Taming a too-loud exhaust...questions
 

My '87 Carrera has a GHL straight through test pipe and a M&K 1 in, 2 out sport muffler. Maybe because I'm getting old, the exhaust is too loud for me nowadays, particularly at higher RPM's...it sounds like a 3.0 RSR on the banking at Daytona when I open it up. This would be fine at Road Atlanta, not so good on the street considering the plethora of law enforcement out there who are rapidly writing tickets at the behest of local city councils and county commissions in order to make up for lost tax revenue. Oops, I got off topic. :rolleyes:

The mufflers have Ben's tailpipe inserts added which helped somewhat but not nearly enough. I am thinking that the test pipe may be an equal culprit along with the muffler so I am requesting some guidance.

1.) Will a Euro-style pre-muffler make a significant difference in noise level as compared to the test pipe? I'm thinking the M&K one since the muffler is a M&K. But it is $330+gaskets & shipping from our host...a fair amount of coin if the difference is minor.

2.) I'm pretty sure reinstalling the catalytic converter would solve my problem and perhaps boost low end torque a bit. The cat that I took off the car and still have has around 100K miles on it but it still looks fine based on what is visible.

This is a street-only car and is (for a Porsche) pretty gently driven. But every now and then, an Italian tune-up is called for and I don't want to attract unwanted attention from the police...so far not a problem. And no, the neighbors haven't complained either. I haven't blasted through the neighborhood in the early morning in this car since the Porsche isn't my DD.

A stock muffler is not an option. I LOVE the M&K! The tone is awesome. I just need to knock the volume level down a notch or two.

Any thoughts/advice would be appreciated!

http://forums.pelicanparts.com/uploa...1303146227.jpg

Many posts in regards to this and concensus is to cap one side since you already have the inserts. I too had an M&K and replaced it due to it being to loud as there was no way I was putting a cap on a two out system. To me it looks silly.
Another idea is to have the outlets replaced with smaller pipes, but I already had 2 inch and the drone killed my ears.

You can get a plug that fits inside the tailpipe, friction fit, easily removable.

You cannot see it without shining a light up the pipe.

install one of these
YouTube - Electric exhaust cutout

M&K offer a cap to cap one of the outlets for less dBs...check with them on their thoughts/ideas.

Add one on the side, cap the two in the center. Reverse the proceedure when you want the full sound.....

I have a dual exhaust system and it was just a bit too loud for street driving.

I purchased a couple of these and they knocked the edge off.

Car Chemistry 3DI25R - Car Chemistry Exhaust Inserts - Overview - SummitRacing.com

Thanks for the suggestions. tcar's idea seems to be the most viable and cost-effective so far.

Still curious if the Euro pre-muffler does any significant muffling as compared to the test pipe.

I did as Aston did, used the car chemistry baffles wrapped in stainless steel wool, and the car is an absolute pleasure to drive, has a nice rumble but is not loud.

Lewis

When you weren't shooting them at me on the highway!;)

ive heard reducing the diameter of the muffler outlet pipes will lower the dbs. So if you have 2" go to like 1.75".

I have a Dansk dual out muffler. Ben fabricated a cap for one side of mine. Works great and fits tight. Reduced the noise quite a bit. Still loud, just not as loud.

So you got a letter too?

Nah, he's just old......

I have a Dansk 1-in-2-out and in combination with my Fabspeed Euro premuffler it is quite loud. I also feel (no dyno, just "seat of the pants") that I'm giving up some midrange torque to gain near-redline hp with the low-restriction exhaust, despite the SW chip.

So......I'm figuring out how to put in an electric cutout for one side. It isn't easy because of the curved configuration of the pipes, and because I want it to be as invisible as possible.

Just capping the pipe made a roughly 10 dB difference! Interestingly, capping the passenger side made a bigger difference than capping the driver's side.

LOL, that reaction is hilarious,

One day you'll stick your peni5 into it.... :D

^ that was a fellow pelican commenting on that :)

LOL...Nope. My neighbors are nice folks. There are pickup trucks around here that are louder than my Porsche.

Yep, that's a fact....I'm 62. Going on 25.

Loud is good, but LOUD is another matter.

In the garage is a '08 Mustang Bullitt GT with Ford Racing GT500KR mufflers. And a '67 Chevelle with Flowmaster Super 40's. Neither of these cars are nearly as ear-splittingly loud as the Porsche at 5000+ rpm. And there is the Harley that has a very throaty set of aftermarket pipes. All three of these vehicles are anything but quiet. Reasonably loud is good!

Ben made my muffler with non-standard pipe spacing and warned that it may be louder than his off-the-shelf mufflers. It definitely is.

For starters, I think I'll block the passenger side pipe and see what happens.

I do appreciate everyone's input. dw 1, thanks for your take on the pre-muffler. You saved me $330+. :)