smitty2919

My 03Z will get a BTR LS1 Stage 2 cam and currently has LT's without cats to a custom midmounted Magnaflow straight through DI/DO muffler (NOT their TrueX design mufflers). My reason for doing this is to make a custom rear diffuser and having mufflers out back do not allow me to tuck the diffuser up high to the bottom of the bumper cover.

Issue I have is drone...surprise surprise. 1500rpm and 1900-2000 are the problem areas. I tried J pipes for 2000 rpm added to the tail pipes but it oddly seemed to make idle and 1500 rpm WORSE while solving the 2000rpm drone. I'm in the range of 110-130Hz and 90+dB at times. I LOVE the idle sound and overall tone of this combo but the drone will make me hate driving.

Looking for some combinations that people report no drone. And no I can't go Corsa due to cost and the large mufflers under the trunk.

Options I'm thinking:
-Add some glasspack/bottle style Vibrant resonators in front of the current muffler.
-Add some Vibrant Ultra Quiet style resonators out back under the trunk (only 4" tall will work) angle them 45* and do turndowns at corner o rear bumper)
-Remove the midmount magnaflow and find some slim mufflers for the rear (~4" tall) like a Borla ProXS or XR1 type or maybe a Dynomax Super Turbo. I would also have to add a x pipe.
-Swap the short 11" long magnaflow straight through for the longer 14" long DI/DO magnaflow with internal X design.
-Find stock Ti system

current muffler:
https://www.magnaflow.com/products/1...raight-through

optional longer muffler with internal X:
https://www.magnaflow.com/products/1...raight-through


If anyone is willing to supply relatively drone free exhaust setups that have LT's and no cats I'd appreciate it.

Current setup:
by https://www.flickr.com/photos/70077101@N03/, on Flickr

by https://www.flickr.com/photos/70077101@N03/, on Flickr

Not4spd

I'm running Borla XR-1 LT, no cats, mated to Corsa Extreme. People say it's loud outside, but in the car it's not as audible. As far as drone goes it's nearly nonexistence. Cruising I can carry on a conversation.

smitty2919

LOL you missed the part I mentioned setups that are NOT Corsa...

TGstring

great thread, I'm curious what info gets provided.

Is the drone due to the mufflers or lack of cats? or both?

does anyone know?

smitty2919

It can be a number of things. Muffler selection/size/design/placement and overall harmonics of the system. J pipes help with a specific RPM +-200prm or so.

There are opinions all over the place with what drones and what does not. I have come across people saying magnaflow systems (rear mounted mufflers that are a packed muffler) have drone.

I'm hoping there are some suggesting on a relatively drone free setups with LT's and no cats that is not $1500 Corsa.

KnightDriveTV

I've had quite a number of exhaust combos over the years, but when I fabbed up this combination of modded TI with larger 4" outlet carbon tips...it was a sweet spot. I have AR Long tubes, no cats, x pipe to these...and I have to tell you, inside the car they are SO easy to live with it's unbelievable, but outside, under some throttle, they still scream like hell. Moment you let off though they can be subtle.

It's why I did a whole build video on the setup, with sound comparisons and vs the BB bullets I had prior. I think this is as good as it gets shy of doing something that has a full dual mode functionality.

smitty2919

KITT, sounds good thanks a lot. I have been watching some Ti videos including the one you posted. From your explanation that's exactly what I want, at first listen I'm not a HUGE fan of the Ti sound but I'm willing to use it to kill this drone.

I bought my car with stock manifolds, stock midpipe and some no name catback which looks like a Borla Stinger/GLH/OBX 6" diameter canister style mufflers. There was no drone but I hated the "motor boat" sound from the stock H pipe. So then I custom made an X pipe in place of the H pipe...again sounded good and no drone.

I have since went to 1 7/8" LT's with no cats to this midmount magnaflow and he drone can be quite annoying. This is a car I need to be able to jump in with the wife and drive for hours.

Tonight the car goes under the knife again.. Plan is to cut out the midmount muffler to swap the custom X pipe back in and re-fab the original catback to work. This is the cheapest option as I already have these parts. If this doesn't work I'm seriously considering calling it quits and going with a Ti setup.

