Single Turbo RX-7's Questions about all aspects of single turbo setups.

wastegate dump out or back in....

Thread Tools
 
Search this Thread
 
Old Jun 3, 2006 | 01:35 PM
  #1  
Thread Starter
Rotor Nut.
Tenured Member 20 Years
iTrader: (34)
 
Joined: Feb 2002
Posts: 2,163
Likes: 2
From: RI
wastegate dump out or back in....

well ive done some searching and never really seen any proof to a +/- to running the wg back in the dp. i heard that you gain about 10-20whp with it dumped out but is there any proof of that? i currently have mine dumping out, and its pretty dam loud. on my previous setup it was re-routed. if it doesnt cost much dumping back in i will probably do it. but if the 10-20whp is a fact ill leave it dumping out. any imput apreciated.
Reply
Old Jun 3, 2006 | 02:09 PM
  #2  
Zero R's Avatar
Just in time to die
Tenured Member 10 Years
iTrader: (1)
 
Joined: Nov 2001
Posts: 4,143
Likes: 2
From: look behind you
We have seen as much as a 40hp difference if it is rerouted poorly. Make sure it is at least 18" off the turbine and the angle of incidence is a smooth transition. The further off the turbine the better. I've had cars here switch out or rerouted DP's and only gain 5hp I consider that wash for the most part. In the end you will probably lose some power but not too much.

-S-
Reply
Old Jun 3, 2006 | 03:47 PM
  #3  
GoodfellaFD3S's Avatar
Original Gangster/Rotary!
Veteran: Army
Tenured Member: 25 Years
Liked
Loved
iTrader: (213)
 
Joined: Mar 2001
Posts: 30,804
Likes: 646
From: FL-->NJ/NYC again!
dumped out is VERY loud. It's like the Gates of Hell open up when that wastegate lets loose
Reply
Old Jun 3, 2006 | 05:42 PM
  #4  
showoff's Avatar
Rotary Enthusiast
Tenured Member 10 Years
 
Joined: Feb 2004
Posts: 1,391
Likes: 0
From: New york
dumping is half the fun of going single lol... u should see the faces of some people when i let the wastegate open up lol its like theyve seen a ghost
Reply
Old Jun 3, 2006 | 05:51 PM
  #5  
maxcooper's Avatar
WWFSMD
Tenured Member 15 Years
 
Joined: Jun 2001
Posts: 5,035
Likes: 4
From: SoCal
I couldn't stand the noise of having it dump. I don't know how much power it cost me to have it routed back into the downpipe, but even if it was 40HP, it was worth it. Fines and harassment for having a noisy car (or whatever else the officer might find under the hood when pulling me over) just isn't worth the risk to me. My re-route isn't in a great spot (inside a bend, just ~10" or so from turbine), but it didn't feel like it changed the performance drastically (though it is hard to tell since the sound level is so different). It is blissfully quiet now, though.

-Max
Reply
Old Jun 3, 2006 | 07:08 PM
  #6  
Zero R's Avatar
Just in time to die
Tenured Member 10 Years
iTrader: (1)
 
Joined: Nov 2001
Posts: 4,143
Likes: 2
From: look behind you
We've also noticed placement and type of dump will dramatically change the noise level. (duh) With one car we ran almost no dump tube this was on one of our long runner manifolds. You almost couldn't tell the difference with it dumped or not noise wise. Car was running a full 4"exhaust though, so it is already a bit too loud for some.
Reply
Old Jun 3, 2006 | 07:17 PM
  #7  
Thread Starter
Rotor Nut.
Tenured Member 20 Years
iTrader: (34)
 
Joined: Feb 2002
Posts: 2,163
Likes: 2
From: RI
zero r would you have a pic of the best spot to dump it. i have a short runner manifold, so i am guessing right near the end of the dp. also thanks for all the responces.
Reply
Old Jun 3, 2006 | 09:20 PM
  #8  
cewrx7r1's Avatar
Eye In The Sky
Tenured Member: 25 Years
iTrader: (2)
 
Joined: Feb 2001
Posts: 7,941
Likes: 133
From: In A Disfunctional World
For an outside dump, you could attach a small ATV muffler.

