2G External wastegate 38mm oem 2g exhaust manifold

[Elpizer2]

Hi guys

I would like to delete the internal wastegate of my 14b turbo. I have a 2g exhaust manifold.

I've been researching and I see 2 options.

1- Weld on the longest tube of the exhaust manifold

I don't like this one because I know it has to be where the 4 tubes are toguether

2- Weld it on the o2 housing.

I like this one, however I am confuse about why would the external wastegate after the turbo??, I thought it has to be before the turbo.


Please if someone can tell me how to do it. I can't buy an expensive manifold right now, So I want to use the OEM 2G

Thanks

 

[curt-s]

By using externally gated O2 housing with the 14b/16g housing, you're effectively moving the wastegate a little further down the same path. You have to weld the flapper open, otherwise hold it open, or remove it altogether and weld the hole. Then the tube on the external o2 housing runs the exhaust gas to the wastegate and allows it to bypass IF the conditions are met.

In summary:

A gate off the manifold moves it to a position before the turbine housing.
An externally gated o2 housing moves it a little further after it's stock location.

They both do the same thing. It can be said that off the manifold/header (depending on what you have) is generally more efficient, but that comes down to design.

However, by placing the gate off only one of the runners, I believe you're also losing a bit of efficiency because you're only venting 1 in 4 gas pulses.. but it's not that much.

Externally gated o2 housings aren't cheap either. You need the housing, the wastegate itself, vband clamps (if it's not a bolt affair)..

With a 14b you're gaining absolutely nothing by going external. Find yourself a new wastegate actuator if yours is broke. I mean, do what you want as it's your car, but if you can't afford a manifold, I've got news for you on switching to external wastegate on a 14b..

 

[Elpizer2]

By using externally gated O2 housing with the 14b/16g housing, you're effectively moving the wastegate a little further down the same path. You have to weld the flapper open, otherwise hold it open, or remove it altogether and weld the hole. Then the tube on the external o2 housing runs the exhaust gas to the wastegate and allows it to bypass IF the conditions are met.

In summary:

A gate off the manifold moves it to a position before the turbine housing.
An externally gated o2 housing moves it a little further after it's stock location.

They both do the same thing. It can be said that off the manifold/header (depending on what you have) is generally more efficient, but that comes down to design.

However, by placing the gate off only one of the runners, I believe you're also losing a bit of efficiency because you're only venting 1 in 4 gas pulses.. but it's not that much.

Externally gated o2 housings aren't cheap either. You need the housing, the wastegate itself, vband clamps (if it's not a bolt affair)..

With a 14b you're gaining absolutely nothing by going external. Find yourself a new wastegate actuator if yours is broke. I mean, do what you want as it's your car, but if you can't afford a manifold, I've got news for you on switching to external wastegate on a 14b..

Okay I see.

Why not in the middle of the 4 bolts?. That's where the 4 cylinders mix?

 

[curt-s]

There are some headers with the wastegate tube run off the 4-1 collector. I don't have any names on the tip of my tongue but they exist. A cast manifold doesn't have the space or form to really allow this.

The stock setup still allows exhaust gas to divert before the turbine. Backpressure from the across-turbine flow gives the gas an alternate exit out the wastegate when it opens. On the 14b/16g, the stock setup is still very efficient. Many people port the hole to decrease boost creep at higher RPM. On a 14b, it's practically unnecessary because the 6cm housing doesn't have the flow capability of the 7cm (or 8, 10, etc.), so boost usually falls off instead.

 

[Elpizer2]

Is this location good for a 38mm external wastegate?

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[curt-s]

No, don't bother welding anything to a cast manifold, you're just asking for trouble down the line and perhaps sooner than you think. Properly being able to divert the gasses isn't guess work and by putting it off the collector on a manifold, you're going to mess up exhaust flow to the turbine housing, reduce or eliminate scavenging effects of exhaust pulses, and introduce opportunities for cracking.

If you really want a manifold with external, find one that runs it off the #1 runner already and get the appropriate parts. It's going to be $ either way.

Why do you want to run external on a 14b anyway?

 

[pauleyman]

Is this location good for a 38mm external wastegate?

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You are way overthinking this.