[malgyver]

Hi all,

2008 335i, FBO, DCI, JB4 G5, 140K miles

I recently changed out my two turbos for newly purchased new OEM Mitsu turbos. While I had everything stripped down, I added stock location silicone inlets, by VRSF. No other mods.

Since the first runs after getting everything back together, I am hearing a very loud whooshing sound at low rpm/low-mid throttle when there is some boost going on.

I was able to get the whooshing to go away by setting Menu 10 very low. At this setting, I can use 1/4-1/3 throttle around town without the annoying whoosh. Of course there is some lag now, but luckily the new turbos really spring into action. This morning, I increased Menu 11 to about 3500, and this helped mitigate the lag brought on by the low WDP.

Curious to know if anyone has any idea of why a higher WDP causes the big whooshing sound at the low rpm boost environment. Curious to know if people are getting this when the switch over to silicone inlets.

FWIW, I though the turbo replacement was not bad. I dropped the subframe and did the oil pan while I was there. I had the rear of the car on ramps, and the front on jack stands. I found there to be plenty of room to work, and lowering the subframe was a snap. Though this is after 25 years of being a backyard mechanic.

Thank you!

[Antetokounmpo]

It keeps the waste gates more closed causing faster and lower rpm spool, resulting in spool noise. The inlets greatly increase the noise, stock airbox is designed to eliminate it.

Driving around town with the wastegates open (menu 10 low) is mostly bypassing the turbos all together, hence why the exhaust is louder and the lag is really bad until you request boost with big throttle inputs.

[malgyver]

Thank you for the input. I was previously running no air box, and only the DCIs. So the only change would be the inlets. But if consensus is that inlets are more noisy that the stock plastic jobs, all other things being equal, then this likely is the culprit.

[Jklad]

Can you post a video of what stock turbos sound like with these inlets?

How's the drivability so far?

Will you be getting an updated custom tune now that you have inlets on the stockers??

[tisdrew]

I have relocation inlets and yeah, they're noisy. I don't believe anything is wrong with your car.

[PhxN54]

My intake system makes the same noise you are describing with stock location inlets with DCI. Definitely an audible difference from OEM inlets to silicone. I had mine installed with OEM turbo replacement about 1.5 years ago and no issues.

[Faredo]

I ended up reinstalling my OEM cowling because it was so loud. livable now.

[puppydax]

Inlets with DCI's are quite loud. I noticed it was louder when my inlet would pop off of the rear turbo. Not saying that is the case, but it may be a bit louder than stock inlets.

[malgyver]

Driveability is great, I don't plan to do any other mods to the car, its a DD and I hardly even have the chance to push it. I don't even have a reason to upgrade the FMIC, as I rarely do more than a pull or two through a few gears.

My cowling and engine cover are off, and I'll be reinstalling those. I guess that will bring the noise down as well.

I am finding, at this point, that setting the wastegate (Menu 10) open, like 800 RPM, and then making the pedal more sensitive (Menu 11 way up) works fine for my simple driving purposes...so I'll probably leave it like that, and will enjoy the lack of Whoooosh while driving around town. The lag is hardly noticeable with the pedal rate changed.