i think it should be. chambered mufflers seem to be more prone to droning then say straight thru muffler designs. Anyone else agree? my upr x pipe and magnaflow design i guess i would say has a bit of drone but i just consider it much louder then the stock mid pipe and not so much drone, atleast not so much in my opinion..ive heard worse with dumped exhaust,heh

 

[diablostang]

Thanks for posting guys. Interestingly, some of you with X-Pipes say no drone and others say yes drone. To clarify, drone is not the pleasurable hollow sound our stangs make..at least to me. Drone is that BOOMY down in your middle ear sound that comes into the cabin and resonates.

Pay attention to the MUFFLERS... That's what creates the drone. I've had maybe 5 5.0 Mustangs with Flowmasters, and have also had Mac, Dynomax and Flowtech mufflers.. and they all droned and gave me a headache. I'm currently running NO mufflers, and there's no drone and no headache. Mufflers like the Mac / Flowmaster / Dynomax / Replicas will all drone.

 

[Pokageek]

Hmm... No mufflers. No drone. That's interesting. But won't it be LLLLLLLLLLLLLOOOOOOOOOOOOOOOOUDDDDDDDDDDDDDDDDDDDDDDDDDDDDDD!!!!!!! As hell? (illegal round here.)

Maybe I should try thrush glass packs?

 

[HISSIN50]

I have no drone BUT, I still have the stock cat back. Didn't Ford kill drone by using different length mufflers?

Seems to me that you're spot-on here.

Seems to me that drone is related to resonance. If someone wants to phase shift the drone-zone, it seems to me that a resonant chamber (a dead-head in the exhaust) could help. It would not be completely unlike the stock set-up.

 

[Pokageek]

Seems to me that you're spot-on here.

Seems to me that drone is related to resonance. If someone wants to phase shift the drone-zone, it seems to me that a resonant chamber (a dead-head in the exhaust) could help. It would not be completely unlike the stock set-up.

Thanks Hissin. But what does this mean in every day terms?

 

[BlackVert]

EL shorties, stock cats, flowmaster 40 cat back

drones cruising 2000-2230 or so

 

[Pokageek]

BVert, when are you going to get some longtubes for that car!

 

[Therian]

Longtubes + mac hi flow catted H (4 cats) + flowmasters

=

no drone.

very nice tone...very deep

personally I'd like to go to a more exotic note. but that can wait

 

[HISSIN50]

Thanks Hissin. But what does this mean in every day terms?

The engineering folks who enjoy fluid dynamics can probably help more than I can. But from what I understand, the exhaust pipe itself has a certain resonance frequency (like a tuning fork). If you shorten or lengthen the pipe, that in and of itself can change the frequency at which the pipe vibrates/drones (you would phase-shift the RPM at which drone occurs. E.g. if you shortened the exhaust pipe X inches, the drone RPM might move from 2000 to 2600 RPM, and if you dont cruise at 2600 RPM, who cares).

The other way to treat it is to create resonance chamber (this is used for wave cancellation - it's common in plumbing, electronics and so on). Now I think you are actually cancelling the waves (all that node/anti-node stuff). This is where that deadhead pipe comes into play, and would likely be what I might try - I know the drone drives you nuts.

Maybe the engineers can pipe (pun intended) in here and offer assistance....... I've done a bit of exhaust work like this but it was all just me crunching crude numbers and experimenting. It'd be nice if someone knew how to actually predict something.......

 

[Pokageek]

Yes but 4 cats = reduced HP.

 

[mustang6tee8]

stock headers, MAC o/r H, JBA catback, (built very well, gorgeous 3" tips, I have the prototype model cause I am very good friends with the son of the owner of JBA!! I've met the owner too, he's a great guy...mostly cause he's an Aggie ) still drones from 1950-2050 rpm, but i've heard that it's because of the head design

 

[The Green GT]

Hmm... No mufflers. No drone. That's interesting. But won't it be LLLLLLLLLLLLLOOOOOOOOOOOOOOOOUDDDDDDDDDDDDDDDDDDDDDDDDDDDDDD!!!!!!! As hell? (illegal round here.)

Maybe I should try thrush glass packs?

No muffs or cats w/ turndowns here.

Drones so much I want to put a bullet through my head sometimes.

 

[Al J]

Motorsports equal length shorty headers, Bassani X p[pe w/CATS, Borla cat-back--still has the 1800-2100 drone.
They all do---except maybe the long tube headers.
I've got a set of stock 2003 catbacks that I'm seriously thinking about installing.

 

[Stanger007]

Mac Longtubes, prochamber and catback - slight drone at 2k that I *LOVE*.

 

[Pokageek]

How about the lon-tube guys...less drone?