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Performance Quiz...


Zulu

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ATP-VVW-177_450-1.jpg

ATP-VVW-177_450-2.jpg

ATP-VVW-177_450-3.jpg

What do you guys think of this downpipe (for a VR6)? Good, bad? Why?

Just testing your guys knowledge 'cause I'm a little surprised this is a production piece.

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There are a number of issues.

For one the wastegate tube is being introduced at a ridulous angle (actually against the exhaust flow). And if they wanted to do it right they would reintroduce it further down on the DP (past the flex joint). You would need an extra flex joint for the wastegate dump but they are readily available (most are 1.5").

Then there is the cheesy way the turbo is clocked.

Ignoring the manifold design itself, much of the issue with the downpipe design seems to be the placement of the wastegate on the manifold itself. It's just sticking at 90 degrees off of a single port which is not optimal unless they have flow data proving that is a good spot. However, looking at the mockup it looks like there are packaging issues and from what friends have said about VR6s everything is smashed in with little room. So since they feel that sticking the wastgate off of a single port is OK, if packaging will allow it I would move the wastegate to the other side of the manifold. Then you would at least have a better method of routing the wastegate dump into the downpipe properly because you can route it next to the hot side of the turbo. With the manifold the way it is with regards to wastegate placement, the only choice for a better wastegate dump placement would be to route it over the cold side of the turbo to be able to reintroduce it further down on the downpipe and at a proper angle.

Basically I think the whole setup is not that great, but that is just me. I applaud their effort though. If they made the turbo kit itself they have a lot of $ tied up in the cast manifold, and the downpipe looks nice with it's vbands. But it's one of those things that sound good on paper but in reality it's not.

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Looking at it again, they can fix the wastegate dump design issue by simply moving the flex joint down to the straight section, and reintroduce the dump right where the flex joint is currently (assuming the flex joint will be effective that far away). Since the downpipe is angled right there, the wastegate could be introduced with the flow, not against it like it is now.

Kind of like this (excuse the world's worst Photoshop):

vr6.jpg

Also, this is all just talk. Without data (specifically flow and backpressure info) changing the wastegate dump could be a waste of time. Perhaps they already did that and determined that the wastegate is just fine the way it is now dumping against the exhaust flow.

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Wow... and it's $295.00

http://www.atpturbo.com/Merchant2/merchant...tegory_Code=BCS

'tis all.

Yay for u bends.

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At least Jared and Salem will get it. :ph34r:

Whats IPD charge for a Volvo pipe thats 10 times simpler.

I"m no expert but is there a legit reason why they just dont run a dump tube to the open atmosphere and keep it simple, wastegate wise ??

Illegal + LOUD

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I"m no expert but is there a legit reason why they just dont run a dump tube to the open atmosphere and keep it simple, wastegate wise ??

I don't know if you have ever driven in a car with an open dump tube. It sounds like an open exhaust every time the wastegate opens. You have every cop you pass on your a$$ constantly, in addition to scaring old ladies and little children hitting the ground or running away when you drive by, waking the neighbors, your cabin stinks like exhaust fumes, etc. Let's just say it gets old real quick.

Besides that it's illegal and probably 1% of ATP customers would buy an open dump tube downpipe on their street driven, daily driven vehicle. Those that would consider running an open dump tube could either mod that downpipe in 30 minutes since it has a vband right there or they would just fab their own.

If you introduce a wastegate dump into a downpipe far enough down and at the proper angle, it does not affect flow in a negative way. It's only when you have a jacked up downpipe design that cannot accomodate a correctly placed wastegate dump that people usually opt for an external dump tube. Don't get me wrong, I have seen people pick up 20-30HP by running an open dump tube, which is great for the drag strip. But you have to ask yourself if it's worth it to run like that every day, commuting to and from school or work in traffic, etc.

The perfect solution would be to have a vband removeable section where you could remove the "closed" dump tube section and bolt up an "open" dump pipe for the strip in addition to a blockoff plate right at the downpipe where the "closed" dump tube introduces. But that is a whole lotta work and you have to do some testing to see if it would even make a difference or not.

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