Having owned a muffler shop for several years, and also having an engineering degree, I became very comfortable with the technology behind Flowmaster mufflers. All my other cars have them.

Hence, when I purchased my 2000 C5, I immediately order 'Flows'. Part number 52580 are blanks, not the entire system. This allows (or should I say forces) a bit of custom work, but it lets one to get creative with the outlets.

These mufflers are a bit larger than stock and are a tight fit. Still having 'priviledges' at my old shop, I did the installation myself. It required a bit of cutting and welding plus some bending and fabicating for the outlets and tips.

For tips I used stainless "Z28" style outlets, and if I do say so myself, it is a very attractive, 'stealthy' looking system. The tone is very quiet at idle and cruise, in fact quieter than I might have expected. But at WOT it is very throaty. There is absolutely no resonance at any RPM. If you want a really 'narly' sound, these mufflers may not be for you, but for a middle aged geezer like me they are probably just about right.

The jury is still out on performance, as the installation was just done on Monday, 4/14. I put a similar muffler on my 454 suburban and got an extra 2 miles per gallon... no lie! Not a whole lotta discussion about Flowmasters on this forum, so I thought my $.02 might be of some help. Flowmaster also makes a bolt on system with SS tips which uses the same muffler blanks, but it will probably cost you a bit more.

 

I installed them on my 1989 coupe that was a street legal racer. I had headers, custom 3" exhaust and the Flowmasters. My family could hear me coming 3 blocks away.

Wayyyyyy toooo muchhhhhh resonance for a C5. I went with Corsa's. But the Flowmasters do open up the exhaust :lol:

 

Don't flowmasters use the same technology as the Magnaflow exhaust?

 

Unless Mags have changed recently, there's a big difference. The Magnaflows I use to install were a straight flow design with a sound absorbing batting. Flows are a patented design of baffles that turn sound energy into heat energy, and supposedly actually create a positive pressure inside the casing. I put one on a stock car once and the resulting flow was so good, it leaned the motors cylinders out and burned a piston (oops).

Anyway, I'm not trying to be a Flowmaster salesman, I just like the technology and casing design. I used/saw alot of different performance mufflers, and liked Flowmasters the best.

 

We do something a bit different. We remove the stock mufflers and add a 2 resonator-tip combos. The two large tips look cool....add HP....lighten the load...and sound incredible. Performance gains are decent, especially when combined with our cold air kit. The sound is managed perfectly. If you own your own shop, give it a try. Heck, why not? The key is going with a very large resonator/tip. Dont try four...they sound horrible. But going with two evened things out.

Want more info....drop me a line

Oh the cost.... complete Stage I kit, with exhaust and our cold air system using 2mK&N filters comes it at less then $600...$750 Installed

 

Flowmaster has two different sets of mufflers for the C5 now. The original 40 series which has the "D" shaped tips has a very traditional Flowmaster sound.

The new ones are the 80 series which are mote like RaceMic described...very mild at idle and very wild at WOT. No in-cabin resonance so you can hold a conversation at normal talking levels.

I have the 80 series on my car and they do have a deep loud growl when you start the car up but then they mellow out until you stick your foot in it.

cc


[Modified by CCrane00, 4:26 PM 4/19/2003]


[Modified by CCrane00, 4:27 PM 4/19/2003]