internal wastegate vs. external wastegate.

[69fordfastback]

what is the difference between an external and internal wastegate?? and assuming there is a difference what is the benefit of using one over the other??

[focusfreak03]

most of it is in the name. the internal wastegate is actually inside of the exhaust housing for the turbo and the opening of it is controlled by a waste gate actuator. the exhuast gas that flows through the internal gate is automatically dumped into the exhaust. the external wastegate is mounted somewhere on the exhaust manifold and is strictly controlled by boost controller(or spring inside the gate) and a boost refference via a barb, usually on the top. the exhaust that flows through the external gate is usually vented to the atmosphere through what is know commonly as a dump tube, but can also be routed to the exhaust to cut back on the noise although it usually causes a loss in power routing it to the exhaust.

both are used to vent exhaust away from the turbo to be able to maintain a set psi designated by the user.


interal gate are usually common to lower power applications and are relatively good at controlling boost when you aren't pushing the turbo to its limits. boost is controlled via a wga and the amount of boost that is able to be held is determined mostly by the size of the turbo, but also the quality of the wga.

external gates are usually common to bigger setups but are versitile because you can use them on any application. external gates are usually more expensive but they allow you to control boost a lot better and even with smaller turbos, you will be able to hold more boost towards redline than you would with an internal gate setup. the tricky part, but not really, is getting the right size external gate for your setup. too small and you will encounter what is known as boost creep. too big and you won't be able to control boost very well be cause it will constantly be fighting to stay shut.

that is all i can think of right now. hopefully some more people will chime in.

[Mr.Bergner]

Man, someone deserves a rep point

[69fordfastback]

that was a really good explanation. thank you. i guess the only other question i have is to what psi is the internally regulated turbo good for. here's the thing. i have a zx3 with basic mods (cai, udp, bosal cat back exhaust, plugs, and wires) im wanting to get around 230- 250 hp

[focusfreak03]

Originally Posted by 69fordfastback

that was a really good explanation. thank you. i guess the only other question i have is to what psi is the internally regulated turbo good for. here's the thing. i have a zx3 with basic mods (cai, udp, bosal cat back exhaust, plugs, and wires) im wanting to get around 230- 250 hp

it just depends on the turbo. even some of the bigger turbos, not sure which ones off the top of my head, have internal wastegates, but most just weld them shut and put an external gate on their setup for reliability and control purposes. if you haven't gotten a turbo yet and are leaning more towards the external gate, make sure you either find one without internal or try and order it with an exhaust housing the doesn't have it. if you find one that you can't get without the internal, then just get it and have someone take the flapper off and weld a plate over the whole. also, if you get an external, make sure you get the right size, 35, 38, 42mm etc. like i said before, to big or too small is bad. on the focus, you will more than likely have a smaller one unless you are doing a major build with a big turbo. i think that the 35 or 38mm sizes should be good for most foci applications.

good luck with the build.

[69fordfastback]

After doing a crap load of reading it deff makes since now. Ive had a turbo for quite some time now. A friend had given me an extra one that had accidently been shipped to him ( though its like a 200$ ebay one). I kinda wanted to go with a name brand one for reliability purposes and thats when i started getting a little stumped. Thnx much for your help though. after approval from the wife things should start getting interesting, and probably frustrating.

[69fordfastback]

but it sounds like the external wastegate is really the way to go regardless...thnx again for the help.....now the hunt for a down pipe

[streetracer]

for 230-250 whp an internal wastegate setup will probably be cheaper and work fine.. there are people pushing over 350whp with an internal wastegate setup.

Focussport made 396whp on a 2.0 duratec pushing 26psi with an internal wastegate

[focusfreak03]

Originally Posted by streetracer

for 230-250 whp an internal wastegate setup will probably be cheaper and work fine.. there are people pushing over 350whp with an internal wastegate setup.

Focussport made 396whp on a 2.0 duratec pushing 26psi with an internal wastegate

i never said that you couldn't have high pressure, high power setups with an internal, but the ability to hold boost better with an external setup, boost control, and reliability is a lot better compared to an internal. plus, if anything goes wrong with the external wastegate, it is tons easier to tinker with it than if you have an internal setup where you would have to take the turbo out which would require you to unhook all of the lines going to and from. plus if the internal wg somehow gets messed up, it could end up being a costly repair whereas the external gate you would just have to get a new one or call the company and get the specific part that you need.

[streetracer]

Originally Posted by focusfreak03

i never said that you couldn't have high pressure, high power setups with an internal, but the ability to hold boost better with an external setup, boost control, and reliability is a lot better compared to an internal. plus, if anything goes wrong with the external wastegate, it is tons easier to tinker with it than if you have an internal setup where you would have to take the turbo out which would require you to unhook all of the lines going to and from. plus if the internal wg somehow gets messed up, it could end up being a costly repair whereas the external gate you would just have to get a new one or call the company and get the specific part that you need.

i konw i was just pointing out the fact that MANY people have high power setups with internal wastegates and it works great. and for 230-250whp internal would be perfect and less expensive.

its smarter to just buy high quality parts in the beginning and not expect them to break rather than to spend more on parts you think might break because its easier to fix..