How To Muffle Wastegate Dumptube.

[MyÜberFastGSX]

So I put together this Wastegate dump tube off my 38mm tial wastegate. And it's very functional. My only problem is that it's way to loud. When the Wastegate opens, it sounds like I'm running open exhaust and it's not a very pleasant sound.

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So my question is, is there any way to dramatically muffle the dumptube?

 

[PSIcho]

I always wanted to try using motorcycle mufflers for that. Let me know if you do

 

[400awhpgsx]

If you welded the dump tube so it flows back into the exhaust pipe it wont be as loud

 

[MyÜberFastGSX]

Ok, I'll try to find a small motorcycle muffler. That's a really good Idea.

Also, it's a lot of hassle to run the dump tube back into the exhaust, because you have to put a flange on both sides, and it can mess up your rear O2 sensor readings.

So I'll try a motorcycle muffler and see how that goes.

 

[PieEyedPiper]

Can you please elaborate how a recirculating your dump tube messes with your rear 02 sensor?

 

[Savage Talon]

A generator muffler is another option you might think about. RV's use them.

 

[selmerguy]

My buddie has a turbo civic that uses a motorcycle muffler for the dump. It looks kinda trick he has the mufflue comming out the side of the front bumper. It is alittle less volume.

 

[bling5tatus]

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There you go hahaha. I think a go kart muffler would work if you could find one big enough.

 

[400awhpgsx]

I'm sorry but imo adding a second muffler is just dumb. If you recirc the pipe back into the exhaust you'll be fine. If you think it will throw the o2 for some odd reason then weld it in behind the o2. Problem solved and you dont need 2 mufflers to do it.

 

[Steve93Talon]

it can mess up your rear O2 sensor readings.

I guess Mitsu should do a recall and swap on o2 dump housings then.

 

[MyÜberFastGSX]

the problem is that it will mess up your rear o2 sensor readings because your adding that exhaust gas behind the front bank o2 sensor, but in front of the rear, so it gets dramatically different readings in the rear than it should.

 

[MyÜberFastGSX]

But I'm on the hunt for a generator or motorcycle muffler.

 

[gsxtacy]

if the atmospheric dump is too loud, recirculate it back into the exhaust PRE-Rear o2 and your problem is solved.

 

[jking29]

the problem is that it will mess up your rear o2 sensor readings because your adding that exhaust gas behind the front bank o2 sensor, but in front of the rear, so it gets dramatically different readings in the rear than it should.

WTF Re-routing the dump back in will not cause you any problems with anything other than extra backpressure in the system. The rear o2 sensor is there just for emissions. The only thing it does is monitor to make sure the catalytic converter is doing it's job. Nothing more.

 

[ilikespeeding]

What about a small resonator?

 

[TurboAnything]

im having the same issue im going to use a small lawnmower muffler like on a 3.25hp mower.

 

[hks-gst]

the problem is that it will mess up your rear o2 sensor readings because your adding that exhaust gas behind the front bank o2 sensor, but in front of the rear, so it gets dramatically different readings in the rear than it should.

Where do you think all the exhaust gasses go from an internal wastegate turbo? The easiest thing will be to recirculate nothing will be affected.

 

[ilikespeeding]

the problem is that it will mess up your rear o2 sensor readings because your adding that exhaust gas behind the front bank o2 sensor, but in front of the rear, so it gets dramatically different readings in the rear than it should.

First, the oxygen percentage wouldnt change based on removing some of the exhaust. That's like saying if you pour half of a pepsi out what's left in the bottle isnt pepsi.

Second, it's recirculated stock.

 

[daren_p]

the problem is that it will mess up your rear o2 sensor readings because your adding that exhaust gas behind the front bank o2 sensor, but in front of the rear, so it gets dramatically different readings in the rear than it should.

Unless I'm going crazy, thats about the strangest thing I've heard in a long time. Think about what your saying. When you recirculate the dump back into the exhaust you are still recirculating exhaust gases from the exact same source, back into the system. So if the rear O2 sensor did actually perform operations like the front O2 sensor, this would have no effect as the gas being recirculated will be no different then what is already in the exhaust (this is a sealed system). But even still, the rear O2 sensor has nothing to do with fuel trims like the front, it is simply there to show that the cat is doing its job properly.

Think about factory operation, it is the exact same. The WG from the turbo is divided in the O2 housing. Where the front O2 sensor is placed in the O2 housing is only on the exhaust side & the WG portion rejoins with the exhaust further down past the O2 sensor. This is exactly what you would be doing by having it recirculated into you downpipe, just the point of recirculation is slightly further down which will have no effect, except for creating less turbulance right after the turbine wheel, which is a good thing.

 

[2gAWDTalon]

the problem is that it will mess up your rear o2 sensor readings because your adding that exhaust gas behind the front bank o2 sensor, but in front of the rear, so it gets dramatically different readings in the rear than it should.

WTF? Sorry buddy, but you are wrong.

WTF Re-routing the dump back in will not cause you any problems with anything other than extra backpressure in the system. The rear o2 sensor is there just for emissions. The only thing it does is monitor to make sure the catalytic converter is doing it's job. Nothing more.

First, the oxygen percentage wouldnt change based on removing some of the exhaust. That's like saying if you pour half of a pepsi out what's left in the bottle isnt pepsi.

Second, it's recirculated stock.

Re route it, it is a easy and will not mess anything up, it works well...
You also dont need 2 flanges as you stated previously... look how I did mine:

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[wishihadatalon]

WTF? Sorry buddy, but you are wrong.





Re route it, it is a easy and will not mess anything up, it works well...
You also dont need 2 flanges as you stated previously... look how I did mine:

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Holy welds WTF

 

[blackGSX2g]

For mine I just hacked off about 6" off of my dump tube and welded about 3" of that at a 90* angle on my downpipe just under the oil pan. Then I used 1.5" flexible exhaust tubing to connect them. That way install/removal is easy and I have the choice of dumping the wastegate to the atmosphere if I ever wanted to by just removing the flex pipe and aiming it to the ground (I've got a plug to plug the hole in the downpipe). All in all it cost me like $3 and maybe an hour of time.


Also as posted before, your rear o2 sensor is only for testing the efficiency of your catalytic converter. Any configuration of wastegate dumps/recirc will have no affect on the sensor. I'm actually suprised you still run the rear o2 sensor, I got rid of mine with my exhaust and have DSMLink turn off the code for it.

 

[2gAWDTalon]

Holy welds WTF

Yha, I know... but they work like a ####in champ...
Oh, and the cars goes...

 

[TSIMonsteR]

For mine I just hacked off about 6" off of my dump tube and welded about 3" of that at a 90* angle on my downpipe just under the oil pan. Then I used 1.5" flexible exhaust tubing to connect them. That way install/removal is easy and I have the choice of dumping the wastegate to the atmosphere if I ever wanted to by just removing the flex pipe and aiming it to the ground (I've got a plug to plug the hole in the downpipe). All in all it cost me like $3 and maybe an hour of time.

Thats a pretty sweet idea, I may try this with my o2 dump and see how it works.

 

[99gst_racer]

I had the idea of using a sport bike muffler to quiet a dumped wastegate a few years back. I basically concluded that they are typically way to big to fit in the front end of a DSM. Those Honda boys have quite a bit more disposable area under their hoods....

I also concluded that re-routing was cheaper, easier, lighter, and more effective at sound deadening. And, as everyone else already stated, your rear O2 sensor has no affect on the engine's tune, so you have nothing to worry about.