glennster

iTrader: (1)

Ran the car 2 weeks ago in great weather 70 degrees and almost needing a light jacket.2 passes since the gears,headers,and DRs netted me a 13.04@108.5 and a 13.03@108.9 with 1.93 and 1.90 respective 60's.I chunked the flowmaster 80 yesterday and put a magnaflow muffler in its place.Heading to the track I netted 13.00@108.3 then something odd happened,I ran a 13.06@110.98,12.98@111.32 and lastly a 13.05@110.9.We are talking a humid night in the high 80s and a DA of 3600 feet.My 60's were an average of 1.95 so thats not that far off.Could that flowmaster be THAT restrictive? My friends thought the car sounded awesome at WOT with the magnaflow,but it needs a bullet to calm the rasp at 2500.Watched a few interesting runs,an 02 SS M6 with lid/catback running 13.6x@105,a 98 GT with supercharger/auto/DRs running 13.6@104 and a 04 mystic cobra with exhaust/DRs/pulley/chip ran a few 12.40s@111.I know theres a mid 12 in my car but I can't seem to get it off the pad without a bog or spin,I had the nittos at 20#.Its all good tho,I'll take a 12 and not have a broken rear end.

Beast96Z

iTrader: (21)

Flowmaster anything is a restriction. But seriously, you swaped one of the most restrictive mufflers for one of the most efficent mufflers. There is no doubt in my mind that you would've gained.

ratio411

Stock muffler- ~200 cfm flow
Flow 80 series- ~360 cfm
Magnaflow- ~1100 cfm

The piping is good on any of these... 2.75" stainless/mandrel bent stock, 3" mandrel on the cat-backs. Too close to matter. The power is all in the muffler.
Dave

Old SStroker

I agree. Look at the flow numbers ratio411 posted.

You pulled out the cork. The 2 mph trap speed is almost purely more hp.

Dynomax Ultraflow mufflers are VERY similar to Magnaflow. They either copy each other or are different marketing arms of Walker.

16nrollininaws6

Are they really that restrictive? GOD YES. You did one of the simplest mods out there, a muffler swap, and you gained 2-3 mph in your trap speed. Thats why "Flow"master is known as chokemaster around here bro. Glad to see your gains now add some giggle gas and a cam and a rear end