NPP exhaust flap part 2- what mufflers to buy?

[mike100]

I had to swap my headers to pass the emissions test here so I'm running a stock exhaust system. At this point I'm not going to put the headers back on so I decided I need to have a little fun with the oem 2.7" pipe set. Recall I had made an automated vacuum circuit to open and close muffler valves based on engine speed and engine load here:
http://zr1.net/forum/showthread.php?t=21474
and here:
http://www.corvetteforum.com/forums/...ust-quiet.html

or in HoTB issue #35: http://www.zr1netregistry.com/LinkCl...alid=0&mid=725

I finally found the 2nd actuator yesterday on Craigslist. These are 2.25" Boysen actuators from BMW 335's. They are actually a little nicer than the GM ones and I'm inclined to think they are going to be less prone to rattling. I bought the BMW muffler for $40 (there's only one actuator per car) and the other one was a gift from my friendly neighborhood muffler guru.


I'm thinking some kind of turbo muffler with dual outlets or maybe even a flowmaster. The goal of the project is to be less restrictive than stock mufflers and still be quiet. It doesn't have to be maximum flow and the straight through type of muffler will probably not be considered. Also it has to be a center inlet to fit the C4 right. Has anybody ever made a quiet flowmaster system (lol).

Boysen exhaust flaps

[HAWAIIZR-1]

Mike,

Cool stuff and I see the gears are always turning in your head. Good luck with your quest and I'll keep you posted on what I end of up doing after I meet with the local custom muffler shop.

See ya,

[Hib Halverson]

The quietest Flowmasters are the 70 series. The next most quietest are the 50 series delta flows.

The system I built for my ZR1 uses 50 deltas.

If I was to do another system, I'd try and fit 70 series on the car but that would be tough. You'd need some tight mandrel bends and a good exhaust fabricator to do it.

[mike100]

Originally Posted by Hib Halverson

The quietest Flowmasters are the 70 series. The next most quietest are the 50 series delta flows.

The system I built for my ZR1 uses 50 deltas.

If I was to do another system, I'd try and fit 70 series on the car but that would be tough. You'd need some tight mandrel bends and a good exhaust fabricator to do it.

oh yeah..the big block ones! I have one on my old f150- it is gigantic (but barely louder than stock)... catalog says its 2 feet long: http://www.flowmastermufflers.com/?p...&partno=530722