Silence rotary exhaust temporarily at home???

M

markb

Well-known member
Wanting to move the car home and out of the shop but it's the kind of neighborhood where you get a fine if you leave your trash can out an extra day and cars can not be parked in the driveway. Oh, and there's the golfers.

No solid answers from Google other than a bunch of "might" work things. Rather than throw money at testing stuff, does anyone have any real world ways to silence a rotary long enough to get it off the trailer and into the garage?

I have maybe 50-100' to cover at most. Unfortunately their is a good incline so pushing it is not an option and the driveway runs at a 90 degree angle to the garage. I've thought about the winch route but would need one inside and one out and it would be a major hassle.

It's a street ported 13b with 3" exhaust and a Burns muffler that has no problem spitting out 103db at the track.
 
Dude I'd put a bigger muffler on that thing even if I lived on an isolated island.. I only thought my car was loud!

Umm sorry, can't help much. Maybe another bigarse muffler or two hanging off the back? use some metal straps to hang it off the rear hatch opening and then connect with some flex tubing?

Figure_A_July_2011.jpg
 
I live in a tight ass neighborhood too and running my motor for 20s doesn't give anyone heartburn. Just run and tell them to screw off if they arch an eyebrow. Geez. If a golfer objects, have them tow it with their cart. I use one at the track and they can pull a bunch.

Dayle
 
Find/fabricate an exhaust reducer to attach to your tail pipe and attach a cheap, or used, street muffler with 1.5" or 2" exhaust size. ( Think $20 Midas special.) If you have enough room and support structure, it can extend straight back. Or, you can turn 90 degrees and run with a support mechanism parallel to the rear bumper. ( ref previous Por$che picture) It will be quiet enough for the rest of the neighborhood. You will be running low rpm thru a small diameter outlet, 2 keys to making it quieter.

My GT1 efforts were given the name "Thundersports" by a neighbor. They thought it was thunder they were initially hearing outside. We were able to reduce the V8 rumble and the E/P RX7 noise in the neighborhood using the smaller muffler for the garage movements. Don't worry about making it trick. Just make it small and quiet. It will not affect the performance of the car. Unless you are trying to do smokey donuts in the driveway, just to really tick 'em off!!!

I also found that neighbors were more receptive to a little noise, when they realized I could offer some sage/experienced advice on their simple car maintenance questions. I didn't work on their cars, but they did enjoy a knowledgable assist with their concerns. Many times their problems were not a severe
as anticipated. I still can't believe the lack of mechanical comprehension of these golfers!
 
I have the same issue with my 12A EP RX3. I got a $20 muffler and made an adapter to fit between the 3" exhaust tip on the car and the muffler and held it place with bungee cords. Now I can let the car idle in the drive way when I back it out.
 
Cheap and worth a try: Make a box of plywood that you can hang off the rear (Like maybe hooks over the trunk edge.) It should extend as far down as possible and surround the exhaust exit. Maybe you could add low-hanging baffles that extend forward around, but not too close to, the exhaust pipe. If needed, add sound damping from insulation board, etc. Line with aluminum foil if needed for temporary reflection of heat...
Oh - a lot of noise comes from car sheet metal vibrating with the exhaust energy... sometimes a fairly small piece of foam/pipe insulation/rubber/caulking, etc. can quiet a large area of metal by taking out the energy of vibration. Tap the body/ trunk/ fender panels - if they "ring" or "rattle" they can be helped in this way. Low cost, low weight help. There are commercial sound-reduction sheets, too... Joel
 
One good choice here would be the basic Supertrapp disc muffler. Weld one to a 2" long 3" diameter exhaust pipe, assemble it with only 2 or 3 discs (fewer discs = quieter, but more restrictive) for your run up the driveway, and attach it in less than a minute with a wide band clamp.

It is so small and light that it would be worth carrying in the trailer in case you visit a track that finds you too loud. Then you'd just add another 6 or 8 discs and use it on the track. For that application a V-band clamp would be more secure, but just as quick on and off, or you could just weld the Supertrapp flange directly to your tailpipe if you don't mind the look of it.
 
