Yes I have. I posted the results here. Some others had similar experiences.

http://www.socalevo.net/index.php?op...&topic=57905.0

 

Invidia O2 housing is the best IMHO. It has a tab to mount like the factory housing, 3" outlet, and has huge openings inside.

 

Here is a log done with the Megan housing. Pull was from 2500-7500 on a dyno so the conditions were not swayed by uneven road or going up hill.
There is definitely some creep in there.

 

NJ, here we again.

Running hi boost does not show the boost creep. Just because you dont have creep doesnt mean the housing isnt hurting your performance. The reason you have boost creep is because the wastegate exhaust doesnt have enough room to flow so it creates back pressure on the wastegate closing it down causing the boost to creep up. When you run higher boost levels you dont see any boost creep, but you are still getting the enourmous amount of backpressure.

 

Wouldn't exhaust pressure cause the wastegate to blow open, not close it down? Isn't that the point of heavy duty wastegate actuators?

How is having a restrictive wastegate worse than a free flowing one that is open less? As long as it can bypass enough exhaust to run the minimum boost you want I dont see the difference, but maybe I'm reading you wrong.

 

I think his wording was just a little off. The creep is because the wastegate passages aren't big enough to accomodate the flow to maintain lower boost levels. At lower boost levels, most of the exhaust flow will need to go through the wastegate rather than the turbine. If the wastegate path is too restrictive, too much of the exhaust flow travels through the exhaust turbine, causing more than intended boost, or boost creep.


Eric

 

I think what Merkzu is saying is ... if you're running say 24 psi of boost and the housing makes you creep only to 23 psi, it doesn't matter. It would matter if you're trying to run 20 psi.

 

Right, I just dont see how a housing that causes a creep from 11psi to 18psi is a factor when running more than 18psi of boost.

 

What about at part throttle?

 

Do the same test and nail the throttle at 4000 instead of 2500 then watch what happens!

I still don't see how people can claim power gains because you are not out flowing the stock housing. The guys with the O2 housings aren't running any faster 1/4 miles than those with the stock piece.

 

At part throttle the WG isn't usually open since the engine isn't flowing enough to warrant it.

 

That depends on your definition of "out flowing." A 16G or 20G turbo won't technically "out flow" a 2.5" pipe. But, restriction can still exist in the form of turbulence or high pressure areas due to flow characteristics.

If you don't see gains with a better turbo outlet pipe, why would you see gains with a larger exhaust? The principle is the same ... larger pipe and larger radius bends = less resistance.

 

lol... saw this one goin' downhill from the start.

 

Not sure on that one, just something that would have to be logged and looked at I guess. I was more responding to the comment that it would somehow create more back pressure than normal at full throttle, high boost.

 

Because hotter faster moving gases require less pipe. As they cool they require more pipe.