So confused about external wastegates

[Jersthecool]

Okay so I have a megan racing manifold and a gt2871r with an internal gate connected to a greddy prospec boost controller which worked perfectly. The engine is currently out of the car so I'm considering going external but I just don't understand how an external wastegate is setup. I haven't removed my turbo elbow or internal gate so I can't get an idea how it connects and I can't find a clear answer from searching.

So I know they sell these so it has the regular turbo elbow which connects to the downpipe and the dump tube or screamer pipe which directs the air from the wastegate directly into the atmosphere. Like this one.http://image.nengun.com/catalogue/original/nengun-1321-02-nightpager-extension_screamer_pipe.jpg

So where would I install an ewg or do I need to do something custom?

[TheRealSy90]

External wastegate is usually installed on the turbo manifold. Putting it on the j pipe will do nothing.

[Jersthecool]

Okay so do I have to get a flange welded on or do they sell manifolds specifically for external gates? Also if I were to install one and remove the internal one do I also remove the little valve inside the exhaust housing on the bottom left here in this picture?

http://www.full-race.com/catalog/images/GT2871R%202.jpg

[fliprayzin240sx]

You got 2 options, either weld the flapper shut in place or you buy a different exhaust housing that doesnt have the flapper. As far as the manifold, if you're staying bottom mount, there are no external wastegate option. You can get a custom stock manfiold and get a wastegate flange welded on it (do a search on Codyace, he does the mod). Or you go Top mount manifold and go external wastegate.

[Frank_Jaeger]

You got 2 options, either weld the flapper shut in place or you buy a different exhaust housing that doesnt have the flapper. As far as the manifold, if you're staying bottom mount, there are no external wastegate option. You can get a custom stock manfiold and get a wastegate flange welded on it (do a search on Codyace, he does the mod). Or you go Top mount manifold and go external wastegate.

Any good comprehensive resources about different turbo setups that you're aware of?

[Jersthecool]

Okay perfect thanks for the info that definitely clears a bunch of things up. Think I'm just gonna wait a while until I round up enough money to go top mount.

[fliprayzin240sx]

Honestly, if I was in your shoes and for simplicity's sake, I'd stay with the bottom mount setup. You already have the turbo, not much you'd really gain by going top mount with a GT2871R. Is there a reason you want to change your setup now? Are you having boost creep issues? Most of the time, thats the biggest reason folks wants to go external wastegate.

[Jersthecool]

I've always loved the sound and I've heard it pulls a bit harder compared to an internal. I got a really good deal on my car but didn't really know what really was in it because the owner who sold it to me had no idea. So I don't even know if the headgasket is stock or upgraded so I never pushed the turbo too hard. Ran 12 psi with the boost controller off and 14 on low and 16 on high boost and I've never had any problems yet. So once my engine goes back in we'll see if it creeps at higher boost.

[Pinggg]

I've always loved the sound and I've heard it pulls a bit harder compared to an internal. I got a really good deal on my car but didn't really know what really was in it because the owner who sold it to me had no idea. So I don't even know if the headgasket is stock or upgraded so I never pushed the turbo too hard. Ran 12 psi with the boost controller off and 14 on low and 16 on high boost and I've never had any problems yet. So once my engine goes back in we'll see if it creeps at higher boost.

It's really not that hard to take a look and see if you have a MHG or not..
just saying, most company like apexi/cosworth stamp their logo on the front of the MHG.

[Jersthecool]

Oh I didn't know that I'll have to take a lot I just wasn't sure because I don't know what stock looks like. Oh well I've got a cosworth on the way which should be here this week so that will be going on anyways.

[Def]

Honestly, if I was in your shoes and for simplicity's sake, I'd stay with the bottom mount setup. You already have the turbo, not much you'd really gain by going top mount with a GT2871R. Is there a reason you want to change your setup now? Are you having boost creep issues? Most of the time, thats the biggest reason folks wants to go external wastegate.

I've never seen a GT2871R that has high RPM boost creep at higher boost. They usually can't hold boost at high RPM as the turbine inlet pressure rises and the WG spring can't keep the flapper closed enough.

[jspaeth]

I've never seen a GT2871R that has high RPM boost creep at higher boost. They usually can't hold boost at high RPM as the turbine inlet pressure rises and the WG spring can't keep the flapper closed enough.

I agree with this 100%

[fliprayzin240sx]

I've never seen a GT2871R that has high RPM boost creep at higher boost. They usually can't hold boost at high RPM as the turbine inlet pressure rises and the WG spring can't keep the flapper closed enough.

Seen it on mine...then again, that was before I milled out the damn flapper hole. Not sure if Garrett made the hole bigger but back in the days, shit used to give me boost creep/spike.

[Def]

I've had tons of trouble keeping mine above 17 psi towards redline. The same actuator on a GT2876R with a really ported WG hole would struggle to keep 16 psi almost all the way cranked down with preload (12 psi spring in the gate when no preload). It was either add more preload and the gate can't control boost at all in the midrange due to travel, or it would bleed off boot at high RPM.

[jspaeth]

I've had tons of trouble keeping mine above 17 psi towards redline. The same actuator on a GT2876R with a really ported WG hole would struggle to keep 16 psi almost all the way cranked down with preload (12 psi spring in the gate when no preload). It was either add more preload and the gate can't control boost at all in the midrange due to travel, or it would bleed off boot at high RPM.


I use to have this issue....then I sent Cody an extra stock mani, and slapped a Tial MVS on there.....had the flapper welded shut.....now it holds like a charm and is much smoother as well