4" turbo back ext cab 02 lb7 (truck had no stock cat) and the cab drone is bad at highway speeds. I've ordered the resonator but am wondering if others have it and has it solved the drone? I like the look and exterior sound but the drone towing will drive me nuts.

Thanks,
Paul

Ruh rho, starting to feel old and alone here :uhoh2:. Nobody else getting this drone - or just ok with it? I realize it's not likely with a cat back but turbo back must be a common thing. Anyway I'll report back when the resonator goes in line.

I have the same system on an 06 and it makes me NUTS.....Have to yell at cruising speed while towing 18K just to have a conversation with the person in the passenger seat. Please let me know how the resonator works out, I'd greatly appreciate it.

Forgot to mention.....Cat is totally GUTTED!!!

I have a dron w/o the cat. It completely goes away with the cat in place.

Forgot to mention, my drone got WAY more quiet when I switched from the chitty 4" u-bolts that came with the kit to stainled band clamps. I sucked them in completely with a 1/2" impact wrent and the drone is much better. Not like with the cat in place, but leagues better than with the u-bolts.

switching the u bolts...... i read that in another post. where did you get the replacements? what brand...? about to do the install so i thought i would go ahead and do it..

I had a 02 with the bullydog 4" SS exhaust it was fun in the city but the highway it drove me CRAZY!!!!!!!! sold that bad boy bought a 06 all stock these days except tires nice and quite tooling down the E-way.

The only thing that sucks is $96.00 for a tank full of diesel here in MI

switching the u bolts...... i read that in another post. where did you get the replacements? what brand...? about to do the install so i thought i would go ahead and do it..


I think I got mine from Kennedydiesel.com. I found out later NAPA also has them.

cool, thanks

My Dad has an LB7 that had an MBRP 4" and a resonator. Now it has a Corsa system with the same resonator. The MBRP system was still brutal on the highway after the resonator was put on. The Corsa sounds great on his LB7.

:eek: I'm glad I kept my kitty on. I just installed the 4" MBRP cat-back system last weekend. It's barely louder than stock. I like it so far. :)

Just went over a pass unloaded and the drone is certainly too loud in the cab while climbing. Seems ok just flat cruising in od. Headaches for the family for a 5hr trip. Resonator still not in at my dealer. Hope some mbrp types will chime in with advice here or I may be returning my setup. Won't make a final call untill the resonator goes in.

More info, drone is only bad @70mph ~2000+ rpm. Unfortunately this is any freeway at an incline. Otherwise setup is great. Seems like this could be solved with resonator so I'm hopin. I'm also wondering if the installer put the muff on backwards (doh). I'll have him check this when resonator is installed. Any exterior markings that I could check (logos etc)or do I have to pull muff and check the louvers inside?

Thanks

Well the mbrp resonator finally arrived and it wont fit, not enough clearance in the sb ext cab kit. The muff was reversed so had the tech swap it around and the high speed drone is gone, thank gawd. Setup still is louder than I'd like but I'll see how it is towing. Considering the aero turbine muff with built in resonator as a replacement. On we go.

When I built my 4" stainless straight pipe exhaust on my 6.5 it had a bit of a drone in the cab which is what I expected. We welded every seam solid except one that we had trouble getting access. It was only about an inch and I didn't think it would make much difference. Well after a couple of weeks we tried again and welded it up with mirrors and such and that made a big difference. It was a loud exhaust and in the cab it was fairly quiet.

Long story short, seal up all the joints as best possible and this will make a big difference.

Had my 4 inch installed by the factory...Sounds quieter than stock??? Haven't towed with it yet though. Have heard that drone is bad if muffler is installed backwards!!
Mike

You could also check into a resonated tip. You would lose the MBRP tip (you might not like that). Installed one on an '03 GM 6litre with a nasty Gibson exhaust. I know I am comparing diesel to gas but that exhaust drone was unbearable and the tip helped a lot. It was 4", 304 stainless double walled and straight cut. I would have to dig to find who made it. I believe it was 12" long. Hope this helps.