Earlier turbo Porsches had a muffled dump, but I do not know if they still do.
Reply
Old Jun 3, 2006 | 10:08 PM
  #9  
Thread Starter
Rotor Nut.
Tenured Member 20 Years
iTrader: (34)
 
Joined: Feb 2002
Posts: 2,163
Likes: 2
From: RI
chuck, what size muffler do you think would fit? just any fmf style muffler.
Reply
Old Jun 3, 2006 | 10:51 PM
  #10  
crispeed's Avatar
'Tuna'
Tenured Member 15 Years
 
Joined: Feb 2001
Posts: 4,637
Likes: 3
From: Miami,Fl,USA
I've seen some of the early Porches from factory that had an entire seperate system for the wastegate. They went as far as using a seperate cat and muffler.
Reply
Old Jun 3, 2006 | 11:36 PM
  #11  
dubulup's Avatar
development
Tenured Member 15 Years
 
Joined: Aug 2002
Posts: 5,714
Likes: 7
From: Lafayette, LA
I run a cat, and felt the car ran stronger with the dump in the downpipe before the car...theory was, it broke down the "whirl wind" exhaust before entering the cat, allowing for better flow thru the restrictive cat.
Reply
Old Jun 3, 2006 | 11:57 PM
  #12  
Turbo23's Avatar
Panda Bear
Tenured Member: 20 Years
iTrader: (4)
 
Joined: Nov 2001
Posts: 1,732
Likes: 4
From: Lititz, PA
Originally Posted by GoodfellaFD3S
dumped out is VERY loud. It's like the Gates of Hell open up when that wastegate lets loose
I cant wait
Reply
Old Jun 4, 2006 | 06:33 PM
  #13  
matty's Avatar
Lives on the Forum
Tenured Member: 25 Years
Liked
Loved
 
Joined: Mar 2001
Posts: 5,014
Likes: 40
From: CT
anyone have a clip of the wastegate dump? not sure what noise it is.
Reply
Old Jun 4, 2006 | 07:21 PM
  #14  
Zero R's Avatar
Just in time to die
Tenured Member 10 Years
iTrader: (1)
 
Joined: Nov 2001
Posts: 4,143
Likes: 2
From: look behind you
Originally Posted by crispeed
I've seen some of the early Porches from factory that had an entire seperate system for the wastegate. They went as far as using a seperate cat and muffler.
Yep, I have been looking for a small type of muffler myself just to see if I could fit something similar.


Also, I do not have pics sorry. What I noticed is with the short runner manifolds they usually point the dump straight down. With our long runner manifolds it points the dump straight back it sits higher up and in the engine bay. I think this is what helps suppress it better.

-S-
Reply
Old Jun 4, 2006 | 07:56 PM
  #15  
GoodfellaFD3S's Avatar
Original Gangster/Rotary!
Veteran: Army
Tenured Member: 25 Years
Liked
Loved
iTrader: (213)
 
Joined: Mar 2001
Posts: 30,804
Likes: 646
From: FL-->NJ/NYC again!
Originally Posted by matty
anyone have a clip of the wastegate dump? not sure what noise it is.
You'd know it if you heard it.