This is the car currently. I love it except the drone lol

Mr. Black

I am running the BTR 2 N/A cam with Texas Speed longtubes a Bassani X pipe and an old Corsa Touring axle back exhaust.

It's pretty loud but manageable. ZERO drone. I've had exhaust combos before that droned horribly and it's a miserable experience especially when it does it during cruise.

Mr. Black

What have you done to the car that will not allow it to run normal mufflers? Since I missed the corsa part too! lol

Efx

You mentioned Ti exhaust. Here is a clip with Ti modded exhaust. No drone. And a bit louder that non modded.

smitty2919

The car is stock but I want to make a rear diffuser so if mufflers are out back they can’t be any more than 4” tall. That’s why I went with a midmount to free up all the space.

Perfect thanks. If my next setup doesn’t work then I’ll call it quits and get a Ti system. I should have something worked out tomorrow night.

smitty2919

Well I was able to get the original catback that came with the car installed. It is currently 1 7/8" LT's, no custom custom X pipe to a unkown brand catback. It is a Borla/OBX style with 6" diameter cans 2.5" pipe with quad tips. It is not magnetic...soooo that tells me it is a decent grade of stainless. The more I dig, the more I think it MIGHT be a GHL catback. I also read GHL setups were polished, which mine did not seem like it was. So who knows. It looks identical to this...but not polished and my tips have a smoother radius/transition to them.



Good news is that MOST of the drone is either moved out of normal driving range and or reduced quite a bit. Downside is that at 1500 rpm drone is still loud and proud and 5th gear under uphill load (to maintain 70mph) it is EXTREMELY loud...almost left with ears ringing kind of loud after you crest the hill and shift to 6th. It has developed a unique tinny/exotic sound at 2300-2500 rpm that I'm trying to decide if I like or not lol. I'll try to get a video up.

I have a feeling that the long term solution (for the money) will be a stock Ti catback. But I can live with this setup for now. If I can't find one, I'm half tempted to find a base catback (easier and cheaper to find) since I'm reading the base and Ti catback are the same except material.

USAZR1

My GHL Bullets have practically no drone, at all, at highway speeds.

smitty2919

At 70-75mph stock Z06 gearing the drone/noise is easily HALF my previous midmount magnaflow. That that is greatly improved but I’m still on the search for the setup that meets 90+% driving conditions instead of the current 75% conditions.

USAZR1

1500 rpm at 70mph, in 5th gear? I'm seeing approximately 2100 rpm at 70mph, in 6th gear, with a 3.90 rear cog and 26.3" tall rear tires. I don't need to downshift to 5th, unless it's a steep hill.
What gearing and rear tire does your car have, Smitty?

smitty2919

I meant the exhaust note in the cabin in 6th crusing 70-75mph was terrible with the mangnaflow setup...constant hum/drone. With the new unknown 6" can setup it's half as loud when cruising. However as you mentioned downshifting into 5th for steep uphill is ear piercing.

Time for a C-5

Tis with long tubes w/cats and a mild cam (a little smaller than BTR S2)...no drone. I know they're not the loudest, but no drone. I'm confident after adding the bypass mod for more volume there would still be no drone.

K-Spaz

I had high-flow cats on mine and I never had the problems with the noise or the stench that other people with catless systems have. I'm a pretty firm believer in them.

Time for a C-5

Could be a combo but I think it's mostly the mufflers. I had early borlas that droned horribly when I bought my car, and still had stock manifolds and h pipe.

smitty2919

Update...car now has 1 7/8" LT's, no cats, x pipe and stock Ti catback.

HOLY CRAP is it quiet Inside the car with a rear divider (03 Z06) it is amazing how well the stock catback works to quiet a LT/catless car. I can defiantly see how people do the bypass mod to get a little more rumble.

This is 100000% an exhaust combo that you can drive anywhere and everywhere. Even getting on the throttle, it's not over bearing and you can be stealthy.

I can report NO drone inside the car any any rpm. Very pleased currently but I also foresee myself possible doing the bypass mod once I get bored of it being this tame. I still have a cam to put in, so I will wait to see how it drives/sounds with a cam before doing any more exhaust changes.

Thanks to KITT for all the PM correspondence about the Ti system. Happy camper right now.