JDM_EH2

how much of a power loss is their by rerouting ur dumptube back into ur DP?? i kinda wanna keep sound levels down but not if its gonna sacrifice a lot of power...thanks

JAY

TTT

id like to know as well

StrokedPSI

Good question, anybody?

JDM_EH2

bump...anyone?

Bailhatch

if you have a 2.5" or bigger DP and exhaust then I would say a closed loop WG would not hurt performance much. If you have an NA style catback (usually 2.3" - 60mm) then it is a very good idea to give you more flow under full boost.

beepy

Running an open dumptube is a great way to avoid boost creep if you are having that problem.

But I don't see how it could give you any more power. Gasses are only flowing through it when you are making full boost! Plus it is bloody loud when the wastegate is open. I really don't see the point except on maybe race cars.

I really think some people do it just out of laziness, or because the downpipe they bought had no place for a dumptube to come in.

Rory Breaker

When the WG is recirculated back into the exhaust stream, it is effectively reducing the diameter of the piping, as I understand it. When the recirculation takes effect, more gas enters the piping than an open dump would. In order to minimize the effect on spooltime and power production from the added backpressure, it is said you should merge the dumptube and the downpipe no less than 18in from the turbo.

Thats the theory behind open dump/closed dump, I havent personally tested the difference.

B18C1CYA

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by newgsrdriver &raquo;</TD></TR><TR><TD CLASS="quote">When the WG is recirculated back into the exhaust stream, it is effectively reducing the diameter of the piping, as I understand it. When the recirculation takes effect, more gas enters the piping than an open dump would. In order to minimize the effect on spooltime and power production from the added backpressure, it is said you should merge the dumptube and the downpipe no less than 18in from the turbo.

Thats the theory behind open dump/closed dump, I havent personally tested the difference.</TD></TR></TABLE>

I have ran it both ways and yes you loose alot of power from what my but dyno told me, the only reason i see to run closed loop is if you dont like the sound, but it makes me wet so i run open

Bailhatch

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by beepy &raquo;</TD></TR><TR><TD CLASS="quote">Running an open dumptube is a great way to avoid boost creep if you are having that problem.
QUOTE]

yes sir

[QUOTE=beepy]
But I don't see how it could give you any more power. Gasses are only flowing through it when you are making full boost! Plus it is bloody loud when the wastegate is open. I really don't see the point except on maybe race cars.

I really think some people do it just out of laziness, or because the downpipe they bought had no place for a dumptube to come in.</TD></TR></TABLE>

well lets see. say you have a 2.5" dp and exhaust. up until full boost at lets say 4000rpm, you are forcing all the gasses through the 2.5". After 4000rpm you then have the 2.5" and the 1.5" dumptube. Less restriciton means more power and better performance as the volume of gasses increases in the upper rpms.

laziness, maybe. Nasty sound and better performance? more likely.

pete98m3

not to mention where you merge them you have a turbulence problem in the downpipe.

some guys have been so bad as to merge them on a 90 lol

beepy

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote &raquo;</TD></TR><TR><TD CLASS="quote">well lets see. say you have a 2.5" dp and exhaust. up until full boost at lets say 4000rpm, you are forcing all the gasses through the 2.5". After 4000rpm you then have the 2.5" and the 1.5" dumptube. Less restriciton means more power and better performance as the volume of gasses increases in the upper rpms. </TD></TR></TABLE>

I agree, but it is a matter of making a good transition from the dumptube into the downpipe at a shallow angle, and possible increasing the diameter of the exhaust to 2.75" downstream of that connection. If you are worried about the backpressure, there are better ways to fix it than to just vent uncatalyzed exhaust into the atmosphere.

But what am I saying? Those that run open dumptubes are likely the same people that don't run a cat.

