This will vary depending on application. It doesn't decrease compressor efficiency it broadens the map to the left. It is funny because some performance guys will tell you they measure a loss yet when you talk to the high boost diesel guys 75-120lbs+ they tell you they get better response and more power. They actually have been made illegal in certain classes for them they helped so much. It really depends on the app. Run too big a turbo on a small motor and you will benefit from not damaging the turbo. Most just like the noise

-S-


*edit nevermind chris basically beat me to it.

 

Here is where I picked up the 'decreasing comp. efficiency' from:

http://www.turbobygarrett.com/turbob...o_tech103.html

<<A Ported Shroud compressor (see Fig. 2) is a feature that is incorporated into the compressor housing. It functions to move the surge line further to the left (see Fig. 3) by allowing some airflow to exit the wheel through the port to keep surge from occurring. This provides additional useable range and allows a larger compressor to be used for higher flow requirements without risking running the compressor into a dangerous surge condition. The presence of the ported shroud usually has a minor negative impact on compressor efficiency.>>

I'm still thinking about running one just to get the sound

 

I agree totally with what they say there, from the person I've spoken to there, it's not the kind of decrease I was led to believe. They were explaining it to me as a shift in the map more than a actual decrease, come to think of it if it pulls the map as a whole to the left it could slightly I guess, who knows. Either way I haven't seen it negatively effect anything other then a slightly softer response which isn't a bad thing. Broken09's car could use that when at 20+psi. It's just too violent for street rubber when it comes on and is actually more enjoyable at 17psi.

-S-

 

I switched to the MP GT-45. It uses the Anti surge housing..I couldn't tell you the difference, since they all come with that housing but, I have heard alot say that it does change the surge line and broad'n the comp map. Then I've heard its mainly for diesel apps since they are running hi boost for longer periods of time, it quiets the "spooling" sound and makes it a whistle instead. Im still looking into it. BUT, I will tell you mine is very loud, whistly wise and a makes distinct noise upon hi-rpm decel from boost(not the bov)...I dunno could be me.

 

So i know that you can send other brand turbos to turbonetics for a custom ball bearing center cartridge. is there any way to get an extended tip wheel into a non BW housing? I'm not looking for 550hp and would rather have faster spool.

 

Anything is possible if you have the money

 

Sure you could do it if the housing has enough meat on it to machine. Your other issue will be the shaft being compatible. By the time you pay for this one off creation should nothing go wrong (ie. chew through the housing etc.) you could just by the BB turbo more than likely.

-S-