Basically, welcome to performance cars with neighbors. I would say a good exhaust with one set of mufflers, and tailpipes out the rear will help greatly. That way when you start it, the exhaust is at the door, not in the garage. And try to get it out of the garage as quickly as possible.

 

Hi Ray - I agree that performance cars and old whining neighbours don't mix too well, but they've been fine with my 472 cube BBF and 800+hp Vortech supercharged Shelby Cobra fake with 4" sidepipes.

The Chevelle is so much louder than the BBF. Not sure how much the extra cubes and blower have to do with it, or if it's just that the Flowmasters want to rattle the fillings out of anyone within 300 feet!

The other problem is that once I leave the underground garages, I have to drive up a short but STEEP section of driveway up to the road level. With the loose convertor in the Chevelle, it's doing nearly 3500rpm at walking pace going up there

 

I have a 3" system all the way out the back with X-pipe installed right behind the trans crossmember. Mufflers are Pypes Race Pro (Straight Thru muffs). It is so quiet, you can hold a normal conversation in the car just cruising. You need to swap out the F-M's and get a modern design exhaust in there.

 

I'd agree that their are much quieter muffs than those you've got now, and a change might do you more good than simply adding more mufflers to it.

Look into what Magnaflow and DynoMax offer, and remember that the larger the muffler case, the quieter it will (typically) be. So get the largest mufflers you can while you're shopping! If you can afford to lose a couple ponies, you can have a quieter car.

 

Craig,

An 'H' pipe or 'X' pipe will quiet the car to some extent, so I would start there. Then go with a larger, more efficient (sound wise) pair of mufflers and tailpipes out to the rear bumper. This should make the car significantly quieter.

If it is necessary for you to install a second set of muffers, they will not reduce your power output at all. The first set of mufflers produce back pressure, but the second muffler will not add backpressue to any measureable amount. Problem with the extra set of mufflers is that in a situation such as yours, available space is not abundant, even for the tailpipes. With mufflers (or even tailpipes) installed under the trunk area, I would fabricate some sort of heat shield over the pipes/mufflers to reduce heat buildup there.

 

I don't kow how many lbs of boost you're running with that monster, but I don't doubt that your power level must be enough that a 3" diameter exhaust is restrictive anyway. So I'm surprised that the previous owner didn't set it up with atleast a 3.5" diameter exhaust. But I suspect that the two causes for the resonence and extra noise is what ray has stated about the lack of tailpipes, and also those Dronemaster mufflers you have. FWIW, alot of guys on this board have chosen the PYPES brand Race pro muffs and they really like how they sound. And as you see from the pics below, they aren't very restrictive. And they're available for 3" and 3.5" exhaust pipe diameters. BTW, I for one sure wouldn't mind seeing some more pics of that car of yours....

http://www.pypesexhaust.com/mufflers.html#02

 

You're getting a LOT of different opinions here. So far I've read:

change mufflers
Run tailpipes
Run an X or H pipe
buy huge mufflers
get rid of the flowmasters
and a few combinations


The easiest thing to try first is to change mufflers. I agree, that FM mufflers are LOUD, and believe it or not, they are VERY restrictive. You could have a quieter, AND better flowing exhaust with just a muffler swap.

If that doesn't work well enough, then slap some resonators and tails on and be done with it. Seriously, GM did it and it worked.

 

are they race mufflers or just 40 series w/o tailpipes
with no tailpipes (not talking dumps) they will be louder, just adding tailpipes will help some
i guess it depends on what your gonna do with the car-adding tailpipes will add some low end torq also
i have 3" with 40 series, tailpipes out to the bumper, while its not that bad, does get old on the road, even in o/d and the converter locked
i was looking at trying the Car Chem inserts for a trip
when i built my ex system, i used header flanges, i can unbolt the whole system in a manner of mins on the lift-kind of did it so i could swap in a quiter muffler, still might try a pair of cheap Summit mufflers, see if it reduces the noise, then swap back after a trip, or try the Pypes stuff, but dont want to spend a fort. and not like it, lol

 

Thanks for all the opinions - I really appreciate it. I hadn't looked at the Pypes product before, but a T304 polished stainless 18" long muffler seems like a good place to start. At under $100, it seems like a great price! (...until I have to pay for shipping to Australia! Anyone coming here for a holiday with some spare suitcase space?!?) At 5" height, it'll sit ever so slightly lower to the ground than the Flowmaster, but that should be OK.

BillyGman - thanks for the pic and the link. More photos of my 68 are in the link in my sig.

engineguy - thanks for the info about the backflow/power loss aspect. Good to know I can maybe just run a pair of bullets under the trunk/ fuel cell if the Flowmaster replacements and tailpipes alone don't quieten it down enough. Good call regarding the heat shield too - a heated fuel cell is not an option!