The Supertrapp is a good solution for the driveway conditions. The ability to tune the sound and compact size would be very effective.

What are some of the types or brands that are most effective, on the track, with the rotary engines? What type of internal structure makes them effective? Is there an effective single muffler system, that is not excessively expensive?

I used a, lava rock muffler, about 20 pounds, from Mazda Comp. Made of stainless steel and literally filled with lava rock. It lasted forever, always around 98 - 100 DB. The car was at the weight limit, so having the weight in the right rear helped my corner weights.
 
The flexible black rubber hoses that commercial garages use to connect a tailpipe to an outlet in the wall or garage door also does a good job of quieting the exhaust. It is useful to run the engine while in the garage to move air safely way from the door. You could also be creative and maybe bungee the outlet end to the car roof and loop the intake end down to the existing exhaust. Grainger or some Napa stores are sources for these hoses. You may be able to borrow a length from a shop since they can usually keep doors open this time of year. If you barrow one beware they get filthy being dragged around shop floors so an open pickup bed is the best way to move. If you buy new, you can hang them from a garden hose bracket to keep them out of the way and clean.
 
Racing Beat pre silencer
It’s supposed to knock the sound down to V8 levels then you and use any old muffler

http://www.racingbeat.com/RX7-1986-1992 ... d=oQJjKbTG

A friend told me about a million times the pre-silencer from racing beat is the only way to go

https://www.youtube.com/watch?v=WANKO3n0HDE

Of course being from TX, I double dog dare you (in the Air Guard we would say you don’t have a hair on you’re a$$) to take it off the trailer without doing anything and run up and down the street put it in the garage real quick

And close the garage door then walk outside to see the neighbor’s reactions :lol:
 
davegt27":wi07u43o said:
Racing Beat pre silencer
It’s supposed to knock the sound down to V8 levels then you and use any old muffler

http://www.racingbeat.com/RX7-1986-1992 ... d=oQJjKbTG

A friend told me about a million times the pre-silencer from racing beat is the only way to go

https://www.youtube.com/watch?v=WANKO3n0HDE

Of course being from TX, I double dog dare you (in the Air Guard we would say you don’t have a hair on you’re a$$) to take it off the trailer without doing anything and run up and down the street put it in the garage real quick

And close the garage door then walk outside to see the neighbor’s reactions :lol:
Click to expand...

The main entry road in my neighborhood is just over a mile long, perfectly straight, and only side roads to the houses (no driveways).. So it's a perfect place to make sure the car runs well before loading the car onto the trailer- just make sure before I drive to the track and find out something's wrong...

Last time I took the car out, I made it to the back of the neighborhood and turned around in a cul-de-sac. by the time I got about halway back to my house, one group of kids had set up lawn chairs at the end of the driveway and cheered me on when I drove by. :mrgreen:
 
Pull spark plugs, disconnect coil and simply drive it on the starter motor. Pause periodically to let starter motor cool off.

I would just fire the thing up and drive it. Neighbors be damned. If you do it once a month, no one should care, if they do, bitch at them every time they mow their yard. Better yet move to a decent neighborhood.
 
Thanks for all the suggestions. I ordered a Walker 17901 which is an econo box 1.5" cheap muffler and reducers which was delivered today. Going to weld it up and clamp it on this weekend and hope it works enough to try and bring the car home. If not maybe the starter motor trick will work or I'll get a Supertrapp.

I want to fly under the radar as much as possible and keep a low profile. The next door neighbors are cool, it's a couple power hungry gate guards that also patrol, a board comprised of women who have nothing better to do and an iron fist management company that are the problem. Heck, they wouldn't even let my contractors back in last Sunday when they left for lunch and I had to sneak them in under a blanket. It's a losing battle to fight them.
 
You must log in or register to reply here.
Back
Top