Ok this might sound crazy but I was doing a lot of reading on drone and I had some before today. I put the truck up on blocks and taped the exhaust with screwdriver all the way along... The muffler had a good ringing to it as well as the front pipe. I clamped 2-24" long 2"X2" angle iron 3/8" thick to the muffler with hose clamps. Then on the front pipe I clamped a round shaft 1" thick 24" long to the front pipe. Went out for a test drive and the exhaust is almost like stock I had to turn the radio down and the ac fan off just to hear it and under acceleration it is a lot quieter!!!! I did a lot of reading here about clamping weighs on exhaust to keep them quiet. I don't know if it is a fluke or what but I have the free flowing exhaust that I want with almost NO cab noise. Can call me stupid but it worked for me.....

Evidently a system that is welded at the joints or has a butt joint with a band clamp helps to eliminate the drone or resonance,per factory.Recently removed the muffler/tailpipe from back of kitty at the bandclamp.When the bandclamp was loosened and slid forward the exhaust to the rear swung rearward about an inch,kinda like a pre-load on the rubber hangers.Wonder if thats just a fluk or if its built that way to eliminate resonance?

I'm gonna try banding something to the front pipe, how much weight did you use there (lbs)?

Ok this might sound crazy but I was doing a lot of reading on drone and I had some before today. I put the truck up on blocks and taped the exhaust with screwdriver all the way along... The muffler had a good ringing to it as well as the front pipe. I clamped 2-24" long 2"X2" angle iron 3/8" thick to the muffler with hose clamps. Then on the front pipe I clamped a round shaft 1" thick 24" long to the front pipe. Went out for a test drive and the exhaust is almost like stock I had to turn the radio down and the ac fan off just to hear it and under acceleration it is a lot quieter!!!! I did a lot of reading here about clamping weighs on exhaust to keep them quiet. I don't know if it is a fluke or what but I have the free flowing exhaust that I want with almost NO cab noise. Can call me stupid but it worked for me.....

When I put on my 5" straight it had a drone that drove me nuts under load. I put my hollow kitty back in and it was just enough to quiet it down to where it sounds good under load.

If you end up trying that 4040XL aeroturbine let us know how you like it. I want a big exhaust but need it to be as quiet as relatively possible.

Ok this might sound crazy but I was doing a lot of reading on drone and I had some before today. I put the truck up on blocks and taped the exhaust with screwdriver all the way along... The muffler had a good ringing to it as well as the front pipe. I clamped 2-24" long 2"X2" angle iron 3/8" thick to the muffler with hose clamps. Then on the front pipe I clamped a round shaft 1" thick 24" long to the front pipe. Went out for a test drive and the exhaust is almost like stock I had to turn the radio down and the ac fan off just to hear it and under acceleration it is a lot quieter!!!! I did a lot of reading here about clamping weighs on exhaust to keep them quiet. I don't know if it is a fluke or what but I have the free flowing exhaust that I want with almost NO cab noise. Can call me stupid but it worked for me.....

SO BY ADDING SOMETHING SIMILIAR IN WEIGHT NOT NECESARILY ANGLE IRON SHOULD HELP? WELL ANGLE IRON WILL PROBABLY BE THE BEST THING TO BE ABLE TO HOLD IT IN PLACE.

I'm gonna try banding something to the front pipe, how much weight did you use there (lbs)?


SO DID YOU TRY IT?

Have to yell at cruising speed while towing 18K just to have a conversation with the person in the passenger seat.

Gee, that might not be a bad thing...this way I can't hear the wife nor the kids fighting in the back seat!!!!!

Mine must be different somehow because mine isn't that loud only at 55 then it goes away.

Diesel Manor has nice T-304SS exhaust bands for ~$11. Also, how can you tell if the MBRP muffler is installed backwards without dropping it and looking inside it??? The muffler has MBRP embossed on the outside, looking at it, mine shows the word "MBRP" going from left (rear) to right (front of truck).

Thanks

Rob

interesting post. I have a 4" on my lb7 for a couple of months now ... and the drone is driving me crazy. I'll have to try the band clamps since mine was installed with the ubolts and only spot welded.

good question about which way the muffler goes ... hopefully, someone can shed some light on this?

rspiecha is absolutely correct on the muffler direction. Before we started putting our logo on our mufflers you would have to make sure during the install that the louvers were facing the right direction (open ends facing the rear, exhaust gas flowing smoothly over them), if not it will cause resonance inside the truck. Depending if the system was installed at a shop somewhere for the customer, they would have to assume that the installer put it in the correct way or pull it off and physically look.
Now that we started putting our logo on our mufflers, the writing should read "MBRP Inc." looking under the passenger side, back to front and has helped eliminate the confusion.

