Any tricks for reducing exhaust note?

[ChrisL]

Just wondering if anyone knows of any simple tricks that I could use to temporarily reduce the sound of the exhaust while the car is being tuned in the garage? I live in a quiet residential area and feel reluctant to do any lengthy engine work in case I overstep the good will of my neigbours.

A very primitive but effective trick that I have seen on the race track (for those cars that had been black flagged for being too loud) is to use a soft-drink can. Cut the base off and a large hole off the side, then clamp it to the end of the exhaust pipe. Has anyone come up with anything more ingenious and more effective?

 

[Chris Kouba]

It'll reduce the noise but also likely not give you a valid tune for the motor, but you can capture some steel wool inside the exhaust pipe (usually wired in a few inches from the end). Hasn't been done to tune motors but it has gotten a rotary motor through tech inspection. The convenient thing about it is it's also "self-cleaning" in that very soon after starting the first stage, the wool is blown from the pipe... Of course that's a different scenario than you have, but it may be applicable.

Chris

 

Hi, i think you have just to bought two baffles... and that i have to do for my neigbors... /ubbthreads/images/graemlins/smile.gif

http://www.gt40s.com/ubbthreads/showflat...=true#Post57735

regards
Olivier

 

[Frank Catt]

If you serious about engine testing in your garage, and have neighbour problems, then do it this way. Leave the car in the configuration you wish to tune and then use it, fit two flexible exhaust pipes to the exhaust outlets, not less diameter than the outlet pipes you will use, and run these through the wall of the garage or through a suitable doorway, take these to a pit dug in the garden of not less than 1m x 1m x 1m, cover with a substantial cover and the earth removed. Run a larger diameter pipe from the pit to as high a level as possible. TRy to keep the distance between the car and the pit as short as possible. You should have reduced the noise substantially, in fact the mechanical noise of the engine would become the loudest thing, so keep the garage doors shut as well. Frank

 

[Charlie Farley]

Frank's idea is spot on.
An alternative is a similar sized acoustic cell. Just simple chipboard , lined with glassfibre/rockwool, similar size. This is a bit easier than sheer grunt of digging.Simply screwed together then dismantled after use.Also doubles up as somewhere to put a screaming child of yours. Beats the ' naughty step' everytime!!!!
/ubbthreads/images/graemlins/tongue.gif

 

[Howard Jones]

How about running the flexable hose out the garage door and into the gutter drain? The big concrete thing with the steel grate on it. That is, if its close enough to the house.

 

[flatchat(Chris)]

These work well---"Supertrapp" www.supertrapp.com/product_sections/auto/index.asp

 

[Paul W]

Building a washing machine size box out of 3/4 inch mdf and lining with rockwool or loft insulation. Anything you put in the tailpipes will affect the tuning so if you could extend the exhaust system and add extra silencers this would also be better. I found that hanging an old quilt on the wall to the rear of my car reduced the low end rumble, but I don't have straight thru silencers.

 

[Pete McCluskey.]

[ QUOTE ]
These work well---"Supertrapp" www.supertrapp.com/product_sections/auto/index.asp

[/ QUOTE ]I'm having them fitted as we speak.

 

Pete. I think they are for cars!!!!! /ubbthreads/images/graemlins/grin.gif /ubbthreads/images/graemlins/grin.gif /ubbthreads/images/graemlins/grin.gif

 

[Pete McCluskey.]

Depends on how many baked beans you eat /ubbthreads/images/graemlins/blush.gif /ubbthreads/images/graemlins/grin.gif