It's a smog device that places Butterfly plates inside the intake manifold right before the intake ports on the head.

 

i understang it is a smog device, but how does it work?
how can a 2nd set of TBodies help environment?

 

I think it's mainly because the cam is fairly agressive and thus we have a low air speed velocity entering the intake valve/cylinder. Those butterflies can speed up air flow into the combustion chamber resulting in a cleaner burn.

 

The intake of some Subaru models (including the Impreza WRX) includes tumble generator valves above the fuel injectors. When the engine is at idle, these valves close and bypass the incoming airflow through a passage to increase the swirl of the air/fuel mixture, resulting in an engine that operates more cleanly.

J.

 

at idle the flaps angle to tumble the air and mix it with the fuel for a better mixture,it helps reduce emissions and thus provides a smooth idle

 

sorry off topic but will having tgv deletes cause the vehicle to fail emissions tests come smog time?

 

affirmative

 

unless you have a Cobb AP and have your tuner shut off the CEL's!

 

does the tgv valve reacts as quickly as needed to the throttle body. does it stay open fully al the time , at all rpm`s except at idle?

and is there a drawback to deleting the tgv on a cobb stg2 set up?

i can see a benefit at WOT, but what about partial throttle?

 

i believe the tgv is only closed during cold starts until the engine warms up a bit. its to help lower emissions while you wait for your car to warm up. after warm up the stay open all the time.
its not really worth it to delete them if your only stage 2. thats a lot of work to do and most do them while upgrading the turbo since you have lot of stuff off already. but if you do do them, ive heard anywhere from 10-20 hp increase.

 

the purpose of deleting them is for a 3" turbo to fit since it would hit the huge sensor of them and it also creates more airflow since you can have them milled out....think of it as no restrictions and on a stage 2 setup it's not necessary....when you get bigger turbos you should do them.

 

it is hard to fully appreciate how obstructed the flow is through the stock tumblers until you've seen all the casting and other crap in there. even when wide open, the obstruction is significant - but not enough to matter for stage2.

 

it is hard to fully appreciate how obstructed the flow is through the stock tumblers until you've seen all the casting and other crap in there. even when wide open, the obstruction is significant - but not enough to matter for stage2.

Is their a documented test on CFM ratings between stock TGV and TGV deletes?

When I did my APS inlet I couldnt believe how restrictive they looked.

 

Yes there are cfm and hp comparisons floating around,do a search. Its not acutally necessary as some people are able to run them with a 3" inlet.I however deleted mine because I installed the APS 3" hard inlet and had them off the car already,so I figured why not.

 

So i unistalled the cobb ap and now im throwing codes for the tgv will that mess up anything i can live with the check ingine light on but will it effect anything else

 

Holy smokes, nice necro post.

I'm assuming you mean you deleted the TGVs, and then uninstalled the Cobb AP and went back to a "stock" tune? If so, yes, you will have problems. The ECU will think something is wrong with your TGVs (which, well, there is) and most likely put you in limp mode, limiting boost and RPM. So yah, not great.