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Wastegates: dump to atmosphere or route back to DP?

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Old Dec 23, 2006 | 08:09 PM
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Default Wastegates: dump to atmosphere or route back to DP?

How are you guys running your wastegates? Is there any advatage to dumping it to atmosphere? What about routing it back into the downpipe? Any advantages to either? If you have pics of your setup throw 'em up.
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Old Dec 24, 2006 | 01:09 AM
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It's mostly about sound and heat control. Dumping it under the hood, straight out of the wastegate, can add a lot of heat underhood and can make some weird sounds. At least route it out under the car... or back into the downpipe.

Jim
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Old Dec 24, 2006 | 12:09 PM
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Corky bell's book says its best to run them seperately, I ran it both ways on my last car and seperate spooled ALOT faster than with them together.
Phil
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Old Dec 24, 2006 | 07:16 PM
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Phil,

I'm not understanding your results ... Changing the wastegate routing shouldn't have any effect on spool. With an EBC, the gate shouldn't even open till you hit full boost anyway (or very near full boost), so there shouldn't be a change in spool time. Without a EBC, the gate will begin to open earlier, but I still can't see spool being quicker ... If you think about it, spool would probably be slightly worse if you make the wastegate discharge more efficient.

Did you redo the downpipe at the same time? Making a better downpipe would positively effect spool.

Originally Posted by Phil99vette
Corky bell's book says its best to run them seperately, I ran it both ways on my last car and seperate spooled ALOT faster than with them together.
Phil
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Old Dec 24, 2006 | 08:06 PM
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Ken Duttweiler makes his customers run the gates with a seperate dump.
It helps in the spooling and boost control.
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Old Dec 24, 2006 | 09:01 PM
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Also it can make more of a mess in the engine bay if you dump it.
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Old Dec 24, 2006 | 09:48 PM
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I can understand how it would help boost control, but how does it help with spool?

Originally Posted by John Wilde
Ken Duttweiler makes his customers run the gates with a seperate dump.
It helps in the spooling and boost control.
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Old Dec 24, 2006 | 09:50 PM
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Originally Posted by John Wilde
Ken Duttweiler makes his customers run the gates with a seperate dump.
It helps in the spooling and boost control.
it wont help spool.. think about it... pretty simple... it wont help spool unless you ahve a voodoo spell on it or something.
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Old Dec 24, 2006 | 11:33 PM
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Originally Posted by Dragframe
it wont help spool.. think about it... pretty simple... it wont help spool unless you ahve a voodoo spell on it or something.

Less back pressure and no reversion could help.
He also mentioned that you should try and make sure
that the exhaust from the wastegate dump tubes does not get into the intake.

Merry Christmas =)
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Old Dec 24, 2006 | 11:41 PM
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Dumping the WG would also help make more power on cars with a smaller downpipe.
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Old Dec 24, 2006 | 11:43 PM
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Originally Posted by Stoichiometric
Dumping the WG would also help make more power on cars with a smaller downpipe.

That is what I am saying, but what do Kenny Duttweiler and I know???
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Old Dec 24, 2006 | 11:50 PM
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BTW I felt that it made improvements on Chris Chow's 1800plus HP SBC I help with.
Maybe not a huge difference but at that level you will take what you can get.
My street cars all have the gate going back into the DP BTW... =)

Festive Kwanzaa and Happy Hanukkah as well
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Old Dec 25, 2006 | 12:26 AM
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Well for one thing, having a separate dump for the wastegate will eliminate the Y in the downpipe where the wastegate pipe would remerge with the rest of the exhuast system. That will create less turbulence in the exhaust system, which cuts backpressure, white helps pretty much everything. Less backpressure will help you get to your peak boost sooner.

Originally Posted by Dragframe
it wont help spool.. think about it... pretty simple... it wont help spool unless you ahve a voodoo spell on it or something.
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Old Dec 25, 2006 | 01:23 AM
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Originally Posted by FastKat
Well for one thing, having a separate dump for the wastegate will eliminate the Y in the downpipe where the wastegate pipe would remerge with the rest of the exhuast system. That will create less turbulence in the exhaust system, which cuts backpressure, white helps pretty much everything. Less backpressure will help you get to your peak boost sooner.
ok... well i could stand corrected...

but explain how dumping the wastegate will make the boost come on faster when the wastegate really has nothing to do with how the turbo spools. THat is all in the motor/turbo sizing.