Well I finally got around to trying a 3 foot galvanized metal slotted angle iron using stainless band clamps against the front pipe (no cat) and it WORKED! Drone is pretty much gone now. It didnt really have much wieght but it did kill that bell bong when tapping the pipe with a screwdriver. Thanks to all who advised me on this, especially super-H. To mbrp I think offering some sort of band wieghts may be a good idea. I called some local muff shops and they had no idea what I was talking about.

No prob I have showed this to some of my friends and they think I am nuts!!!!! They smile and say that I have too much time on my hands.... Glad to hear that it worked have pulled the camper 5 times this summer and the wife and kids have no say that the exhaust was worth the money cause the engine fan is not running all the time...

I realize this is an old thread, but i'm gonna give this a shot as I also have really bad drone with my 4" :(. I will post back if it works for me...

FWIW I did find the angle iron quieted it down but not enough. I'm back to looking for a new muff, maybe a corsa.

rspiecha is absolutely correct on the muffler direction. Before we started putting our logo on our mufflers you would have to make sure during the install that the louvers were facing the right direction (open ends facing the rear, exhaust gas flowing smoothly over them), if not it will cause resonance inside the truck. Depending if the system was installed at a shop somewhere for the customer, they would have to assume that the installer put it in the correct way or pull it off and physically look.
Now that we started putting our logo on our mufflers, the writing should read "MBRP Inc." looking under the passenger side, back to front and has helped eliminate the confusion.

Jeff has the easy fix here make sure your muffler is on right, can't see strapping angle iron nothing but headache's down the road

Thanks for this added input, Tried the angle iron trick, maybe helped marginally, but not a lot. Also, the muffler is on the correct way, MBRP letters back-to-front. I did notice however the hollow sound when hitting it with a screw driver.... muffler and tailpipe have no ring at all when hit, but the long front pipe rings, or "echos" really loudly when hit... that could be the problem....

Very informative thread.. I would never guess weights or Angle could fix a drone.. You fella's got a fix for the drone of a 6" stack?? :D I am guessing Dynomat..

Very informative thread.. I would never guess weights or Angle could fix a drone.. You fella's got a fix for the drone of a 6" stack?? :D I am guessing Dynomat..

If you have stacks and are tired of the drone you could try a hushpower muffler. They work real good, keep the outside noise sounding good, but cut down on the drone, and cab noise.

PC ... did you ever get that resonator on your MBRP system? Same issues here as posted by others... trying to get rid of the cab drone.

Thinking of getting the resonator, but looking for feedback from those that have added it and if it was effective.

Otherwise, it's on to plan B.


Thanks!

Actually just yesterday I got a shop to take off the stainless mbrp muffler and install a flo-pro 4" aluminized muff and drone is gone. From what the shop owner said they are removing the stainless setups regularly because of drone. The larger aluminzed flo through don't have the resonance stainless has. So far it is definately quieter - but I have yet to tow.

Interesting..thanks for the info. This is probably a dumb question, but my MBRP is the aluminized system ... does that mean my muffler is aluminized as well?


Please let me know how the new setup works while towing.

If yours isn't a shiny muff then it's aluminized. Your crew cab should fit the resonator, my ec had no clearance for it.

I have 4" aluminized with stainless Aero Turbine muffler. To quiet the drone you will need a longer muffler. The shorter ones dont work well for quieting that rpm range. I have tried several brands and lengths. Over 26" and it should get fairly quiet.

Also I used my timing to quiet the drone. EFI Live.

i am wondering if this may be an mbrp issue because i had a flo pro 4'' straight pipe on my last lmm and had no drone at all. this lmm has a 5'' mbrp with muffler and has a bad drone at about 1600rpms (both aluminized). i understand that the 5'' may be part of the reason. however, it seems like alot of people are having these issues w/ mbrp's 4'' exhausts as well.