Eike

Hi,

I need new mufflers. The B&B I have on my '91 C4 are creating a intolerable loud droning below 2000 rpm so I don't like to drive a long distance without ear plugs.

I plan to install a 383 which will be naturally aspirated but primed for a blower. That's why I want mufflers which don't do a lot loss of power (or should I use cut-outs???) combined with a good V8-sound. Doesn't have to be very loud. The main thing is no or little drone.

I have hooker headers on and 3" pipe with X-pipe so the mufflers should be stainless, have 3" in and oval dual out. In case they don't have the oval tips, I can TIG weld my old B&B tips on.

Are there any mufflers like I need on the market or do I have to get some custom-made ones?

Best wishes
Eike

Black89Z51

I think the only exhaust that doesn't drone at all is the Corsa.

Joe C

- that would be my best guess too...

69mako

I had flowmaster on my 94...took them off a week later. The drone was so bad I had to wear ear plugs

I run LT4 mufflers on my Vette now....they sound a bit louder than the stock LT 1 mufflers...and no drone

PLRX

Stock

SJW

I ditched a nasty, droning B&B exhaust in favor of a Corsa system last year. Best change I ever made to the car. Zero drone. Should have done it years ago.

Live well,

SJW

5abivt

Any idea how old your mufflers are? when you look into the tips do you see baffling and metal walls? the older system shouldnt. If its older it will drone more but is freer flowing. if you want to sell the muffler without tips Ill buy them.

And yes Corsa is your only option.

STL94LT1

There was no special LT4 muffler.

PLRX

Eike

I can see some metal things but it's not much ... can see the the light at the end of the tunnel.

I know hoch the Corsa sounds on a '92 LT1 and don't really like it. Sounds a litte tinny for me.

Maybe I have to go with 2.5" pipes instead of the 3" ... geht some cut-outs and custom made stock-design mufflers. I'd like to try flexible pipes as interface between headers and pipes, too. Could decrease vibration and twist of the pipes. Many cars have them on, could not be a bad thing?




Pipe diameter is another point to think about - do I really need 3" pipes? Everyone says different ...






Best wishes
Eike

CAJUN C4

I run these on my 95' No drone just a good exhaust note..Only other adition is an X-Pipe.Eveything else is stock.

http://www.youtube.com/watch?v=ZXLzKQjRV7E

Magnaflow LT1 Tipped Mufflers.See: www.Corvettecentralexhaust.com

jmgtp

I run the Magnaflow 3" catback on mine and I don't think it drones. Maybe just a tiny bit but it certainly doesn't bother me. That said I'm not entirely satisfied with the sound, very deep and mellow, not all that agressive. I'm going to remove the resonator from the system to see if it adds more bite to the sound.

69mako

Thanks for the input; I didn’t know if there was a difference between an LT1 or an LT4 muffler…

Anyone else hear a difference between the two....or am I nuts

flightmate

The only difference between the LT1 and LT4 exhaust is the addition of a crossover H pipe on the LT4. Mufflers are the same.

BADDUCK

Go back to the stock set up with a cross over on the rear y-pipe. There are OEM (stock) style mufflers available, even a "no drone" type, at Corvette Central. No need to throw a lot of money at this issue. A lot of those charts you see are produced to sell exhaust systems not cure drone. GM had already cured drone you just reintroduced it with those B&B mufflers.

GREGGPENN

That's exactly what those are for. I'm thinking about adding those to my setup but I have sidepipes that may not be as isolated from the frame as conventional exhaust.

I think most of the conventional setup is hung with "rubber" straps except for the transmission hanger. Even that has an isolation component. I'm not saying the flex pipes won't help, they might.

Are you sure your vibration is "mechanically" transmitted vs sound waves? Kinda hard to see/hear/feel your issue though the typed sentence!

BTW...Those flex pipes aren't exactly cheap either....So I'd want to make sure of their potential to help before paying the money to get them.

BrianCunningham

they did a good job designing it, at least LT1/4's

most aftermarket exhaust just sound better, no real power gain.

GREGGPENN

Bonus post....

Another interesting thing in my case is I can hear/feel more vibration with the new stroker. It's right between 1600-1700 rpms (with my stick). I don't believe the issues is with balance on the motor as balancing was part of the build.

I do think the way headers may focus sound -- as compared to stock manifolds -- would be part of the challenge. In that case, the type of muffler could be more critical. In my case, I decided to try a SpinTech "Sportsman" muffler. It's a pulse-wave muffler (like Flowmasters). Often, that's good for power, but not for resonance.

The owner of the SpinTech design mentioned his design lowers the sound frequency. And, having them, I would agree. Stock setups are quieter and higher in pitch. You have to be outside the cabin harmonic frequency to avoid resonance. An X, Y, or H pipe can help thru internal cancellation of sound waves. Without that, muffler selection would need to take pitch into consideration. Those Corsa's must do that. I also believe the use of a 3-way converter setup works thru their linear internal design which favors higher-pitched sound. In my experience bullet or center converter setups don't cut it. But, the combination of the two works.

A local shop also said the addition of an X or H pipe may not cure performance exhaust resonsance. In some cases, he's seen it amplify the problem. Like other performance parts, you're kind of on your own -- looking to fabricate a custom solution. With exhaust that may require some trial and error.

For convential exhausts (vs my sidepipe setup), I would always consider the strategic addition of bullet cats or bullet muffers (aka glasspacks) as a means to inexpensively "cure" a resonance issue.

If possible, stay away from mufflers who's internal resonant frequency lies in the 1500-2200 rpm range. Most don't list that characteristic though...

turbotim23

Does the B&B system have 4 outlets that are open? I've heard that a lot of the droning is from air resinating through the 4 outlets that flow. That's why corsca is so much quieter one outlet is closed off and fake. I'm going to test this myself on my next trip, I'm going to plug one outlet on each side. Maybe fit a pvc pipe plug in one of them. Also there was some thing called hisholm resinators in a post a long time ago. That looked like a much better way to fix droning. You mount these in a L shaped 90 degree dogleg off the main exhaust pipe, I think in the rear section of exhaust system. They change the tuned length of the pipe so that you don't get droning in that place in rpm band. It moves place where it drones to some place in rpm band you'll never see. Hope this helps Tim

BrianCunningham

Yes, they're open

3in B&B with LT's on my supercharged 383LT1



Eliminator (straight pipes) on the old stock engine for comparison