 

3" exhaust w/18" length muffs with a X-pipe installed and full tails. Here's a video link of mine running with that setup. Motor is a 469", 10.3/1CR with 245/252, .650/.650 hyd roller. Less motor than yours for sure, but you get the idea. There's another video riding in the car, you can hear how quiet it is in the car.

http://s134.photobucket.com/albums/q116/VGIORDANO_2007/?action=view&current=MVI_1110.flv

 

For some reason blown cars and chambered mufflers are extremely loud. I ran into this issue when I built the blown engine for a Camaro I had. Dropped it in with the same exhaust I had run for years N/A and instantly the car was "give me a ticket loud". I tried adding a set of bullet mufflers ahead of my chambered mufflers and it helped but, the very best fix was to install a pair of Borlas mufflers and get rid of the other 4 mufflers, the two Borla's were quieter than the four muffler system was.

A H-pipe will help some as well but, those flowmasters behind that blown engine it going to make a lot of noise.

 

For some reason blown cars and chambered mufflers are extremely loud. I ran into this issue when I built the blown engine for a Camaro I had. Dropped it in with the same exhaust I had run for years N/A and instantly the car was "give me a ticket loud". I tried adding a set of bullet mufflers ahead of my chambered mufflers and it helped but, the very best fix was to install a pair of Borlas mufflers and get rid of the other 4 mufflers, the two Borla's were quieter than the four muffler system was.

A H-pipe will help some as well but, those flowmasters behind that blown engine it going to make a lot of noise.

Hey Royce which Borlas did you end up running?? Thanks Chris

 

GM used to put "resonators" (2nd mufflers) on alot of their large luxury models in the late 60's, early 70's. Most looked similar to a glasspack and were located outside the rear framerail, behind the quarter panel dropoff. On a stock or mildly modified Chevelle rearend there is plenty of room.

BUT, your 4 link suspension may cause a bit of a routing issue.

In the early 90's, before the Yuppie/Harley explosion, cops were hard asses about loud pipes. I worked for a parts store that was a Walker (DynoMax parent company) distributor. Myself and another employee with a stout '69 Camaro, experimented with several mufflers to remain under the radar, without killing our performance. The Camaro guy was more into the "show" and I, into the "go" scene. He settled on what used to be called "Hemi" mufflers, while I chose a newly introduced unit intended for HiPerf fullsize trucks. They were 3", large shell, internally tubed, stainless oval's. Basically, more similar to the straight through design, than the droning chambered type, however, you could not look out the otherside, because the perforated tube snaked ("S'd") within the shell. They fit within the stock '66 (under backseat) pocket, despite having Lakewood Ladder bars, so they should, also, fit in later models.

In all but W.O.T. conditions, noise between the two was comparible. My choice had next to no additional back pressure and little effect on performance. They are heavy, though. Last I checked (SEMA several years back), a similar muffler was still being offered, I believe, under the DynoMax label. In 1992, they were $175 each, jobber, so they weren't cheap. Mine were wiped out from a broken driveshaft, or I'd probably still be running them.

 

Borla makes what are supposed to be pretty good race mufflers that some claim aren't annoyingly loud, but I've never used them, and they're very expensive. They're the XR-1 muffs. They're of a similar design as the PYPES Race Pro muffs I posted in the pics, but they don't offer the offset/offset inlet/outlet configuration that Chevelles usually use which is why I didn't choose them.

 

Holy CRAP!! IT"S A RACE CAR!!!! If you don't like loud Vehicles DON"T BUY THEM!!! If you bought a BLOWN BBC Your not worried about the Neighbors! If you worry about everyone around you all the time then you will drive a Ford Focus! Wear ear plugs.

 

The XR-1's or Sportsman mufflers is what I run. I have run both the 3" and now I have 3 1/2"

The part number for the 3" is 40944 (16" case)

No they are not cheap but, they are very well built and will last forever. They are also a lot cheaper than tickets.

I'll try to dig up a picture of my current exhaust system. I can get a sound clip for you tomorrow if you want.

As you can see the case size is small so there really is not need for an offset inlet/outlet. This exhaust system is 3 1/2" compare that to the size of the mufflers for reference. The muffler case is 16" long.

 

That would be cool I would love to here it....

 

sound clip would be great....

I have been struggling to figure out how to get an X pipe in with my Gear Vendors there....your picture was great and I think I will go the route of the H pipe as well....

whose exhaust are you using and what size is it?

Thanks

 

sound clip would be great....

I have been struggling to figure out how to get an X pipe in with my Gear Vendors there....your picture was great and I think I will go the route of the H pipe as well....

whose exhaust are you using and what size is it?

Thanks

That's one of the reasons I went withan H-pipe over an X plus I don't really care for the sound of an X-pipe, at least the ones I have heard in person. They sound kind of raspy and have a funny pitch.