Bailhatch

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by beepy &raquo;</TD></TR><TR><TD CLASS="quote">

I agree, but it is a matter of making a good transition from the dumptube into the downpipe at a shallow angle, and possible increasing the diameter of the exhaust to 2.75" downstream of that connection. If you are worried about the backpressure, there are better ways to fix it than to just vent uncatalyzed exhaust into the atmosphere.
</TD></TR></TABLE>

true, If your going to do closed loop definatly don't halfass it. I was assuming that it was done correctly in my example. For some reason the ones i have done are always on 3" turbo back setups so i'm sure the loss in power was minimal.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by beepy &raquo;</TD></TR><TR><TD CLASS="quote">

But what am I saying? Those that run open dumptubes are likely the same people that don't run a cat.</TD></TR></TABLE>

yup sometimes. or it might be the guy stuck with a stock cat and little exhaust that wants more flow and ran out of $.

At least it's not always open, unless i'm driving

why won't the damn quotes seperate! ah ha!

JDM_EH2

well ill have a 2.5" flared to 3" DP made by phil (project dc2) closed loop will be done by him so im sure it wont be done "half-***"...then ill have a 3" exhaust. does anyone have any sound clips of an open dump tube?

shermanyang

iTrader: (1)

i could careless what others have to say about i should run my dump tube into my downpipe. if it makes more power, i'm there! and if domestics can run around with straight pipes and open headers and such...why the hell can't we?!?

either way...if i were to even route my dump tube into my down pipe...it would still pollute the same way, as i'm running a test pipe like 90% of most FI people on this board.

and it sounds bad *** when it opens up...it's like music to my ears.


oh yeah, and i really don't want to risk any boost spikes because at the moment i'm only running a cheap drag mani.


Modified by shermanyang at 5:42 PM 7/25/2004

f1 vtec

im waiting to put on my open dumptube soon how does it sound anybody?? apparently a garage near my house told me it would sound nice bcos he put one on a pulsar gtir and got some good outta of it??

oscarmayer

i've only seen on the dyno a 2-4hp difference w/, and w/o it goign back into the downpipe. now i can see some turblance issues if it's at a 90*, but if you have ti done right and angles at a nice degree and a smooth transaction at the top of a bend where ti will push flow around the curve like it is SUPPOSED to be, then you'll losses are very miniumal, and you should not have to worrie about it. it goes back to proper design and knowledge of flow charastics.

b_ron007

open dump sounds straight up nasty!
I LOVE IT!
if ur along side a car or walls, or en thing, u'll see what i mean. it gets loud as hell. one dude ask me what the hell was that that kicked in....lol....it was funny!

i say go open dump, u'll have more power....and thats a fact! only time u hear it is when ur at full boost or WOT, well thats for me at least.

JDMCRX

iTrader: (2)

I have open dump love it ******* makes the car sound mean. V8 guys here are like WTF when my 4 door is raping there cars lol.

There was a post on here a while ago this guy did a test and it was like 15-18hp gain with open dump on his loud.

Patron

I'm too lazy to reroute it.

DaX

iTrader: (1)

I've never heard any loud nasty sounds at full boost. I run no filter [only screen] so maybe the loud *** turbo is covering the sound of the dump? I don't re-route my dump into my exhaust, but I have a dump tube that is about 24" - 30" long.

b_ron007

you sure bout that? is it even opening up? its a very distinct sounds, hell its a open exhaust, just a minature open down pipe, higher pitch tho.

DaX

iTrader: (1)

I'm rock solid at 8psi...i'm sure it's opening. I guess the sound of the turbo is overcoming it.

b16hybridsol

side exit dump tube on my car, bieetchs!

Blackack26

I used to run open dump and it sounded awesome in 1st and 2nd, but on the highway in 3rd or 4th it sounded like ***.

I didn't really notice much of a loss, mabye 3-4 hp but it sounds much better now. Also, the dump is merged in on a 30 degree angle around 20 inches from the turbo.

patdemps

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by b16hybridsol &raquo;</TD></TR><TR><TD CLASS="quote">side exit dump tube on my car, bieetchs!
</TD></TR></TABLE>

looks good


im thinking about ditching my filter and throwing a screen on my turbo so I can hear it more over the open wastegate. i love the sound however, id like to quiet it up just a bit and i want to hear the turbo more. plus i hear quite a few guys are running a screen....i just need to get a bit more info on how to mount it on the turbo, etc before i do it.