external wastegate

[denn454]

i've been looking around for a 3" downpipe, i'm seriously thinking about using the stock flange and having someone i know at an exhause shot make one. one thing i keep on seeing that doesnt' make any since to me is an external wastegate. isn't the wastegate built into the turbo, not the down pipe? what is this, how does it work, and is it better?

 

[malibuick231]

If you are still running a stock turbo you dont need one.People use the external gate if they have boost creep.The external gate has a bigger puck.

 

[denn454]

but what is it? what does it do? just curious to know.

 

[malibuick231]

A external wast gate is a spring loaded valve used to control boost.Most are mounted on the down pipe.Some people mount them on the cross over pipe.

 

[nonosv6]

an external wastegate will allow better boost contol because of a bigger puck,here is why........ your exhaust gasas are what is used to spool (spin) the turbine wheel which spins the compressor wheel on the other side of the shaft,which creates boost.the more exhaust that is allowed to spin the turbine wheel the more inlet air you'll compress,the more boost you'll create.a wastegate is basicly a valve that opens at predetermained(by chip,wastegate rod setting,manual relief valve,bleeder valve,or by what ever means of boost control you are using on your setup)amount of pressure (boost) in order to regulate the boost by allowing exhaust gases to bypass the turbine wheel there for not providing as much gas flow to spin the wheel as fast,there for not creating as much boost.(hope this is making sense)...its like a fuel pressure regulator,only its regulating boost..i'm not sure but i think the valve(puck) on a terry houston 3"downpipe is like 1.3" ,atr 3"dp is 1 1/2" both are internal,which are bigger than a stock elbowed puck..this allows better boost control because it can let more exhaust gas out than a smaller puck..as for external wastegates,the deltagate has a 1.25" which is rated for like 450hp but a racegate has a 1.65"puck is rated at 900hp,atr's billet wastegate has a 1 3/4" puck...i'm sure there are lots of other details that i'm missing.. please experts join in....this is just a raw version of how i understand they work... a bigger puck allows for more better boost control with less likelyhood of boost creep(where the exhaust gases out flow the wastegate puck which in turn allows more boost than what was set by boost controler) and more consitant steady control of boost without surge(or as much)........well thats my understanding of it anyways....hope this helped a little..hope it didn't confuse you anymore than might be.........joel

 

[GNVAIR]

Question is do you need an external gate. Its a matter of personal preference. I have heard that Terry Houston used a heavy duty stock style waste gate actuator with one of his pipes on his 8 second race car. I am sure there are other guys who have done similar. The most common reasons for poor boost control with the stock style waste gate is improperly sized hole in turbine housing, too small of a puck, binding or sticking of puck, weak spring in the actuator or holes in the waste gate hoses.
Many guys swear the stock set up is junk and replace it with high dollar external gates.

 

[ijames]

In theory the external gate will make more power, because of the turbulence inside the stock style turbine housing where the flow divides just before the turbine wheel, and the turbulence where the bypassed flow rejoins the turbine flow just after the wheel, according to Corky Bell. Unfortunately, he can't say how much more .

 

[denn454]

so basically its the exact thing, only a little bit different. i think i got it, about as much as i can without seeing one for myself.