Help! Car won't pass German inspection because it is too loud

[BigDuke6 17]

Feck, feck feck, feck, feckity-feckity feck!

 

I have a 2.5 inch stainless steel Magnaflow exhaust system on my 69 Mach 1. At the TUV yesterday, I exceeded the noise limits by about 7 dB. What is the best way to bring the noise levels down? I have seen the car chemistry disk inserts but note that the mfg only tests to 4000 rpm. I suspect that those things kill as many horses as dBs after 4K rpm. What about welding in some glass pack mufflers before the regular mufflers? Would that do the trick? Any other advice?

[Flanders 46]

Is it possible to replace the exhaust with a stock exhaust (or a few generic mufflers welded together ;) ) for the test only? And then go back to the magnaflow after the test?

[jholmes217 65]

Does your exhaust have a X pipe or H pipe? Those help by dividing the exhaust into both mufflers instead of one.

[BigDuke6 17]

Does your exhaust have a X pipe or H pipe? Those help by dividing the exhaust into both mufflers instead of one.

 

it has an X pipe. I have two 14 inch mufflers.

[Pakrat 1,043]

There's a bunch of old tricks you can try to quiet it down. You can make a thin sheet metal plate with small holes drilled thru it and insert it bewteen the pipes and headers or manifolds, it may choke things up but it should quiet it down. You could also put a temporary reducer on the end of the pipe instead of your tip with some stock turn downs, I think it would have to sound quiter coming out of 1 3/4 instead of 2 1/2. Another old trick was stuffing the end of the pipe with chicken wire, steel wool, fiberglass or a combination, this works realy well but you want to make sure it doesn't blow through on you when it revs.

[Lemon Owner 11]

I had the same problem and this is what I did to fix it and it worked a treat. My exhaust tips were a little larger than the exhaust so I made a 1 1/2 inch round by 8 inch long sausage out of chicken wire. I wrapped the heat resistant material out of an old oven around the sausage and then covered that in more chicken wire. I stuffed that tightly up the exhaust tips so they were out of sight. Only took me like half an hour. Make sure they are pretty tight so it doesn't spit them out. I left mine in for months without a problem. It halfed the noise and gave the car more torque down low. :scooter:

[BigDuke6 17]

Is it possible to replace the exhaust with a stock exhaust (or a few generic mufflers welded together ;) ) for the test only? And then go back to the magnaflow after the test?

 

A good idea is a good idea. This is exactly what my shop is going to do. The other thing that I have to change that makes no sense is that the TUV wants me to remove my MSD dizzy and put in a stock points dizzy in order to pass. This makes zero sense but if I want to pass inspection and get a historical plate (historical plate means one time tax of EUR 170 as opposed to a regular plate which means EUR 6000 a year in road taxes), this is what I have to do. The pisser is that I had kept my stock dizzy for 5 years. It was sitting in my basement taking up space. I tried to ebay it and listed it for sale on the Dutch Mustang forum for $10. Nobody wanted it. 6 months before my wife got hired in Germany, I tossed it. 6 months later, I need it but it has already been binned. So I have to buy a new one, ship it over, install it for one day, pass the inspection, and then try to sell it. All told, I got off ok. It could have been worse.

[Pakrat 1,043]

So it only has to pass this inspection one time?

[BigDuke6 17]

So it only has to pass this inspection one time?

 

that seems to be the case. I was under the impression it was an annual event, like in the NL. I had to get my car inspected every 12 months in the NL and I thought this was the case here. I guess not.