Quote:
Originally Posted by Bender
Hi Psycho. Wow!!!! 130db is loud for a unloaded engine. I would check the meter or area it is being tested. It should be in an open area with car on a flat surface. In my rally years. My 2l escort with all the fruit, 2 1/2" exhaust and about 10" long large straight through muffler would be under 96 at 4000 rpm. Supercars are under 96db under load with meter in the middle of the track. So 130db is loud. I checked your photos. Nice build mate. In one of the photos you have a tube with aunger plates welded to it and some steel wool wrapped around it. Is that your muffler mate? I may be totally off the mark but if you are trying to copy the Gonzo mufflers. They were a bit different to that. On the gonzos the aunger was a full spiral with the tube welded in the middle. That was then mounted in the muffler with no steel wool. Theory being the exhaust travelling around the spiral would have a different speed to the exhaust coming through the centre tube. Canceling out the noise vibration. Unfortuately the noise always sounded flat and the centre would rattle. SBR and Triple 8 ran that style for a while. The cars always sounded terrible but under the limit. I have built steel wool filled mufflers before and recently chatted to an exhaust guy in Qld. He was saying use rock wall or dry wall. One of the 2. Lol. He said it is not as tinny as the steel wool muffler. If you are interested I can check again to see what he is using. Hope this info helps with your build. Sounds like you are close to rego. Bender
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G'day Bender
Yes the left pipe was 129.5 and the right 130 at 6ft ground level on the road out the front of the house, the factory five pipes doesn't have much of a baffle at all just a perforated barrel with bugger all glass wrap very loud and raspy just a big hotdog. I made up some steel spacers between the gaskets and with some 13mm holes drilled out and used the augers with the wool as you saw in the pictures. Because I can't split my pipes without taking to it with a saw I have welded in some Flexi tube so I can insert them around the bend in the opening, the wool has reduced the flow and sound very well and has also cushioned the rattles internally. To secure the augers in I welded two nuts on the tube and wound bolts in so when in place I use a 14m spanner and just wind them out until I can't wind no more this locks them into the pipe very well and I have tested them out driving for 300km under different acceleration. As for Rego I will be visiting my engineer tomorrow for his final so hopefully all goes well. This mod for the exhaust is just for Rego I will be removing the plates after and I will only be sitting at 95db for a end result. I will try and upload a video of the car without the mods and you will hear how loud she was I might have to edit some of it as the swearing from the bystanders may offend others heheheheheheheh.
Cheers Psycho