silencer below 100db ?

[Thomas Rouw]

Rene PM sent.

sorry guys I need a little more time to shoot some footage with decent sound.

bellmouth radius' are used to silence/alter reflections.

grtz Thomas

 

[René]

thanks, we will wait for it then ;-)
is there also a see through (or open) model of those type mufflers?

 

[Rune]

So finaly the silencer is ready and the db at 4500rpm is 102 db . I will try to pass the tecnical check on the raceway with that , can make some small cones to put inside or two 90deg pipe at the end and see how it work . But for now it must be as is.

 

[clive]

I would be interested in comments from the fraternity if one was to use the Russ Noble design, but incorporate cats into the straight section after the collectors, burying them within the muffler.

Local V8 cats are now able to clean up the exhaust emmissions to the point where I don't anticipate any probs with the tests for rego, using a well set up computer, but noise has always weighed heavily. I would love a system that worked and didn't look too over the top.

 

[Mick Ridley]

Clive,

Because of how Russes system works, putting the cats where you suggested, (in the secondary pipes) would have the same effect as if you had straight through secondary pipes and fitted cats to them, providing the volume of the chamber which the secondary pipes are in,(the muffler) wasnt greatly reduced

 

[Rod Brace]

I still can't find a picture or a diagram that shows how that muffler finished it's outlets. I don't see it in post 19 or any other?

 

[Ian Anderson]

Post 13 above

http://www.gt40s.com/forum/gt40-tech-engines-induction-exhaust/30777-silencer-advice-2.html

Or post 21 in above post

Ian

 

[Rod Brace]

Ian I don't see how post #13 how the exhaust exits? 21 doesn't have any links or pictures? Is there any pictures of post#13 finished? P.s. Merry Christmas!

 

[Jac Mac]

Ian I don't see how post #13 how the exhaust exits? 21 doesn't have any links or pictures? Is there any pictures of post#13 finished? P.s. Merry Christmas!

Pic attached with flow patterns and exits/tailpipes drawn in . Russ got a bit stuffed up in the construction via my phone calls and emails( I was not as computer savvy back then ) and this ended being much larger than necessary. Basicly Tailpipe tuned length must end in an internal box to give a definite clear pipe end signal and all gates should be Vee shaped favouring flow to the tailpipe and therefore killing any reversion flow. All gates/gaps must have an area greater than the tailpipe dia area so that there is no restriction other than the surface drag internally. The center divider between LH & RH sides can be varied in length- longer retains the V8 or 180° sound or no divider effectively creates an 8 into 1 effect. I prefer the 8/1 myself. As I pointed out we have had no problems in the one fitted to TVR other than muffler vs ground. Russ's car which you may not be aware of was badly damaged in a freak track condition accident ( spray drift from irrigator on neighbouring farm land onto track surface due to sudden wind change ) and has not yet been repaired.

 

[Rod Brace]

Thanks Jac! Is there any pictures of it done?

 

[Mike]

These make great mufflers

 

[Rod Brace]

Yes they do! I would love an Audi r18 diesel twin turbo to put in my car! They are quiet fast and get great mileage.

 

[Jac Mac]

Thanks Jac! Is there any pictures of it done?

Click on the 'Silencer Advice' Link of post #27 in this thread and there are two short video & sound clips of the car/silencer etc in post #27 of that thread that show rear exits. As I pointed out it ended up being larger (much) than necessary.

 

[Randy V]

Not sure where I snatched this pic from but I found it on my hard drive...
Interesting configuration with catalytic converters and mufflers..

 

[Jac Mac]

Drawing of how the GT40 muffler was meant to be made.

 

[Rod Brace]

I still don't understand is the bottom where the exit is completely open or does it not have the bottom sheet welded on it yet and it is supposed to have a pipe coming out when finished?

 

[Jac Mac]

deleted. tried to make dwg clearer, did not work... guess you will just have to wait for construction pics in a few years time!

 

[40 Bud]

If you draw a 4 branch collector at each of the black arrows and a megaphone or extension for the exit at the red arrows you will have the overall look. Pretend you have x-ray vision and are looking thru the top of the muffler to follow the exhaust gas path thru the green and red pipes and thru the appropriate baffles and out at a red arrow.

 

[Rod Brace]

I can open the silencer link now I see how it I'd done. Titanium sheet would make it a lot lighter.

 

[Andy]

I would suggest also to incorporate Helmholtz resonator areas (death ends in the muffler). The volume of these room needs to be in tune of your engine.
1/4 or 3/4 of the wavelength needs to be found.
This means it is only effective in a certain area of rpm and best to choose 2000-2200 rpm for cruising. (=134Hz for V8)