After doing a lot of research I've come to the conclusion I'd like to hear some .org opinions on something.
I am in the process of taking off my internally gated setup and switching it to an external setup. After years of boost creep and massive fluctuations at WOT the last 2 seasons, I've had enough of the limits of internal gating. Even with the Profec-B spec 2 I cannot get it under control and it's rather annoying - and embarassing - to take somebody out for a rip only to have the car surge like a bronco at wide open throttle.
The 2 reasons I never went external in the first place are the space to run the dump tube and the noise should I go atmospheric dump.
While I do realize a lot of people argue "just plumb it back in 18 inches down the downpipe", that would really be a problem for me for a few reasons. Space is a concern as is having another pipe making it increasingly difficult to get the downpipe out. I had to drop the frame 3" this season just to get my downpipe MINUS routed dump tube into the car. And I barely did it. Furthermore I don't want to sacrifice a ton of power to do this, which I've seen a lot of dynos to prove on a high hp car (400+ hp) it costs quite a little chunk of power. (20-25 + hp)
I don't want to flange it by the downpipe if I don't have to - more flanges = more opportunity for leaks. I don't want it to be solid with the DP either for the abovementioned reasons.
My biggest concern though - if I go open dump - is the sheer noise. I'm a creature comfort person (yes I realize that goes against turbocharging as well as high HP)... and I don't like to attract the attention of everybody on the street.
I'll be running a 44mm Tial so I can control boost up to 30 psi with ease - so it'll be quite a bit of flow going back into the dp.
So here are my options:
- Flanged back into the downpipe just before the catalytic converter but after the 02 sensors
- Open dump. (I would do more than aim it straight down I'd still curl it over the subframe to the underside of the car)
- Open dump with a small muffler just for the dump tube
I would love any and all opinions... good or bad. I've done a lot of reading about this and just cannot decide what to do. Open dump is fine but it's just "too" loud imo... hence the muffler idea. Lets me dump it without having to merge it back into the exhaust. 44mm is a lot of air to merge back into a 2.5" system. (I told you - I don't want much noise lol)
Bear in mind I'll run 15 psi on the street (and I rarely hit that cuz I drive around like a grandma due to our ridiculous road laws) and 25-30 psi at the track.
Thanks guys.
-Chris-
-Sweetness-
-Turbocharged-
Slowly but surely may some day win this race...
I say open dump. The Reaper has a dump that puts it back in the downpipe right next to the flange to the turbo. This has been a major pain when doing work and putting it back together. My Friend Josh had a open dump opn his Ecotec turboed cavy. Normal driving it was fine, yes you heard extra noise at WOT at 18psi, but the car was already load at that point, you had to really know what you were listen to to know it was that also.
FU Tuning
I have a top mount header, dump tube and 3" downpipe with your name on it.
- 93 mph in the 1/8 mile
Member of J-Body Of Michigan.
Jeremy I wish. I really do. I've just spent too much already on the DP fabication as well as all the charge pipes + powdercoating.
$$$ is talking louder than desire... so I'm sticking with a log so that I can keep using everything else I have.
Through a search I did see that you mentioned in March this year that you previously had a re-routed and this time you'd go open dump though. Any real reason? (This was before you decided to scrap the project)
Thanks man.
-Chris-
-Sweetness-
-Turbocharged-
Slowly but surely may some day win this race...
I was running an open downpipe at 9psi, needless to say it got a lot of attention. It was rather tiring pulling out to pass someone on an 80km/h hour, and trying to daisy foot the throttle to keep it from scaring the guy beside me. Now, I think, given your situation however, when running that much boost, you're going to be building boost for quite a while before it kicks in. With that said, you know its going to be making quite a bit of noise to begin with, not to mention the fact that you are going to be quite aware that you have your foot to the floor and you're taking that risk of getting attention anyways at that point. If its going to cause that many maintenance issues, there is no sense in installing a permanent pipe routed to your downpipe, it will just become more cluttered and you're going to be even more frustrated.
My suggestion for you would be to go with either dump, and again for the reasons I stated, I don't think this is that bad of an idea for your situation. Secondly do what you didnt want to do, have a removable/flanged dump merge pipe that you can remove before trying to take out the downpipe. It just makes more sense to me given your concerns. The muffler on the dump tube sounds like even more hassle imo.
" To study and not think is a waste. To think and not study is dangerous. "
I decided to do an atmosphereic wastegate dump strictly for more power and better boost control. I figured i'd still be able to drive around town without the wastegate opening and still have a fairly quiet exhaust but at WOT it would be loud anyway...
- 93 mph in the 1/8 mile
Member of J-Body Of Michigan.
I run open dump tube, Like everyone is saying.. it is very loud but the car is already going to be loud without it..
I only did it because it was so much easier than trying to reroute it back into the DP..
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Just run an open dump you sally ass. And a muffler? Dude that's gonna sound even worse than leaving it open.
Blew it up, build numbers coming soon
Quote:
I figured i'd still be able to drive around town without the wastegate opening and still have a fairly quiet exhaust but at WOT it would be loud anyway...
you only hear it when you want to! same principle as turbo cars and gas mileage
Open dump, you dont drive too hard on the street and you want everyone to know you are at the track
Pffft as if you're ever gonna hit the track
Bets on Darren getting there first? hahaha
I'm so not his friend after this...
14.330 @ 96.37mph
I run an open dump and honestly, it's not loud at ALL. I only ran a .4 bar this season for the remainder of the motor break-in, but even on a Civic we did running 18psi, it's barely notice-able. When you do hear it, it sounds great.
It's gotten to the point where we don't even offer our customers the option to plumb it back in unless they're ADAMENT about it.
