02 dumps and wastegates...im confused.

[Rubberman2003]

I have a 90 gsx, i was curious about these 2 things. Some people talk about o2 dumps and i see these shiny things near the turbo. What do these do? Can i get some pics of these and a wastegate. What do they do, are they used for performance with the stock 4g63 turbo? Sound (like BoV's) or what? I know this is kind of newb, but thats why i posted it hear

I have a 3" turboback exhaust, no 02 sensor or cat. If that means anything.

 

[LTUDSM]

This is an externalwastegate.t is replacement for your stock wastegate actuator,The external wastegate mounts on the O2 housing Or External wastegate housing which bolt on the O2housing. The External wastegate make a very nice loud sound like (blaaaaaaah)

O2 Dum tube is a little different from an external wastegate,it bolts direct on your O2 housing and thats it.you don't need to remove your stock wastegate actuator if you want to install the dump tube,and the sound should be the same like external wastegate,I'm not sure,never heard of Dumptube sound

 

[Thomas91169]

http://www.dsmtuners.com/gallery/showphoto.php?photo=57490&size=big&password=0&sort=2&cat=503

the shiny thing that looks almost like a BOV(same concept) that comes off a exhaust manifold is a external wastegate setup. it opens up to allow air to go around the turbo, thus controlling how much boost the turbo creates. most times the external wastegate setups are dumped back into the atmosphere, but can be rerouted back into the exhaust. externally gated setups can more accurately control boost over their internal bretheren.

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o2 dumps are a wee bit different. they are meant for internally gated turbo's. the o2 housing is right after the turbo, it allows the wastegate side of the turbo and the exhaust side to meet up, before going into the downpipe. that is, unless its a o2 dumped housing. the gases from the wastegate side are just routed down into the atmosphere, and dont go back into the exhaust system. this is a bandaid fix for boost creep(the real cure is porting of the wastegate housing+ bigger flapper), but most people do it to be like their externally gated counterparts, and for the obnoxious sound they emit(like a wet fart at full boost).

im sure someone could add to what i already have.

 

[blackGSX2g]

A wastegate is a device that bleeds off excess exhaust pressure to stop your turbo from over-spooling. There are both internal wastegates and external wastegates. The stock turbo on your DSM has an internal gate which is built into the housing of the turbo. Its got a diaphragm activated wastegate actuator that is teed into a positive pressure source so that when you hit your desired boost level, it opens the wastegate door and stops your turbo from spinning faster.

An external wastegate is effectively the same thing, but is generally larger in size and helps to hold steady boost levels on a modified car. Most people have them coming off of the exhaust manifold, but I have seen a few off of a modified o2 housing.

An external 'o2 dump' is basically a straight pipe coming off of the wastegate directly to the atmosphere. It is very loud and you need to have the pipe aimed away from anything affected by extreme heat.

EDIT: Wow, I guess I was too slow

 

[Rubberman2003]

I think i see now. I was thinking of a o2 dump being on the downpipe, but i forgot the o2 sensor on 1g's is on the turbo assembly. Anyone have any sounds of these. Can you couple this with a BoV vented to the atmosphere?

 

[DGajre777]

A bov vented to atmosphere has nothing to do with an o2 dump. If you decide to vent PROPERLY, you'll need a GM Maf and a MAFT. The o2 dump is on the exhaust side and the bov is on the intake side. The stock ECU using the stock MAS supplies enough fuel based on the air going in through the intake, if you blow, the engine will get less air and basically it'll say WTF which will lead to your car running rough and bad.

 

[ZachM31]

just think of an O2 dump as a separate exhaust pipe for your wastegate, and yes, there is internal and external wastegates... there is even a turbo out there that doesn't use a wastegate, kind of cool huh? just check out a VATN turbocharger, variable area turbine nozzle, no exhaust gets wasted.... basically no turbo lag, but oh well.. nothing that we'll see on our cars anyday haha...

 

[DashLaflash]

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Back from the dead! Does anybody know if this O2 housing will work with the VRSF FMIC? From the looks of it, its going to dump the wastegate gasses right onto the intercooler pipe and coupler. Please post up pictures if you have them.

 

[LiquidX]

From what I've noticed, the setup will work fine, however, I have read quite a few instances of the tube doing what you mentioned. It would just take 5 min with a welder to fix that issue however.

In my opinion, they don't drop low enough to evacuate out the gasses well enough from under the hood unless you are vented up top.

If you have emissions testing where you live, the dump tube is considered an exhaust leak since it's pre cat and generally do not pass inspection.

 

[airmail96]

Some people use that flexible house to extend the dump further, only thing is I'm not to sure where to get it from or how to search for it .

 

[DashLaflash]

Well my car is a '95 so I don't need emissions testing . I found this thread on dsmtalk using the SSAC kit which is similar to the VR Speed kit as far as I know.

SSAC o2 Dump: DSMtalk.com

He said he had to do a little cutting to get everything to fit. He also had to heat wrap the intercooler pipe since it was touching the wastegate pipe. I would use heat reflective tape instead. There are pictures in post #2.
I may just buy it and give it a shot. Worst case senario I would have to have it modified. I wanted to get it thermal coated before using it though.

 

[LiquidX]

Thermal coating the o2 housing would only be worth while on the downtime side. The dump is only open during full boost. So unless you are going to be in full boost constantly, it's not worth it in my opinion.

 

[DashLaflash]

Well I would get the entire O2 housing coated not just the dump tube. I went out an looked at my car and I really don't see this thing working. The VRSF kit has less room than the one in the link I posted. O well one more reason to hate the VR Speed kit.

