So I'm starting to make my DP and i'm wondering if I should dump the WG back into the exhaust or into atmosphere. I know that most people say it's better to dump to atomosphere if you wanna make more power.

BUT....

I got to thinking, and when the WG opens, the turbo is already operating at the pressure you want. Meaning it is not required to spool anymore (or very little as it approaches the dersired boost level). So dumping back into the exhaust would have no effect on the 'spool' of the turbo, since it doesn't need to build anymore pressure at that time. Personally I don't like the sounds of an open WG, so after thinking about it, I don't see why you would dump to atmosphere, for any reason, unless you like the Open WG sound.....

Am i missing something here?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Scott - 93HB Si &raquo;</TD></TR><TR><TD CLASS="quote">So I'm starting to make my DP and i'm wondering if I should dump the WG back into the exhaust or into atmosphere. I know that most people say it's better to dump to atomosphere if you wanna make more power.

BUT....

I got to thinking, and when the WG opens, the turbo is already operating at the pressure you want. Meaning it is not required to spool anymore (or very little as it approaches the dersired boost level). So dumping back into the exhaust would have no effect on the 'spool' of the turbo, since it doesn't need to build anymore pressure at that time. Personally I don't like the sounds of an open WG, so after thinking about it, I don't see why you would dump to atmosphere, for any reason, unless you like the Open WG sound.....

Am i missing something here?
</TD></TR></TABLE>

you dont like the sound open atomosphere.....your crazy

but i wouldnt dump it back into the dp

 

if you only need 'X' amount of exhaust gas to spin the turbo to a certain boost level, you want to get the rest of it away as quickly as possible. Think of it in an N/A application - if you can get as much gas out of the head as possible on the exhaust stroke, you will pull in a stronger/larger intake charge on the next stroke.

Regardless if I am correct in my theory or not, I've seen as much as a 40whp difference between venting it and returning it, on a stock motor w/ a bolt on turbo kit.

 

If you run closed loop, make sure it does not enter the DP inside of 18" from the turbine outlet. After 18" has a significantly reduced impact on the disruption of the exhaust flow.

 

I am having the same debate... I am too lazy to weld it back into the exhaust system, but at the same time, I don't want my engine bay to be filled with soot from the exhaust gases. I think I may just use a flex hose to dump it under the car.

 

i just feel that if your just trying to go for looks then it would be agood idea but that would make no sense casue 9 out of 10 of us are using FI to gain the most power poss why would u want to cheat your self out of some so eaisly gained me the **** that builds up under my hood adds character to my car

 

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

you dont like the sound open atomosphere.....your crazy

but i wouldnt dump it back into the dp</TD></TR></TABLE>


it sounds like ****... broken lawn mower x2..

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by TurboSedan &raquo;</TD></TR><TR><TD CLASS="quote">If you run closed loop, make sure it does not enter the DP inside of 18" from the turbine outlet. After 18" has a significantly reduced impact on the disruption of the exhaust flow. </TD></TR></TABLE>

What does it matter where you dump it back in? Sure it will disrupt the exhaust flow, but think about it, even if the exhaust then becomes more restrictive at that point, it doesn't matter because your turbo is done spooling, and it's at it's desired output, so dumpiung back into the DP say 6" vs 18" down stream won't have any effect on the power of the motor. As long as the open wastegate doesn't exceed the flow capabilites of the exhaust it should be fine right?

Wait, I might be onto something here...is the general consensus of 'Open atmosphere makes more power' true because you guys are all running small exhausts?

 

Do a search on open-loop vs. closed-loop. You should find the answers you seek. If the wg dump enters the exhaust stream significantly earlier than 18" it will cause more HP loss than if over 18".

 

I should turn my dumptube so it points up and cut a hole out of the hood so I look like a choo-choo train when it opens.

I see what you're saying man, what could we use to prove it? Dyno plots?

 

backpressure is the key here.....double check me by doing a search as the topic was covered extensively a while back...but by dumping the exhaust closer to the cat, you eliminate the potential back pressure which is the why you get the hp loss. FMAX ran a test like that and saw a 40hp gain by running open loop, but I have seen closed loop run with minimal hp loss due to where it was dumped back into the DP. My theory may or may not be accurate, but I do know that when placed correctly, you can run closed looped with minimal hp loss.

 

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


it sounds like ****... broken lawn mower x2..</TD></TR></TABLE>

what kind of wastegate do you have ....mine dont sound like ****

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by silverEH2 &raquo;</TD></TR><TR><TD CLASS="quote">

what kind of wastegate do you have ....mine dont sound like ****

</TD></TR></TABLE>

they all sound the same.....sounds like a break in the exhaust system

What i think i'll do is build 2.5" outta the turbo, then flare to 3" under the oilpan somewhere, and add the WG dump in where the flare is....Gonna build it tomorrow.

 

don't know if you're running a cat, but you can get one that is 2.5" inlet and 3" outlet.

 

Basically causes turbulance in the exhaust

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by silverEH2 &raquo;</TD></TR><TR><TD CLASS="quote">

what kind of wastegate do you have ....mine dont sound like ****

</TD></TR></TABLE>

well to me the sound isn't very appealing... i like it quiet, just hearing the turbo and bov... btw i have a tial hp wastegate

 

I don't know how much everyone cares but I do beleive I read that the FMAX test isn't very real-world accurate b/c the original design of the dump they did their test with routed the wg dump upwards into the exhaust, IE back TOWARDS the turbo, almost reverse flow of the rest of the exhaust gas. That's why it sucked so bad. Supposedly it's been redesigned since then.

 

Here is my custom 2.5" DP.

 

Nice looking DP there.

 

yes it is

 

how bad can it possibly sound? besides, I am routing my dump tube to a motorcycle muffler. that should sound nice.

 

search lazy scott.
but yes dump it atleast 18" away.
or dont listen and make less power than the car is capable of

 

Anyone know if a company makes merge collectors with one 3" that's straight, and then a smaller, say 1.5" or 2" tube that comes in with a nice smooth merge, like this, only with one side straight and the other merging into it.

That is how I want my WG or be plumbed back in to reduce turbulance, even if it's 24" downstream. Every little bit helps, IMHO.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by vinny &raquo;</TD></TR><TR><TD CLASS="quote">how bad can it possibly sound? besides, I am routing my dump tube to a motorcycle muffler. that should sound nice.
</TD></TR></TABLE>

would this **** anything up? I dont know how much backpressure motorcycle mufflers have but im sure it would sound better

 

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

well to me the sound isn't very appealing... i like it quiet, just hearing the turbo and bov... btw i have a tial hp wastegate</TD></TR></TABLE>

how much boost are you running