I'll have a sound clip up for you guys by noon PST.

 

thanks, whose exhaust are you using?

Also, where the heck is your transmission cross member?

Billy, I just removed a true dual and might still go that route.....Torque Tech, 3", but I did have the Flowmaster 40 series though and really did not like them (to put it nicely.)

I have the 22" case magnaflows sitting and waiting to go in, so they might sound better even without an H pipe...

 

thanks, whose exhaust are you using?

Also, where the heck is your transmission cross member?

Billy, I just removed a true dual and might still go that route.....Torque Tech, 3", but I did have the Flowmaster 40 series though and really did not like them (to put it nicely.)

I have the 22" case magnaflows sitting and waiting to go in, so they might sound better even without an H pipe...

I don't like the Flowmasters on most cars either. I once heard a small block Nova that actually sounded ok with the Flowmasters, and I was pretty surprised when the guy told me that's what muffs he had on the car. But he didn't even know which Flowmasters they were.

My guess is that you'll be happy with the Magnaflows, but only if they're the wide open type without the chambers in them. I once had the wide open Magnaflows, and I liked them. They sounded pretty good during full throttle, and they weren't annoyingly loud during cruising or idle. The PYPES Race Pro muffs are of a similar design without any baffles, so I chose them this time around since I needed muffs for 3.5" diameter exhaust, and the last time I checked, the Magnaflows like many others are NOT available for 3.5" diameter exhaust. So that made my decision easy.

I have the Torque tech exhaust that came with the Dronemaster muffs too, but I plan on installing the set-up with the PYPES Race Pro muffs that I bought. Again, Torque Tech set-ups are the only ones that I found which offers a mandrel bent set-up for GM A-body cars in the 3.5" diameter size, so that was the reason for my choice. They're very good people to work with too. I'm surprised that you scapped the entire Torque tech set-up instead of just swapping out those dronemasters for another set of muffs.

 

An x pipe or H pipe with Borla Muflers may ne the hot set up to quiet it down.
I would not run 2 sets of mufflers.

 

Ditto on the large case Magnaflow/Dynomax hemi turbo type mufflers night and day difference. Youll love it so will your neighbors, never seen a car with Flos get quiet no matter what you did to it.

 

Sorry for the delay, I had to pick my car up from the upholstery shop, had a headliner made for it and when I went to get it this morning, there were a few things that needed to be done and the street was flooded, they were flushing the fire hydrants, so I left the car there until tis evening.

Here is a link to the clip on You Tube. http://www.youtube.com/watch?v=DSLsGgDjFXE

 

Sorry for the delay, I had to pick my car up from the upholstery shop, had a headliner made for it and when I went to get it this morning, there were a few things that needed to be done and the street was flooded, they were flushing the fire hydrants, so I left the car there until tis evening.

Here is a link to the clip on You Tube. http://www.youtube.com/watch?v=DSLsGgDjFXE

Thanks for posting that up Royce. Judging by how loud the blower sounds compared to the exhaust it seems pretty loud still....

Your Skylark is Wicked. I checked out your photo bucket and all I can say is WOW!!:thumbsup:

 

If you are asking about my tranny crossmember, I don't run one I let the tranny sit on the H-pipe to save weight, lol. Kidding of course. The crossmember is round tube and you can just see the end of it if you follow the H-pipe over to the frame (it's grey).

 

wow I just listened to that clip and maybe it is just the speakers on my netbook but, that didn't even sound like my car. It is much deeper.

Ok I listened to it on my desktop with decent speakers and it sounds much better, still not quite like in person but, it gives you an idea.

 

This motor will need the biggest muffs that can fit and an X. 18" muffs will still be too loud. 22" Magnaflws on mine, and I love them. I had an X prior, and removed it for this combo. I cant tell a difference. Joe Sherman found that Magnaflws only lost ~5hp on a 1000HP motor. So the way I look at it, just swapping those Flowmasters out for the Magnaflws will likely give a huge increase in power while quieting things down. Then, a set of bullets can be added if needed in the tails.

Its a win/win changing the muffs.

 

I would think that any of the three (magnaflow wide open muffs, Borla XR-1, or PYPES Race Pro )will quiet things down atleast a little bit while at the same time allow free flowing exhaust without a power loss since all three of them employ the same design using the perforated pipe running through the middle of the case with sound deadening wrap around it instead of having baffles like other mufflers use.

 

I run 3-1/2" Borla Sportsmans behind a Dr. Gas X-pipe and people say my car is quiet to them. I wonder why I set off 5-6 car alarms everytime I go out? Or why, when Irwindale first opened I got tossed for being over the decibel limit and had to stick some 3-1/2" Flowmasters at the end of my tailpipes to reduce the noise? I did notice a small performance loss with the 2nd pair attached, but probably no more than the extra weight would have caused.