inri

Howdy y'all

I currently have a set of 3.5" 30 series mufflers from SlowMaster..err Flowmaster on my '69 RR.

I love the sound they make and they are super loud! I've read online the Dynomax Ultra Flo's are a great muffler for the strip because they flow much better due to having a straight pipe in the muffler vs Flowmasters baffles, chambers, trap doors etc. However, from what I've listened to online Dynomax mufflers don't sound quite like a Flowmaster. In my opinion Flowmaster is the master of muffler sound, but not necessarily the best muffler for quicker E.t's.

I saw a flow chart online for 2.5" muffler exhaust comparisons where the Dynomax Ultra Flos flow serious scfm compared to the Flowmaster muffler; oftentimes more than doubling the Flowmaster depending on type of muffler. More flow means more power for high horsepower engines?! Me thinks.

I really like the loudness and tone of the Flowmaster, but I'd like to potentially improve my E.T. perhaps I could have the best of both worlds? How is that?

My theory is: I could install (2) electric 3.5" exhaust cutouts in front of the Flowmaster mufflers and open them only when I take the car to the track? This would in theory accomplish two things: Flowmaster sound on the street, and better E.Ts on the track.

I really think I might be able to pick up a .10th or so bypassing the Flows...

Has anyone done something similar? Results?

moe7404

years ago i had a RB 500" max wedge, in a 300 J. it was loud to. my muffler man reduced the last 2-3 inchs of each pipe buy 20-30 % that made it way less loud with out losings power. and the size was not a giveaway. good luck.

TVLynn

When you open the exhaust you would need some way to re tune it.. IT may run slower

inri

TVLynn,

This is new information to me... hmmm.... I didn't realize that I would have to re-tune the car to offset the cutout. Which, by way the muffler wouldn't be completely bypassed as the cutout would open the Y pipe and allow exhaust gases to travel out that and the muffler. I'm assuming that roughly 55% or so of the exhaust gases would still exhaust through the muffler as the muffler is connected straight to the header, whereas the Y pipe cutout is slightly at an angle.

Pontiac (Poor Old Ninja Thinks It's A Cadillac) came out with a similar concept in 1969-70 VOE (Vacuum Operated Exhaust) but cancelled it after a boched commerical during the Super Bowl. Search for VOE in the wiki page:
http://en.wikipedia.org/wiki/Pontiac_GTO

Drag Pak

OR, you can direct the "y" to the inboard side directing the exhaust to be muffled in the original direction down the center of the car, and run the electric dumps on the straight back section of the "y" with collector extensions cut to the correct length. Thereby having straight through exhaust from the header out the collector and extension!

I put a paint stripe on the collector extensions and after a couple test passes I cut them off at the end of the burned paint.

I did this on my 70 AAR. It works functionally straight through correct, and it looks rad from the side having 3" collector extensions on the ends of the headers visible under the car.

Cheers

Peter

inri

Peter,

Thanks for showing me how to install the Y pipe differently. What lead you to do this on your 70 AAR? Sound, looks, ET?? What mufflers did you have on your car? Did you notice or feel a difference in power/torque or in track times?

Drag Pak

inri

I drag raced my Cuda to many wins and a Club and Class Championship.

I grew tired of getting under the car to open the "y" dumps. I installed Race Ready Performance Electric dumps (Very good pieces and a lifetime warranty) and I wanted the outlets (collector extensions) straight back from the header for any possible restriction elimination purposes.

I ran the stock AAR mufflers and side outlets.

Car went 12.79 with 2500 rpm launch(on the converter) with 3.55 gears at 3556 lbs.

I never raced the car through the mufflers for a comparison.

The electric cuttouts are also good for forwarning your friends of your arrival and a hoot for loud cruise-ins!

Cheers

Peter

TVLynn

ANY change can make a difference when you are looking for that last .10 second