View Single Post
RarlyL8 RarlyL8 is offline
Crotchety Old Bastard
RarlyL8's Avatar
Join Date: Jan 2000
Location: Huntsville, AL
Posts: 13,524
I have the same opinion when it comes to sound. I like musclecar on the outside and a muffled rumble on the inside. You have to easily have a conversation with the passenger while the car is at idle with the windows down.
You can do that with my mufflers, a bit more difficult with the Zork. Having the engine in the rear and the pipes pointed back helps a lot.

I do have a decibel meter but I don't seem to get accurate readings from it. The background in my quiet neighborhood reads 65db and the exhaust noise reads 82db ???? That seems way off.

The method we plan to use to quiet the mufflers should not affect performance significantly. The current design has the 3"ID turbo outlet pipe going into a 5"ID baffled expansion chamber and then back down to a 3"ID tailpipe. The plan is to pack the expansion chamber walls with carbon fiber mesh so the ID remains at 3" throughout the muffler with very little added weight.

The best news when it comes to exhaust systems on the turbo is that when you are at highway speeds you hear very little exhaust noise at all. Only when you reach boost threshold do you hear the turbo whistle and then at full boost you hear the roar of everything wide open.

The noise that has the most potential to annoy over the long haul is the cackle on decel. You can modulate the throttle and make it as loud as a shotgun or down to a burble. Push in the clutch and all noise stops immediately as if you shut the car off. It's an interesting experience.

I was expecting the first production set to arrive Friday but it didn't happen. So maybe Monday. I'll get them polished up and mounted for a few pix by next weekend and put a few miles on to see how they work out. I'll fish out that noise meter and see what can be done there as well.
RarlyL8 Motorsports / M&K Exhaust - 911/930 Exhaust Systems, Turbos, TiAL, CIS Mods/Rebuilds
'78 911SC Widebody, 930 engine, 915 Tranny, K27, SC Cams, RL8 Headers & GT3 Muffler. 350whp @ 0.75bar
Brian B. (256)536-9977 Service@MKExhaust Brian@RarlyL8
Old 10-27-2007, 05:43 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #25 (permalink)