Some on please do a waste gate write up. Explain differences between, advantages and disadvantages of internal and external waste gate. Difference between header and turbo housing sourced external gate. I am all kinds of confused on this matter. There are awesome write ups on just about everything but I cannot find one on waste gates.
Some one needs to do a Waste Gate 101
- Thread starter jpratt
- Start date
There's a few major differences between internal and external gates:
- External gates are normally larger
- They have two pressure sides and not just one as compared to the internal
- Mounted to the exhaust manifold as you've noted
The most significant between the two, in my view, is external gates use two pressure inputs as opposed to just the one on an internally-gated turbo. The way the internal gate works is by taking a pressure input, be it from the compressor discharge or post-throttle body manifold spot, that applies pressure to the spring-loaded diapghragm (spring rate being whatever the factory set it at), that then controls some sort of mechanical rod that flings open a swing valve in the turbine housing to allow exhaust gas to discharge around the turbine wheel. Normally the swing valve and the hole it covers is very small and doesn't allow for big boost setups. The external gate, however, has much more precise control over boost (not to mention it's much larger overall to handle more exhaust). It has a pressure input on the side port that pushes the gate open, directing exhaust gas around the turbocharger completely when intake manifold pressure hits whatever the spring dictates. It also has a pressure input on the top side of the diaphragm that acts as counterforce to whatever is hitting the side port in an attempt to try and control boost pressure and/or keep the gate shut. An electronic boost controller takes advantage of this by controlling the amount of air that's bled off of its solenoid that would otherwise go to the top port. The more target boost you want, the less air is bled out of the solenoid, keeping a measured amount of pressure on the top port, counteracting the pressure naturally hitting the side port.
Hope that helps,
B
- External gates are normally larger
- They have two pressure sides and not just one as compared to the internal
- Mounted to the exhaust manifold as you've noted
The most significant between the two, in my view, is external gates use two pressure inputs as opposed to just the one on an internally-gated turbo. The way the internal gate works is by taking a pressure input, be it from the compressor discharge or post-throttle body manifold spot, that applies pressure to the spring-loaded diapghragm (spring rate being whatever the factory set it at), that then controls some sort of mechanical rod that flings open a swing valve in the turbine housing to allow exhaust gas to discharge around the turbine wheel. Normally the swing valve and the hole it covers is very small and doesn't allow for big boost setups. The external gate, however, has much more precise control over boost (not to mention it's much larger overall to handle more exhaust). It has a pressure input on the side port that pushes the gate open, directing exhaust gas around the turbocharger completely when intake manifold pressure hits whatever the spring dictates. It also has a pressure input on the top side of the diaphragm that acts as counterforce to whatever is hitting the side port in an attempt to try and control boost pressure and/or keep the gate shut. An electronic boost controller takes advantage of this by controlling the amount of air that's bled off of its solenoid that would otherwise go to the top port. The more target boost you want, the less air is bled out of the solenoid, keeping a measured amount of pressure on the top port, counteracting the pressure naturally hitting the side port.
Hope that helps,
B
I think what Mr.Pratt (no stranger to TR's) is saying - We have several in depth write ups on other running gear for these cars, but no definitive wastegate explanation.
We need one for the archives.
This includes, but not limited to photo comparisons and real world test results.
One could probably do this just by going through all the threads on the topic and putting them in some order.
We need one for the archives.
This includes, but not limited to photo comparisons and real world test results.
One could probably do this just by going through all the threads on the topic and putting them in some order.
Absolutely what I would like to see.
HKS Cast Manifold & Wastegate
There's a couple of pictures of an HKS Standard (external) wastegate with also a photo of two of its springs; a 5lb and a 10-11lb.
Exhaust Manifold, Turbocharger, and Wastegate
And a bit more from a few years ago off a customer's car, a Tial gate...
There's a couple of pictures of an HKS Standard (external) wastegate with also a photo of two of its springs; a 5lb and a 10-11lb.
Exhaust Manifold, Turbocharger, and Wastegate
And a bit more from a few years ago off a customer's car, a Tial gate...