I consider myself hardcore/diehard/whatever-----removed a/c in the dead of texas summer, removed p/s, diff brace, etc, and if I go single turbo I will NEVER get the wastegate vented to atmosphere on a street-driven car.
Reply
Old Jun 4, 2006 | 08:18 PM
  #16  
Turbo23's Avatar
Panda Bear
Tenured Member: 20 Years
iTrader: (4)
 
Joined: Nov 2001
Posts: 1,732
Likes: 4
From: Lititz, PA
*****
Reply
Old Jun 4, 2006 | 09:15 PM
  #17  
hondahater's Avatar
spending too much money..
Tenured Member 10 Years
iTrader: (2)
 
Joined: Dec 2002
Posts: 10,116
Likes: 1
From: louisiana
so what does a open wastegate dump tube do that just an open wastegate doesn't? Is it for sound?
Reply
Old Jun 4, 2006 | 10:47 PM
  #18  
BASTARD's Avatar
®
Tenured Member: 20 Years
iTrader: (4)
 
Joined: Dec 2003
Posts: 2,282
Likes: 3
From: NorCal
route it back in... nothing sounds more ghetto then an exhaust leak
Reply
Old Jun 5, 2006 | 07:31 AM
  #19  
GoodfellaFD3S's Avatar
Original Gangster/Rotary!
Veteran: Army
Tenured Member: 25 Years
Liked
Loved
iTrader: (213)
 
Joined: Mar 2001
Posts: 30,804
Likes: 646
From: FL-->NJ/NYC again!
Originally Posted by Turbo23
*****
yum!
Reply
Old Jun 5, 2006 | 07:48 AM
  #20  
dubulup's Avatar
development
Tenured Member 15 Years
 
Joined: Aug 2002
Posts: 5,714
Likes: 7
From: Lafayette, LA
Originally Posted by BASTARD
route it back in... nothing sounds more ghetto then an exhaust leak
nothing smells worse than an exhaust leak as well
Reply
Old Jun 7, 2006 | 01:53 AM
  #21  
Thread Starter
Rotor Nut.
Tenured Member 20 Years
iTrader: (34)
 
Joined: Feb 2002
Posts: 2,163
Likes: 2
From: RI
took a look under the fd. i cant find a spot where i could fit an atv exhaust. are they any mini types?
Reply
Old Jun 7, 2006 | 08:01 AM
  #22  
rarson's Avatar
Senior Member
Tenured Member 10 Years
 
Joined: Nov 2004
Posts: 627
Likes: 0
From: Fallston, MD
I would re-route. I've never heard a rotary external in person, but judging from my DSM it would be VERY loud, and I just don't like attracting that much attention. An alternative which I saw in an old tuner mag would be a motorcycle muffler (the particular Integra which used it had it routed right out the front bumper, in front of the driver's side wheel).
Reply
Old Jun 8, 2006 | 12:47 PM
  #23  
$tinkfoot's Avatar
Junior Member
Tenured Member: 20 Years
 
Joined: Jan 2006
Posts: 26
Likes: 0
From: indy
my wastegate is an open dump and it is loud.

to descirbe the sound would be hard but if i had to i would say it sounds like-

1/2 harley davidson at redline.
1/2 jolly green giant burp after drinking way too much beer.

i want to get it routed back into the exhaust system.

any1 know where, generally speaking, would be a good place to get something like this done(as well as have a EGT gauge installed)?

i'm guessing midas muffler might not be a good place.
Reply
Old Jun 8, 2006 | 02:59 PM
  #24  
PDViper77's Avatar
HAHA V8
Tenured Member: 20 Years
iTrader: (9)
 
Joined: Jul 2004
Posts: 2,953
Likes: 1
From: West Palm Beach - FL
What is your problem people, I think it sounds badass. Hell I have 2 tial - 35mm wastegates and you dont see me complaining. (They both dump to the atmosphere).
Reply
Old Jun 8, 2006 | 03:07 PM
  #25  
LUPE's Avatar
Banned. I got OWNED!!!
 
Joined: Apr 2005
Posts: 5,506
Likes: 0
From: Belleville, IL
Originally Posted by PDViper77
What is your problem people, I think it sounds badass. Hell I have 2 tial - 35mm wastegates and you dont see me complaining. (They both dump to the atmosphere).
try running it hard and then talk
Reply



All times are GMT -5. The time now is 07:02 AM.