The wastegate does not open untill a set boost point is reached, and untill that boost is reached, where the wastegate is routed to has no effect on anything. So the turbo is spooled and to a set presure (set by the spring in the wastegate or a boost controller), THEN the wastegate opens.

Understand where im coming from now? The idea of dumping the wastegate is to eliminate boost creep and basicly let everything breath better AFTER the wastegate has opened to release some pressure. Turbo spool happens before the wastegate even comes into play... so how would its piping effect spool?

It won't (effect spool)... but im still a "newb" so if you know something im more than willing to learn.
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Old Dec 25, 2006 | 09:58 AM
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John,

Nothing against you at all, I'm just extremely curious as to why it helps spool, and so far I have yet to read anything in this post that explains this. Forget peak power potential or boost control - those make sense when talking about the WG. But spool? Think about the extreme - fastest spool would be achieved by completely blocking off the wastegate.

Originally Posted by John Wilde
That is what I am saying, but what do Kenny Duttweiler and I know???
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Old Dec 25, 2006 | 11:26 AM
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Originally Posted by Eddiep
Phil,

I'm not understanding your results ... Changing the wastegate routing shouldn't have any effect on spool. With an EBC, the gate shouldn't even open till you hit full boost anyway (or very near full boost), so there shouldn't be a change in spool time. Without a EBC, the gate will begin to open earlier, but I still can't see spool being quicker ... If you think about it, spool would probably be slightly worse if you make the wastegate discharge more efficient.

Did you redo the downpipe at the same time? Making a better downpipe would positively effect spool.
We changed exhaust housings from a combined unit(exhaust and WG) to a seperate 2.5" exhaust side and a 1.75" side for the WG. It spooled faster and made more power. I dropped .2 and gained 2mph at the track.
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Old Dec 25, 2006 | 12:49 PM
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Originally Posted by Eddiep
John,

Nothing against you at all, I'm just extremely curious as to why it helps spool, and so far I have yet to read anything in this post that explains this. Forget peak power potential or boost control - those make sense when talking about the WG. But spool? Think about the extreme - fastest spool would be achieved by completely blocking off the wastegate.

NP,

I will try and call to you the correct information next week.
My wife is having contractions though, so I can not make any promisses.
We ran a wastegate totally closed at Orlando this year. It was not the greatest idea, It pegged that 3.5 bar map sensor in under 2 seconds. This was wish a 272ci motor and GT47 88MM. The closed gate or will spool the fastest, my point is the a gate vented out side of the down pipe will spool faster than one in.
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Old Dec 25, 2006 | 12:54 PM
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Originally Posted by Phil99vette
We changed exhaust housings from a combined unit(exhaust and WG) to a seperate 2.5" exhaust side and a 1.75" side for the WG. It spooled faster and made more power. I dropped .2 and gained 2mph at the track.

its not rocket science.. simple... the wategate does not affect spool.. dumped or not... (unless the wastegate is leaking exhaust by before it opens)

I mean no disrespect, but it is pure physics and law.

Your car got faster because of YOU CHANGED THE TURBO HOUSING... well DUH!!! YOU CHANGED A MAJOR PART IN THE TURBO, therefore effecting spool.

You changed soo many aspects of what is going on there that your results will not be like if I were to dump my wastegate apposed to having it merge into the DP.

Originally Posted by John Wilde
NP,

I will try and call to you the correct information next week.
My wife is having contractions though, so I can not make any promisses.
We ran a wastegate totally closed at Orlando this year. It was not the greatest idea, It pegged that 3.5 bar map sensor in under 2 seconds. This was wish a 272ci motor and GT47 88MM. The closed gate or will spool the fastest, my point is the a gate vented out side of the down pipe will spool faster than one in.
Do i really need to amke a diagram to show you why it wont effect spool (dumping instead of merging)?

Im not here to make enemys guys, but you seriously just must not see this.. its simple...


Turbo spool happens before the wastegate even comes into play!!!! so how would its piping effect spool?

THe turbo spools, makes boost, THEN the wastegate opens at a set pressure. At that point, and only AFTER the turbo has spooled and is MAKING BOOST will the wastegate routing have an effect on anything

Last edited by Dragframe; Dec 25, 2006 at 01:03 PM.
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Old Dec 25, 2006 | 02:43 PM
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If the wastegate dump comes into the dp

I dont see how that would affect backpressure, if you had decent muffler.
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Old Dec 25, 2006 | 05:21 PM
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Dont wastegates start to open before peak boost is reached?
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