Why do one or the other? Pros and Cons?

I read on another forum that it depends on your exhaust manifold??

Thanks for the help

 

People tend to say that the 38mm doesnt allow you to control boost as well as a 44mm. I have a 38mm on my car and do not see any problems with it.

 

The main difference, or the majority will say anyways, is that the 44mm will let you control boost better at lower boost pressures. Obviously, once the target boost pressure is reached between the turbine and the wastegate, the gate will open and allow the excess exhaust to by pass the turbine and be either re routed to the exhaust or it will just dump to the atmosphere. Since the 44mm is larger than the 38mm, it is supposed to control boost better on lower boost pressure applications, obviously because at lower boost pressures the car will need to release more exhaust gas through the wastegate. The 38mm is by no means a piece of sh*t like some will say. I can see there being a difference between wastegates at very very low boost settings, but generally when you are buying an aftermarket turbo kit, your target boost pressure should be at least 25psi. I see absolutely no boost creep with my setup at 25psi. Both AMS and ETS use 38mm wastegates on their kits. Both work well, it is all up to the manufacturer to decide on which wastegate they want to use for their turbo kit.

 

Either will work for you. The main difference is the 44mm unit uses a clean and easy v-band fitting, while the 38mm requires two bolts and a gasket. The 44mm unit costs more, but IMO, the convenience of the v-band fitting makes it worth it.

 

^^ That too. Another reason is that since the 38mm does not use a v-band fitting, people have seen issues with the gaskets blowing out and causing a leak at the wastegate.

 

well for my case 38mm it is~ thanks guys!

 

a gasket should not be used where the wastegate bolts to the manifold. The metal o-ring that goes inside the bottom of the wastegate is the gasket/seal.

it has been said before by DB that in his tests the 38mm can cause surging. When I had my 44mm on my 35 kit, I NEVER had surging.

Now on my GTi it is another story, anything over 27psi the 38mm wastegate surges like crazy.

If I where you I would get the 44mm. Its easier to set up and you wont have to worry about any issues with it

 

The gaskets I was talking about are between the wastegate and the dump, not between the manifold and the wastegate. Sorry I didn't clarify that.

I've never had issues with my 38mm wastegate as I'm pretty confident I can speak for the majority of those who have either an ETS or an AMS turbo kit as well. Jeff, you also said that my compressor would housing cause surging, I have yet to see that too.

 

no problems here with my 38mm wastegate......going to upgrade to 44mm though with the new kit.

 

sorry I shouldve been more clear
I plan on running at least 30 psi and meth

 

Very informative thread, been having a moment making the decision but after the good sound advice here, it’s clear as day!