Has anyone installed an O2 dump and noticed the car is a bit louder at idle/cruise? Seems odd but was thinking maybe the stock o2 housing muffled the sound more compared to the thinner metal of the o2 dump or I have a leak.

Also was wondering about anyone thats running a 25psi FP wastegate with an o2 dump. When do you start to hear the dump? I was cruising around and it seems like around 10psi the wastegate must be cracking open a bit because I can hear it starting to come out of the dump.

 

Make sure you're using the right gasket. The stock gasket is not divided and will allow exhaust gas to flow up from the down pipe into the wastegate port. The o2 housing should have come with a divided gasket.

This is actually a VERY common call we get because people think the WG is opening.

-Michael

 

Is it a bad thing if you use an OEM gasket that allows the exhaust gases to sneak out the dump tube?

 

Yes, this is bad. It will cause turbulence In the down pipe among other things.

 

If you dont use a proper twin scroll gasket and it allows the dump tube to vent at idle, it's a big problem. It essentially creates a giant exhaust leak right next to the o2 sensor and it wrecks your AFR. I personally just used some copper spray with no gasket and it works wonders.

 

I'll have to double-check which gasket I got then. I bought a MAPerformance 02 dump from another member and it included a gasket, but I'm not sure if it was divided or not. In the event it is NOT divided, it sounds like I'll use copper spray instead.

 

You would have to take it off to use the spray so why not just use the correct gasket?

 

I used the divided gasket that came with the dump. Any other reason it sounds louder?

 

Smoke test. Then fix the leak if there is.

25psi actuator have you checked it's calibration on just reference?

 

Edited

 

put your hand over the dump tube when the car is on. If you feel exhaust out of the dump then the gasket is blown out, and you're in the situation described in my previous post. The wastegate should be 100% closed at idle = no change in sound over the stock housing.

 

^What he said.

If the wastegate is open at all off-boost, you have a problem. Aside from checking the gasket, make sure that the wastegate holds pressure until its specified opening point. And as someone else said, a good way to check this is via smoke test.

 

When I installed my o2 dump and Fp 84mm compressor cover I forgot the donut gasket and I was having a leak between the o2 dump & downpipe, also I was having a leak from the o2 dump tube which I had to preload the wg. Just check those areas.

 

I run a fp fed with a 25 pound spring and a EPM 02 dump. The dump should be just as loud as your previous setup until you hit max boost setting. I have an AEM TRUE boost so I raised the crack pressure as much as I could so the boost would only "dump" at wot. On my stock turbo it obviously opened much sooner and easier but basically only under heavy or wot.

 

Here, I find myself agreeing with Michael's reasoning, because in this case he is right. If an undivided gasket is installed between O2 hsg and DP, you could get exhaust gas crossover from the turbine exit area into the neighboring flapper exit area of the turbine housing and thus out through the dump tube. This exhaust crossover would take place even at idle and has nothing to do with WG spring tension, as it would take place and be audible, even with the flapper valve tightly shut . It is independent of bypass flow.