Ian runs his Mustang open … no problems … not loud
Ill see if i can get a vid
I run a TiAl 44mm as well and i dump it to the atmosphere through a 90 degree elbow with a 2.5" long extension pipe on it. On a rotary its really loud but if you think about it, your normal exhaust is going to be fairly loud (i would imagine) anyway. Just dump it and save the hassle of re-circ.
I had a dump on my DSM. It was only loud at full throttle. But when it was loud, it was extremely loud.
I’m pretty sure it made a large difference on performance though as I was on stock t25 turbo, and posting some of the quicker 1/4 times on the DSM forums for people with a stock t25 turbo.
I ended up taking it off, and going with traditional exhaust, and never tracked it, but it did feel noticably less powerful.
I was running open dump on the bimmer all last year. im done with it. sometimes i like to enjoy my car and open it up a bit without grabbing attention of everyone within 5 miles.
however the most important reason for why im going to recirc this year is because i cannot hear whether or not my motor is detonating under full boost and wide open throttle.
i vote recirc but maybe with a cutout for when your feeling naughty.
the shittiest part about this is i’m coating everything before i run it. hmmm. maybe ill leave one section of the DP bare until i run it… we’ll see
thanks a bunch for the input guys 
You could do what I’m doing and have a flange at the downpipe for the wastegate merge. This way you can run recirced with one wastegate tube and then a blockoff plate and open dump… This way you can coat the shit and decide later which you like better prove if there is an actual difference besides noise.
This is my reasoning also… I like to hear the motor… and I don’t need attention when I stab the throttle. You can easily hear my car from 2miles away. EvoMR on the boards whent to recirced because of noise violation at trackdays, his car was much more tolerable on the streets and no more exhaust fumes ever. With an open dump you will smell the fumes sometimes or alot of the time.
:word:
ive never experienced an open dump while inside of a car until my own this coming season, i just have this feeling im going to get sick of it after awhile… maybe, we’ll see
i never got sick of the sound of an open dump… you guys are a bunch of pussies complaining about it being loud i personally love the sound of it.
I never heard mine as I was driving it with an open downpipe as well…
What do they sound like? I think Don was the only one that I know knew what
they heard. He is also the only member that rode in the car.
I think it’ll sound cool bill. And it’ll only be open when your WOT right? doooo it! If it annoys you that much you can always change it
Im thinking about going open dump with my car. It really shouldnt bother you if you drive the car regularly, its only going to sound loud as hell if your at WOT. If you want to hear more of the turbo sound than exhaust then route it back to the DP.
Depending on where your waste gate is kinda makes a difference, but for the most part it sounds like your running with open headers, because thats what it basically is…
Recirculating will cost you power. It’s a trade off. Noise for power
I’ve heard this many times, and not that I doubt it, but I’ve yet to see dyno vs. dyno.
So, i’ll ask, power loss to what extent?
I think I understand why you would lose a bit of power by introducing turbulence & volume to the exhaust…
But would it really be a noticable loss? Throughout the powerband, or just near to full boost onset?
yes on the dyno we saw something like 20-30 wheel horse loss on sams car with nothing else changed… only thing changed was the dump was recirculated. It changed the volumetric efficiency of the exhaust and thus affected the entire breathing as a whole.
I would just not coat the piping until you try it dumped if you cant decide. Worst case you need to merge it and coat it later.
Thats what I did as Im going from merged to dumped on the cavy. Figure a week of downtime and it could be coated and back in.
Dan
my take is that I would not go out of my way to add an open dump, but if I was building a car and having an open dump made things easier and cheaper then I’d probably go with the open dump
I don’t see why you wouldn’t its not like the car is going to be quiet anyways…
Damn, that is a very impressive power loss. What type of overall power was the car making? percentage-wise was it very significant?