If you don't have muffler you will get pulled over in a minute.

That is one thing we are working on right now. We just released an Active Exhaust System that works with headers. It is based on our ST street series muffler that have either GT3 or S tailpipe configurations. The sound level on this muffler at idle and cruise is just a bit louder than stock, jump on the throttle and it is Sport loud. The valves allow an alternate high volume path to exit along with the standard path. Here is a picture of the prototype being tested using OEM early exchangers. Production units will have the valves angled back. We are testing these with our new long tube headers now as well.

http://forums.pelicanparts.com/uploa...1574434176.JPG

http://forums.pelicanparts.com/uploa...1574434176.JPG

We also have a version of these new headers that will be modified to accept 997 and 991 GT3 mufflers. A couple of Pelicanites have sent me the mufflers and secondary systems to work it up. Those systems should be finished before the new year. There is a twin cat system in the works as well, lots of exiting things coming for 2020!

The wail on a racetrack ... that's a beautiful sound but puttering about in a parking lot, why is it so loud ?

I did not realize that "AWESOME" had a decibel level.

"which is essentially a pair of megaphones masquerading as a muffler"

^^^ OK, so there's loud and there's racecar loud ... without the muffler or with a fake muffler, it's closer to the latter. Yeah, in one's neighborhood, better check with the neighbors since it is loud at any speed. That active exhaust tech makes sense for the BOBW.

Is that idle wavering on the M491 or is it just the exhaust puttering ?

Per data from Bill V. @ 6500 RPM its about 325 Hz. and I'm also guessing 110 decibels.
About as much fun as you can have with your clothes on IMO

the idle is lumpy from a combination of a custom Sal Carceller chip designed to work with the headers and muffler.

I have no idea what hp the engine is generating, I'll go to a dyno this spring. The car is MUCH quicker than it used to be but there are far too many factors to determine the cause. In doing the headers and muffler, also done:

Swapped in a spare 1975 915 that shifts like a Honda. I have to rebuild the original to the car box as it has a terrible 5th gear whine. The '75 was rebuilt at one time and I think it has custom gearing and probably a 7:31. When i rebuild the original one I'm also taking the '75 apart to replicate it as best as possible.

In swapping that box in, I had to use a different clutch cable. Doing that found that I only had one bushing in the throttle bell crank at the pedal box so I was never getting full throttle.

I also removed all AC components, blower and the wing (saved 30 lb on that alone) for an estimated over 100 lb loss in the rear of the car. It actually sits higher now from all of the weight loss.

So with all of those things changing at one time, I am looking forward to seeing what hp the chip and exhaust produce.

The second (newer car) sounds like dog crap compared to the first one..

Go straight pipes!!!!

I love my turbo with the zork, never been stopped, never been bugged by neighbors.
If the budget ever allows I will replace my old headers with some tuned from Rarly8.

If you haven't seen the above videos you should, I almost skipped them. The sound track in the first one makes my heart flutter.

nkotselas,
Have you gotten a suitable answer in this thread?
My car has B&B headers and muffler.
It is loud, but not obnoxious like a race car.

Here is an old startup video
Compare the volume of the starter with the idle.
Let me know if you want me to take another specific recording.

<iframe width="560" height="315" src="https://www.youtube.com/embed/K0BMRi9sfWI" frameborder="0" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>

I took some SSI decibel measurements several years back (link). I think my hearing is improving with age because it sounds much louder now.

http://forums.pelicanparts.com/porsche-911-technical-forum/7731-performance-test-done-ssi-vs-stock-sc.html

These threads are always good for a laugh...

A muffler is what manages your sound level. Headers do impact it marginally, but the majority answer to this inquiry is, what muffler will you bolt to these headers.

I got pulled over once, stock exchangers, Fabspeed cat-delete and muffler delete. Cop stopped me to "hear the car take off".

Not sure what the aversion to police is in this thread. smh

Good point about the mufflers. When I installed my headers, I also installed a dual out Dansk muffler.

I ended up having a cap/cover made for one of the exhaust tips later in life. However, I only use the cover when I decide to leave the house early am. Without it, the SC is very loud when cold. Not bad once it warms up.

Seems like someone on this board named Ben fabricated the cover. Hard to remember, but it is a very well made stainless steel cover.

There are a different sort of police on this coast.....:rolleyes:

Party poopers you might say:rolleyes:

I'm also the wrong guy for input on this thread :p

I have headers and M&K 911R and am seriously considering megaphones for the street :cool:

Still alive and kicking...thanks.