 

[spadepro22]

So could I bolt on this dump tube o2 without wielding anything, and it would help out my boost creep, or would I have to have something like this

MAP 38mm External Wastegate O2 Housings / Stainless Steel (DSM) - Modern Automotive Performance

 

[crash89]

An external dump wont help your boost creep problem. A lot of guys with 16g's seem to have this problem. You'd need to do some porting to actually cure that. Either o2 would work, I would personally go with the one from MAP. I actually almost bought that one, but I wanted an external dump!

 

[WES_393]

The wastegate your showing is for externally gating internally gated turbos. You would have to completely remove the flapper and port the flapper hole to get the most out of it. But yes, it would help boost creep.

The O2 dump like shown above goes in the same spot as the setup you showed. They are different versions of the same part. One doesn't require the other. Also, with either one you wont have to weld, they both bolt on to the hot side of the turbo. I personally have an O2 dump and I'd rather have the setup you showed. It would be much quieter and nearly eliminate boost creep if done correctly. However, price is a big factor between the two.

 

[spadepro22]

With the 02 dump, would I still have have to get rid of the flapper and port it, or will just porting it and keep my ported 2g o2 work since my turbine housing is ported also.

An external dump wont help your boost creep problem. A lot of guys with 16g's seem to have this problem. You'd need to do some porting to actually cure that. Either o2 would work, I would personally go with the one from MAP. I actually almost bought that one, but I wanted an external dump!

External dump wont help my boost creep, but either 02 would work. I dont understand, explain please. Thanks

 

[crash89]

With just the external dump (shown in post 3) you really arent doing anything to cure anything at all. Just installing a shiny piece of steel on your exhaust and making your car loud. Its still the same turbo and WG system but instead of the exhaust going through your exhaust pipe its dumped at the ground. With an externally gated system off the o2 (your link from MAP) you will need to remove your internal wastegate flapper and port the hole a little larger. This in the end will definitely help with boost creep.

Just so you're clear on boost creep, what happens is that in high rpm's, your engine is pushing out so much exhaust that even with the waste-gate remaining open, it isn't able to divert enough gas to keep the turbine from spinning faster, so your boost pressure continues to build. This is a problem because boost pressure will continue to build uncontrolled, and it may push past the point where you still have adequate fuel capacity, and cause a lean running condition.

After re-reading my previous post I can see how you got confused. I was trying to say that either o2 housing would work as in bolt on and you would be able to run it and clear the LICP. But only the external gate will really "help/solve" the problem.

 

[spadepro22]

With just the external dump (shown in post 3) you really arent doing anything to cure anything at all. Just installing a shiny piece of steel on your exhaust and making your car loud. Its still the same turbo and WG system but instead of the exhaust going through your exhaust pipe its dumped at the ground. With an externally gated system off the o2 (your link from MAP) you will need to remove your internal wastegate flapper and port the hole a little larger. This in the end will definitely help with boost creep.

Just so you're clear on boost creep, what happens is that in high rpm's, your engine is pushing out so much exhaust that even with the waste-gate remaining open, it isn't able to divert enough gas to keep the turbine from spinning faster, so your boost pressure continues to build. This is a problem because boost pressure will continue to build uncontrolled, and it may push past the point where you still have adequate fuel capacity, and cause a lean running condition.

After re-reading my previous post I can see how you got confused. I was trying to say that either o2 housing would work as in bolt on and you would be able to run it and clear the LICP. But only the external gate will really "help/solve" the problem.

Got you. 100% clear now thanks man. On the boost creep, Ill hit 10psi really quick then it will hold for like a sec or 2 then shoots to 18-22(I want to run constant 18), but Im not running lean. Is this actually boost creep?

 

[JusMX141]

With just the external dump (shown in post 3) you really arent doing anything to cure anything at all. Just installing a shiny piece of steel on your exhaust and making your car loud. Its still the same turbo and WG system but instead of the exhaust going through your exhaust pipe its dumped at the ground. With an externally gated system off the o2 (your link from MAP) you will need to remove your internal wastegate flapper and port the hole a little larger. This in the end will definitely help with boost creep.

Believe it or not, o2 dump housings do work and work relatively well at what they're designed to do. They're more annoying, sure- but the wastegate flow is being released into an unpressurized location, so it is the path of least resistance and the exhaust flow would rather go toward that location than get routed back into the exhaust system.

I wouldn't believe it if I didn't see one at work on a customer's car last year- I installed an Evo III 16G, the most creep-prone turbo that exists, on a 2G with a catless 3" turbo-back system. I didn't do any fancy porting to the turbine housing at all, just installed an o2 dump like the one in post #3 which I recommended to help keep boost under control until he got Link and the rest of the supporting mods in the car. Held 11-12psi rock-steady on the stock internal gate. If that setup had a recirculated o2 housing there's no way it would have held that low of a boost number.

 

[spadepro22]

Believe it or not, o2 dump housings do work and work relatively well at what they're designed to do. They're more annoying, sure- but the wastegate flow is being released into an unpressurized location, so it is the path of least resistance and the exhaust flow would rather go toward that location than get routed back into the exhaust system.

I wouldn't believe it if I didn't see one at work on a customer's car last year- I installed an Evo III 16G, the most creep-prone turbo that exists, on a 2G with a catless 3" turbo-back system. I didn't do any fancy porting to the turbine housing at all, just installed an o2 dump like the one in post #3 which I recommended to help keep boost under control until he got Link and the rest of the supporting mods in the car. Held 11-12psi rock-steady on the stock internal gate. If that setup had a recirculated o2 housing there's no way it would have held that low of a boost number.

So I could run the 02 dump and not have to port the flapper?

 

[laser90]

So I could run the 02 dump and not have to port the flapper?

You "could" but it "might" not cure any boost creep issue you may have.